Turbo Question

[opticnerv]

I'm a freshman at my local community college. I will be transffering to four year university with an FSAE team for sure.

I've read that turbos are legal to use. Has anyone ever used a VGT ( Variable Geometry Turbo ) ?

A pretty cool video maybe some one can copy the idea and use it on their car.
http://www.youtube.com/watch?v=MU1od1_kx5g

[coastertrav]

So, this is either spam, or you accidentally gave us a link to the wrong video. (regardless, I watched the whole video and quite enjoyed it).

This also goes to show that the approval process is worthless.

[RenM]

i guess not, because there are no vtg turbochargers available in the size needed for fsae.

[TorqueWrench]

There is a variable nozzle turbocharger in our size range available. Not quite the same, but same general concept. Acts as a small turbo at low RPM and a larger turbo at high RPM.

[ibanezplayer]

I am unaware of anyone using the Garrett GT15V, however it is offered to FSAE teams under their sponsorship program.

"The GT15V turbocharger has variable nozzle turbine vanes. The vanes are controlled by a pneumatic actuator and can be used with a maximum turbine inlet temperature of 825°C. The design and calibration of the control scheme is up to the Formula SAE team."

You can find lots of information about what Garrett / Honeywell do and require for sponsorships (free turbo each year) by simply googling "garrett fsae" and looking at the first link. The 4th link down leads back to this forum which has links to useful turbine maps, drawings, etc.

Hope this helps.

[TorqueWrench]

Yeah, that would be the turbo I was talking about. The GT15V is pretty nice, our Turbo-Diesel Clean Snowmobile team is running on this year. It may be a bit big for our application though (didn't crunch any numbers....yet). Garrett does say the GT15V was designed to be run on diesels and says that on gasoline you would have to carefully monitor exhaust temperatures at the turbo to avoid damaging it.

I know that it is set up from the factory to be vacuum actuated, but they swapped it over to pressure to avoid having to run a full vacuum system on the car. I think Garrett even helped them out sourcing the new actuators.

[JamesWolak]

Opticnerv,

The only team that i know to use a VVT setup is University of Wollongong. They used the GT15V and from what i understand they produce a powercurve that would embarrass most FSAE teams.

The real question is should you run a VVT or even a turbo period? On a 600cc the answer is simple, no.

[Mikey Antonakakis]

James, where can I find more info about the Wollongong setup?

[opticnerv]

I'm not a spam bot, and I didn't post that video by mistake. I just thought it was a pretty neat video.

From what I read about FSAE, you build a car that is judged in different areas by industry professionals. Ford just introduced a new concept to the market, it's called... never mind here is their own words.

"Taurus SHO returns as the sporty version of Ford's new flagship sedan with a 3.5-liter EcoBoost(TM) V-6, an estimated 365 horsepower and uncompromised V-6 fuel economy"

They are using a twin turbo setup. VGT turbos in my opinion are better than twin turbos, but that's just a personal opinion.

I'm sure if any team presented a car that performs extremely well, and is economical the judges would be impressed.

Do the rules allow switching ignition maps ?

[ibanezplayer]

Originally posted by opticnerv:
Do the rules allow switching ignition maps ?

Yes. The rules outline a set list of things you can and can not change after a car has gone through tech-inspection at competition.

As crappy as this may seem, you should take a read through the rules. When I first became interested in FSAE I always had questions that the senior members would always answer with "The rules ...." "yes but the rules...." etc.

It is something I advise all new members to do. There are some sections you can skip over, but for now take a look at the rules of actually building the car. You might see some trends between the rules and the cars...

[andrewd]

Originally posted by JamesWolak:
Opticnerv,

The only team that i know to use a VVT setup is University of Wollongong. They used the GT15V and from what i understand they produce a powercurve that would embarrass most FSAE teams.

The real question is should you run a VVT or even a turbo period? On a 600cc the answer is simple, no.

I can vouge for the Wollongong power curve.

100Nm from 6000 to redline.
Peak power is just above 90hp at output shaft from 8000 to redline.

[Mikey Antonakakis]

Originally posted by andrewd:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JamesWolak:
Opticnerv,

The only team that i know to use a VVT setup is University of Wollongong. They used the GT15V and from what i understand they produce a powercurve that would embarrass most FSAE teams.

The real question is should you run a VVT or even a turbo period? On a 600cc the answer is simple, no.

I can vouge for the Wollongong power curve.

100Nm from 6000 to redline.
Peak power is just above 90hp at output shaft from 8000 to redline. </div></BLOCKQUOTE>
100Nm??? If it makes that from 6000rpm to redline, and assuming from the second sentence that it can rev over 8k, that means it's making 111hp at 8k? Really? :/

[RenM]

it still has to have an air restrictor so the answer will be no
I guess the power will be the same from 8000 to their redline with decreasing torque.

[Hector]

Originally posted by Mikey Antonakakis:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by andrewd:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JamesWolak:
Opticnerv,

The only team that i know to use a VVT setup is University of Wollongong. They used the GT15V and from what i understand they produce a powercurve that would embarrass most FSAE teams.

The real question is should you run a VVT or even a turbo period? On a 600cc the answer is simple, no.

I can vouge for the Wollongong power curve.

100Nm from 6000 to redline.
Peak power is just above 90hp at output shaft from 8000 to redline. </div></BLOCKQUOTE>
100Nm??? If it makes that from 6000rpm to redline, and assuming from the second sentence that it can rev over 8k, that means it's making 111hp at 8k? Really? :/ </div></BLOCKQUOTE>

Yeah, It's impossible to have 100 Nm of torque AND 90 HP at the same RPM. You can assume whatever you want, but I'm guessing either you misread whatever data you saw, or they have an optimistic dyno.

We had our car, same engine, same tune, measured on three dynos in one season. All three measurements were taken at the wheels. Results: 101, 72, 63. Take your pick. I'm apt to believe that the 72 is probably closest due to theoretical vs. actual accel times.

Anyways, just finished finals and bored so here's a fun little graph I made of Wollongong's theoretical power curve based on "100 Nm from 6k to redline). Hope redline isn't at 15k, because they're making over 150 KW (200 HP)!

http://farm3.static.flickr.com/2775/4175359940_971dde99d3.jpg

[Mikey Antonakakis]

Originally posted by RenM:
it still has to have an air restrictor so the answer will be no
I guess the power will be the same from 8000 to their redline with decreasing torque.
that's a much better answer

[Fred G]

Wollongong ran one gear last year...

[andrewd]

Originally posted by Mikey Antonakakis:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by andrewd:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JamesWolak:
Opticnerv,

The only team that i know to use a VVT setup is University of Wollongong. They used the GT15V and from what i understand they produce a powercurve that would embarrass most FSAE teams.

The real question is should you run a VVT or even a turbo period? On a 600cc the answer is simple, no.

I can vouge for the Wollongong power curve.

100Nm from 6000 to redline.
Peak power is just above 90hp at output shaft from 8000 to redline. </div></BLOCKQUOTE>
100Nm??? If it makes that from 6000rpm to redline, and assuming from the second sentence that it can rev over 8k, that means it's making 111hp at 8k? Really? :/ </div></BLOCKQUOTE>

sorry, yes RenM is right, torque does taper off. but only about 10Nm

response is interesting too, seen some interesting numbers with turbo speed and acceleration rates

[JamesWolak]

Hector,
I have ran on multiple dynos and have had different results also. With turbo setups dyno coef will make a difference and a lot of chassis dynos "add" 10%-15% to your results to make up for driveline loses (I know a team that made better power curves on the chassis dyno then on a engine dyno because there driveline loses were less than the assumed 10-15%). But my results did not spread as widely as yours and I would guess something else was going on in addition.

Mikey,
I think you will find that all of the larger displacement turbo setups for FSAE hit their peak torque and quicly taper off after that. Where that power peaks starts to fall will matter on their setup. Making it very possible to create the numbers AndrewD provided.


Opticnerv,

I think most Judges will be more impressed with an engine setup that is appropriate for FSAE and the knowledge to support it. Producing ridiculous horse power numbers with trick turbo setups is very temping but not applicable. If you troll though these boards enough (like I have) you will find that multiple teams have won acceleration with lower horse power results. Some basic vehicle dynamics info and tire data will help you understand why. You also have to think about how the points system gives fuel economy more points than acceleration. We shouldn’t be bragging about horse power numbers, we should be bragging about our BSFC numbers. The car also has to be drivable, think about skid pad. It requires very little longitudinal acceleration, more linear throttle response, and a lower engine speed. If you think about all this with you setup Judges will be impressed, yes they will still want to hear about a cool widget here and there but I wouldn’t focus your efforts on that.

[Hector]

Originally posted by JamesWolak:
Hector,
I have ran on multiple dynos and have had different results also. With turbo setups dyno coef will make a difference and a lot of chassis dynos "add" 10%-15% to your results to make up for driveline loses (I know a team that made better power curves on the chassis dyno then on a engine dyno because there driveline loses were less than the assumed 10-15%). But my results did not spread as widely as yours and I would guess something else was going on in addition.

Nah, we are far from a "new team" and our powertrain guys definitely know what they're doing. The 101 hp number is easy enough to explain: we did that one at a tuner shop, where their job is to make money by making horsepower for rich kids in their imports. My guess is that their dyno was "optimistically" calibrated. It was precise, but not accurate.

The other two came from more reliable, less biased sources. I'd go with them.

[Mikey Antonakakis]

Originally posted by JamesWolak:
Mikey,
I think you will find that all of the larger displacement turbo setups for FSAE hit their peak torque and quicly taper off after that. Where that power peaks starts to fall will matter on their setup. Making it very possible to create the numbers AndrewD provided.
Yeah that was my understanding, you can only drop so much pressure over a restrictor, right? Unless there are some negative absolute pressures I don't know about. Even so, 100Nm is impressive.

[kapps]

Originally posted by Mikey Antonakakis:
Yeah that was my understanding, you can only drop so much pressure over a restrictor, right? Unless there are some negative absolute pressures I don't know about.

Once you hit sonic velocity through the restrictor due to the difference in MAP and atmosphere, you are choked. Look in your fluids 2 book for the fairly simple formula for calculating this pressure. You could have a vacuum in the manifold and it will still flow the same mass of air. This is why turbo setups produce such interesting power curves.

[Mikey Antonakakis]

Originally posted by kapps:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mikey Antonakakis:
Yeah that was my understanding, you can only drop so much pressure over a restrictor, right? Unless there are some negative absolute pressures I don't know about.

Once you hit sonic velocity through the restrictor due to the difference in MAP and atmosphere, you are choked. Look in your fluids 2 book for the fairly simple formula for calculating this pressure. You could have a vacuum in the manifold and it will still flow the same mass of air. This is why turbo setups produce such interesting power curves. </div></BLOCKQUOTE>
'twas a joke, but nice explanation

[kapps]

Yeah, I figured that. I was just feeling generous for people looking into restrictor design and want hand-outs.

[Pete M]

Ignore what andrewd said, i think he's mis-remembering (top bloke though). I was the engine leader in 2007, and i still mostly remember the details.

Yes, we do make 100 N.m, but only on maximum boost (18 psi in my day), which is pretty hard to achieve in any event but acceleration. It is helpful when the driver exits a corner in the wrong gear though. We definitely don't make 100 N.m all the way to redline, that would be impossible with the restrictor. On the dyno, we choke just under 7000 RPM and make about 100 hp there. That then tapers down to about 80 hp by redline, but not as a straight line.

To answer the original question, yes we run a GT15V and have done so since we started with turbos in 2004. To my knowledge, no one else has had much success with one (i'd be happy to hear i'm wrong though). I think a lot of people are just scared off them by the garrett warning though. Ignore what they say about temperatures, they're just being overly cautious because it *is* a diesel turbo. We've never failed one due to heat and trust me we've tried. If you manage to melt one, you're either doing something very, very wrong, or attempting to run even harsher anti-lag than we did in our first couple of years... We've had these turbos all sorts of glowing, they love it. The real problem with the GT15V that garrett doesn't warn you about is that on a 600, the vanes are not adequate as the only control mechanism. We run a custom external wastegate in addition to the vanes.

As for whether turbos are appropriate for fsae or not, my answer is: I don't know. I think they're one of those borderline things like wings. On some tracks, it is a big advantage, on others it's useless extra weight. The enduro track at FSAE West 2006 was a good example of the former and the track at FSAE Aus 2006 was a good example of the latter. Turbos aren't necessary to win, nor are they a handicap if done properly. There seems to be a bit of a misconception that turbos are hard, but i don't think we really invest much more manpower in engine than some of the well-developed NA teams. The turbo is a bit of a cheat. You can have a crap intake, a crap exhaust and the turbo will just boost past it. The last 10%, sure, you have to have as much effort in those things as NA, but our package is remarkably insensitive to things like restrictor design etc. There's a whole suite of new problems like lubrication and scavenging, but none of them are insurmountable if you're willing to put some effort in.

One thing that is definitely true though: a powerful engine will never make a car with bad suspension quick. Consider that when deciding where to put your efforts.

Edit: Oh, and wollongong did run one gear last year (there were a lot of other problems with that car though). It was ditched this year in favour of a 3 speed because lack of throttle control at low rpm and heaps of engine braking at high rpm meant the car was not super drivable at the extremes of speed. Had plenty of power everywhere though.

[dazz]

You guys definately flew the turbo flag this year - being the only ones at comp running one. Was the most exciting car to watch on autocross for me too! All kinds of sideways action and an unbelievable save to miss a cone at the end of the main straight before the chicane hats, on the ragged edge for sure.

<STRIKE>Though Monash with their wings were truely flying, to put THAT big of a gap over Swinburne and UWA is absolutely amazing. (be sure to check out the autocross for FSAE-A 09 times when they become available - WOW</STRIKE> Just found out that there was a typo on the times, still won the event by 0.77secs though.

[TorqueWrench]

All this talk of torque curves and HP numbers makes me want to take the old Polaris FSAE engine off the shelf and slap the Aerocharger back on it. If I can find where that thing went (we have been telling inventory a vacuum pump was one for the last 3 years).

[The Neck]

....something about choked flow....

[andrewd]

Originally posted by Pete M:
Ignore what andrewd said, i think he's mis-remembering (top bloke though). I was the engine leader in 2007, and i still mostly remember the details.

Yes, we do make 100 N.m, but only on maximum boost (18 psi in my day), which is pretty hard to achieve in any event but acceleration. It is helpful when the driver exits a corner in the wrong gear though. We definitely don't make 100 N.m all the way to redline, that would be impossible with the restrictor. On the dyno, we choke just under 7000 RPM and make about 100 hp there. That then tapers down to about 80 hp by redline, but not as a straight line.

To answer the original question, yes we run a GT15V and have done so since we started with turbos in 2004. To my knowledge, no one else has had much success with one (i'd be happy to hear i'm wrong though). I think a lot of people are just scared off them by the garrett warning though. Ignore what they say about temperatures, they're just being overly cautious because it *is* a diesel turbo. We've never failed one due to heat and trust me we've tried. If you manage to melt one, you're either doing something very, very wrong, or attempting to run even harsher anti-lag than we did in our first couple of years... We've had these turbos all sorts of glowing, they love it. The real problem with the GT15V that garrett doesn't warn you about is that on a 600, the vanes are not adequate as the only control mechanism. We run a custom external wastegate in addition to the vanes.

As for whether turbos are appropriate for fsae or not, my answer is: I don't know. I think they're one of those borderline things like wings. On some tracks, it is a big advantage, on others it's useless extra weight. The enduro track at FSAE West 2006 was a good example of the former and the track at FSAE Aus 2006 was a good example of the latter. Turbos aren't necessary to win, nor are they a handicap if done properly. There seems to be a bit of a misconception that turbos are hard, but i don't think we really invest much more manpower in engine than some of the well-developed NA teams. The turbo is a bit of a cheat. You can have a crap intake, a crap exhaust and the turbo will just boost past it. The last 10%, sure, you have to have as much effort in those things as NA, but our package is remarkably insensitive to things like restrictor design etc. There's a whole suite of new problems like lubrication and scavenging, but none of them are insurmountable if you're willing to put some effort in.

One thing that is definitely true though: a powerful engine will never make a car with bad suspension quick. Consider that when deciding where to put your efforts.

Edit: Oh, and wollongong did run one gear last year (there were a lot of other problems with that car though). It was ditched this year in favour of a 3 speed because lack of throttle control at low rpm and heaps of engine braking at high rpm meant the car was not super drivable at the extremes of speed. Had plenty of power everywhere though.

Thanks Pete, my memory has somewhat faded after so many years.