Garrett check valve setup results??? [Archive]

KevinD

05-31-2006, 08:15 AM

as the team that provided the checkvalve system, we just got done replacing a turbo sunday due to seal failure. it has been very evident that the check valve system is not a 100% solution as we have had oil build-up in the intake after every day at the track. when the seal went we half filled the overflow bottle with oil, not to mention an enormous amount of oil in the intake, all the vacuum lines, and even started coming out of a microscopic hole in the intake manifold, which was a good thing i soppose...

additionally, i ran across this rule the other day:
3.5.1.5 System Sealing
The engine and transmission must be sealed to prevent leakage. In
addition, separate catch cans must be employed to retain fluids from any
vents for the coolant system or the crankcase or engine lubrication
system. Each can must have a volume of ten (10) percent of the fluid
being contained or 0.9 liter (one U.S. quart), whichever is greater. Any
crankcase or engine lubrication system vent lines routed to the intake
system must be connected upstream of the intake system restrictor.

because it is a crankcase vent going to the intake, it seems to me running it after the turbo is against the rules anyway.

i have been logging data of pressures both before and after the turbo though, to get an idea of the pressure ratio. we have not been seeing the enormous pressure ratios that some teams have claimed, but it may be because of my sampling rate and the minute amount of time that surge will occur. THe Pressure ratios i have seen even with the check valve system are above and outside of the compressor map of the compressor we are using. in an 80 second autocross run, i saw a pretty good distribution of data points above 2.5 Pr with points as high at 2.75Pr. the map for our turbo doesn't exceed Pr = 2.3 which i have not figured out if this is the choke line, or just an arbitrary point where they stopped mapping efficiency (200,000 rpm compressor wheel speed). regardless, there is no question in my mind that the check valve system is not the 100% solution. moving the throttle plate after the turbo is the ultimate goal to make these turbos last longer then a couple dozen hours. from what you say about some teams destroying compressor wheels due to surge, i would have to say that our compressor wheel was still intact. the only failure was the seal, which might imply the check valve system is working somewhat in keeping the wheel from getting damaged by limiting the amount of surge. we have replaced the dead turbo and are going to move the crankcase vent upstream of the restrictor to comply with the rules. like i said, we can give it a try without the check valve system to see if it is actually doing anything, and i can try sampling a little faster to see if i am missing anything. however, all this testing may have to be post california unless you can convince rex to give it a try http://fsae.com/groupee_common/emoticons/icon_smile.gif

Kirk, i'll e-mail you shortly with some data you might useful for this.

iolair

05-31-2006, 02:03 PM

Just curious....as it relates to draw through applications, what is the mechanical difference and implementation of the seals that Garrett uses today as opposed to the seals that Rajay used 25 years ago or what Turbonetics uses now?

John

Kirk Feldkamp

05-31-2006, 03:16 PM

The GT12 and GT15V use regular ol' piston ring seals. Without pulling up the drawings, I believe they both use dual piston rings on the compressor side. We made a few carbon seal retrofit units last year, but the retrofit was more expensive than the entire turbo. In FSAE use the carbon seal units didn't even seem to be able to stop the oil problem.

Has ANYONE using ANY brand turbo been able to completely cure the compressor seal leakage problem without the use of a dry sump? I'm trying to solicit both positive and negative feedback, but the former is proving difficult to come by.

-Kirk

VFR750R

05-31-2006, 03:28 PM

The IHI units we used to use (RHB5) not the RHF? currently sold had zero intake oiling. Zero. They used a carbon seal from the factory and were very effective but at the cost of a overly large unit that does not build much boost and had considerable lag.

IHI does sell some smaller units, RHB3 and RHB4. I do not know if they utilize the same seal type. Leed time for either was large, you had to order them from Japan as of 2003.

Wright D

05-31-2006, 04:31 PM

In the past we had solved some of our oil leakage problems with a bit of a band-aid. We have used an electric fuel pump to suck oil out of the turbo. This is of course is at the penalty of added cost, and weight. It is however less expensive then a full fledged dry sump in terms of cost, weight, and complexity.

I would love to see the turbo rule changed to allow the turbo to placed in front of the throttle body; fsae seams to be the only place where a draw threw type of system is still so predominate. I for one would have preferred to gain experience in a turbo system that is used more frequently; that why I wouldn't have had to relearn things after moving on from fsae.

VFR750R

05-31-2006, 07:28 PM

I might be alone here, but I don't see a reason to change the rule. The rule is to make NA cars and turbo cars be on the same playing field, which isn't true in the real world. And I would say working on a system such as this makes you think much harder about what is really going on and I'm confident in saying I know more about turbos and engine dynamics in general because of the current rules.

Not to mention the fact that it would open the door to some large power gains.

Garlic

05-31-2006, 07:30 PM

What larger power gains???????

VFR750R

05-31-2006, 07:40 PM

I've said to much http://fsae.com/groupee_common/emoticons/icon_wink.gif

Garlic

05-31-2006, 07:47 PM

Sorry I don't buy it. I know what everyone is thinking but it wouldnt work and it is impractical. Anyone that tries it will find that out in a hurry.

Moving the throttle does not change the power possible. Plenum 'resevoirs' are impossible to make work effectively.

Captain Redbeard

05-31-2006, 09:12 PM

Here at Dartmouth we ran our first turbo system this year. We used a GT12 and initially had the same oiling problems as everyone else. After talking with the guys at UTA and testing the check valve system ourselves I feel confident in saying that it is NOT a good solution to the problem. Our final package had zero oil leakage into the intake and all we did was use the suggestions previously provided on this forum. Here is a list of the techniques used:

1. Mount the turbo high enough to allow for a nice big drain back to the crankcase. Make sure the drain comes into the crank case above the oil line.

2. Run a vent line from the crankcase to before the restrictor in the intake. We intially had problems with drawing oil through the vent line but we then routed the line so that it ran very high on its way to the turbo, this seemed to help. Also, there seems to be a lot of oil foaming or spraying in the crankcase so we mounted the vent with a 90 degree fitting to discourage oil from sucking into the hose.

3. Don't overfill the oil. We noticed that if the oil was too full we would burn oil until it reached a certain level and then stop. We simply left the oil at that level and the data acq shows that we still maintained sufficient pressure on the track.

4. Restrict the oil flow to the turbo with a .046" hole. Any smaller and the pressure dropped to below the recommended minimum.

After these items were implemented, we saw ZERO leakage into the intake and didn't have to add any oil even after several weeks of testing (10-20 hours).

-Matt

Kirk Feldkamp

05-31-2006, 09:47 PM

VFR750R,

Although I wholeheartedly disagree with you, I'd like to keep the conversation on track.

However, I will digress for the sake of relevant conversation...

I'm having a tough time coming up with potential advantages a team will have over any other team if the rule is changed as proposed. Sure, everyone will have a plenum, and that's ok. There will still be tradeoffs, that fact is unavoidable. Transient response has the potential to increase, but that's a level playing field.

The fact remains that the ultimate power potential of an engine is directly related to the air mass flow rate through the engine. If the restrictor rule is followed as the rules intend, NO MATTER where you place the throttle, the air mass flow rate is still directly related to the restrictor diameter. Nobody can argue that. If there is a path around the rules with the current wording, by all means chime in. I may have missed something... I will never claim to be perfect.

To comment on your "level playing field" concerns, you don't need to look any farther than ALMS and LeMans. Both NA and turbo cars run in the exact same classes with various size restrictors for various NA/turbo/supercharged/gasoline/diesel/# of valve setups. There is no reason that couldn't happen for FSAE. If you check out the ACO rules starting on page 22 of the ACO Rule Book (http://www.imsaracing.net/2006/competitors/aco3.pdf) you can see what I'm talking about. You can also see that the differences in restrictor sizes (and flow potentials) between the different classes are very small. If this were done for FSAE, the size differeces would be so tiny it would be rediculous. Anyway, I digress.

I've said this before... but the biggest problem I have with the current rules is that they give turbo teams unnecessary hassle in order to get a workable solution. I have talked directly to the people that wrote the rule in question and gotten the reasoning behind the throttle placement rule. After hearing the reasons, my opinion is that the rule was ill concieved. It has also been expressed to me that the rules committee likes how the current rules have created an even spread of engine choices. Frankly I don't think the rules should ever be aimed at "guiding" the choices that developing students make in a design competition. Shoot, if it weren't for the 450 singles becomming widely available, there wouldn't be any singles running in FSAE (except maybe the Briggs-guys!). Same goes for the 600s! I don't think there will EVER be "right" way to build an FSAE car... just look at the differences between a RMIT car and a Cornell car! Both are super fast within the rules, but they are completely different cars. Ultimate engine power putput probably has the least significant impact on a FSAE team's finishing rank than almost any other factor!!!

My concern is that there seems to be a fundamental lack of understanding of the function of the restrictor within the context of the FSAE rules.

I have heard the comment from a number of current and former powertrain design judges that FSAE engine tuners do not dial in their systems as well as they should. In the case of a turbo team, this rule change would remove a gigantic impediment to taking the time to tune the engine correctly.

In my opinion FSAE has two main goals:

1. Develop excellent engineers that have extensive hands-on, real world experience.

2. Provide a centralized gathering that companies can use to recruit the excellent engineers right out of school.

From the standpoint of Honeywell Turbo Technologies, my opinion is that we want to recruit engineers that understand the dynamics of a real world turbo system. The more time a student has tuning and developing a real world turbo system the better! I challenge you to find ANY modern turbocharged production vehicle that runs the throttle before the compressor inlet!

The solution that Matt from Dartmouth has posted is exactly what we've been encouraging teams to do for years, and it seems to work ok. However, with only 10-20 hours on the engine, I have reservations with saying it will prove to be a complete solution. Only time will tell. I am of the belief that if the turbo can't operate trouble free for years, then there is a problem. In OE operation these turbo DO run for 100000+ miles, so there is something about the FSAE rules that is making this an impossibility. The differences between an OE setup and the FSAE setup are pretty simple to see...

I've rambled on long enough.

Everyone,
Please keep chiming in if you have something to contribute.

-Kirk

Wright D

06-01-2006, 01:24 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:

Not to mention the fact that it would open the door to some large power gains. </div></BLOCKQUOTE>

Unless I am confused, doesn't the proposed rule change still place the restrictor in front of the turbo, just like the current rules, it just simply moves the throttle to after the turbo. In both cases (existing rule and proposed rule) the maximum steady state power should be the same. When the throttle body is wide open its effects on pressure loss should be small (if you have a descent design), so there would be no real gain for the turbo cars.

In fact an NA set up might benefit as well by moving the restrictor to in front of the throttle body. The throttle body would no longer muddy up the air entering the restrictor.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
And I would say working on a system such as this makes you think much harder about what is really going on and I'm confident in saying I know more about turbos and engine dynamics in general because of the current rules. </div></BLOCKQUOTE>

In fsae there are no blow off vales, recirculation loops, or any of a number of other things that you see on production cars, or other forms of racing. So I do feel a little "left out" having never gotten the change to work with these items until after graduating. Yes my fsae experience was great, but considerably different than the systems that I design now.

The design challenges faced by an fsae team are different than those faced by other racing bodies that allow turbo chargers. This is partially because the fsae rules that govern turbocharger placement are different than most (if not all) of the other racing bodies. I think a rule change that gives fsae more in common with other forms of racing would only help propel more fsae students into successful racing careers.

VFR750R

06-01-2006, 04:56 PM

As far as the FSAE not being in common with 'real' racing. Just because the throttle is in the same location means nothing of the rest of the system. No employeer is going to look poorly on FSAE rules and not hire you because the experience doesn't align with their racing. I got hired into NASCAR for heavens sake, it's like apples and potatoes. Now being in an industry that works on that specific system you would rather have new engineers be experienced that way, but that doesn't mean shit. My employeer would have rather have FSAE be about NA Chevy SB2's turning 9500rpm but tough, FSAE has nothing to do with fitting every companies plan for a perfect setting to breed new employees. Every companies definition will be different. Changing the rules for Garrett is like changing the 3pt line in college basketball to the NBA distance because some of the players might end up in the NBA.

If everyone was turbo or NA it would be easier. But I don't think you realize the consequences of moving the throttle on a turbo system. If you check the ALMS rules I bet they have a phrase that says something like the restrictors must be mounted directly to the inlet of the turbo. I would garuntee you I could make 130hp for short bursts, maybe even long enough for an entire accel run. Plus it makes it hard to police intake leaks, you could have your intake manifold practically break off and make big hp NA, whereas now if you have even a small leak the car won't idle.

I don't want the rules change but I would be ok with this wording. I can't find the previously proposed rule change so it might already be worded like this.

On all cars.

The restrictor will be the first part in the intake system, air filters will be allowed before the restrictor.
No Individual Throttle bodies will be allowed.

Turbo Cars:
The turbo compressor will be immediately after the restrictor. The tube connecting the restrictor to the turbo has a maximum inside diameter limited to the compressor inlet diameter. The maximum distance between restrictor and turbo is 20 inches which should allow for any packaging issues.

The throttle should be next and also be 20 inches from turbo outlet. The tubing will not exceed 2.5 inches in inside diameter. Any plenums should be downstream of the throttle.

Naturally aspirated cars:
The restictor should be immediately followed by the throttle. The maximum distance between the restrictor and throttle should be no more then 20 inches. The tubing will not exceed 2.5 inches in inside diameter. Any plenums should be downstream of the throttle.

This puts alot of limits on the intake but they would be necessary for the two different power packages to remain on equal ground. These limits could also be changed, but there should be limits everywhere I've outlined them. I could also go for a volume based equivalency on the tubes I have maximum diameters and lengths on.

I just don't see the justification for the rule change on a basis of intake oiling. Turbos blowup because of overspeeding and surging not leaking seals by the way. And yes the current FSAE rules promote overspeeding and surging....now that's a good reason to move the throttle.

VFR750R

06-01-2006, 07:40 PM

I would like to add another thing based on a conversation I just had with NCstate alum NJM.

The FSAE rules in many cases present unique problems such as the throttle before the turbo that require unique solutions. This requires the teams to think rather then pick parts off shelves that are just like every other system out there.

I think tires is another area where the FSAE senario is unique and does not represent the 'norm' in other forms of racing and that is where the real value of this competiton is. You can get up to speed very quickly when you graduate and go work in the industry, and until we are building ALMS cars there will always be differences between FSAE and ALMS.

Kirk Feldkamp

06-01-2006, 08:02 PM

VFR750R,

You make some good points. I appreciate your input, especially in relation to the rule change proposal wording and requirements.

Let me be clear on this, we as Garrett don't care at all about making our turbos "look good" in FSAE. Sure, it's nice if teams do well with them; but that is absolutely not the reason behind our effort to change the rules. The reason we support FSAE with ~50 free turbos a year is because we want to give teams the opportunity to use a turbo when they otherwise couldn't afford to do so. One of our senior engineers was SAE President a few years back, and he wanted to support FSAE in his own way. It's really that simple. It is a nice side benefit that we can keep in close contact with the kids using our turbos. My example of what we'd like out of an FSAE alum was simply intended to provide an example. I appologize that it sounded like that's why we're trying to get the rules changed.

Our concerns about the current rules are based on receiving so many turbo returns because of the problems I've described. The more data I've collected from various teams, the more I can see that throttle-lift surge is a major reason for the failures. That is completely related to the position of the throttle within the system. Another goal of our efforts is to make it more feasable for turbo teams to work on actual engine system development, rather than troubleshooting.

You are correct about the ACO requirements of the restrictor mounting (Page 8). It has to be mounted directly on the face of the turbo. I have no problems with requiring that. All I care about is the position of the throttle within the system. (side note: the ACO rules specify a restrictor diameter and a minimum diffuser angle of 7 degrees. There are other sanctioning bodies that specify restrictor diameter and diffuser length, like you proposed. It doesn't matter which way you do it.)

Your concerns about intake policing are valid. As things stand right now, there is an extremely high liklihood that teams regularly swap restrictors. I don't think there any examples of teams getting caught doing that either. As the rules are written right now, it is generally a big pain for a tech inspector to have teams pull off their throttle body and check the restrictor diameter. If the rules were changed as proposed, the restrictor would be one clamp away from an easy check. I don't see how this example would be any different than intake leaks (or potential "restrictor bypasses"). A locksmith once told me that locks are only good at keeping honest people honest.

I like your idea of requiring a minimum of distance between the throttle and the restrictor as it may close the door on some way around the rules. I think that the "all air entering the engine must pass through the XXmm restrictor" rule is an effective "catch all" for all these discussions. If teams follow this rule as intended, there would never be a problem with circumventing the rules.

It is unnecessary to restrict systems to a single throttle body, but that is not the point of the rule proposal. I would have absolutely no problem with restricting the engine to a single throttle body. The benefit of allowing multiple TB's would be that teams could use the stock TB's without having to design/source one. I figure you should at least give teams the option to use the stock TB.

I like the idea of maximum intake volume or tubing diameter. I see where you're going with it. Deciding on a volume would be analagous to the original decision of how big to make the restrictor.

I was fortunate enough to get my hands on some data from a team that somehow got a good turbo speed sensor. Their data clearly shows that even with the GT15V they aren't overspeeding the turbo. They are even using a bunch of antilag! If they're not overspeeding the turbo, then why are their turbo's dying? If you boil down their data, you can see that they're hitting pressure ratios of 3.5 each time the driver comes off the throttle. You can even see the "ringing" of the surge events!! There are lots of reasons why the rule should change, I guess I have chosen the oil issue because it is the most blatently obvious problem, and the easiest to explain to most people.

Have you written the rules committee to voice your opinion/concerns? I encourage everyone to do so!

-Kirk

Chris Davin

06-01-2006, 08:09 PM

Actually, Judd, the new rules as Honeywell wrote them have a provision for a stall test that seems to take care of the problem you identified. Take a look at the end of the 2006 rules.

I'd be more concerned about the effect on the value of the competition to students. One concern I'd have is that if it suddenly becomes a piece of cake to run a turbo (and Honeywell is supplying them for free) then teams will experience a lot more engine failures. These failures will eat away at budgets and testing/development time (trust me - I know!). The way the rules are structured now, teams are required to perform some clever engineering to get a turbo on their cars. It encourages original thinking and presents students with a problem that has not already been solved by the automotive industry for decades. There are a number of straightforward solutions to the problem, as an inspection of some of the current turbocharged FSAE cars would reveal. I understand that Honeywell wants to expose as many students as possible to turbos. But, I am not convinced that having a large number of teams perform relatively little turbo engineering would be any better than having a smaller number of teams gain a very thorough understanding of their turbos by engineering a solution to the oiling problem.

Just my thoughts for the night. I do admit this is a very interesting issue and I would like to hear what others have to say about it.

VFR750R

06-01-2006, 08:21 PM

I would still like to see no ITB's. If teams are allowed to use the stock ones, you will see that on a majority of cars and that is just too easy http://fsae.com/groupee_common/emoticons/icon_wink.gif
But really the reason for no ITB's is to prevent enourmous plenums. Teams will still have to decide what they want, power or throttle response.

That's awesome that you got some real rpm data on track. I wouldn't be surprised with a GT12 that you aren't overspeeding at high rpm without some sort of electronic wastegate control. I wonder whether you would see the same thing with the GT15V considering the differences in turbine housing. But that's cool that you can see the surge when the throttle is closed, doesn't surprise me other then the total Pr. Damn.

Marshall Grice

06-01-2006, 08:43 PM

shall we mandate custom built shocks because buying them is too easy?

I don't see how buying a single TB has any advantage to buying a set of ITB's from a design stand point? The system still must be sealed and restricted. all of the same design processes and objectives remain regardless of the number of TB's. Our team currently uses the stock ITB's plus an additional TB, only one of them has a throttle plate.

Kirk Feldkamp

06-01-2006, 09:06 PM

I think Marshall is on the right track here. The same question applies anywhere on the car. We've seen one student built engine (that I can think of). Why are we not all up in arms that teams aren't doing all they can to make their own engine? Shocks, tires, ECU's, etc.... teams are free to choose what they want to use, or if they want to purchase them!

I think the same questions should be applied to the turbo as well! Why are turbo teams required to reinvent the wheel when nobody doing a non-FSAE turbo system chooses to use a throttle body the way the rules require? It just doesn't make sense!

The fact that everyone needs to keep in mind is that the current engine rules were ONLY written to limit ultimate power outputs. The current required throttle placement was completely incidental. I've talked to the author of the rule in question! In all honesty the problems the throttle position rule have caused were an oversight. There was NEVER any intention to cause the problems teams see when they choose to use a turbo. We're trying to offer a solution that allows teams to choose where they want to put the throttle, while still restrict the power output of the engine. The rules are so open in with respect to the overall vehicle design, I'm not sure why the rules need to continue to restrict this particular design aspect. Like Marshall said, the design process and objectives remain regardless of what teams choose to do.

-Kirk

Charlie

06-01-2006, 09:56 PM

No offense to anyone, but if you really think you could gain some kind of advantage with a huge plenum after the restrictor, you simply haven't done your homework on the subject. It makes me wish this rule were adopted, just so you could see all the contraptions that people come up with.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
But I don't think you realize the consequences of moving the throttle on a turbo system. If you check the ALMS rules I bet they have a phrase that says something like the restrictors must be mounted directly to the inlet of the turbo. </div></BLOCKQUOTE>

ACO rules actually don't have any restrictions on this. However, they do say that anything between the restrictor and turbo inlet must be circular, and of a diameter no bigger than the turbo inlet. This does limit your plenum size basically by packaging. However it appears that the restrictor is always mounted directly to the turbo anyway, nobody seems to be taking advantage of the super secret advantage.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I would guarantee you I could make 130hp for short bursts, maybe even long enough for an entire accel run. </div></BLOCKQUOTE>

Well, not sure what your guarantee gets me if you're wrong. http://fsae.com/groupee_common/emoticons/icon_wink.gif But there's no way. How much air does the engine comsume per second? A lot. And that isn't what your plenum needs to be- your restrictor will start taking SOME (and continually increasing) effect as soon as you start to draw air from the plenum, not when you've used it all.

You might be able to get a half second of full power at the most, I don't care how big your plenum is.

Of course, having a short 'burst' of power right as you open the throttles is good right? Sounds like anti-traction control to me! When is a FSAE car NOT traction limited out of a slow corner?

This competition, like most racing, has always been about DRIVABILITY, not peak power. Someone might figure out the best way to get some kind of crazy transient peak, but have a car that drives like crap, and is slow.

In the end it's similar to the idea tons of New FSAEers have about the restrictor. 'Lets have a big vacuum leak and make more power!' In a quick think about theory that works. There is not idle limit, after all. Well in the end that doesn't work. Neither would this.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Plus it makes it hard to police intake leaks, you could have your intake manifold practically break off and make big hp NA, whereas now if you have even a small leak the car won't idle. </div></BLOCKQUOTE>

Well SAE should have been policing this in the proper way a long time ago. By sealing the intake and the engine has to stall immediately. But it's difficult with a 140 different throttle body designs. With a restrictor before the throttle, it's easy, and it's a no brainer, easy to overcome.

TO SUMMARIZE: http://fsae.com/groupee_common/emoticons/icon_wink.gif

I like this proposed rule change. It simplifies the concept without taking away any complexity of the good kind. If it's a concern you can have a restrictor mounted to the turbo directly. But I'd rather it wasn't. Teams will find out a lot more about how fluid flow does (and doesn't) work.

Kirk Feldkamp

06-01-2006, 10:13 PM

For discussion sake...

(Pages 8-9 of 2006 ACO rule book.)

5.2 - Turbocharged engines :

5.2.1 - Air restrictors location : a one piece and airtight right cone
must be fitted between the restrictor(s) and the inlet diameter of
the charging device :
a/ The cone must have a mandatory opening of 7? minimum ;
b/ To each base of the cone, over 10 mm maximum in length,
a round shape is permitted within the diameter of both the
restrictor(s) and the charging device inlet.

5.2.2 - Charging devices incorporating ceramic components,
variable diameter inlets and adjustable internal vanes are
forbidden. Adjustable internal vanes fixed on the turbine
housing are permitted for the diesel engines.

5.2.3 - Boost pressure : see Appendix 1.

It took me a long time to find this section...

-Kirk

Wright D

06-01-2006, 10:27 PM

When we were discussing this proposed rule change in another treed, the topic of plenum size came up. For fun "I did my home work" so all could in a post.

As it turns out a 50 gallon plenum is good for about three seconds of wide open throttle. Three seconds is less time then even the acceleration run. You can check my math at the link below. So I would think a 130 hp out put might be possible, but very short lived.

Change the rule, open up more engineering possibilities, solve a lot of headaches, and make every one happy. Well almost every body http://fsae.com/groupee_common/emoticons/icon_wink.gif

Throttle Position Rule Change Feedback? (http://fsae.com/eve/forums/a/tpc/f/125607348/m/17910749031/p/2)

Ben Inkster

06-01-2006, 11:30 PM

Personally, I think the discussion of engine power with the restrictor location is a moot point. But i don't like the idea of making things easier for turbo teams simply because it is difficult with the current arrangement. There are a lot of examples of other systems in FSAE that are difficult and/or expensive (suspension has already been mentioned) but that doesn't mean they should be changed to make things easier for everyone. I would have thought that teams that are pursuing or have successfully implemented turbos enjoyed the design challenges, but maybe i'm being naive (having never designed an fsae turbo system).

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> As it turns out a 50 gallon plenum is good for about three seconds of wide open throttle. </div></BLOCKQUOTE>

for us metric people 50 gallons = 189 L ... Big but not impossible, I once had the idea of using wing elements as a plenum chamber, hmm http://fsae.com/groupee_common/emoticons/icon_wink.gif

-Ben

repeatoffender

06-02-2006, 02:06 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ben Inkster:

for us metric people 50 gallons = 189 L ... Big but not impossible, I once had the idea of using wing elements as a plenum chamber, hmm http://fsae.com/groupee_common/emoticons/icon_wink.gif

-Ben </div></BLOCKQUOTE>

sounds just like a spaceframe chassis as your fuel tank?

VFR750R

06-02-2006, 05:14 AM

Agree to disagree, but 3.15sec is a lonnnnnng time. Especailly considering the accel run would now take less then 4sec to complete. You can't tell me the average hp of any engine would not be enhanced by such a device and the limit need not be 50gallons. Think about the smaller engines. 450 singles and 500 twins and even 250 4's would be able to put out much greater average hp around the track and in accel.

And anyone who thinks hp doesn't win the competition....your right, but the most average hp will go to the team with the biggest plenum and it will have an influence on any teams finishing spot.

Charlie, you still will have a throttle, and if all of you get your ITB way, throttle response and linearity will be great preventing you from using to much of this 'anti-traction'. In fact, to some degree you wont be using 100% throttle for the first 1-1.5 seconds of accel which could prolong the plenum from reaching the depression which chokes the restrictor by long enough to have some advantage all the way to the end.

Either way, if the plenum theory is mute, then there still should be no problem limiting the volume between turbo and restrictor.

I stand my ground on ITB's. Modern 600cc bikes all come with em, but we'd have to modify a set to fit the YZF600, there are a lot of teams out there that dont' run a CBR600F4I. And the advantage would then go to NA teams which could still use enormous plenums even if you restrict the turbo cars between restrictor and turbo.

Charlie

06-02-2006, 06:21 AM

Power that is not dependent on throttle position = car that is impossible to drive

50 gallon plenum /= 3.15 seconds of full power... it would be maybe half that before it starts rapidly decreasing.

More power, especially on throttle, /= a 25% reduction in accel times, unless it makes the tires sticker!

This is getting ridiculous....

VFR750R

06-02-2006, 06:51 AM

Why is power not dependent on throttle position. It will be a smooth transition while the plenum is depleated. I didn't mean to say that you would have max power for 3.15 seconds and then it would 'turn off' Obviously the power potential would decrease throughout a run, but you can't deny there would be more available.

Shoot, with the throttle downstream of the turbo what's to keep you from putting in an electric supercharger to keep the restrictor choked at any time the plenum pressure drops below a certain value. That could greatly increase the time to depleat it. The restrictor could be choked all the time. You could take the turbo off and just have a giant plenum between your feedback looped supercharger and ITB's.
Tell me the max hp or even average you would see is the same as it is now.

Chris Davin

06-02-2006, 07:00 AM

The stall test, as written in the proposed rule change, is designed to prevent the possibility of high transient power by using an enormous plenum.

Dan G

06-02-2006, 07:33 AM

You guys are still forgetting my 50 gallon ziplock bag idea. No pressure decay while the bag deflates and the engine runs "unrestricted". Use VFR's e-charger idea to refill it when the throttle(s) are closed and the restrictor would otherwise only be flowing at 5% of capacity. With the proper use of high flowrate/low restriction check valves, you might even be able to get away with PRESSURIZING the 50 gallon "variable volume plenum" when you slam the throttles closed at full load on a turbo car and would otherwise surge or recirc (post restrictor, pre turbo) through a BOV. Think about that for a second. 50 gallons of air at 10 psi. Sure it would decay while the throttles were closed, but you'd probably still have a few pounds of boost on tap when you made it through the corner and were ready to mash the go pedal again.

Also, on the massive plenums = horrible throttle response topic, as long as the throttled volume is sized correctly, there'd be no real difference than a traditional system. Other than the possiblity of breathing near-atmospheric pressure for a longer period of time.

But I agree with Chris, any massive plenum designed to provide a substantial level of "less restricted" power would also have a hard time with the stall test as it would take much longer to run out of reserve air at idle speeds than at WOT.

Kirk Feldkamp

06-02-2006, 09:07 AM

Heh. Does anyone find it strange that the two Cornell guys are against the change?! Who would have thought we could get this political in FSAE? http://fsae.com/groupee_common/emoticons/icon_biggrin.gif They've spent so much time developing a bulletproof system, it's in their best interest to keep the rules the way they are. I can't blame them for that.

All this 50 gallon plenum discussion is hallarious. I would LOVE to see a team bring a car with a 50 gallon drum on the back. I don't think you guys realize how GIGANTIC that is. It's like the size of RMIT's entire car. I doubt you could EVER even get a 20 gallon plenum to fit within the rollover zone. Beefy sidepods, maybe... Not to mention that any team that did that would be murdered in design. Rediculous.

Charlie is right about the 50 gallon time estimation being WAY too high. Look at the calculation Dustin did. That was a quick calculation done to see how long a 600 uses 50 gallons with zero intake restriction and 100%VE!!! Think about what that means! There is absolutely no way that you can do that with the dynamics of the FSAE restricted intake system. As soon as the engine starts to evacuate the plenum, the pressure drops, ie it's no longer at atmospheric pressure. The more mass flow, the greater the pressure drop. Think of the control volume from the intake valves up to the restrictor. The restrictor will start to kick in LONG before you guys are talking about. Shoot, you guys are going to get me to dust off my fluid's book and fire up matlab if you're not careful. http://fsae.com/groupee_common/emoticons/icon_wink.gif

I'd also love to see someone try the electric supercharger idea that VFR750R brought up. Good idea in theory, horrible idea from an implementation standpoint. I highly doubt the power benefit could ever offset the weight penalty of having the charging and battery system to run an electric supercharger at full pin for 22km.

I think the ACO stall test (where I copied the idea from) is designed to check for intake leaks and anything circumventing the restrictor rule. It is an interesting side benefit that it effectively limits plenum size to something reasonable. Good call Chris, I wouldn't have noticed that.

50 gallon ziplock bag?! All this crazy talk is what scares the rules committee. Knock it off guys! http://fsae.com/groupee_common/emoticons/icon_razz.gif

-Kirk

KevinD

06-02-2006, 11:01 AM

these cornell guy are funny. with as good of results as they have had, i would think they would have more common sense then to think you can get 130hp from a practical FSAE car with the TB post compressor.

lets think about this, we learned this year that having a massive amount of power doesn't win detroit right? who won the event? thats right, a single. who won autocross? thats right, a single. the only event where power makes a difference was in acceleration where a 600 won, and even that car didn't have a turbo. hint hint, 600 turbo not nessesary, I.E. massive HP not nessesary. there are two ways to make your car go faster. F=ma right? rather then adding a 50 gallon drum to your car and having the judges laugh at you (ever lif a 50 gallon drum? they are rediculously heavy... and if your going to the lengths of making a carbon drum around a mandrel, you obviously have your priorities messed up), why not just make your car 50 pounds lighter? thats what we did, and now that we have a smaller engine package, in cali we will see how much having 130hp is nessesary to win events...

heres a joke i love to hear for you cornell guys who think have 130 hp will give you an advantage in the accel event...

what do a 500hp mkIV supra and a 1000hp mkIV supra have in common? they both run 10's.

case and point, for the past two years helsinki has claimed to have 105hp. neither year have they won accel. why? cause driver ability, and traction are far more important in a sprint that is hardly long enough for the HP difference to take effect. heck, my street car is faster in a 75 meter sprint then the FSAE cars... and it is a daily drive 4 door sedan (awd and 300++ hp evo 8). the traction i get off the line makes passengers and myself dizzy. something i have never felt from the formula car because it doesn't have the traction.

Dan G

06-02-2006, 11:34 AM

The whole "50 gallon" thing was meant to illustrate the extreme case of what the proposed rule change could allow. Obviously the idea of carting around a 50 gallon drum is absurd. As is the idea of using a 50 gallon plastic bag.

So you can either ignore all the silly ideas in this thread, as they couldn't be practically applied (although I am semi-geeked about that "boost bottle" idea) and are just extreme cases of what-ifs, or join in to toss around your own spin or propose reasons why the ideas themselves (not the practical applications, or arguments over whether you NEED more power) would or wouldn't work.

http://fsae.com/groupee_common/emoticons/icon_razz.gif

VFR750R

06-02-2006, 04:36 PM

You guys are so resistive to this but Dustin didn't include the fact that the restrictor would always be adding air to the plenum. There is always a leak into the plenum to offset the air going out. As long as the plenum pressure is above .53% atmospheric, your making more power then you could.

I mean if you can't understand that a car that only chokes the restrictor above 9000rpm could add considerably to the avg hp by having a large source of reserve air, fine I'm an idiot.

The electric supercharger idea is not stupid, you could certainly implement it correctly. That is not a challenge at all.

To be honest the light is right crap is burning me up. A 475 car ran second in autocross, and was setting blistering laps in endurance. I do not see any finite correlation between speed and autocross/endurance times or skidpad. Accel showed a light 4 cylinder good, but the times were way off from a good year and turbo 4's have won more then their share of accel times over the years. Until somebody shows me some back to back data that shows that a 400lb car is physically faster then a 500lb car, this offsetting 10lbs here and there stuff is what is ridiculous. Some many other factors are more significant, power being not one of them either.

Garlic

06-02-2006, 06:17 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
I mean if you can't understand that a car that only chokes the restrictor above 9000rpm could add considerably to the avg hp by having a large source of reserve air, fine I'm an idiot.
</div></BLOCKQUOTE>

Nobody's arguing that the effect isn't there. It's that it's neglible! A non-issue. You might as well be arguing that putting the restrictor on the ground level is best, after all, the air is denser down there. http://fsae.com/groupee_common/emoticons/icon_razz.gif

I agree that a 50 gallon plenum might have some benefits to engine performance. Package it without detriment to any other systems and get back to me. http://fsae.com/groupee_common/emoticons/icon_wink.gif

iolair

06-02-2006, 06:44 PM

One only has to look at the ALMS superstar C6R to verify that large plenums do in fact work quite nicely and they are no where near the size of a 50 gallon drum. The C6R has a Katech 427 (almost 12 times the size of a 600 cc engine) that generates approximately 790 HP unrestricted.

The airbox/plenum chambers are sealed and fed by two 1.25" sonic restrictors that limits HP to approximately 590....still an amazing amount of HP considering the orifices are the size of two 50 cent pieces. You can see the size of the restrictors that feed the air boxes on each side of the motor in the second photo.

http://www.pbase.com/image/61204619.jpg

http://www.pbase.com/image/61204620.jpg

Even the tiny restrictors (pre-sonic) will allow the plenums to fill quickly each time the driver lifts the throttle and depending on the speed of the turn, this allows the C6R to blast out of the corners under full unrestricted hp for a moment or two. As the RPM's increase the manifold pressure drops as the little orifaces lose their valiant battle to keep up. Since the restrictors are metered orifaces, they do not go sonic until a specific pressure drop is reached.....at that point the engine will pull the air out of the inlet manifold/airbox at a much faster rate than the restrictor can supply it to the tune of a minus 200 hp.

John

BTW, if you all think this is nonsense, please....talk to Katech!

Jason Harding
Katech Inc.
http://www.katechengines.com
586-791-4120 x234
jason@katechengines.com

Garlic

06-02-2006, 06:52 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by iolair:
Even the tiny restrictors (pre-sonic) will allow the plenums to fill quickly each time the driver lifts the throttle and depending on the speed of the turn, this allows the C6R to blast out of the corners under full unrestricted hp for a moment or two. As the RPM's increase the manifold pressure drops as the little orifaces lose their valiant battle to keep up. Since the restrictors are metered orifaces, they do not go sonic until a specific pressure drop is reached.....at that point the engine will pull the air out of the inlet manifold/airbox at a much faster rate than the restrictor can supply it to the tune of a minus 200 hp.
</div></BLOCKQUOTE>

Any NA racing engine (with ITB) has a large plenum, it's the best for power, restricted or non-restricted.

I don't doubt that the vette is unrestricted out of corners, or that it becomes restricted as RPMs increase, out of corners. That's normal operation for a restricted engine! Low RPMs aren't usually under much restricted effect.

And while you imply this, I don't believe for a second that it really reaches 790 HP at any time on track. Sorry.

Like someone else said, transient power out of corners does not help performance, at least not on something with plenty of low end grunt like a vette. It's like the opposite of traction control.

No offense, but I'm not sure what your function at katech is, but it does not appear to be very deeply involved in the C6R engine project. I've been involved in very similar projects and the dynamics are just not like you are saying.

No doubt it blasts out of corners, and tapers off up top, but that's normal for a restriced engine. I can't imagine that if the plenum was smaller you'd notice any difference. It's vacated almost instantly. And that's not just calcs on my part, I've been a part of it!

iolair

06-02-2006, 07:57 PM

>>And while you imply this, I don't believe for a second that it really reaches 790 HP at any time on track. Sorry.<<

No, I certainly did imply 790 HP at any time as it relates to a restricted motor, that is absurd! What I did say "depending on the speed of the turn, this allows the C6R to blast out of the corners under full unrestricted hp for a moment or two."

That does imply full momentary manifold pressure *at* the RPM that is it coming off of the corner.....never to exceed 590 HP!

>>No doubt it blasts out of corners, and tapers off up top, but that's normal for a restriced engine. I can't imagine that if the plenum was smaller you'd notice any difference. It's vacated almost instantly. And that's not just calcs on my part, I've been a part of it!<<

Interesting, you have seen the C6R perform and you know the size of the restrictors....I guess it must be magic!

Please, an explanation of how it really works!

John

Chris Davin

06-02-2006, 08:08 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by turbotwig:
Heh. Does anyone find it strange that the two Cornell guys are against the change?! Who would have thought we could get this political in FSAE? http://fsae.com/groupee_common/emoticons/icon_biggrin.gif They've spent so much time developing a bulletproof system, it's in their best interest to keep the rules the way they are. I can't blame them for that. </div></BLOCKQUOTE>

Them's fightin' words!

Here is my reply to your accusation:

First of all, VFR750R and I are alumni. Aside from team pride, neither of us have an interest in seeing Cornell or any other team win. My primary concern with the rules change is evaluating its effect on the educational value of the competition, since I think FSAE had such a powerful effect on my education. Based on my four years of experience with engine failures, I am thinking that the extra maintenance and cost, along with the subsequent loss of development and testing time, would be the dominant effect if lower-budget and lower-manpower teams start running turbos. I understand that having teams run turbo setups that are more like street cars is an advantage, but it's also less of a design challenge. Sorry, that is my opinion. I did NOT share this opinion with anyone from the Rules Committee when the issue was being discussed last year, mostly because I didn't want to be seen as having a conflict of interest (and it seems my fears were justified). In hindsight, perhaps I should have kept quiet here as well.

Another point I'll make: even if I were trying to protect Cornell's design, would that really be so bad? The Cornell engine package as it exists today is the result of thousands of man-hours invested by many people (myself included) over a period of many years. There's a lot of thought and engineering behind it. If this work has gained Cornell an advantage in the competition, wouldn't you say that we've earned it? I would say that any racing series, whether it's Formula SAE or Formula One, should be structured such that engineering effort and original thinking are rewarded.

What if someone proposed that Western Australia's Kinetic suspension be issued to all teams upon registration for the event? Would they be accused of being "political" if they objected? Western Australia has done a large amount of engineering to design their suspension and they deserve whatever advantage it has afforded them. I would say they would be justified to object if someone proposed that their design be given away. Now, I understand this is not exactly what's happening here, but I think it's similar enough to illustrate the point.

By the way, Cornell's solution to the turbo problem is quite simple and straightforward. It's also been pointed out in this very thread that there are other solutions that are quite effective as well. Cornell has gone to no extra-ordinary lengths to protect its design from anyone. The gory details of the Cornell engine package have been available through a number of ways, not to mention simple inspection of the Cornell car at competition. There is very little in the way of any team getting a Garrett turbo for free and integrating it into a reliable leak-free engine package. The rules change would just take some of the problem-solving out of it.

Garlic

06-02-2006, 08:11 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by iolair:
Please, an explanation of how it really works!
</div></BLOCKQUOTE>

How it really works is, the engine is only 'less restricted' for a fraction of a second, and even that probably doesn't even last until the driver reaches full throttle.

Sorry, I thought that your last comment stated that the engine was transient 200 HP up on it's 590 HP. After re-reading I see you meant something else.

Garlic

06-02-2006, 08:17 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by iolair:

That does imply full momentary manifold pressure *at* the RPM that is it coming off of the corner.....never to exceed 590 HP!
</div></BLOCKQUOTE>

No doubt, that *at* corner exit RPM, the engine is not in the restricted RPM range.

iolair

06-03-2006, 08:06 AM

>>I can't imagine that if the plenum was smaller you'd notice any difference. It's vacated almost instantly.

the engine is only 'less restricted' for a fraction of a second, and even that probably doesn't even last until the driver reaches full throttle.<<

Since the air box is sealed with only the restrictors feeding it and the rather large air box is vacated almost instantly....which implies little or no pressure, how do you account for the C6R's performance up to where the restrictor goes sonic if there is little or no air pressure in the air box?

Or does the performance taper off as the RPM's increase because the pressure in the air box tapers off and decays at a much slower rate up until the restrictor goes sonic and limits the HP to 590 at X RPM?

John

Garlic

06-03-2006, 08:15 AM

Sorry if I was unclear.

By 'vacated', I meant it has reached it's stable restricted state, as you'd see at that RPM in steady state.

I am only speaking of the RPM range where the restrictor is at maximum flow (which is not sonic, but if you like, that can be an interchangable term)

That's what this discussion is about- whether or not a large plenum can give more (usable) transient peak power in the restricted RPM range. Or, that the plenum delays the onset of the restrictor, which it does, but to no measurable power gain.

iolair

06-03-2006, 08:43 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I am only speaking of the RPM range where the restrictor is at maximum flow (which is not sonic, but if you like, that can be an interchangable term) </div></BLOCKQUOTE>

In a earlier post I think I referred to pre-sonic, but sub-sonic would be more appropriate.

John

Chris Davin

06-03-2006, 10:09 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KevinD:
these cornell guy are funny. with as good of results as they have had, i would think they would have more common sense then to think you can get 130hp from a practical FSAE car with the TB post compressor.

lets think about this, we learned this year that having a massive amount of power doesn't win detroit right? who won the event? thats right, a single. who won autocross? thats right, a single. the only event where power makes a difference was in acceleration where a 600 won, and even that car didn't have a turbo. hint hint, 600 turbo not nessesary, I.E. massive HP not nessesary. there are two ways to make your car go faster. F=ma right? rather then adding a 50 gallon drum to your car and having the judges laugh at you (ever lif a 50 gallon drum? they are rediculously heavy... and if your going to the lengths of making a carbon drum around a mandrel, you obviously have your priorities messed up), why not just make your car 50 pounds lighter? thats what we did, and now that we have a smaller engine package, in cali we will see how much having 130hp is nessesary to win events...

heres a joke i love to hear for you cornell guys who think have 130 hp will give you an advantage in the accel event...

what do a 500hp mkIV supra and a 1000hp mkIV supra have in common? they both run 10's.

case and point, for the past two years helsinki has claimed to have 105hp. neither year have they won accel. why? cause driver ability, and traction are far more important in a sprint that is hardly long enough for the HP difference to take effect. heck, my street car is faster in a 75 meter sprint then the FSAE cars... and it is a daily drive 4 door sedan (awd and 300++ hp evo 8). the traction i get off the line makes passengers and myself dizzy. something i have never felt from the formula car because it doesn't have the traction. </div></BLOCKQUOTE>

Kevin,

Maybe you've misunderstood me. I'm saying that, even if there were an engine package that could theoretically develop 130 hp (or some power significantly higher than has been in Formula SAE before) there is a rule written to prevent it, and even this ignores the practicality of such a hypothetical system.

As far as your comments about the importance of power in FSAE, well, you're entitled to your opinion. However, if you think that Cornell's engine philosophy has been about peak power, you're mistaken. It has been about having a wide powerband that's drivable by our relatively inexperienced drivers. Many people, particularly those who are relatively new to racing or to Formula SAE, tend to focus on the peak power number (after all, that's how engines are rated) and ignore the far more important factor that is the shape of the curve. Whether it's a 500 pound car, a 300 pound car, a single, a 4-cylinder, turbocharged or naturally aspirated, shape of the curve will be important. The only exception would perhaps be a CVT but these are difficult to integrate.

We could argue all day about the merits of the different design philosophies in Formula SAE. The bottom line, at this point, is that there is no clear one best concept. I also can't help pointing out that the Cornell car won the Road and Track cup this year, so it was clearly not a slouch. It's an interesting debate but it's far from settled. I will be interested to see how your 250cc four-cylinder turbo does this year at Formula SAE West.

Off-topic: It says in your profile that you work at Lockheed Martin. Me too, in SI-Owego. I would assume you work at Missiles and Fire Control in Dallas. How do you like it?

iolair

06-03-2006, 10:17 AM

I guess my point is......if Katech used a smaller volume air box, the air pressure decay rate would increase thus lowering the average manifold pressure, thus lowering the average HP up until the choke point.

http://www.pbase.com/image/59337870.jpg

John

Homemade WRX

06-05-2006, 10:17 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
I've said to much http://fsae.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>
funny I had said the same thing and garlic doubted then too...still not saying how...
regardless the rule isn't chagning (having talked with Michael Royce about it)...he told me that all of the consultants for the proposed rules said that turbocharged systems would have a considerable power gain.

As turbotwig pointed out: I'd be in favor of the rule to make all of the teams who just tweak and improve designs that they've been working on for years to have to start fresh, like many of the newer teams.
I'd also be in favore of ITB's for NA motors if the rule were to change. That should make for lots of design for teams as to which is really better (NA ITB or turbo/super single TB). Imagine all of the innovation that would occur if the rules changed.

to agree with KevinD power isn't need...we were running 4 seconds faster than cornell in endurance when we were putting down 28 hp and 18 lb-ft on our toasted 600...hell, our car was heavy as hell this year too 530 lbs...explain that one...guess suspension/tires are the only things that really make a difference...power and weight don't...???... http://fsae.com/groupee_common/emoticons/icon_wink.gif

take it easy,

Bill Kunst

06-05-2006, 10:17 PM

Sorry for this, but...

Yeah, you know it has to be good when it starts like that. I think that we need to work within the realm of realism. I remember telling someone two years ago that we were going to switch to a massless magnetic fusion drive and they were perking up wondering about more details. A fitty gallon drum is about as rediculous as a dildo shifter. I take that back, as the latter would be closer to anything realistically gripped by most of the dorks on this topic making it completely feasible. Anyway, I digress.

As we embark on this journey back to realism, there are a few things that I would like to say.

1. There is a right way, a wrong way, and a stupid fucked-up way. This nonsense of throttling before the restrictor is the third option. No more needs to be said. And for those of you that figured out how to make this work reliably for turbo applications, you embark on the equivelant of fixing the hole in your engine block with tooth picks and crazy glue. We all know it is dumb, and those that don't want it to change are not looking for the best interest of the comp. IT DOES STILL TAKE ENGINEERING TO PUT A TURBO SYSTEM TOGETHER THE RIGHT WAY, MORONS.

2. Simply making this change to how it should be done will solve the problems "the right way". Any incurred power additions will be addressed in point three.

3. It is in everyone' best interest to see this rule changed. In changing this rule, it is in everyones best interest to see a rule made that doesn't include stupid-ass loop-holes. This is why you should give help in making a better rule, not waiting for them to make a rule and find one year of freedom in a design that has no life expectancy.

4. We all know that there is a realistic maximum that we would expect for a plenum volume. Or the distance to certain components. Without 50 gallon plenums and the "I have already said to much" bull, would it be possible to come to a conclusively better rule.

My proposal to an addition to get rid of unlimited plenum volume is to set it at a max of between 2-4 gallons.

2-4/50*3.15sec=.125-.25sec

This would mean that you would have a quarter or less seconds of massive huge power. I think that is realistic.

Add this on to the proposal on diffuser angle, restrictor requirements, max length to components and you have a rule that will still allow design to occur while fixing one of the stupidest rules we have. Be helpful and you will see a change, be a dick and you will be sucking oil past your seals forever.

Bill Kunst

Garlic

06-05-2006, 10:52 PM

Well said response with no remorse, I love it! http://fsae.com/groupee_common/emoticons/icon_wink.gif

I agree, except for <STRIKE>#3</STRIKE> sorry meant #4.

Part of me says leave an unlimited plenum volume, this will teach those with super secrets how fluid flow really works.

But realistically, this rule probably won't pas without some sort of restriction, so I'd say instead of limiting plenum size, (hard to police), just say no plenums. Only circular tubes no bigger than the diameter of turbo inlet.

This will still leave open the possibility of someone trying a maze of tubing for that extra 'advantage.' And of course they'll keep it a close guarded secret because nobody is smart enough to have the same idea.. unless they let the cat out of the bag! http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

Bill Kunst

06-06-2006, 06:32 AM

Garlic,
Explain how #3 isn't right. If you looking at the most winning teams, they are not running around the rules. They are consistently making regeneration vehicles, always trying to better a design.

Fsae is one event (basically) a year. In any racing, you may have 20 or more. This is why it is rediculous to design towards a loophole (so few points, so many potential problems, and only one showing). This is epescially true in the engine department as redesigning your engine system every year can become a burden.

I also agree with your conclusion on the power that is thought to be available. I suppose with a pneumatic accumulator you could build enough power to rival a top fuel dragster (for a jillionth of a second).

I would also like to point out that the rules committee and inspectors have the power of gods. If they decide that your 1000 gallon intake doesn't meet the intent of the rules or may not be safe, your done. I like this fact for all those who think that they are going to make an absurd 130hp.

Oh yeah, lets put that into perspective. Stock motors (4cyl) put out 110 to 120 horse sucking massive amounts of air ( 300cc*15,000) 4.5 million cc's, or 4500 liters at 100% ve. Even at 50% ve, that is a mind blowing 2250 liters of air per minute (or almost 40 liters a second). If anyone thinks that they can make 130 hp, for any length of time, raise your hand and wait for me to call on you. This is ludicrous, really, and should not even be considered a just argument. Not to mention the fact that if you build your dumbass 50 gallon intake, it has to be able to withstand about 15psi, at about 20 sq ft of material, you are looking at some serious loads and weight.

Like I said, keep your hand raised.

Bill Kunst

06-06-2006, 06:44 AM

Sorry,
I know that I grossly underestimated the sqft of the intake. Think more like 40 sqft, in that range, and also it will be more as you shape it to be a backpack for you car as there just is no room for it. Even so, lots of load, lots of material, lots of weight.

Garlic

06-06-2006, 06:47 AM

Sorry, I meant to say #4 (hence my comments about plenum volume)

I completely agree with #3. I will edit my post accordingly.

buddy

06-06-2006, 09:51 AM

For my own education...

Does anyone here know how "suck-thru" carb. turbo systems avoid this problem?

buddy

Homemade WRX

06-06-2006, 10:21 AM

yes, I agree they need to limit plenum size (not take a way), but I never said I was out to increase peak power (not a fan of huge plenums)...

and for limiting plenum size, make a mandated "box" (3 dimensions) that it has to fit within...
as for the suck through carb systems, I'm curious too and need to talk to a friend who has run this set up on his drag car.

BryanH

06-07-2006, 06:09 AM

Mr Garlic, In the old days : http://fsae.com/groupee_common/emoticons/icon_cool.gif I did many suck thru's. fav carb was concentric float bowl S.U. bolted to flange welded directly onto compressor housing to eliminate fuel puddling on cold start. The inlet manifolds were fabbed from steel and kept as short and small in Vol. as possible also to keep fuel atomized and eliminate any possibility of puddling. Fuel atomization and economy with this setup is really good, slightly better than EFI, BUT power is down big time on short runner, big plenum, no turbo inlet restriction setup. (eg stock 13B turbo with cut down inlet/draw thru carb/12psi boost/108rwkw. same engine EFI 145rwkw) I used Garrett or Hitachi T3/T4 turbo's with carbon seals and NEVER had inlet oiling problems. A few of these setups did 100,000+kms. As long as there was same/less pressure in the oil drain tube v. the turbine housing there was no turbine side smoke screen.
cheers

Kirk Feldkamp

06-07-2006, 08:14 AM

Carbon seals... that's probably why you were able to do that.

If I remember correctly, the turbo Cornell uses has carbon seals. Am I also correct in remembering that Cornell uses a dry sump with a scavenge section dedicated to the turbo oil drain? That's the "right" way to do it within the current rules if your team has the time, money, and manpower... which most teams just don't have.

-Kirk

Poe

06-07-2006, 09:39 AM

We at NC State use the stock wet sump system with an independent external scavenge pump for the turbo oil drain. It was quite inexpensive, was designed and manufactured by one person, and took maybe a month to design and implement. It works pretty darn well with the regular GT12 seals. I like the design challenge the current rules present.

Kirk Feldkamp

06-07-2006, 09:44 AM

Is your scavenge pump mechanical or electric?

-Kirk

Poe

06-07-2006, 09:49 AM

It is mechanical.

Travis Garrison

06-07-2006, 11:03 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">...eg stock 13B turbo with cut down inlet/draw thru carb/12psi boost/108rwkw...I used Garrett or Hitachi T3/T4 turbo's with carbon seals and NEVER had inlet oiling problems.. </div></BLOCKQUOTE>

How could you even tell on a rotary? http://fsae.com/groupee_common/emoticons/icon_wink.gif

Bill Kunst

06-07-2006, 01:52 PM

Poe and others-
If the rules designated that you had to use tractor tires for competition, would you feel that those rules would need changing? This is about the rules being right or wrong. All other rules are based upon a decision of safety or what we believe to be right. You can do a heim in bending, but it is wrong! You can put your tb before the turbo, but it is wrong. In either case there is a way to design around this and in both cases it becomes a circle jerk.

Making something heavy to be as strong as the right way is stupid, and judges and other teams will tell you that. Making all the accomodations to do a nonstandard sequence of parts in a system is dumb as well. Bandaid-ing this turbo problem is rather dumb on all accounts, even if you can do it. Adding all the complexity and to an already failure-prone system to create something you will never find "in the real world". Further more, this is supposed to be a real world comp.

Why are we engineering around a problem that shouldn't exist? Look at every racing group that exists, every set of rules, and tell me what normally happens. Rule is made, certain people win always, rule is changed, other people win always, rule is cahnged, no one wins all the time. This is just like the weight they add to the speed world challenge cars. If you win, they add weight, if you lose, they take some away.

Here is my suggestion. For those who would like to see this rule changed, build a powertrain system that will fit the proposed rule change. Use every method to make this mystical 130hp, and prove us all wrong. Then help Royce and his pals adapt the rule so that it makes the situation fair for everyone. Sounds like work? This may be the only way to change it. It seems like everyone is afraid of something that might happen, and if that is the case we shouldn't be racing cars.

CMURacing - Prometheus

06-07-2006, 04:34 PM

i know someone else said this, and i'm not adding much with such a post, but why not just change the order to say that restrictor-turbo-TB-plenum is acceptable, with rules similar to the ACO (ie the restrictor outlet has a max length to prevent this being a "secondary" plenum, and the TB must bolt directly to the compressor outlet)?

Poe

06-07-2006, 05:11 PM

Purely out of curiosity, are the folks in favor of this rule change on teams that currently run a turbo, on a team which is thinking about running a turbo in the future, or are they on teams that run normally aspirated? I'm not trying to start any kind of argument here, I was just wondering.

VFR750R

06-07-2006, 06:17 PM

Bill.....I dont' know where to start.

I'm familiar with NC states system and it uses a std gear set out of a F4I with a custom housing. Like Poe said, very effective, fairly cheap, easy to implement.

The cornell dry sump just takes it a step further. Our view was, if you're going to go through the trouble, keep going and get all the benefits afforded by a dry sump. But, we went to a dry sump when we swaped turbos. The current turbo is a piston style seal like a GT12, not carbon faced. If the rules changed we could go back to a wet sump, but I don't know that we would.

To Bill and some others including myself. This is an engineering forum, let's keep this an engineering discussion. Back up opinions with calculations when necessary. In the future, I will try to do so, but since I no longer participate in FSAE I have no need. I do suggest someone with some time and excel or matlab create a system of equations with displacement/time (volumetric effeciency*RPM), volume of plenum, plenum pressure, and restrictor flow/plenum pressure. Let's put this thing to bed.

Bill Kunst

06-07-2006, 09:33 PM

VFR-
5/8" and 3/4" rod ends in bending also work well compared to 1/4" and 5/16" sphericals.

I also hope that when you say put this to bed, you mean to change the rules. I have been watching these discussions on the turbo layout (I think that there has been at least three that have discussed it) and I am fed up with those that use the turbos(and for many years) and don't want to change as THEY may have to "re-engineer" something. This isn't about protecting teams with tons of research, its about making a move towards a legitimate layout for the intake.

For reference, I am an Alumni of UW-Platteville, a team that is under manned, under funded, and under appreciated. The likelihood of them running a turbo is low. The likelihood of them getting the time or people to do any significant testing is slim. For teams like this, this rule would make it easier. But this is not because you can than just bolt together a system. What "bolt together" or "jegs" car has ever done well?

Further more, WHERE IS THE 130HP FOR 3.15 SECONDS COMING FROM? I would like to see your reasoning and would also like to see this laid to rest.

BryanH

06-08-2006, 05:33 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Travis Garrison:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">...eg stock 13B turbo with cut down inlet/draw thru carb/12psi boost/108rwkw...I used Garrett or Hitachi T3/T4 turbo's with carbon seals and NEVER had inlet oiling problems.. </div></BLOCKQUOTE>

How could you even tell on a rotary? http://fsae.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

Tire smoke is white.........

Homemade WRX

06-08-2006, 08:17 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bill Kunst:
Here is my suggestion. For those who would like to see this rule changed, build a powertrain system that will fit the proposed rule change. Use every method to make this mystical 130hp, and prove us all wrong. Then help Royce and his pals adapt the rule so that it makes the situation fair for everyone. Sounds like work? This may be the only way to change it. It seems like everyone is afraid of something that might happen, and if that is the case we shouldn't be racing cars. </div></BLOCKQUOTE>
that would be nice but costly to a low budgeted team...that would require a team with extra time (many people) and funding (well established)...fitting that bill, a team that most likely is already set in there way of design and doesn't want to see the rule changed...that being the feeling that I get from several people on this thread...

I might try and tie that into my senior project if I have time ontop of all the other bits that I'm doing for it...if the direct injection falls through, I might just do it...

Bill Kunst

06-08-2006, 09:29 AM

Well, lets find someone with your need for a project and a company with interest(honeywell) to fund this little project. In all reality, this would be fairly cheap compared to the number of returned turbos. What would it take to design and intake that you could switch component location? Not much.

Here is the test.
Single tb versus itb(after plenum) on NA with location change that is being suggested.

For the turbo app:
Single tb versus itb(after plenum) with change in location. Same max boost level

Single vs single tb with change from before restrictor to after turbo/before plenum.

On the turbo: Do a setup with and without recirculation/BOV. On the without, let the turbo ramp pressure before the TB's in both situations.

Obviously on the Turbo ITB setup, there is going to be some room for power gains do to not recirculating. The problem that comes in is that when you don't release the pressure before the TB's in either case, severe damage can occur to the turbo (stalling/ surging opposite the problem already encountered).

Total cost:
engine with ITB's and and stock computer w/power comander: $2000

A TB for the single setup: $150

Recirc valve: free
BOV: $100

A computer to run STB setup: 1000

Materials to build a universal intake: easily under $500

Total cost, under $4000, if you have your own dyno. Help me if we missed some major items. Also, I am serious about this proposal. Great project for senior design, and honeywell, so give insight if I am off base.

Bill Kunst

VFR750R

06-08-2006, 09:59 AM

Bill, you just don't get it.

First, don't use rod ends in bending as justification for changing intake system rules.

Next, why would you want to change to a system where the turbo cars could even have a slight advantage. What's in it for you? And solely for the purpose of being like other racing series is a joke.

And on protecting 'research', do you not think that we could come back with another killer engine package just because of this rule change?

I'm still not convinced we NEED to change, but I'm not against it if the rules acknowledge the fact that plenum size can be factor in performance.

Bill Kunst

06-08-2006, 11:47 AM

To answer q's:
Nothing for me. Not to be like racing, to be like the rest of the god damn world.

Ask yourself why cornell finished 35th. Oh yeah, the killer reliable engine package failed to compete in two events. This is understandable because alot of teams do not finish all the events. HP will not finish events, neither will oil seals coming out of the turbo.

Anyway, When I said give insight if I am off base, I meant in testing procedure and cost of testing. I really didn't care if you think that this rule shoudn't be changed. We have established that you think it is a great rule and that you don't agree with one of the largest turbo manufacturers in the world.

There is an advantage either way with plenum volume. I do not believe that there is a significant advantage of the standard we have now and the single tb directly after the turbo. This is why testing needs to be done. We have to much time inbetween comps to have conclusive evidence, that is why strict dyno testing will have to be our solution for testing.

Please only reply to my posts with solutions, not negative nancy bull. This rule can be changed, and should be. It should also be changed in a way that limits negative effects.

VFR750R

06-08-2006, 01:56 PM

We've never had a 'turbo' fail at comp. Actually to my knowledge, this years engine is the first to blow up in at least 10 years, and it wasn't because of where the throttle is in the intake system.

By the way, your opinion is no less negative nancy bull then mine. In fact, since you have no fsae turbo experience, and you've not provided anything but a price sheet, I really don't care if you think we Should change the rule.

I just don't understand your blind enthusiasm for a rule change when there are solutions to every problem the current rules have, but i guess that's just my opinion.

Matt Gignac

06-08-2006, 02:25 PM

I don't think that "because it's like this everywhere else" is a valid reason for changing a rule. Some series mandate a specific engine, but I don't think anyone wants that for FSAE. Some series ban moveable aero, some aero devices altogether, we can go nuts with that.

Long story short, FSAE is not like any normal racing series, and therefore why should it have any of the same rules?

In it's current shape of affairs, I believe there is still a considerable advantage to using a turbo. The low-end torque increase we get is worth it in my mind. However, to get this advantage, you need to pay a price, i.e. get the system to work well with the current rules. And there are a number of ways around the problem. In the past four years with Garrett turbos we have:ran oil flow restrictors, made custom carbon seals, said "hey, all the oil we're burning is improving fuel economy" and there are a number of other ideas we haven't tried yet.

Matt Gignac
McGill Racing Team

Bill Kunst

06-08-2006, 09:05 PM

Ok,
You got me. I just wanted to see people race ALMS cars at fsae comps. Or your not listening. Unfortunately, Turbotwig probably is either sitting back watching this unfold. There is a lot of gains to be made for the nonturbo group under this as well.

As far as turbo experience, I worked for a well known shop in Ill. for almost two years doing custom street and race cars that can be seen at www.speedlab1.com (http://www.speedlab1.com) . As a part of the team at that shop we developed many forced induction street and race cars to some pretty extremes.

Will this be of enough value to you? Absolutely not.

Do I care? Not really.

You don't believe that this rule should change because there are solutions to the problem the way it is. I have a hard time believing that these solutions, as turbotwig has said, are a long term solutions. You should expect sometime of life from the turbos, not one or two seasons of FSAE, which accounts for so few hours in respect to the proposed setup. Like I have said, I also believe that there are right ways and wrong ways to deal with problems.

I was really hoping that someone like Micah would take this on in senior design, hence the price sheet asshole.

Get yer attention, good. I wasn't making fun of cornell, I was showing you that a NA single cylinder car can beat turbo anything because power doesn't win. But you took it close to heart, and that's okay.

This is what I am hoping for minus other wording that will need to be worked on by the committee:

Put the throttle right after the turbo. On NA allow itb's.

Explain how this would vary from the power difference already seen between NA and forced induction. If you can show me, it would be great. I would even stop replying on this topic, forever.

BryanH

06-09-2006, 07:04 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bill Kunst:
There is a lot of gains to be made for the nonturbo group under this as well </div></BLOCKQUOTE>
Now you are down to the guts of the problem in making any change to the rule. When I read the rules first time the inlet rules seemed antiquated,(WTF have they got the bits back to front?)
3 years later I think I know exactly what the rule makers were thinking.
Sad fact of life is that not everybody plays strictly by the rules and in restrictor class racing even a small "air leak" results in big power gains. In our local Club car racing series this is a constant problem, latest blatent cheat was only found out when he sold the car. He was a friend and it's hard to accept that he stooped that low.
Throttle first means that the rule is self policing, It would be just too much to expect already hard working officials to check every car at the every event, and If they didn't the accusations and innuendo would be endless. Been there done that so my opinion is that the inlet rules are carefully thought out and there is no need to make any changes to a successful formula.

Bill, a low powered car didn't win fsae, RMIT's power/weight is about the same as the other front running cars, light weight means slower tyre warm up which hurts on a single event/lap but once the tyres are hot....
HP is required but its #4 on the list.

p.s. Multi TB and turbo is a calibration issue I would not wish on any student
Cheers