160,180,or 195 t-stsat?

[rbrown-90]

This is in a 90 Gt street car. I ran a 160 t-stat in and my car jerks and seems too rich. I was hoping to gain a little power by lowering the engine temps. After researching it seems that with the car not warm enough the computer runs rich(like on start up). And I have heard of some wear issues with the engine too cold. Stock long block and other mods in sig. Any input is appreciated.

 

[bat-stang]

At the 160* temp., the computer doesn't get *into* closed loop operation (nor does it make much heat). Most non- drag applications do better with a least 180*-185* thermostat. I run a 185.

(wrote it wrong, sorry)

 

[John and Renae]

I ran a 180 in my old notch for most of its life. I tried the 160 at one point and the car never cooled properly. Most of it was the fact the temp was too low and the cooling system cannot cycle properly because basically the t-stat will be open 100% of the time. It is just too cold a t-stat and as previously stated the car will never get out of closed loop...it will run really rich and will have issues related to that.

 

[~Ray~]

The computer does not do that, I've been running 160's for years including now.

 

[bat-stang]

(I edited my earlier response-- I meant to say 'goes into closed loop' sorry for any confusion)

South Houston Motorsports disagrees with you, as do several other known tuners. Didn't say your car wouldn't run; I'm sure anything can be tuned around, but there are reasons other than emissions for the 192* thermostat. Also, the way I understand, a programmable computer CAN run in open loop. I have been of the mind that the EEC IV, because of its adaptive program only does this until the parameters within the computers programming are satisfied,then it goes into its closed loop program. From the sources I know and have read, this doesn't happen below 170* and some even feel that the best thermostat for performance applications is 180*. Of course we all have our opinions.

Ray, could you expound on your position? The car will run rich--however some blower companies (I see you run a KB) recommend certain thermostats for their components--but that makes them (imo) the exceptions and not the rule.

 

[bat-stang]

The computer does not do that, I've been running 160's for years including now.

Not to be a butt or anything but before I forget: Ray I have followed your posts for awhile and I think you are obviously very knowledgeable; in the future could you explain yourself with more indepth responses? I am of the opinion that you are misrepresented often and considered argumentative but I don't think that is true. I am here to learn and interact. I don't know much about datalogging, nor (as on another thread) tuning of the different Ford computers. But none of us want to feel like we are being corrected because we are stupid. If we want that, well, we'll go to corner carvers.:thumbsup:

 

[~Ray~]

I know some newer mustangs/Cobras have that issue you speak of but ours do not.

Our computer while in Closed loop "idle & part throttle" uses 02 sensors to measure A/F Ratios adjusting constantly to acheive stoich "14.64". In Open Loop "WOT" the computer stops reading the 02 sensors & uses fuel pressure, certain load, rpm, temperature, etc, etc. Secondly a cooler ECT "cooler thermostat" in our computers would actually call for leaner condition also "not rich" but even so a 20* difference is so little of a difference anyways & as I said is not used in WOT anyways.

Sure a 180 is more optimal for ring/cylinder wear but who cares when the wear is so little on a motor you'll surely have rebuilt or replaced in the next 10,15 or so years anyways.

 

[bat-stang]

Interesting...So what is causing our thread starter his problems with his lean condition? Does he need to cycle the computer or should we be looking elsewhere for the problem?

 

[buddha93]

Either run the 180 or the stock 192. Heck, I even run the stock one in my setup. There's no black magic horsepower to be found in running that cold of a t-stat.

 

['93blownCOBRA]

I live in Mississippi where it is blazing hot most of the year. I also run a blower which can get the engine temp up quickly after a few passes. I have run a 160 in mine since I put the blower on it along with a bottle of Water Wetter. In the cold of the winter street racing at night that huffer really turns on too.

Matter of fact - I rarely put a wrench on the dang thing. It just heeps going and going. Has always run like a top.

I check my TPS from time to time to make sure it's good too go and I also regularly yank the thottle body and carefully clean out the inside of the intake.

blown...

 

[~Ray~]

Interesting...So what is causing our thread starter his problems with his lean condition? Does he need to cycle the computer or should we be looking elsewhere for the problem?

Well he said he has a rich condition if that's true then the first thing I would look @ is his 02 sensors & fuel pressure & yes resetting computer is always a good start, unplug negeative terminal from batter for atleast 30 minutes then hold the brake down for 15 seconds & reconnect the terminal start it let it idle for a few then drive it a few times & see if it don't improve.

 

[rbrown-90]

Thanks for all the info guys. I did put a stock 192 in last night. The 160 ran so cold that the heater was not warm (the hoses under the hood had no pressure as well). I have not noticed any power gain or loss. For some reason the idle does seem better. I will also try to reset the computer and look into the sensors too. Is is possible to have bad sensors and no engine codes?

 

[ScrpnVNM]

I have to disagree on the "no issues with the 160º" thing. I had the same problem as r-brown-90. The car had a 160º t-stat when I bought it and you could smell how rich it was running. Went back to a 192º t-stat and I haven't had issues with running rich again. I didn't notice any driveability issues with it, except the TPS had to be dead on at around .97-.99vdc, or else the thing would flood and stall. I guess different set ups call for different measures.

I think if there was a problem with your sensors a KOEO/KOER self test would let you know.

 

[BADBOYSPACK]

Well he said he has a rich condition if that's true then the first thing I would look @ is his 02 sensors & fuel pressure & yes resetting computer is always a good start, unplug negeative terminal from batter for atleast 30 minutes then hold the brake down for 15 seconds & reconnect the terminal start it let it idle for a few then drive it a few times & see if it don't improve.

I also follow alot of your posts but where the hell did you get that off the wall thing about holding the brake pedal down before you reconnect your battery terminal in order to reset the PCM ? There is another way to reset the PCM if the car is an automatic and requires several different things to be done for the PCM to relearn basic stratigy.

Another thing is if a car is not in closed loop, the car IS running rich. Expecially is you have no cats on the car will smell it more than if you have cats on the car.

I run a 180 stat because I couldnt find a 185 on locally and I live in Central FL and it get very hot here in the summer.

 

[~Ray~]

I also follow alot of your posts but where the hell did you get that off the wall thing about holding the brake pedal down before you reconnect your battery terminal in order to reset the PCM ? There is another way to reset the PCM if the car is an automatic and requires several different things to be done for the PCM to relearn basic stratigy.

That's the guys on Tweecer forums say to do, supposably the computer holds a light charge or something dunno if it's true but I always do it now just to be safe.

Also yes when you first fire up the car it takes about a minute for the 02's to warm up so the computer go into closed loop "start trimming fuel". But stock cars should be fine here that only effects a modified or untuned condition so.

 

[5liter]

The 180 degree tstat is optimal for performance and keeping the engine a bit cooler. The reason most people do it (aside from keeping an engine cooler) is because the computer will pull some timing when the car is operating @ a higher temp. Remember heat is the engines worst enemy (along with friction which causes heat), however going too cold causes problems with the factory PCM's normal operation (not to mention your heater).

 

[93Cobra#2771]

OK, a few myths to dispell here

1. Ray is correct on the brake pedal thing (partially anyhow). You don't have to disconnect the battery for 30 min, though. Disconnect the battery and step on the brake pedal for a full minute. That clears ALL short and long term memory on the EEC. It pulls residual power from the EEC through the brake on/off circuit. Don't bother pulling out your schematics, it isn't listed. Trust me, it works and has been verified by myself.

2. A 160° tstat will not keep the EEC from going into Closed Loop operation. However, the EEC does see that the car is staying cooler than expected, and will throw some more fuel to it through multipliers to try to heat the car up.

3. Yes, our EEC's can be forced to run in Open Loop operation at any time you want it. Or Open Loop all the time if you so desire.