brianchevy

My 87 IROC (305 TPI) is a dedicated race car. Never driven on the street and only used for autocross, drag racing and track days.

I have wired my dual fans to a switch (which I keep on most all the time). And I am allowed within the rules of SCCA to "modify" the thermostat but not "remove" it.

So, I am thinking of drilling out the center so it won't matter and running with no effective thermostat. Also I am planning on a "tuning" dyno run to get the engine setup just right.

Bottom line... Is it preferred to run a race engine with a bored out thermostat so we get maximum flow?

Brian
Atlanta

V8 Slayer

Why not just get a 160 degree?

brianchevy

I could most certainly do that.
Would that be BETTER than "modifying" the one to not function at all?

I'm trying to get familiar with what temp's the SBC want to run and I'm just curious what the other racers do.

Brian

V8 Slayer

I definatly think throwing in a 160 or 180 degree would be much better than drilling the stock one..

amean94ta

yes a 160 will work better

the reason:
the cooling system is designed to slow the water down so it can cool or "heatsink" into the water too much flow will cause it to run hotter.

we went through the same thing on my best friends bbc blower car he put a open plate in there and it made it hotter so we stepped down to a plate the size of a dime works great now

you need to find your balence of flow and heatsink that works best for you but i see no problem with you using a 160

V8 Slayer

Hypertech and Jetchip make a 160 degree thermo for F-Body's, (if you didnt know.)

xpndbl3

go to any parts store and grab a SBC 160 thermostat for $5 and not pay $25 for one that says hypertech on it

amean94ta

i belive the lt1's are different but yours should be std sbc

Stephen 87 IROC

Thermostat, race car, do those words go together in a sentence? I'm not sure how they're going to tell if you remove it.

Purpose of a thermostat is to restrict coolant flow through the engine to aid in warm up. Once the engine reaches operating temperature, the thermostat is open then it's the job of the rad and fan to keep the engine from overheating. If the cooling system is efficient and the temperature cools down, the thermostat will close enough to provide a restriction to bring the temperature back up again.

Your SCCA car will probably need a thermostat to maintain a constant warmer temperature so a 160* should work fine.

In a drag car, especially one with an electric water pump, you want to be able to keep coolant flowing through the engine when not in use to bring the temperature right down again. When you get back to the pit, you leave the water pump and electric fan on to cool the engine down between rounds. If you had a thermostat, it would close and prevent the coolant from flowing through the block. Drag racers normally remove the thermostat for this purpose. Trouble is, now the coolant flows through the block too quickly and doesn't have enough time in the block to allow heat transfer into the coolant and the engine runs too hot. They sell restricters that fit in where the thermostat is. A kit comes with 3 different size openings. Depending on what size is used, you can limit how fast the coolant flows through the block but still have unrestricted flow when the engine is colder.

Out of all the factory replacement thermostats on the market, the best one to buy is normally known as a failsafe. If the thermostat ever fails, it will fail in the open position so the engine will never overheat.

My alcohol engine has a hard time building any heat. My upper rad hose is a 1" heater hose and I use a rad from a Pontiac Firefly. I normally don't even turn on the rad fan until I'm ready to stage.

Z28SORR

It's not just drag racers that use restrictors. Road racers use them to illiminate the problems with thermostat's failing closed.
I believe the "intent" of the SCCA rule is to allow you to change the thermostat not actually modify it, i.e. you can not make it non-functional.

brianchevy

I've purchased a 160 degree Heavy Duty Thermostat ~$9 from the local Pep Boys and I'll see how that works for me.

Thanks for all the advice guys!

Brian

firebird_7678

I usually drill a 3/16th hole in my thermostat in my racing engine. That way it acts as an air bleed, and also lets a small continual flow of coolant to the block. It helped out on my 355 dramatically with cooling issues.

brianchevy

I installed the new 160 therm today. It's a nice piece. A heavy duty one that I think will do the trick.

I hate having to take off the TPI to install it, but.... it wasn't too bad. now I know that I have some cleaning to do under there before I fire it back up.

Thanks so much guys, I'll keep it cool now and we'll see how that helps on the power front. Generally COOLER = POWER, but from what I've been reading on this board.... I can't believe you can be too cool from the power perspective... is that really possible?

s10er8

yeah a hot engine makes more power to a certain extent. its the cooler intake charge that makes more power

jaykar

Or you could get a 170 stat from Chevy.

Later