can i run a 160 stat and jets cold fan switch with out having the computer reprogramed for it. also will this cause problems between open and closed loop operation. the weather here is getting really hot 90 to 95 everyday. i got a 180 in there now but the temp still gets up there if traffic builds up.

 

Its better to get the custom prom or make one yourself its possible that the computer will never reach closed loop if you use a 160 stat. Plus its not worth to go any cooler than 180. TPI were made to run hot. Stick with the 180 stat and bypass the throttle body coolant line.

 

You didn't say which car and engine you're talking about, but because it says your '86 TPI rests in peace, I'll assume you're talking about your '89 TBI. But from my own experience with a 160* stat in my TPI, installing one is the best thing I ever did for the cooling system. And running it with a fan temp about 20* higher is a very good combination.

On the TPI engine with with dual fans, the computer controls the primary fan, and the fan switch in the head controls the secondary fan. And one myth is that the computer must be reprogrammed to run with a lower stat. But it doesn't. Everything worked perfectly for me without reprogramming the computer. In fact, everything worked MUCH better than stock like this.

But on your TBI, I believe, and I could be mistaken about this, your only fan isn't computer controlled. It's controlled soley by the fan switch in the head. And if that's the case, running the Jet 180* switch(on at 195*/off at 185*) should work very well for you in combination with a 160* stat.

Yes, your engine will warm-up a little in traffic, but not much, and that will be normal. But it will cool down quickly when you start moving again.

With stats and fan switches that 'match,' the fan(s) will run all the time. And that's not what you'd want... at least, that's not what I'd want.

 

my iroc motor is in my firebird now, i swapped everything over but i couldnt use my dual fans, wasnt much left of them after the crash (but you should see whats NOT left of the cobra that hit me) can i run a 160 stat with the fan switch with the single fan

 

Running a 160* stat is fine no matter what the fan temps are. So yes, you can run that stat.

But now I've got to ask, with the TPI swap, computer and all, how is the one and only fan connected? Is it connected to be operated by the computer(like the primary TPI fan), or is it connected to be operated by the fan switch in the cylinder head(like the secondary TPI fan/TBI fan)?

If it's connected to be operated by the computer and coolant temp sensor, then you don't even need a fan switch in the cylinder head(except to plug the hole), because the switch won't be operating anything.

But if it's connected only to the fan switch in the cylinder head instead of being operated by the computer(like with TBI), then yes, that switch should work well and would be a good choice.

I suppose it can be connected to both and would turn on with the lower temp of the two, in which case the fan switch in the head would do the operating because it's set to turn on at a lower temp than the computer program. But I've never tried this, so if that's your plan and it doesn't work, don't hold me responsible, lol. But it seems like it might work. And if it did, then if the switch ever failed, at least the computer would act as a 'backup' and turn the fan on at the warmer temp way before things could go bad.

 

Are you saying on a 90 to 95 degree day the coolant will be running at 160 degrees? That's what I read in this.

On such a high ambient temp day, the coolant temp should be over 200 degrees no matter what stat you have or when your fans come on. Now, without a stat, I can agree, you will have a lower coolant temp gauge reading.

 

I run a 160 in my L98 and even on the hottest days stuck in grid-lock traffic on the way home from work, the temperature never goes above 180 max. Of coarse, my fans have been rigged to come on the moment the car starts up so obviously, that plays an important role in how the car is able to run so cool even in extreme conditions.

I also bypassed the coolant going through the throttle body.

Regardless, despite what some people might tell you, no, you don't have to get a custom tune and no the car will have no trouble at all going into closed loop.

If anything, you should see a noticible improvment in acceleration and throttle response. I know I definetely did.

In the winter though (if you drive in the winter that is) go with a 180 - 195 stat. Otherwise, it'll take forever for your heater to start blowing hot air.

 

Hmm, I didn't think what I said was confusing, given the series of posts down to that point. I didn't say no matter what the 'coolant' temp is or what the gage reads. I said no matter what the 'fan' temps are. But maybe I should've completed that sentence better by saying no matter what the fan temps are 'programmed for.'

In other words, I'm saying this:
----------

 

while on these issue...is it good to rig both fans on a 89 IROC to start as soon as you turn on the engine.....i have a 160* stat put yesterday and wanted to rig the fans to turn on right after turning on the car...so is it good bad....

 

I've read here where people have rigged the fans to start-up immediately, and they haven't had any complaints about it. But it just doesn't seem safe to me, so I wouldn't do it.

I'd think it would take the engine longer to warm-up at start-up. Plus, with the fans running all the time, you'd run the risk of burning out the fan motors or relays, which would leave you in a jam. So my personal opinion would be don't it.

I once had a heating issue that kept my fans on all the time, and the relays burned-out. It was no fun being stuck, waiting for nightfall to try to get home. But like I said, others here have done it. So it's your decision.

If you choose to do it, then I'd suggest getting some spare relays to keep in your car, just in case...

 

nice...thanx...then i guess what i will do is rig one to run when i turn it on manually and the other to turn on by computer..or have the car turn it on when it needs....i think i will sit on these question for a while...but as far as doing this what do you guys think...i just dont want the car to run too hot...trying to keep it below 220* probably around 190* to 210*...then again i read that these cars were meant to run kinda hot....hhhmm....

 

Rigging the secondary fan for manual operation and keeping the primary fan computer-controlled is a good set-up.

As for how hot these cars were 'meant' to run, an awful lot of people are running stats of 160*, 170* and 180* without any problems at all. And any of these will work well without making any changes to the stock PROM. And being in Texas, you might consider a lower-than-stock-temp stat.

Just changing the stat will help the car run cooler. And even in traffic, unless you're really in some heavy stop-n-go or at a very long traffic light(like in the suburbs of Chicago, lol), you'd prolly get moving again before engine temp got up to fan temp. And if you rigged the secondary for manual operation, if temps began to climb beyond what you'd like, then just flip on that fan before the stock-temp primary fan kicks on, and it'll cool down--all while having made no changes to the stock fan temperatures.

 

I recently installed a 160* and it cools great. But it throws an SES light in the early morning or at night. Never during the day. So I'm guessing that with the cooler temps that it never reaches closed loop, never gets warm enough. But in the day when the street temps here in AZ get over 150*, getting to closed loop temps is no problem.

 

Imagine this. GM had to choose 2 temps as ideal. A target temp (normal operating temp) and a temperature range (a plus or minus 30° margin of fluctuation). They chose 90°C (194°F) at 1000 RPM as the target. Knowing if they could keep the engine temps at between 170° and 230° they would have a combination that would be relatively safe at the same time providing a balance of decent power, gas mileage, acceptable emissions as well as heater function.

This ideal situation was necessary because they are putting one thermostat (195) in every car they make. However this one size fits all solution doesn't fit every condition. Your thermostat should be a tuning device that is calibrated for your driving, your environment and your engine.

A 160° thermostat in Arizona traffic with the A/C on is not the same as running a 160° stat in Minnesota. So it's possible, in certain conditions, to drop in a 160° stat and totally screw up all the calibrations in your car that are based on temp. And yet in hot climates if you're not running a 160° stat your car is going to fry.

In a nutshell GM is saying your car starts working correctly at 170°... we want you at 200°... and we're getting worried about you at 235°. Whether you agree with them or not you have to find your range of zen and do whatever it takes to get it there... and keep it there.

My personal target is 180°. In Phoenix it took me a 160° stat, no A/C and a lot of prayers to keep it there. Now in New Mexico I keep it there with a 170° stat.

 

As far as power goes, the colder your engine is, the faster it will be. Even if it's bone stock.

Having a 160 stat does not mean it's always going to run at 160. I have a 160 stat, and around town driving (stopping at red lights..etc) the temperature is around 175-185. And thats usually where I drive my car. If I jump on the highway with no stop and go, the car will go down to 160 then.

 

Especially on a TPI motor where the intake is basically one giant heat sink.

 

Well I'll throw my 160* stat experience in here. I just removed my 160*stat nad put in a 180* stat because it kept throwing a code 32. I cleared the code by battery disconnection and I hope it doesn't return. It hasn't yet and I've driven 10 miles. Usually it will come on by then. Cross my fingers.

Don't fret, as I seem to be the only one where a 160* stat would throw a code 32. I searched and searched and no one else shares my symptoms. I'm hoping that the code actually comes back on because then EGR really is bad and not because the the engine can't reach closed loop do to being to cold.

As of right now, I got some midrange power back by switching to the 180*.