i am setting up my 1987 iroc 350 tpi....for autocross now and have some cooling issues i want to address before it becomes a problem i want to be able to keep the motor from running over 200 degrees(i think) or so....what is a good temp for the motor? given i have a 350 tpi...what degree thermostate do you think is good how about the cooling fans....i dont want to buy a new radiator nor do i want to buy new fans....they should work for my purposes....tell me what you think...

 

id try a 180 or 160 thermostat in it and see what happends.

im not sure if the stock fans would keep it under 200 while your racing,even if you had both of them on HIGH all the time....its worth a try tho.

 

what do you think of the fans...do i put them on a switch...and if so how exactly do you wire it up....will it interfere with anything else...will a check engine lite come on...what exactly do you do

 

Once a thermostat is open, it's open. If the temperature keeps going up then the rest of your cooling system isn't removing enough heat. The thermostat will only maintain a minimal operating temperature. If for some reason the cooling system is working too well, ie -40 below, the thermostat will close to keep heat in the engine but if the engine runs too hot, there's nothing the thermostat can do providing it's not stuck closed.

A cooling system needs proper coolent flow through the engine and rad. Even though a rad may look fine, the tubes can be plugged internally restricting flow. The rad also needs a good air flow across it to remove the excess heat. If maximum amount of air is flowing through the rad, coolent flow is unrestricted through the rad, water pump is operatiing properly and the engine temperature is still too high then the rad isn't big enough to remove the heat produced by the engine. Time for a bigger or more efficient rad.

Bypassing the tranny cooler inside the rad and using an external cooler will take some of the cooling demand off the rad since it doesn't have to try and cool the hot tranny oil.

 

the 160 stat should work well

and putting a separate trans cooler on it is a good idea, and probably better for the trans.

i would try the hypertech fan switch as well, it will turn the fan on at 176.

i know on my LT1 and LS1 with 160 stats the coolant temp stays right around 170 on the highway down here in hot florida

 

What Stephen said is right, but there are some "gotchas" with 3rd gens.

1. Stock stat is 195*F opening point. It'll take until about 210* before it's fully open (maximum flow). Most stats are like that. Takes about 15-20* more temp to go from barely open to fully wide open. I haven't found an application yet that a 180* stat couldn't handle. You may wish to purchase a "high flow" stat for your application, however.

2. Stock gagues are notoriously inaccurate. Gague on my 92 regularly reads hotter than actual by about 15* and that's not really all that uncommon (205* actual = 220* indicated). Add to that the complication that NOBODY really knows what that hashmark between 100 and 220* actually indicates and it can leave you scratching your head ( I think it means 185*, but who knows). The location of the stock temp sensor may be partly to blame. It's in the driver's cylinder head between 2 exhaust ports which could read higher than if it was screwed into the intake manifold. None of this my apply to you since road-race guys rarely trust stock gagues and usually upgrade to "real" gagues from day 1.

3. You may or may not be getting enough airflow through the rad to do any good. Airflow through the rad on these cars is not so great- you need all you can get. Obviously, the plastic spoiler bolted to the bottom of the radiator support is CRITICAL to getting airflow through the rad. The biggest rad in the world won't do any good without airflow through it. The spoiler must be undamaged and not flopping around. If in doubt, replace (still available through GM). Electric fans are nice. The stock ones won't keep up at WOT without the chin spoiler but neither will aftermarket ones. Nothing beats the car's forward motion for shoving air through the rad- that's why the spoiler is so important. There are ways of rigging the stock fans to run all the time- check out the cooling system articles over on thirdgen.org (tech articles section). Lotsa good info there.

4. A good condition water pump can make a world of difference. If in doubt, replace. Fancy high flow aftermarket aluminum units might be a good choice for your application, but stock ones also work just fine. Ditto your radiator. If you don't know it's history a stock replacement can be had for just over $120 at most parts stores. It's very difficult to tell the difference between an inadequate radiator and an inadequate water pump. Symptoms are almost identical.

If after trying ALL of that stuff above you still can't keep it cool THEN it may be time to upgrade your rad. FYI- I built a fire-breathing 400ci engine with aluminum heads for my brother's 87 GTA and we kept it cool on 95* days using a stock rad and fans. It was also oval track raced from time to time without overheating. We could tell we were kinda "pushing the limits" of the stock cooling system, but it never failed us.