SikGT

Well I plan on flushing my cooling system today and I want to change the thermostat as well. I have an OR/H installed and I haven't ever had a tune or anything like that done to it. Just have the MIL Eliminators on it so I don't know what the pipe would be doing to my air/fuel ratio. Running Lean or Rich, I don't know. But I want to put a colder Tstat. Maybe a step down from stock spec. My question is would it affect my A/F ratio negatively in conjunction with the midpipe and also would I benefit power wise or acceleration response if I did this? Thanks for your replies.


Manny

02 Mustang GT

AJ06GT

No, your thermostat has absolutely no affect on how the engine runs other than it's temperature. It wont make your car any faster or slower, nor will it affect your A/F ratios.

97targa

Your fan is set to run at certain temps and when you changhe your T-stat it will not run insync with each other, but never the less I put a 180 in mine and haven't had any troubles, but I have a bit more than just exhaust!

BuzzCut

Sorry but it does. It determines on when the computer goes into closed loop mode. Where do you people get this crap?

AJ06GT

Uhh, sorry, no. As I said, all it affects is how fast your engine gets warm. Closed loop mode is based on a temperature, not based on what the thermostat tells the computer (the thermostat is purely mechanical on our cars and in no way connected to the computer so it wouldn't be possible). No matter what change you do to your thermostat, the thermostat itself will not affect the A/F ratio. Going into closed loop mode allows the computer to adjust the A/F based on parameters set in the computer.

Next time you're going to act attacking and say something like "Where do you people get this crap?", at least know what you're talking about.

Edit: While I was just now eating after posting this, I was thinking about it, and to give you the benefit of the doubt, perhaps you think that if he gets a cool enough thermostat that his car will never make it into closed loop mode. I'm not sure what the computer is exactly set to, but the temperature to go into closed loop mode is fairly low. Low enough that no thermostat you get will keep you too cool for it. And also, you'll actually hit closed loop in the same amount of time no matter what thermostat you have, so it would still have absolutely no affect.

SikGT

Well I just got back from the shop from having my cooling system flushed and installing a 180 degree thermostat. Man it made a difference! The car feels like it does when I first start it in the morning. Really responsive and it feels like it has more zip to it. Even after it has reached "normal" operating temperature. Car just wants to go. Fans turn on with no problems and car seems to just drive better. Shop did it all for like $20 bucks. Not bad for some cheap maintenance.

AJ06GT

Forgive me for saying this, but I honestly doubt anything you just said. The coolant flows throughout coolant passages in your engine. It never in any way affects the fuel or air or any other important systems, and therefore you car can't be affected, performance wise, by flushing out the coolant system. Hell, even if you were running it so hot it overheated, it wouldn't feel incredibly different until the entire engine blew up. Don't get me wrong, it's good maintenance to do. You need to keep good coolant in there so you don't have freezing or overheating issues, and if you don't flush, the internals can rust and corrode as well. $20 isn't a bad price I suppose assuming they did an actual flush of the system and that included the new antifreeze. It's common to put your foot down a little more after getting something done to your car causing you to think it might be better off, but flushing the coolant system can't restore any performance because it can't kill any performance either.

SikGT

Well it does feel more responsive. I drove it around a bit to see cause after awhile of driving the car seems to feel a bit sluggish. But even after driving around awhile the car felt still responsive. And yes they did do the flush cause I was standing right there as he did it. I wanted to make sure that they did switch the thermostat.

cliffyk

[/align][/align]You are dead wrong about this, the thermostat directly controls the engine's runningtemperature by controlling the flow of coolant--and a lower temperature thermostat will cause the engine to run cooler, assuming that the cooling system has the capacity to shed heat faster (which any properly operating cooling system does). It (the thermostat) is not an open/closed operationaldevice, the degree of opening (no pun intended) varies constantly during engine operation as the temperature of the coolant flowing through it rises and falls.[/align][/align]If the coolant is too cold it closes to restrict or completely block the flow, as the coolant temperature rises it opens to permit more flow. The OEM thermostat is not fully open until 205°F or so, a 180°F t-stat will be fully open by 190°F and will cause the engine to run cooler--if you doubt this then take the t-stat out and you'll find that the engine will run stone cold...[/align][/align]Next, the fuel trim is indeed affected by the engine temperature**, it has to be so the engine can operate properly (and meet emission standards) while warming up. If in closed loop mode the PCM sees a cooler engine it will compensate by enrichening thefuel mixture--this is a fact, you can see it with a wideband sensor.[/align][/align]In conclusion, and although I generally do not seek to provoke things, I have to agree with BuzzCut and ask "Where do people get this crap?"[/align][/align]-----------------------------[/align]**-from the factory workshop manual: "Input from the ECT [Engine Coolant Temperature] or CHT [Cylinder Head Temperature], IAT, and MAF sensors is required to activate the fuel trim system"[/align]

gjscott

The thermostat does not control the flow of the coolant, it simply diverts the flow to the radiator by opening at a predetermined temperature. The water pump speed affects the flow but does not control it.