turbocharging an air-cooled car for Lemons?

i've got a bunch of guys who are half-heartedly interested in doing a Lemons corvair. even at min safe weight, it's gonna be too heavy for the NA 2.7L, so i'm thinking boost. and since heat is the enemy of both turbochargers and air-cooled engines, an intercooler is a must. there are two ways this can be accomplished: modify a set of carbs to operate in a blow-through arrangement, or convert to megasquirt EFI. fabrication is not an issue, as i've got a very talented guy on board for whatever we decide to build.

there are intercooling options as well, but an FMIC is not one of them since the car is rear-engined. now, an air to liquid would make sense given the packaging constraints, and in short events the water reservoir could be filled with ice to get the intake air way below ambient. but in an endurance event, ice wouldn't last and not only would power fall off but the engine would be more at risk due to the higher temps as well.

so i'm thinking about building a big housing for an air to air, and air-conditioning that housing so the intercooler can be kept below ambient for long runs. think of it as putting the intercooler inside a refrigerator. in fact, maybe i'll just run a big-ass alternator and use my old dorm fridge as my IC!

i know all about the laws of thermodynamics, and i know that there are no 100% efficient devices, so i know that the alternator or AC compressor is going to cost me some HP and that'll increase the heat load into the oil and into the engine cooling air. i can overcome those with proper design of the engine cooling systems. i'm not trying to make more power on the same amount of fuel, i'm trying to stuff more fuel into the engine.

discuss.

ACing the intercooler is going to be a net loss in power, in my opinion. It's them pesky thermodynamic laws again. A liquid to air intercooler would be the way to go. That's what Esprit SE's use. Add a radiator up front and a couple of lines with a small electric water pump and a Garrett liquid to air IC and you'll have it. In my opinion. Or, go air to air with the thing sticking up out the back deck.

A/C is actually a pretty wonderful method. Get temps below ambient easily. With a modern vaciable displacement compressor, the power loss should be minimal.

Depends on the track you will be running alot of them dont give you a chance to use alot of power. It better to have a car that can run with no issues.

Cheapest easiest route would be low boost draw through and run E85. Alcohol provides a lot of cooling, especially with draw through. I know you can get E85 conversion kits for Holley carbs pretty cheap.

Why not get a stock turbo Corvair. Save a lot of work.

water injection will cool it.

I doubt the A/C will have enough thermal mass to cool down you incoming air... Using compressed C02 maybe spraying on the intercoller might work.

I would stick with water to air or air to air if you can. You need thermal mass and a good delta.

ignorant wrote: water injection will cool it. I doubt the A/C will have enough thermal mass to cool down you incoming air... Using compressed C02 maybe spraying on the intercoller might work. I would stick with water to air or air to air if you can. You need thermal mass and a good delta.

The part in bold should be super simple to accomplish and cheap as hell too.

Having run the lemons race in a car that only lasted 4 hrs I would HIGHLY suggest you stick with a reliable solution as the winners of the race were NOT the high HP ones but the reliable ones who were ultra efficient with their pitstops...

iceracer wrote: Why not get a stock turbo Corvair.Be too slow to rear-end anybody.

fixed.

stock turbo corvairs suck. small side-draft with tiny accelerator pump, mounted about four feet from the intake valves. i've done my time in that cell. no desire to go back, thanks.

water injection is a definite. Ricardo was right.

i understand that to finish first, i must first finish. i won't really be breaking any ground with this car, other than the lower-than-ambient IC possibility.

thanks for the ideas. keep 'em coming!

if you do the front mount heat exchanger remember that radiator size is not as important as the seal around it. also, a diverging path for that air will help too,think small nozzle high pressure front and low pressure big outlet rear, cause its pressure that moves air, not speed, airspeed through your heat exchanger is nothing compared to airpressure on it. i would run a rear mount air to air and fab up some awesome ducting fwiw..
oops, edit, a water sprayer would be the tops, but you cant have water spill on the track. if you can engineer a way around dripping water on the track and maintaining sufficient airflow through the heat exchanger then that would be the optimal solution. water sprayers are only a windshield squirter away though, so they are appealing....

What are you thinking your power to weight ratio will be? I think you're over-analyzing this...our Subie was a real dog with the 1.8 (110 flywheel hp) and ~2550 pound curb weight (in race trim) but with good handling it really wasn't much of an issue, with a good driver behind the wheel we rarely got passed. Sure, we might have been a couple of seconds off the fastest lap times at Thunderhill, but faster/fewer pit stops, better drivers, etc. would have made a MUCH bigger difference. One simple problem could easily eat up any gains (and then some) a few horsepower would give you.

Bryce

Nashco wrote: What are you thinking your power to weight ratio will be? I think you're over-analyzing this...our Subie was a real dog with the 1.8 (110 flywheel hp) and ~2550 pound curb weight (in race trim) but with good handling it really wasn't much of an issue, with a good driver behind the wheel we rarely got passed.

without boost it'll be about the same as your sube. making it turn and brake will not be a problem. i just really like cars that can point-and-shoot.

I would look for some wind tunnel pictures and see if a top mount intercooler with a scoop would be a viable option. You're making this too complex for LeMons. A TMIC and/or water injection would be as radical as I would recommend going. The water to air intercoolers on a budget will be too complex/fragile to be reliable for 24 hours of demolition derby.

As proved by the Audi R10 TDI vs Pugeout 908 HDi battles, the slightly slower, but more reliable Audi's have cleaned up the 12/24 hour endurance races. A glitch free, easy to drive car will work its way to the front.

As has been said, adding power to a car is not a good lemons idea.Ultra reliable is the only way to go. That's coming from someone who's blown up two stock motored with a reputation as bulletproof cars (E23 and a Mk2 supra). Make sure you have lots of cooling. Way more than you think you need.

If you go want to go with the turbo, mount the intercooler where the rear window used to be. Since all the glass has to come out, there should be plenty of air flow.

You're going to have problem cooling the engine itself... there are only a few guyings running turbo Corvairs on the track and all of them have had issues with keeping the engine cool enough (even with huge front-mounted oil coolers, etc)... it's simply a matter of available head cooling surface versus the amount of power you're making...even at 8-10psi... Chevy themselves knew this was a problem even with dead stock Corvairs (one of the reasons for the nasty carb they used)... and they only approved it with the knowledge that drivers would run out of road before the temps reached dangerous levels... on a track, you don't have that advantage to give the temps a chance to reduce.

(I recently sold my 300hp turbo 140 to go for a more reliable Weber engine to play with on the track...)

Talk to Warren about his issues on the track... his experience might help you.

Good luck... I'd love to see a Corvair running this... Bill

I'm probably just mentioning stuff you already know, but cooling is all-important with Vairs. I co-drove stage rally Vairs for two teams back in the day, with a variety of engines, and by far the most common problem when a lot of heat is involved was valve seats falling out. That said, be sure you have several spare fan belts on board, and the tools to install them. Anyone who has driven Vairs much can change a belt really fast.

The most reliable engine we used in the rally cars (which got us two top ten finishes in SCCA national Pro Rally events a LONG time ago) was a nearly stock turbo with forged pistons, balanced engine, lightweight flywheel, staked valve seats, wrapped, nearly zero backpressure exhaust exiting through one of the backup light locations, running the Carter YH! In a light car (2200 lbs with full roll cage, twin rear shocks, and 1/4-inch aluminum skid plates under engine, gearbox and fuel tank, with full road lighting), 3:55 posi diff and velvetouch brake linings, it was a pretty quick car - but we only ran flat out for maybe 20 minutes on a stage, then had a few minutes to cool down before the next stage, so I'd think that the LeMons would be way tougher as far as heat generation would be concerned.

Brake lining availability might be tough - check Clark's and the Oregon Underground - but cheap might be difficult. Handling-wise, I always liked GM HD convertible springs, Bilsteins (although any stiff shock will work), quick-steer arms (or modify your own), and lots of castor and some negative camber on the front, with a little negative camber on the back. A well set up late Vair on good rubber will amaze some people, for sure.

wcelliott, Not intending to hi-jack this thread but what Weber engine did you order or did you mean a Weber carb engine ??? Feel free to PM me ..........

showa1 at cox dot net

canoe canoe

Canoe you say?

At CMP the drivers of at least two cars were using windshield washer spray nozzles to cool tranny coolers etc so I'm thinking that wouldn't be that big of a deal. IIRC alcohol evaporates more quickly than water so if you spray that instead of water you get better intercooling and less evidence, er, liquid on the track.

Jensenman wrote: At CMP the drivers of at least two cars were using windshield washer spray nozzles to cool tranny coolers etc so I'm thinking that wouldn't be that big of a deal. IIRC alcohol evaporates more quickly than water so if you spray that instead of water you get better intercooling and less evidence, er, liquid on the track.

I never knew alcohol was better for cooling like that....... that could be awesome, alcohol/water injection and sprayers..... as for durability issues for injection, that only comes from tuning for it, just using it to drop temps and not using it for more ignition advance should be fine.

showa wrote: wcelliott, Not intending to hi-jack this thread but what Weber engine did you order or did you mean a Weber carb engine ??? Feel free to PM me .......... showa1 at cox dot net

I meant a Corvair 140 running IDA40 3bbl carbs... with the proper head mods, slant exhaust stack mods, and the right cam, the engine makes reasonable (and reliable) power while the Webers allow what would otherwise be a track-only engine to be streetable... not cheap, but then a turbo 140 built to survive isn't either...

But in the true grassroots spirit, the engine came installed in Patrick's previous Challenge car! And is being reunited with other parts I bought from him way back when...

Bill

Many years ago I ran across someone with a Corvair that had air scoops positioned at the upper middle of the rear fender arches (just behind the firewall break). He mentioned that although they were rather difficult to install (compound curve at that point) they made a huge difference to cooling.

You might consider an on-demand water drip (drool?) system into the fan (no need to spray, the fan should take care of that). If it gets hot, just open the spigot. You could run some tubing around the inlet (make sure it is well secured, there can be a lot of suction there) with a few spaced holes. I guess you could use a pump if you want to position the water tank lower, but simple is always better.

I tend to agree with the less power / more reliable trend here. If you do do a turbo, you might consider completely isolating it from the engine cooling air, it's certainly not a great setup to have a red hot turbo sitting in the inlet path of your cooling flow (which the stock is).

And if you want real turbo answers you should contact Ray or Warren, they are the real gurus on that subject.

ignorant wrote: canoe canoe

dude, the way i paddled your mama, she changed her name to canoe.