the srt engineers tried real hard to squeeze every bit of performance they could out of this truck. they had the option of using a 170 / 180 t-stat instead of the 195 they actually used and gotten nice gains from it (a full tenth in the 1/4 w/ the 180 is it?) but decided to go the 195 route. what are the risks of running a lower thermostat?
According to the manual: The values stored in long term adaptive memory are used for all operating conditions, including open loop and cold starting. However, the updating of the long term memory occurs after the engine has exceeded approximately 170°- 190° F, with fuel control in closed loop and two minutes of engine run time. This is done to prevent any transitional temperature or start-up compensations from corrupting long term fuel correction. Long term adaptive memory can change the pulse-width by as much as 25%, which means it can correct for all of short term. It is possible to have a problem that would drive long term to 25% and short term to another 25% for a total change of 50% away from base pulse-width calculation
I do not think dropping it 15-20 degrees is bad. However going to a much lower range will not give the coolant time to actually cool enough in the radiator before being pushed back into the block. Now I know it's a different ball game, but this was a HUGE issue with XJ's with the I6, people would throw a lower tstat on and next thing you know you are on the trail and you are boiling over.
Bud, great post I've always thought too much of a drop can cause negative effectives on the open vs closed loop fuel timing and not mesh well with what the computer is programed for optimal running temp. From what I know the only ill effects on the Jeep is some having the coolant come out of the cap with the aftermarket T-stat but it did happen to me ONCE with the stocker. I'm leaving my stock t-stat in
Actually, they used the higher t-Stat for EMISSIONS reasons only. I and several others have been using 170 and 180 t-stats for over a year and a half... No issues other than cooler engine temps and regained HP..
I'm well over 2 years using lower temp thermostats. No issues ever. I assume my engine will wear out in 150,000 miles instead of 200,000 miles. (of course I'll never see either of those numbers, so it won't matter)
I have a 180 in the SRT-4 and I've had it for months and no problems what-so-ever. Know of a bunch of people in my area as well as other states who are running the 180 t-stat with a few even running 160.
The 180 T-stat will let the engine get up to the temp for activating the short term adaptives and closed loop PCM operation. If it doesn't for more than some period of time I believe it will throw codes. If you put in a 176 T-stat I think this is what you will see.
Here is one of those subjects that has been beat to death :bang: on every forum since late 2005!!! The factory t-stat is rated at 203 and runs the engine at 210-218 (sometimes higher) in my experience. Without a doubt and it has been tested and proven many many.:wallbash:. many.. many.:wallbash:. many.. times that a lower temp thermostat will increase horsepower and torque by 7-10hp/tq and added with other mods this is a substantial gain. It also, in conjunction with a fan mod will tremendously reduce heat soak time.....:wallbash:
LOL....this is a subject that I beat my 2006 Jeep on the dyno trying to prove one way or the other and it still makes me chuckle when I see it come up. I second guessed it and swapped back to stock several times only to finally realize that the vehicle performed far better at the track and dyno with cooler temps.
I have been running a 160* Tstat in my car for over a year and never gotten a code for it...runs on the highway at 157* with no problems.
Everyone pretty much has it covered, but if you live in a very cold climate, such as -10 and lower degree winter weather. I would stay away from the 176, as codes will start to pop up.
