Greasy Monkey

My friend has a GTO w/ an electric fan, alum. heads, alum. water pump, im not sure about the rad. or thermo but he says it never gets above 150. I was just wondering if that was bad? I'd heard that cool motors wear out quickly, is there any truth to that? Thanks!

Mark A Shields

It's worse for computer controlled cars, but I'm not sure how 150* would hurt a motor. The fuel may not burn completely, but on a GTO, which prolly doesn't have cats, I assume, may not be that bad.....

GilmourD

My brother's Rustang is FI... Idiot didn't put a thermostat in it. The thing doesn't get above 130*... Car runs like sheeeeeet until you stomp on it a few times, then it smooths out.

chris1roc

I did all the cheap mods in my car and I would have to say that I noticed the biggest difference with that one.

85_ZED28

you mean your t-stat?
what temp. should be used for summer driving?

Mark A Shields

For a TPI car, I'd go with a minimum of 180*.

In a non CC car, 160* in summer, 180* in winter works nice, if you need heat.

AlkyIROC

What mark just said and those are minimums for daily driven cars.

If an engine runs too cool, condensation will build up in the crankcase. Ever pull a valve cover off and find a white goo coating everything? That's water mixing with the oil. Water inside the crankcase isn't good.

You need enough heat to burn off the moisture and not too high to reduce performance.

Changing the thermostat in a FI car means the chip needs to be reprogrammed. If you run a 180* stat and the computer thinks it's a 195* stat, it will always stay in a warm up cycle since it thinks the car is still too cold. It's like driving around with a choke still partly on. Once it's been reprogrammed to understand that 180* is the operating temp, everything should be fine.

In my race car I liked getting to the starting line at around 145*. At the end of the 1/4 it was at 195* and I don't run a thermostat. Now that I'm switching to alcohol it will be hard to get it over 145*

IROCThe5.7L

Damn. Im running a 160 with a stock computer. The previous owner put in a 160 because he was gonna throw a Stage II chip in, but never put the chip in.


Car runs great though.

Mark A Shields

You'd prolly pick up a nice mpg gain with a 180* stat.

IROCThe5.7L

Yea I think so too. With the new O2 I put in this summer, Im gettin around 17-19 MPG with normal driving.

MdFormula350

yeah with a stock chip id stay with a 195, but a 180 would work.. and a 200 turn on fan switch.. as long as its close to the 190 - 195 mark.. at least thats what i would do for an tpi thirdgen

Free Bird

iTrader: (1)

I have to disagree. My car runs faster w/ a cooler water temp. Hands down. No programming. It warms up fine and performs well when its cool. If the temp get to 200-210 then I can notice a definate change in the way the car drives.

Mark A Shields

No one is sayin a cooler runnin engine will make it slower. unless i missed soemthing.

ZZ28ZZ

You get condensation in the crankcase when eng cools.
Can't be avoided.
Water makes the oil acetic, which isn't good.
The OIL temp needs to get hot enough to evaporate the moisture (>212*F).

ERICK87Z28

Cool running motors will actually last longer...high temps kill gaskets, o-rings, hoses, etc. Cool temps will contibute to denser fuel mixture, so economy will go down, but performance will be better. A computer-contolled engine will not like the cool temperatures, but it doesnt sound like that is a problem here. And the engine is only going to get so cold, it will never run so cold as to be a problem. Think about it...starting your car on a cold winter day, everything is about 32 degrees, maybe less! Runs just fine. Everything within reason, my son.

curt86iroc

also, the most wear on the cylinder walla occurs at lower teperatures. thats why you should never get on your car before its warmed up because thats when the most wear occurs.

curt86iroc

also, the most wear on the cylinder walls occurs at lower temperatures. thats why you should never get on your car before its warmed up because thats when the most wear occurs.

Greasy Monkey

Cool, thanks for the info guys!

curt86iroc

whoops, double post....

Kingtal0n

<b>Cool temps will contibute to denser fuel mixture</b>

Cooler INLET temps mean denser air.
Cooler WATER temps dont, indirectly of course. This also depends on the type of intake and head etc. etc...

an aluminum intake will absorb heat faster thus heating up the air charger before it burns. if the intake is absorbing heat, obviouselly it is cooling off the water as it passes through. indirectly, the water gets cooler, and indirectly, the air charge heats up.

but this isnt what im trying to say...
the hotter the engine, the higher the compression ratio, the more timing advance, = the more fuel you need. i left some things out but thats not the point.

The point is, keeping an engine cool while cruising, such as on the highway, means you can run more timing and less fuel without detonation. this means higher MPG. to an extent... that is.. simply put adding timing and leaning out the mixture will heat the engine up, along with combustion temps. keeping the water below, say, 170* while cruising does NOT mean your "wasting fuel because its not all burning" this is where the extra timing and less fuel comes into play. just cause your motors cool doesnt mean your hurting performance/mpg.

now several reasons why it WOULD involve things like coolant temp modifiers in the PROM. if the PROM sees your coolant temp is too low it will enrich the mixture... using up more fuel. yes, the extra fuel will burn too making more power requiring less throttle opening, but your still burning more fuel. un-necessary, but thats how fuel injection works. the only way around THAT of course, is taking matters into your OWN hands and re-programing the chip the way YOU want, yadaa yadaa... i can go on all day...

Example:
My car got 9 MPG on the highway. I added vacuum advance (+10* tiiming under cruise) and then i got 12 MPG. yay, but i wanted more. i reduced jet sizes until it would barelly run, then stepped up 2 sizes, and matched the power valve to a point right after part throttle. this netted me 14 MPG on the highway, simply because of less fuel. but then the engine got hotter and would not run... lack of fuel! new radiator (griffon) and now i keep it at 170* on the highway, and can run even LEANER jets and MORE timing. less fuel! 15 MPG now.

I ROCK

For ANY thirdgen the first thing I'd do after buying it - a TTA fan switch. This will switch on (can't remember the exact temp) the secondary fan to prevent the engine - you hope - from ever getting too hot. I'm running a stock prom and a 180 fan switch with no problems, but though the years I like my particular car to be between 170 and 190 at all times. It's also interesting to hook up an engine analyzer and see what the temp REALLY is versus what the guage says. I'll take any of the negatives from running too cold (within reason) any day over the negatives from running too hot. Ideally you could set up a system to stay at 190-195 exactly, but that's a bit tricky.

rezinn

Yes a cooler running engine will produce more power, hence cold air mods and "throttle body coolant bypass," etc. But our computer controlled cars were designed to run at a certain temperature, and running below that causes them to use more fuel. Your oil can build up sludge if it doesn't see high enough temperatures; there are many reasons to run the right temp thermostat and keep the car running at it's proper temp.

DartByU

I saw a chart many years ago that compared cylinder bore wear vs. engine temp, seems that 180-210 deg. was the best for engine life, engines that ran at 160 had more wear and 150 and below it was a lot more wear, so if you want the engine to last a long time keep it above 180.

TBI305Camaro

I had a 180 degree thermo in my TBI with a hypertech fan switch...no problems out of it. My guage never read above 160 but I think it was more like 180 degrees.

Slade1

FI cars need to run at least 140 F to be in closed loop. Its the basic setting of the prom and after that temp it will run in closed loop regardless. The O2 sensor dictates fuel mixture, not the coolant temperature. As long as the exhaust gas is hot enough to work with the O2 you shouldn't see any problems there.

Running a 180 or a 195 makes no difference to the ECM once in closed loop, it will not see 180 and then richen up the mixture to heat it up. It's either its in open loop mode <140 rich mixture, or in closed loop running off sensors.

I have on average 24-28 mpg on highway. Putting in my 195 makes no difference to the mileage at all. That is where mileage does matter and when the engine is running more or less at 180 F. It's now on average 30 F around here, I'm running my 180 stat and mileage is no different b/w summer and winter. Sure everything runs colder but it doesn't affect it.

As for goo on my valve covers, haven't seen that happen on mine once. 180 is more than enough to get water to evaporate out of the system. Sure getting it to 195 will make it happen faster, but water will readilly evaporate given the energy generated in heat by an engine. It will not go and condense while running on the valve covers, those absorb heat as well.

Another note is that GM made their LT1's come with a 180 standard thermostat. Does white goo build up on their valve covers??? Nope, odds are running a 180 will not do that to your either.

rx7speed

the motor itself should run better at a hotter temp.

the colder the motor runs the more heat get taking into the motor block and cooling system rather then using that heat to put more pressure on the piston which would make more power. the downsides though would be a chance of having higher intake temps and that would lower power, also you have a greater chance at overheating, and detonation


I would still say use the stock therm and find a way to get the intake to stay nice and cool rather then go about putting a lower therm in there