Cheese Weasel

Hey guys,

I'm building a car as a mixed "street car + road racing + open-road events (think Silver State Classic, etc.)" -type car, & I'm not sure what will be needed in order to keep it cool while doing all of that.

The car is a late-third-generation Firebird, so it's a "bottom breather" (meaning that it doesn't have a traditional grille for air to go through the radiator), which makes me a bit more concerned about overheating. I've searched several threads here on LS1Tech, & while some people seem to advocate spending the cash for aftermarket radiators like Ron Davis/Howe/Be Cool/etc., others have recommended the stock LT1 ('93-'97) radiator.

I would be comfortable with the stock LT1 radiator if I was planning on keeping the car naturally-aspirated, but I'll be adding a turbocharger to the engine compartment, & shooting for about 700 horsepower.

If any of you guys have experience with road-racing a turbocharged "bottom breather" F-body for at least 20 minutes/session, & have any suggestions and/or recommendations, I'd sure be grateful if I could get the benefit of your experience.

Thanks in advance.

gnx7

iTrader: (28)

If you only want 700hp just stay n/a and save yourself a ton of headaches. Production ported LS7 heads, high compression, MSD Atomic intake and 400ci+ can make 700hp n/a.

Otherwise check out Brian Faessler's turbo Mustang with rear mount turbo, a/w intercooler where the passenger seat once was.... of course $$$$ transmission and other goodies. Supposedly he is only making around 700rwhp but the car has a ton of aero work and it does kick BUTT. The splitter is even made out of plywood..... https://www.google.com/search?q=Bria...w=1920&bih=974

His dad Paul also races a turbo 410ci early Mustang that RIPS......
https://grassrootsmotorsports.com/ar.../break-maiden/

The guys at CG&J made me a full custom radiator for my '69 Chevelle turbo 5.3 in about a week for 1/2 the cost of the ones you listed.... it is beefy and bad ***! The stack shows the a/c heat exchanger, then the a/w intercooler HX unit, and finally the dual pass radiator. My buddy made it all work including fan setup.
http://www.cgj.com/

pdxmotorhead

The class level your car would fit in things like the silver state, you'll have a full blown space-frame car by the time you meet spec for the big speed end..

I'd use a full splitter, a cowl hood, so the splitter grabs the air rams it through the slot through the radiator and vents over the windshield for downforce. The radiator will pass enough air, and cool as long as you have the square inches of surface area per HP of engine. Start with stock radiator and move up as needed.

Since your forced induction E85 is going to be almost mandatory to keep the valves cool for the sustained run. Lots of oil cooler..

Good luck..

LS1-IROC

iTrader: (4)

You will need some form of heat extractors on the hood. My turbo IROC gets ridiculously hot under the hood when I push it hard for a sustained time even with everything wrapped and a blanket on the turbo.

Cheese Weasel

No doubt a good suggestion, but the engine is already built - so if I want to make that number (& I do have some flexibility there), I'll have to boost it.

Hmmm. My thought was that I could perhaps pick a class that I wanted to run in, & register in that class. Are you saying that if a car is capable of 170mph that it has to run in that class?? (I haven't really looked into it yet.)

Makes sense. I already have a fiberglass hood that I'm going to use, so it wouldn't take too much work to open the back of it to allow underhood air to exit at the base of the windshield - and I've already been thinking about a splitter...

Well, that right there is really the heart of my question - since I really don't want to have to buy more than one radiator, I was hoping to learn which one is a 'known-good' solution for this issue.

Thanks PDX, I really appreciate your response. I was hoping to avoid the use of E85, since it seems to be more temperamental than gasoline in terms of storing it over the winter - but if that's the best route to take, I'll just deal with it. FWIW, I still miss living up there & watching the vintage races every summer in Seattle & at P.I.R...

Yeah, I kind of suspected that, but I appreciate your confirmation - I'm kicking around some ideas for how I can vent the heat through the 'glass hood without it looking like a "homemade hack job," maybe I just need to spend some time with the ol' photo editing software...

Thanks again for the responses guys!

Cheese Weasel

Still hoping for radiator (& associated) suggestions, so I'll "expand the scope of the question" a little bit:

You guys who are running 3rd- or 4th-gen cars on road courses with turbos, what radiators are you using??

And what other things have you found useful?? (BIG thanks to 'gnx7' for the great info via PMs also!)

Come to think of it, I think I'll browse FRRAX if I get some time today as well...

Thanks in advance guys!

neverstop

I know two guys who road race and open track fairly stock LS motors (vettes) with vortech A&A kits on them, one guy makes 550whp on a stock ls6 and my other buddy makes 640whp on a stock ls3 with nothing more than methanol. both got away with that for many 10s of thousands of miles and years. my buddy with the ls6 setup is a very very good driver too and he has some cooling mods and front end aero work but nothing too insane. they are both just on aggressive street tires though so no slicks.

street and standing mile stuff is easy, the road racing is what will be a challenge. 700hp motor is pretty easy with an LS though so I wonder if that is your ultimate hp goal if turbo is more complicated and expensive than necessary? I would think a simple TI trim vortech kit with e85 and a big oil cooler and big high quality radiator and a lot of front end aero thought would work great and be fairly simple. trackspec makes great hood vents too. or just sell what you have and get a nice fresh stock ls3 and put heads/cam/intake and can make 550whp pretty easy just right there which is maybe 650hp at the crank.

honestly I'd be more concerned with brakes racing a car that big for 20 minute straight.

my own unsolicited $0.02 though is I would not try and seriously road race a forced induction car. that type of racing is already so hard on stuff and so much going on that adding a turbo just makes it even harder

kingtal0n

iTrader: (1)

the most important physical aspect will be the insulation between the engine compartment, cooling reservoir, and the "cold side" of the engine, the compressor, intake, intercooler.

A street car that sits in heavy traffic faces a similar problem, temps going up and nowhere to put all that heat sometimes. It starts soaking into the intake plumbing, making gasoline more and more dangerous to use.


So first step is to isolate the turbine/exhaust from everything else. Wrap it, coat it, contain it. Blanket it. Make it so that the heat is contained. This will improve turbine efficiency, and reduce underhood temperatures.

The radiator should also be isolated- but not insulated. It gets anti-insulation, you want it to release the heat into the environment. So keep this in mind when designing insulation strategies: you want the radiator to relief the heat energy, but to do so AWAY from all of your intake pipes and engine. So some kind of 'wall' or shield between the radiator airflow (exiting the radiator fins) and the engine/intake/intercooler is desirable. This is where special ducting plays a role because you want to be ducting that hot radiator heat out of the engine bay somehow anyways.

Finally the intake side, isolated, insulated? No. Think of intake ducting as a radiator: It is made of aluminum for a reason. Don't insulate it, just isolate it. Shield it, duct it, make it a separate part of the car somehow, but also let it radiate and if possible should have some airflow over it (just like a radiator).

Now that you've setup the engine bay's temperature traffic it is time to discuss how you are going to control the internal temperature of the exhaust gas. 100% water injection is an easy way to bring the exhaust gas temperature down when necessary. Water injection ensures that your hard work insulating all the exhaust plumbing wont go up in melted metal fire.

JoeNova

I raced a TT SN95 in NASA, and while I wasn't competitive thanks to the class I was tossed in, I learned a lot.

Water cooled turbo, larger radiator, and fans that disable at a certain speed.
Do everything you can to keep heat from the exhaust getting into the engine bay. Wrap is the easiest. Ceramic coating will last longer and be less of a hassle. Intake ducting placement isn't much of an issue, even near exhaust, as long as its gets fresh air and isn't sucking in underhood air.

cam

iTrader: (9)

With above some cubes and a NA approach is what I would do for this. Theres more advantage to NA during road racing events than power alone. Turbo power is a handful to get loaded properly, and hold wheel speed between all the accel/braking events. My guess is your blowing off the tires or bogging non stop with such a car.

For something extreme? North of 1000 hp then a pure alc TT build with the right components would perform well and with alc heat will be less of an issue but there are safety concerns with that fuel so... delicate touch is required.

All that said most road racing is not won or lost based on peak power, its the best sorted out chassis and brakes that dont over heat or tires that melt off that win. A light weight package is also massively beneficial

Bob@BruteSpeed

iTrader: (16)

We found that a large engine oil cooler helped more than anything else on this ProCharger equipped C5. Bob

MY_2K_Z

iTrader: (1)

Bob stop twisting my arm!!! Every time you post that pic I start looking for a c5 to build. That has to be the nicest c5 I've ever seen.

cam

iTrader: (9)

Thats how Porsche used to do it. High volume of oil and a couple coolers cooled the whole engine. No coolant on those old 930 turbo units and they had the **** run out of them for years on the road courses.

On another completely unrelated note I have to say one of the single best purchases I made for my Camaro is that drive shaft you sold me Bob. It truly has proven itself bomb proof! Survived a few engines, numerous clutches, a couple of diffs, numerous gear sets, and lots of sticky tires and not a single issue with that aluminum PST/Spicer shaft.

neverstop

I still think leave the motor N/A for road racing and then for straight line stuff just spray it with a 250-300 shot and stand alone fuel system with race fuel. imo a forged ls motor will easily take a 250 shot on race gas if the tuning is good which is piece of cake to break 700-750hp and nitrous makes insane torque. put in two 15lbs bottles in the trunk so not worried about running out and then be g2g

then none of these issues when road racing, car will be much lighter because none of the turbo stuff or all this extra cooling mods, less complicated, more reliable and cheaper and you'll have insane power when you want it for standing mile or drags. if you've never been in a car on a big shot of nitrous I'd recommend you go and find someone at cars/coffee who will take you for a spin, the absurd torque of a big nitrous shot is seriously impressive.

Bob@BruteSpeed

iTrader: (16)

That is great news, thanks!! Bob

Bob@BruteSpeed

iTrader: (16)

Sorry!! lol At the prices C5's have gotten to, they can be affordable to many who would of not considered one in years past. They are fairly light too. Bob

pdxmotorhead

Biggest step you can take to build a winning car is to know the rules.. BEFORE you start building it..

Best investment I ever saw on a race car was a full strip, bare tub, cleaned to 100% bare metal. On some of the American sedan cars, (Mustang/camaro) I've seen hundreds of lbs taken off the tub that way..

Black89Z51

iTrader: (2)

I currently road race an 89 corvette. I shouldn't be the first to tell you that nobody. Literally NOBODY running big bore class, or even small bore classes runs a turbo.

Of all the races I've participated and attended, nobody runs a turbo. For one, they have on off power and are horrible out of a corner, but also like you said, they generate a metric **** ton of heat.

As suggested before, run a built NA motor if you're going to road race. You're wasting money if you think you'll be competitive and reliable running a turbo setup. I've been doing it for over 10 years and have NEVER seen a turbo V8 run. There's a reason for that.

pdxmotorhead

FWIW , Silverstate has brackets, when you enter you pick you bracket, go faster than the bracket allows and your time is thrown away.. They also have radar traps on course to make sure the lower classes don't exceed their tech speed. Supposedly there is also photo radar on course year round to make sure you were not out there practicing... But that may be urban legend..

pdxmotorhead

+1 been road racing since 1999 and only small bore cars turbo, also because they don't make enough tire to stick a WOT turbo to the ground in a turn.. Plus I helped build a comp-Z06 a couple years back, 725 NA to the ground, 1 20 minute session per set of tires.. at a couple grand per set..

Put a 460 outlaw sprint motor in a c5 once,, ran on methanol, nobody saw him coming at a run what ya brung enduro... we had to block 30 percent of the radiator to keep the heat in the motor on the road course..