Motor Selection

[Ryan Boysen]

Hey FSAE Nuts,

Our design team is having a world of difficulty deciding between motors. We know the typical response would be a CBR 600 motor but we are also looking into a one cylinder motor. Any thoughts between the two? What are you all using, or better yet, what would you prefer? Any other ideas? Let us know!

[rjwoods77]

Use a single or twin. The 600 4 cylinder has been beaten to death. Go small, go light. If you want to stand out and actually have a shot at doing well(since all the top teams have super developed 600 4 cylinders that you wont get close to replicating). People couldnt beat Ferrari until the rules changed a bit. Look what happened. Suzuki bergman engine with the electronically controlled cvt(even has programmable "gears") would be a real cool engine to use. The cylinders are near horizontal. Lean your driver back and stick the engine under your back. Use the stock computer to retain all functions. Simple idea. Very cool. Intresting possibilities. Would have to reduce capacity some but it shouldnt be to hard.

[rjwoods77]

http://www.globalsuzuki.com/motorcycle/moto/burgman650/pi_1.html

Has to be the coolest possible formula engine and drivetrain package next to what i am doing.

Picture this thing in a deakin style car. There is a cool idea.

[Ashley Denmead]

Originally posted by Rob Woods:
http://www.globalsuzuki.com/motorcycle/moto/burgman650/pi_1.html

Has to be the coolest possible formula engine and drivetrain package next to what i am doing.

Picture this thing in a deakin style car. There is a cool idea.

Well send one over rob and we'll make your cool idea a reality "DEAKIN STYLE"!!! hahaha

Ash

Deakin Uni FSAE team leader

[Alexandre D.]

One really important question is: Is that engine easily available?

You need at least 2 engines. If you break something, or open it, is it easy to find replacement part. If there is a 1 month delay for an head gasket, it can be a problem.

[DaveC]

I'm sure this will not go over well here, but...

Intuitively, I believe a carbureted Yamaha R6 running E85 would be the best choice, unless you want to use a turbo, then a FI system w/a]standalone. Why? I *believe* (I didnt double check) E85 has the highest heat of vaporization of any of our fuel choices, so it will cool off the A/F charge as it heads to the restrictor, plus the carburetor's venturi will accelerate the air into the restrictor. I'm also not sure if the design judges would be OK w/carbs, but if they make more power, maybe it can be justified. Not to mention cost, it would have cost me about $5000 to have a FI system on one of my personal motors, a custom made (just for my motor by AED) ported Holley 850 DP w/ billet baseplate was $750. This carb is AWESOME. If you dont mind tuning carbs, you can get great results from carburetion. I also get 8 mpg from a 550 hp, 650 lbft tq, 8.1L motor in a 5100 lb truck. I was expecting a lot less...

[jack]

look at cost. you could probably pick up 6 or 7 CBR F3's F2's or older YZF's for the price of 2 singles. spare parts wil be cheaper too.


If you want to stand out and actually have a shot at doing well(since all the top teams have super developed 600 4 cylinders that you wont get close to replicating)

this is terrible advice. how much power you have has nothing to do with how well you do at comp. clearly, rob has never been. 3 more horse power than cornel wont get you a win. to do well, all you need to do is finish the enduro. cars allmost never DNF because of an engine problem that was soley the "fault" of the engine. as far as the design event goes, you could be running any engine under the sun, and it wouldn't matter. what get you points there is knowing why you picked a paticular engine and knowing why you did this or that to it.

[Garlic]

Originally posted by DaveC:
it would have cost me about $5000 to have a FI system on one of my personal motors, a custom made (just for my motor by AED) ported Holley 850 DP w/ billet baseplate was $750. This carb is AWESOME.

Holy crap dude, you are in your own little world. This is great advice to someone with a SBC. A resticted 600cc engine should run a Holley, gimme a break. Go back to your internet forums.

[DaveC]

Holy crap dude, you are in your own little world. This is great advice to someone with a SBC. A resticted 600cc engine should run a Holley, gimme a break. Go back to your internet forums.


Cool, good to see open minds. Oh, I never said to run a Holley on a fsae car, I just gave a quick example somewhere they work well, and cost a fraction of what fi costs. I don't know offhand exactly what carb might suit a 600 cc bike motor best. An example of carbed 600s elsewhere are Microsprint cars, FI is alowed but carbs are still most popular. There is a restricted 600 class, much like FSAE Motors, carbs still seem to work best there, too. Also, many 600cc sportbikes are carbureted, a fact you obviously are unaware of.


Do you have any proof EFI will work that much better? I know you'll try to spout off all sorts of theoretical garbage, and I dont realy want to hear it. I'm sure I know how EFI systems work. How about real world testing on 600cc racing motors? As I said carburetors seem pretty popular on the sportbikes...

A couple of you guys on here so far seem pretty out of it, really. You attack any ideas contrary to what you believe is true, and have a really high opinion of yourselves. This is the second time you have been exceptionally rude to me, try acting like that in real life and see where it gets you. LOL, another 16 yr old here? and Garlic? Give ME a break, loser.

[Ehsan]

Also, many 600cc sportbikes are carbureted, a fact you obviously are unaware of.


Without being rude to you, you are completely wrong. All four major manufacturers run nothing but fuel injection on their top of the line 600cc and 1000cc sportbikes. Yes bikes like the Katana and YZF600 are carburated but that is to keep costs down since they are beginner bikes. FI has been used on the top of the line repli-racers for a few years now and I never see them switching back.

Listening to other ideas and having an open mind is definitely the way to go. But at this point in time, carbs are like drum brakes. They work and can be used, but whats the point when there is superior technology out there. Fuel injection is superior to carburetion due to the simple fact that and engine does not want the exact same Air to fuel ratio all the time. Fuel injection allows for this adjustability on the fly; carbs don't.

If carbs were that great, then every single modern car would not be fuel injected and serious race series (NASCAR being the exception) would be running them. Whaddya guys thing? a carburated 2007 Ferrari F1 car?

[raska]

Most 600cc sport bikes have been FI for a few years now.

A Holley DP and a vacuum advance distributor are things we joke about running with, but maybe we should consider it seriously. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

On the motor issue, that is a huge difference you are considering there. I would recommend the 600cc 4 cylinder until you really have a purpose to upgrade. Like it's been mentioned, a popular engine is often a good thing, and you'll probably find the 600 more forgiving in terms of drivability, and propelling the car. I would only consider a single cylinder once you were prepared to be at a stage where the engine and rest of the car would be well suited together (i.e. very light, other comonent designs that you are happy with, etc).

[James Waltman]

I'm sure that a carb can be made to work well enough.

Originally posted by DaveC:
...plus the carburetor's venturi will accelerate the air into the restrictor.
I don't think the setup you describe would work that way. I think you are describing: throttle, carb (venturi), restrictor. Most (all?) teams are already using venturi style restrictors. So now it becomes: throttle, venturi, venturi. If you have a venturi for a restrictor you probably won't gain anything by throwing another one upstream. I think the best way to do it would be to use a single barrel carb and make its venturi the restrictor diameter. I think some teams have done this but I can't remember who.


Originally posted by DaveC:
...$5000 to have a FI system...ported Holley 850 DP...was $750.
The ECU from Performance Electronics is only $798 for FSAE teams and only $998 retail. Great unit for the price (or for twice the price but don't tell Brian Lewis)

I'm too lazy to tune the carb on my truck (SBC, Quadrajet) and it runs like crap since I brought it to Denver.

[BeaverGuy]

About using a carb, placing it before the restrictor is probably a very bad idea. The restrictor has a a limited mass flow rate, by mixing fuel with the air prior to the restrictor you further reduce the amount of air that can be inducted into the motor. You would also endup condensing fuel out on the restrictor. At Mach numbers as low as 0.6 and the ambient air temp at 293K the local air temp would be 273K not accounting for any heat transfer with the fuel.

Using the fuel to cool charge temps after a turbo is probably the way to go. Cornell does it and they claim to have charge temps as low as 0C at the head.

A complete efi setup can be had for $1000 and unless you are using the stock carbs and intake that is the only cost difference.

For engine selection I would look at the overal design concept for the car. Depending on that concept I would select a motor that best fit and leave any exotic modifications for future years.

With that said I wouldn't treat all 600 4 cylinders as equals. I wouldn't really consider the F4(i), 600RR, or '06 R6 unless that was all I could get. They all have very high redlines with a short stroke and midlevel compression ratios 12 to 12.4:1. The ZX-6RR has the same bore and stroke but a compression ratio of 13.4 or 13.8:1 depending on the year. It also has a programable computer available from Kawasaki so it would be possible to use the stock fuel injection setup and sensors. It would require some modification of the throttle bodies but it could work. I would give a good look at the older Honda motors and a some of the newer motors from Yamaha along with the Kitana from Suzuki, and '00-'02 ZX6R/'05+ ZZR600 from Kawasaki. They have longer strokes whick give them a lower redline. However, their compression ratios aren't that great ranging from 11 to 12:1, with the exception of the Kawasaki which has a compression ratio of 12.8:1 and a coupe of the Yamahas with 12.4:1. The ZX6R/ZZR600 and ZX6RR however have a really long duration intake cam. There is a shorter duration cam available from WEB CAMS for the '99 ZX6R that should work with the '00-'02 and might work with the ZX6RR if a ZX6RR sprocket could be fitted to the ZX6R cam. The Kawasaki's also have a positive neutral finder that could make an air or electronic shift mechanism easier to implement as you can't shift into second from first unless the vehicle is moving.

[Garlic]

Enough with the theoretical garbage guys. LOL are you all 16 years old? LOL

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

It's interesting DaveC that anyone that thinks your ideas are way off base must be an internet know-it-all, when you are one of the best examples I've ever seen.

[Faterooski]

Before everyone bashes carbs, how many teams have failed because of FI-system related electrical problems? I agree that FI is the best way to go on these things, but its not the only way.

[DaveC]

Ehsan,
I know the current bikes are fi, I'm just saying carburetors have been used on 600cc sportbikes, a lot, and not too long ago, either. So, I just think to dismiss carbs in a rude, abusive way like Garlic, is a good sign of a closed-minded juvenile. (In your last post, youre repeating what I said, make that 13 yrs old, youre not up to 16 yr old maturity levels...)

James,
I havent though about it too much, but I'd think Venturi, Throttle, Restrictor would be the order, but a single barrel with the restrictor "built in" could work, I dont know and probably never will. We use FI on our car, so I probably wont be putting much effort into researching it. If we were starting from scratch, then I might look into how the carbed motor would perform, but $800 for a programmable ECU IS a pretty good deal. I have not seen a decent standalone for anywhere close to that price, and am suddenly interested in possibly having it for my rally car (which will be staying EFI) http://fsae.com/groupee_common/emoticons/icon_wink.gif...

Oh, I did find you guys a Microsprint site, interestingly enough, they get more power out of a carbed motor than a FI one, and they make restrictor class motors as well. http://www.ftzracing.com. May not be F1, but these cars are much closer to what were doing than an f1 car, and just like fsae, there are "high" and low budget teams too. I like the tri-y header they make, as well.

[jack]

we have enough problems trying to start our older cars with stock carbs/no restrictor. i am pretty sure getting carbs to work right would be 10 times the work of fi, and the same amount of cash. why am i even talking about this? should we keep an open mind and run drum brakes and radial tires?!

do a search, we have talked about how bad this idea is before...

[DaveC]

some people just suck at tuning carbs...

[rjwoods77]

DaveC,

You are a habitual line stepper. A habitual thread stealer. Your arguments are countered at each step. Before you open your mouth use the find option on this site. Things have been discussed plenty but in a reasonable way. "It works on a big block" has really nothing to do with anything. Just stick to the facts man. My buddy races a 600cc sprint car and is very suceesful at it. Everyone in 600cc sprint racing are switching over to FI over the carbs because of reliability and power. Carbs would be a great idea of they would work but they dont. Restrictor screws the pooch. I have an idea. If you are gunna post things like that (stuff where you dont actually research and think about before talking) then you should post on this site.

http://stuntaz.cjb.net/

Thats what you sound like to the people on the board. Now before you get all hot at me,some poeple thing I am nuts as well. But I at least have a decent argument behind things.

P.S. Retailiate like a snot nosed teenager and you will get owned by me. http://fsae.com/groupee_common/emoticons/icon_mad.gif

[rjwoods77]

Aaaaaannnnyyyywwwwwwaaayayyyy...

Back to resonable conversation. Ryan another neat motor to try out would be this if you can get it.

http://www.apriliausa.com/models03/offroad/eng/modello.phtml?id=77

[DaveC]

Everyone in 600cc sprint racing are switching over to FI over the carbs because of reliability and power.

Bunch of crap. Not true. In fact, FTZracing builds 600cc R6 motors for use with a restrictor (3/4") that makes 120 hp on alcohaul. And, guess what, its carbureted. Your "buddy" is doing quite well, while FTZ's customers are winning races.

I think the thread was about motor options, I gave an opinion, then get slammed for it. I knew it would happen, but I'm still shocked at the idiocy level by some people here.

Yeah, Rob lets hear about some more cool, expensive motor options you found on a google search, and have no clue about. Like your Suzuki motor that displaces too much, no big deal, just sleeve it or destroke it, right. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif Lets hear your decent argument on how great of an idea this is. Do you even know if these motors are for sale or anything about parts availability?

Some other people have disagreed with me here, but have done it with some level of courtesy. You and Garlic are just mean bastards.

[jack]

wow. looks like we finally got a good flame war going over here on fsae.com

i suppose it was only a matter of time http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

anyway, this is a thread about engine selection, can you guys go talk about carbs somewhere else please? http://fsae.com/groupee_common/emoticons/icon_razz.gif

[CMURacing - Prometheus]

OFF-TOPIC

don't most teams here have someone like davec running around wondering why there aren't turbos with 30+ psi of boost, big wings, and carbon brake discs on fsae cars? i know i was one of them once, wondering why teams don't run rotary engines. then i read the damn rule that states engines must be piston-driven.

on the engine front, i thought the new kawasaki's (ie zx6-rr mentioned somewhere) were 636cc?

[RagingGrandpa]

Man, what a trainwreck.


That Aprilia 450 V-twin is sexxy, looks like drysump as well, correct? When was it released? (Didn't say in the link)

[raska]

Originally posted by CMURacing - front, i thought the new kawasaki's (ie zx6-rr mentioned somewhere) were 636cc?

The new ZX6-R's (since '03 I think?) are a bike designed just for the street and have 636cc, but the "600cc race version" RR is 599cc.

[VFR750R]

DaveC, I'm sorry for the life lesson in here. Everyone in here is a technology chaser...including myself. Carbs can work as good as fuel injection, in certain cases, but are not as flexible. Fuel injection can compensate for changes in barometric pressure and temperature...carbs can't. Fuel injection also has the advantage of fine tuning every point in the operating range without effecting adjacent areas of the power band.

Specific to FSAE.
You're right, the heat of vaporization of E85 and even gasoline is significant and theoretically increases the density going through the restrictor. Real life is a different story and I'm going to force you to do the research as to why it won't work. You figure that one out, I know several cup teams that will give you a million dollars for your idea.

Minisprints are going to FI. Just because one race engine builder (FTZ) hasn't figured out how to make more power then with the carbs that they have been perfecting for years, doesn't mean they aren't working on a FI setup. (They are selling you something, so of course their carbs are better then competitors FI systems).

I'll add that many people think FI is leaps and bounds better but you're still mixing the same air and fuel together. Power increases are minor but significant. Most of FI's benefits have nothing to do with peak power.

I hope you don't feel like I'm bashing you, you just think you know more then you do. If multiple people tell you the same thing, either you're wrong or you've come up with the greatest idea in FSAE, that no one in the 24 years of the competition has thought of...congragulations, kick everyones butt at competition with it.

If it was easy, F1 engine budgets wouldn't be 250 million a year.

[Charlie]

Well said.

Carbs can be tuned well for peak power but not the whole range like EFI. Hence you'll see similar power numbers with a carb.

But for an event where drivability is a must, and fuel economy is a points-scoring event, EFI rules no contest. Drag racing, maybe a different story.

[DaveC]

If everyone here could be as nice disagreeing as VFR750R I think that would be a good thing.

I'm certainly not trying to say a carb is the only way to go, either. The topic started around what motor to look into for a starting team. While a well though out injected system may be a better performer all things considered, I think a carbed setup would give up very little, is much less expensive, and combined with E85, could do very well. I'm not anti-FI, but completely disregarding a carb as a viable option might not be the best idea either. I guess it depends on time and money, I've never had an abundance of either. The advantages touted by FI just dont seem to amount to much in real life. In high $$$ race vehicles and turbo cars this obviously isnt the case, but on a car thats *supposed* to be on a budget, where does thousands in FI equipment fit in, and how much of a competitive advantage do you think you have with it? Can you afford to keep extra sensors, and a spare ECU on hand? Keeping a spare carb on hand isnt a big deal.

There are huge, overpowering, completely crushing arguments that favor EFI, no doubt, but it just doesnt seem to be quite as beneficial in practice. How much faster is your car going to be? I bet not much, unless you got a turbo.

I'd be interested to know how many cars DNFed because of a sensor / ECU / electrical / fuel or other problem directly related to the FI system...

[rjwoods77]

Look up the production numbers on the bergman and then open your mouth. Expensive motor. You can pick up wrecked bergan for 3000. Engine, cvt, digital dash readout, electronics. Expensive how? I was looking into running this for our car but went with something different.

The bread and butter of sprint racing(what most people run) is almost always stock motor classes or limited modifications. My buddies sprint car is a stock new version suzuki with fuel injection and specail exhaust. Makes 110 hp and didnt touch a thinge except oiling systems that lest him run the car between 12-15k all throughout the track. Restricted alcohol engines, not in any kind of numbers in the national arena. Call up Hyper racing and ask who their bread and butter buisness is.

Garlic and I are not mean bastards. We just call people on their BS. Keep digging that hole.
Yo Yo Yo Yo. Icy hot sucka.
You got those mad skillz in Boulder.

http://stuntaz.cjb.net/

[VFR750R]

A carburetor is cheaper, but I feel it should only be used by a rookie team. And a rookie team may be helping their chances the following year by using FI from the start. You could always use stock fuel injection and get a $250 power commander. Not optimized for sure, but I don't think any worse then a carb, and not expensive.

Jetting a carb for a restricted engine could be as much a nightmare as any FI system, but I don't speak from experience. I have owned 5 motorcycles, all with carbs, and I know modern CV type carbs are masterpieces of function, but can be a PITA.

In the rare case someone on the team has substantial motorcycle carb experience, you almost have to try it just to see.

Another issue not mentioned in this thread yet. Fuel distribution issues in the manifold. Designing a manifold for equal fuel distribution with a single carb is amazingly difficult(this time speaking from experience), but again part of the last 10% of engine performance not needed to compete in FSAE.

[rjwoods77]

Ryan,

Couple more ideas. Seems weird but a super lightweight formula car with a kart engine thing might go over. Maybe twin kart engines that drive each wheel separate instead of a diff. Something along these lines perhaps. Just trying to encourage a little differnet thinking.

http://www.kartweb.com/TechArt/New_Product_2002/Biland/...0_4_stroke_motor.htm (http://www.kartweb.com/TechArt/New_Product_2002/Biland/biland_sa_250_4_stroke_motor.htm)

http://www.e-kmi.com/FYI/061305/061405_fyi_Eagle.htm

http://www.ritzsite.demon.nl/DAF/DAF_cars_p17.htm

[DaveC]

Rob,

I gotta wonder how you even know that stuntaz site exists. Maybe youre just into that kinda thing... Anyway, 120 hp, 3/4" restrictor, no turbo sounds pretty good. I know theres some very general conversion for what it would be on gasoline, it is alot lower, but still pretty good. I just found that site as an example of what can be done with carbs. Pretty impressive, both in terms of numbers and results, I think.

The Bergman is $3K, our f4i motor was $500.


Another issue not mentioned in this thread yet. Fuel distribution issues in the manifold. Designing a manifold for equal fuel distribution with a single carb is amazingly difficult(this time speaking from experience), but again part of the last 10% of engine performance not needed to compete in FSAE.


This is an unfortunate fact. Intake design for TBI or carbs must take into account fuel distribution and keeping the fuel in suspension, at the expense of optimal airflow and resonance tuning.


Maybe twin kart engines that drive each wheel separate instead of a diff.

What am I even supposed to say here? I get bashed for suggesting a carb for a beginning team, you suggest this. I dont need to say ANYTHING here to make you look foolish, your doing just fine, Rob.

[VFR750R]

Where and how many .75" restrictors. That's almost exactly 19mm....so 120HP, i gotta call BS. Not against you DaveC, but FTZ. They must be claiming at the crank before the transmission, but that would still put it above 100hp at the countershaft.

[DaveC]

Yes, that is at the crank... I guess there could be more than 1 restrictor, probably so now that you mention it...

[Ryan Boysen]

Hey Everyone,

Thanks a lot for all of your info and ideas. I understand some ideas were looked at differently by everyone, but we considered all available options, including Carb vs. FI http://fsae.com/groupee_common/emoticons/icon_wink.gif The other options were considered. From the looks of it our team has settled down with the idea of the Yamaha FZR6. The CBR 600RR is our second choice and our back-up.

One thing you all were talking about were the low prices of your motors. i.e. $500 for an F4i. Where do you guys look for these motors? and How would our team go about finding one. Ours is planned to be bought with a salvaged title, but maybe you all have sources that we are over looking? Thanks!

[DaveC]

$500 is a low figure, I'm not sure how we got that good of a deal, I think the average price might be a good bit higher.


A carburetor is cheaper, but I feel it should only be used by a rookie team.

No... really...? some tiny, miniscule bit of agreement that going w/ a carb might be OK for a starting team that has LOTS of other stuff to figure out and $$$ that needs to be spent on many new things. As I said, its pretty hard (impossible) to argue carbs are "better" than EFI, I just wanted to get a feel for what the reactions here would be. This was pretty interesting, there are defenately some rational people here whos opinions I'd respect, and others... maybe not so much. I still DO believe a carb w/ E85 could be %92.53 as good as any EFI system, and probably be more reliable. I really am interested in the attrition rate due to failure of EFI / ECU or related parts. I know last year our team DNFed due to a faulty electrical component, it might have finished with a carb. Anyway, enough.. thanks for putting up with me here.

Oh, I called FTZ, they said ONE 3/4" restricor, but the car IS running on straight alcohol... I am a little skeptical, dont blame you for calling BS, they may own an optimistic dyno. http://fsae.com/groupee_common/emoticons/icon_confused.gif

[BeaverGuy]

I have a hard time believing that claim. I did a calculation about a week ago on theoretical max power with a 20mm restrictor, 0.787". At 75 g/s of air, which is a little generous, with complete combustion at stoich conditions, and 35% total efficiecny, volumetric, mechanical, and thermal combined, it comes out to 106HP. If you could have complete combustion at 12.5:1, lambda of 0.85, AFR it comes out to 126 HP. A 0.75" restrictor would only flow about 68 g/s of air in the same conditions and the lower AFR for alcohol doesn't quite make up for the lesser amount of air, only making 115 HP at lambda of 0.85 on methanol. http://fsae.com/groupee_common/emoticons/icon_confused.gif

But if it truly does put out that much power and the throttle is before the restrictor, I would consider it. As it would probably compare pretty well cost wise to the combined purchase of a motor and ECU.

[Denny Trimble]

Originally posted by DaveC:


Cool, good to see open minds. Oh, I never said to run a Holley on a fsae car, I just gave a quick example somewhere they work well, and cost a fraction of what fi costs. I don't know offhand exactly what carb might suit a 600 cc bike motor best. An example of carbed 600s elsewhere are Microsprint cars, FI is alowed but carbs are still most popular. There is a restricted 600 class, much like FSAE Motors, carbs still seem to work best there, too. Also, many 600cc sportbikes are carbureted, a fact you obviously are unaware of.


Do you have any proof EFI will work that much better? I know you'll try to spout off all sorts of theoretical garbage, and I dont realy want to hear it. I'm sure I know how EFI systems work. How about real world testing on 600cc racing motors? As I said carburetors seem pretty popular on the sportbikes...

A couple of you guys on here so far seem pretty out of it, really. You attack any ideas contrary to what you believe is true, and have a really high opinion of yourselves. This is the second time you have been exceptionally rude to me, try acting like that in real life and see where it gets you. LOL, another 16 yr old here? and Garlic? Give ME a break, loser.

http://img.photobucket.com/albums/v471/cdmandus/awgeez3.jpg

[Schumi_Jr]

Hey Charlie,

I thought carbs were better 'cause they dump that shit in there, whereas FI squirts that shit! http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Mechanicaldan]

Hey Ryan-

Just keep checking E-bay. Different brands and different engines come up at different times. One week there might not be any listings, and a few days later there might be 3-4. Try searching for "motor", "engine", and "car kit", along with the manufacturer name (ie. Honda) and make (ie CBR) $500 is cheap. Average is probably $800 + $150 for shipping.

[VFR750R]

DaveC, dont' get sarcastic with me, and don't quote me for fuel to the fire.

This being my last post against carbs (I promise), my quote is out of context. If you have no experience with modern motorcycle carbs, i feel it's worth the money to stay away.

But by all means, prove me wrong and post your dyno curves here.

[Matt Gignac]

One thing nobody mentionned was how carbs would react to high g forces. That's something that you'd definitely need to think about. Most of these setups were designed for nowhere near the levels of acceleration a typical FSAE car will see.

And Rob, about your idea of twin kart engines that kind of replace the diff, we're trying something similar this year for a capstone project. McGill just got a huge grant to investigate alternative energy systems in cars and specifically efficient electric drive systems, and some of these drivetrains will be implemented in old FSAE and baja cars.
We're going to have two DC motors hooked up to a common controller in parallel, and look at ways to control the torque distribution electronically. Maybe CVTs too.

Matt Gignac
McGill Racing Team

[rjwoods77]

Originally posted by Matt Gignac:
One thing nobody mentionned was how carbs would react to high g forces. That's something that you'd definitely need to think about. Most of these setups were designed for nowhere near the levels of acceleration a typical FSAE car will see.

And Rob, about your idea of twin kart engines that kind of replace the diff, we're trying something similar this year for a capstone project. McGill just got a huge grant to investigate alternative energy systems in cars and specifically efficient electric drive systems, and some of these drivetrains will be implemented in old FSAE and baja cars.
We're going to have two DC motors hooked up to a common controller in parallel, and look at ways to control the torque distribution electronically. Maybe CVTs too.

Matt Gignac
McGill Racing Team


Could be cool and could be a waste to go with dual cvts. Depends how much gear reduction you need from the motors. Average CVT's has a 3:1 low gear and a 1:1 high gear just for your knowledge. If you could do it without any furthur reduction then you could have a nice setup on your hands. I know of the perfect cvts(the one I am using) for the setup if you are planning on feeding less than around 50hp on each motor. Very small and very lightweight cvts.

[Faterooski]

Gotta put in my two cents here. Just wondering what the power loss would be having two CVT's as opposed to just one or a plain 'ole 6 speed sequential. I'm not shooting the idea down, I really don't know how efficient a CVT is. Also, with the dual motor thing, wouldn't it be a nightmare trying to run two motors off of one restrictor?

[Storbeck]

"¾" restrictors are placed between the carbs and head..."

Sounds like they are talking about four seperate restrictors, which makes the power numbers less impressive.

[Greg H]

Ryan,
Try talking to insurance companies. We got a 2005 CBR600RR donated after someone took it directly into a curb after only 500 miles. As a bonus, there are a lot of other parts that we can eBay through campus surplus to give us more money to spend for the team.

[TG]

Originally posted by Rob Woods:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Matt Gignac:
One thing nobody mentionned was how carbs would react to high g forces. That's something that you'd definitely need to think about. Most of these setups were designed for nowhere near the levels of acceleration a typical FSAE car will see.

And Rob, about your idea of twin kart engines that kind of replace the diff, we're trying something similar this year for a capstone project. McGill just got a huge grant to investigate alternative energy systems in cars and specifically efficient electric drive systems, and some of these drivetrains will be implemented in old FSAE and baja cars.
We're going to have two DC motors hooked up to a common controller in parallel, and look at ways to control the torque distribution electronically. Maybe CVTs too.

Matt Gignac
McGill Racing Team


Could be cool and could be a waste to go with dual cvts. Depends how much gear reduction you need from the motors. Average CVT's has a 3:1 low gear and a 1:1 high gear just for your knowledge. If you could do it without any furthur reduction then you could have a nice setup on your hands. I know of the perfect cvts(the one I am using) for the setup if you are planning on feeding less than around 50hp on each motor. Very small and very lightweight cvts. </div></BLOCKQUOTE>

I don't know exactly what they are called, but are you using the 3 ball type cvt's where the contact on the ball determines the ratio? I believe yamaha or one of the motorcycle companies was trying to work it on one of their dirt bikes.

[rjwoods77]

No. Jr Dragster style clutch. The things are so freaking developed these days due to the demand in that series.

[Scannee]

i have a hard time believing that claim. I did a calculation about a week ago on theoretical max power with a 20mm restrictor, 0.787". At 75 g/s of air, which is a little generous, with complete combustion at stoich conditions, and 35% total efficiecny, volumetric, mechanical, and thermal combined, it comes out to 106HP. If you could have complete combustion at 12.5:1, lambda of 0.85, AFR it comes out to 126 HP. A 0.75" restrictor would only flow about 68 g/s of air in the same conditions and the lower AFR for alcohol doesn't quite make up for the lesser amount of air, only making 115 HP at lambda of 0.85 on methanol.

Hi Guys, im a suspension man on this years car however im doing my dissertation on a class 3 design. I have basic manifold designs and a lecture with his Phd in CFD is helping me however i havent approached the effects of the restrictor on a log style inlet manifold. Does someone have the equation that has been calculated abouve or a reference were to find it?

Thanks

Steve

[BryanH]

.86 lambda means exactly that, insufficient oxygen for complete combustion.....Hang on, doesn't ethanol bring along it's own oxy molecules?
And the lower AFR means it has quite a lot of them, then there's the latent heat bizzo
Cheers Bryan H
"In God we trust, all others bring data"

[John Grego]

E85 does bring along its own oxygen molecules, but SAE makes you run a 19mm restrictor instead of a 20mm with gasoline. That cancels out the advantage.

[Bryan Hagenauer]

Ryan-

Getting those cheap motors isn't easy. All the advice is spot on- watch ebay, call insurance companies and especially check the motorcycle wrecking yards. They're the ones buying the wrecked bikes from insurance auctions and selling on ebay. Make sure those yards know who you are and what you are looking for. Of course, my team has an advantage being in sunny California, where a down payment on a new YZRXRR-600 seems to be the normal way to spend your first paycheck after your 18th birthday. Less than a mile down the road from the dealership, the insurance company just bought the bike.

At first, you are going to have to pay a premium for engines that you know are in good shape. A year or two down the line, you're going to have a pile of spare parts for that particular engine model. When that time comes around, you stop caring just how perfect a motor is because you can fix so many problems with it. I personally bought a gsxr for $250 that merely had a bad second gear. We've also found an ebay motor that was sitting in a guys backyard against the wall for like 3 years for dirt cheap. Take advantage of the fact that you are one of the few customers that is willing to swap out a tranny or some other major repair. Being able to buy these motors is a distinct advantage to using a generic motorcycle, rather than the Aprillia or special race model like the 599cc ZX-6RR, even if you make 3 less horsepower and weigh 3 more pounds.

However, the same exact reasoning can bite you in the ass when you realize that the motor you are using has SERIOUS drawbacks but are already so invested that you don't want to take the $$ hit to switch (@#&*&^king GSXR engine mounts and crappy oil system).

[Neal Stanley]

I would just like to add my 2 cents to this engine debate. One of the things I think you have should consider about an engine is the type of gearbox. If you take a look a the faster cars (the Amod) you will see cars that have a CVT. Why? Well that's not hard to figure out. Properly set up CVT will always be in the right gear at any location on the track, the car will pull hard any time you give it gas. Also the engine RPM is control buy the primary clutch, when you get on the gas the engine will rev to the governed power band and stay there. This makes the engine much easier to tune.

A car with a gearbox you need to be in the power band of the motor to pull hard and also you have you have to shift, cutting power to the rear wheels. The engine needs to be tuned thru it's RPM range, making it much harder to tune. All of this makes it harder to set up, and it still will not out run a properly set up CVT.

As far as carbs to fuel injection . Both have there advantages and disadvantages. But I will pick a card every time. Maybe I am just old school, and the carb is easier for me. But many of the racing cars with motor cycle engines pull of the fuel injection and install carburetors, take a look at the CSR and DSR cars. The biggest problem with carburetors is the fuel bowl. Let me put it this way about a cab, if you are pulling enough "Gs"� in a corner to upset the float level then you are not fast enough, yet.

Neal
SCCA Amod

[Neal Stanley]

Sorry about the typo's, hopefully you get my point of view. The last point I made about the float level really reads bad . I was in a hurry, The point I was trying to make is that in really high G turns ( say over 2 "Gs"�} the all of the fuel will be pulled to one side and allow air to the jets.

Neal
SCCA Amod

[rjwoods77]

Hey Neal,

Lets go A-Mod. Got any pics or a website of your car. I love to see the variety that that class has to offer.

Hey Everybody,

I know a bunch of guys who race vintage and other assorted Ohio Runoff classes. And we all have to be honest here about a couple things. Most of the guys involved (owners) are old school guys(40's and up) who pay large sums of money to people(pro car builders/ex-racers) to build their car. Their labor rates are f'ing obscene and it is just plain cheaper to not deal with those labor rates plus an extra 5 to 10 grand in injection costs because got forbid they show up in the paddock with anything but MoTec or PI research(or whatever the latest on Indy/CART cars). Also a majority of these builders are old and set in their ways so they dont want/need to learn new tricks. If carbs were so a great alternative the higher forms of autoracing would be using them. So I think/know the carb/efi debate has less to do what is better and more to do with customer confidence in their own abilities/knowledge.

I am not anti-carb but agree they have their place in certain forms of motorsports but that is based mostly of budget and confidence/knowledge. Everyone has to remember that old timers experience of EFI is from the 70's through early 90's which has got to be 20 years of god awful efi systems. After owning 3 fords from the 80's, I used to thing EFI was an unreliable piece of shit that just failed all the time(f'ing Ford EEC-V ignition modules, who the f'ing was the idiot who designed that). But fords are a bad example because they are the worst cars to work on but that besides the point. http://fsae.com/groupee_common/emoticons/icon_smile.gif If I could get a carb to work well in FSAE I sure as hell would because it would cut off about 5000 off the cost report and open up so much time for the team to do other things.

[Neal Stanley]

Rob, you make some go points. Did you do know that the average age of a builder in Amod is around 60. It is hard to teach an old dog new tricks. Only one car I know of has EFI. Also we do don't have to deal with that restrictor. The point I was making was about engine selection. You must also consider the trans. If you go with the CVT then the power band of the engine is much easier to tune to. On my car when I go full throttle the engine goes to 10400 and stays there all the way as the clutches shift in and out. Because the clutches work from RPM and torque it is always in the right gear. The engine does not have to go thru any RPM range as the gears are changed. Makes tuning with a carb very easy. I feel it makes the car much quicker, easier to drive, and very predictable. One other point is that when you come off of the gas there is no engine compression to slow you down. The whole system is much easier on the engine, the engine just lives with in the power band set up by the primary clutch. Not many Amod competitors carry a spare engine.
Neal
Pic of my car during construction.
http://www.lightningprollc.com/?page=gallery&gallery=im...r=AutoCross%20Racer/ (http://www.lightningprollc.com/?page=gallery&gallery=images&folder=AutoCross%20Racer/)

[Neal Stanley]

Let me add something to the EFI/Carburator debate. That has not shown up in any of this thead. The carburator throttle bodies use a venturi to draw fuel. EFI throttle bodies have no such restriction so a smaller EFI can flow more air than it's equivolent sized carb.
Neal

[rjwoods77]

Originally posted by Neal Stanley:
Rob, you make some go points. Did you do know that the average age of a builder in Amod is around 60. It is hard to teach an old dog new tricks. Only one car I know of has EFI. Also we do don't have to deal with that restrictor. The point I was making was about engine selection. You must also consider the trans. If you go with the CVT then the power band of the engine is much easier to tune to. On my car when I go full throttle the engine goes to 10400 and stays there all the way as the clutches shift in and out. Because the clutches work from RPM and torque it is always in the right gear. The engine does not have to go thru any RPM range as the gears are changed. Makes tuning with a carb very easy. I feel it makes the car much quicker, easier to drive, and very predictable. One other point is that when you come off of the gas there is no engine compression to slow you down. The whole system is much easier on the engine, the engine just lives with in the power band set up by the primary clutch. Not many Amod competitors carry a spare engine.
Neal
Pic of my car during construction.
http://www.lightningprollc.com/?page=gallery&gallery=im...r=AutoCross%20Racer/ (http://www.lightningprollc.com/?page=gallery&gallery=images&folder=AutoCross%20Racer/)


I hear you on the cvt. Thats why i am using one myself. Carb is the easy route out but iif it came with the engine and isnt really hurting anything/low budget than sure. I would image in your case the engine is injected from the factory. Carb and turbo boo. The car looks real nice though. Way better than most garage contraptions I have seen over the years. Not feeling the near parallel a-arms at all corner but to each his own. Is that a yami cvt too?

[Neal Stanley]

Rob, the motor comes from a 2003 RX1 and it comes with carbs. When each of us build a car, any car, it is a art of compromises, gain here lose there. There should be underlining design goal for each thing we do. In my case I went with a draw thru turbo system using a carb. As you know in autocross you may only get into the throttle for a few seconds at a time. So a carb and turbo boo , no it's a carb and turbo hooray! Turbo as close the engine intake as possible, carb with acceleration pump, and water/methanol injection to cool the charge. Easy to set up and tune. No turbo lag and lots of instant power.

Neal

[rjwoods77]

How much under the 900lbs are you before ballast? What kind of hp you getting? What width belt and hows it hold the power(i.e how long before center to center goes to hell)?

[Gatorman]

So.... carbs can be beneficial in many applications, but are not the most ideal choice for this competition.

Back to the orignal debate of engine choice... like anything else, I think it comes back to cost/benefits for each application. It seems many teams are trying to re-invent the wheel here and often bite off more than they can chew. If you have the resources (i.e. 30+ team members, $40k+ per year, etc) I say go for some really trick systems like the maxim motors, flexure susp, carbon tubs, etc. Otherwise stick to the basics and focus on finishing.

If you're like most of the teams I have seen, with only a handful of guys who do most of the work and have limited funds, you have to be realistic in what you choose to do. I think a thumper engine can be just as competetive as a four cylinder can, and vice versa, it just depends on the whole package. BUT I think if you looked closer at some of the top teams, you may find that more run stock engines than you may think. MSU has blown their "built" engines right before competition several years in a row and have still finished very well.

It all comes down to the development stage of the year. Whatever you do decide to use, develope the piss out of it and make the entire package work as well as it can. I think if you tune what you run well enough, and all the systems are designed to work together, you will be competetive. You don't have to make a ton of power, just be able to use everything you make via tuning, drivetrain, suspension settings, tc, etc.

Then put a lightening fast driver in your car like Ducati and you're all set....