Road Racing a Modified Corvair

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xrotaryguy
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Road Racing a Modified Corvair

Post by xrotaryguy »

I see videos of people road racing V8 Corvairs now and again. I'm not sure what road race classes those cars might fit into.

What about a somewhat highly modified turbo corvair? Like something triported with port fuel injection and electronic fuel injection?

Autocross is good for cars like this. You might end up in a Mod class but there's no question about whether you can run. Not so sure about road racing.

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notched
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Re: Road Racing a Modified Corvair

Post by notched »

You won't see a turbocharged Corvair engine road racing because of the heat load on the engine. The cooling system on a Corvair is marginal with the turbo. The problem is that the turbo is good for brief pulls. But if you have owned a turbo Corvair you would know that the head and oil temperatures go up and do not come back down quickly........even with bigger oil coolers. The cooling system just can't pull the heat out of the heads.
Naturally aspirated Corvair engines do not have this issue and have been widely raced for decades.
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xrotaryguy
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Re: Road Racing a Modified Corvair

Post by xrotaryguy »

What about with intercooling and a big external oil cooler. Air cooled Porsche do it, though admittedly with a more sophisticated oiling system.

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notched
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Re: Road Racing a Modified Corvair

Post by notched »

xrotaryguy wrote:What about with intercooling and a big external oil cooler. Air cooled Porsche do it, though admittedly with a more sophisticated oiling system.

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Guys are still experimenting with Naturally aspirated Corvair engines trying to keep them cool and keep the belt on.
Its not completely the heat load of the turbo charger or even the outlet temperatures..........its the power increase which is taxing. Its darn near impossible to get the heat out of the Corvair heads.
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66vairguy
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Re: Road Racing a Modified Corvair

Post by 66vairguy »

Power equals heat, no matter the size of the engine.

Some Corvair books state the stock Corvair cooling system is not adequate for a WOT turbo for more than a little while.GM engineer Benzinger is quoted as saying at a convention that GM knew the turbo cars would overheat at full throttle for sustained periods, but who would drive a turbo WOT for more than a minute as the car would be at top speed by then, an illegal activity on public roads.

For racing I've heard of folks adding water/alcohol injections nozzles above the Corvair fan. Not sure how effective it is.
xrotaryguy
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Re: Road Racing a Modified Corvair

Post by xrotaryguy »

Power = heat makes perfect sense. Something like 80% of the power that an IC engine makes is actually just wasted as heat. Put more power to the ground, make more heat. Fair enough.

Misting is an option but not one I've seen on an air cooled engine; I've seen misters and foggers in front of the radiators of water cooled cars. That's not comparing apples to apples though.

So if someone is making... let's say 220 hp with a NA motor on the track and not overheating, and hp is the reason a engine would overheat, it seems that a well-cooled turbo could make the same power on the track without overheating as well.

Sorry if it seems like I'm trying to convert an obvious "no" into a "yes" by blathering on and on. However, I do like the idea of turbocharging as opposed to building an NA motor to make 200+ hp for drivability.

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notched
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Re: Road Racing a Modified Corvair

Post by notched »

You could pose the question to Warren or Michael Leveque, Bob Coffin, Seth Emerson or any of the other guys who road race Corvairs and ask why it couldn't.
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xrotaryguy
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Re: Road Racing a Modified Corvair

Post by xrotaryguy »

I suppose so. :)

My initial question was actually how realistic it was to race an unusually prepped Corvair; if it was actually possible to class such a thing.

We got a little sidetracked. :)

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xrotaryguy
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Re: Road Racing a Modified Corvair

Post by xrotaryguy »

Turns out a number of people have had success with cylinder head misting.

http://www.shoptalkforums.com/viewtopic.php?t=10006
66vairguy
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Re: Road Racing a Modified Corvair

Post by 66vairguy »

xrotary - you asked why a NA 220HP engine won't overheat while a 180HP turbo does.

Well first the 220HP may overheat if WOT long enough, but more to the point, basically HP = RPM X TORQUE.

A NA 220HP engine peaks power at a much higher RPM than a Turbo (in this case). So more air is moving in and out of the engine which helps cool the heads and of course the cooling fan is turning faster (although there CFM and pressure increases drop off at higher RPM).

The 180HP Turbo engine has a higher torque rating at lower RPM, basically more power per RPM and this tends to cause the heads to absorb more heat. Also note the Corvair Turbo max HP is at a conservative RPM - with some high tension valve springs and some induction modifications the Corvair Turbo will make more power at higher RPM and generate more heat in the process.

As far as vapor cooling the heads - adding some alcohol to the water mixture (within reason) will enhance the cooling effect (evaporation lowers the air temperature which is enhanced by the alcohol). However only a good thermal dynamics engineer can determine if the system would be adequate. As others have mentioned - you have to get the heat OUT of the head via the fins so surface area comes into the equations.

Always fun to speculate.
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lostboy
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Re: Road Racing a Modified Corvair

Post by lostboy »

66vairguy wrote:xrotary - you asked why a NA 220HP engine won't overheat while a 180HP turbo does.

Well first the 220HP may overheat if WOT long enough, but more to the point, basically HP = RPM X TORQUE.

A NA 220HP engine peaks power at a much higher RPM than a Turbo (in this case). So more air is moving in and out of the engine which helps cool the heads and of course the cooling fan is turning faster (although there CFM and pressure increases drop off at higher RPM).

The 180HP Turbo engine has a higher torque rating at lower RPM, basically more power per RPM and this tends to cause the heads to absorb more heat. Also note the Corvair Turbo max HP is at a conservative RPM - with some high tension valve springs and some induction modifications the Corvair Turbo will make more power at higher RPM and generate more heat in the process.

As far as vapor cooling the heads - adding some alcohol to the water mixture (within reason) will enhance the cooling effect (evaporation lowers the air temperature which is enhanced by the alcohol). However only a good thermal dynamics engineer can determine if the system would be adequate. As others have mentioned - you have to get the heat OUT of the head via the fins so surface area comes into the equations.

Always fun to speculate.
Some people mist their front mount intercooler with co2 or n2o could always rig up a nozzle a move the fan for long pulls on any engine. Pretty cool idea either way.


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Allan Lacki
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Re: Road Racing a Modified Corvair

Post by Allan Lacki »

Hi xrotaryguy,

Before we can provide advice, you'll need to define "road racing" for us. Do you want to do a few HPDE events now and then, where you can run just about anything? Or, at the other extreme, do you want to drive in a national SCCA championship series, where rules for cars and classifications are very formal and strictly enforced?

For HPDE events like those conducted by the NECC Motorsports, Terry Stafford has been running his '64 turbocharged Corvair for years, and until recently, so did Smitty Smith. They're not on the track for hours at a time and they only do a few events per year. But they do have fun doing it.

You also mentioned V8 Corvairs. Mike Levine campaigns his mid-engine V8 Corvair in vintage races quite successfully. He isn't racing every weekend. I think he does about a half dozen events per year. There are a number of other guys doing the same thing with normally-aspirated Corvairs. (Most of them are active on the Corvair Racers Facebook group).

I also believe Michael Leveque does some racing in SCCA with a Corvair. If I recall correctly, he's using a center mount four barrel. His engine is extensively modified, but not turbocharged. Michael is also active on the Corvair Racers Facebook group.

Al Lacki
xrotaryguy
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Re: Road Racing a Modified Corvair

Post by xrotaryguy »

Thanks for the thorough response, Al.

HPDE is certainly something I need to do. I feel like that's a good and mostly-safe way to start wheel-to-wheel racing. I'd like to go beyond that though. Not as far as SCCA though. I have a bad habit of building (autocross) cars that don't class well. I like driving them though so maybe it's actually a good habit.

Vintage racing would possibly be a great place to end up. I'd really like to run something that can be driven on the street as well as on the track. That's why the turbo option seems like a good one. With a modern turbo setup, you can basically make all the power you want (or the power train can handle) and yet, you still get a nice idle and generally good road manners.

This is more of a long term goal, not something I'm going to do this year or next.
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lostboy
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Re: Road Racing a Modified Corvair

Post by lostboy »

I just want to piss of local kids with civics.... that counts as road racing, right? I'm kidding, mines strictly for cruising.


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Pandora
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Re: Road Racing a Modified Corvair

Post by Pandora »

Some Corvair books state the stock Corvair cooling system is not adequate for a WOT turbo for more than a little while.GM engineer Benzinger is quoted as saying at a convention that GM knew the turbo cars would overheat at full throttle for sustained periods us open tips
, but who would drive a turbo WOT for more than a minute as the car would be at top speed by then, an illegal activity on public roads.
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joelsplace
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Re: Road Racing a Modified Corvair

Post by joelsplace »

E85 should help a lot. Move the turbo out of the engine compartment, ceramic coat the crowns, combustion chambers and exhaust ports. Does anyone know how much these things will help?
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