If I change the thermostat to a 180, I'm assuming OE is 190-195.
Can anyone clarify for me?
Your EEC will go to closed loop with a 180 degree thermsostat, don't worry. But why are you moving to 180?
No it won't,i ran a 182 in mine for year and it was always in open loop.
Closed loop would be if you ran a 160 stat which is way to low.
The lowest stat you can run properly in a 5.0L is a 180.
I think you have your closed loop and open loop backwards..
Why not, letting her run a bit cooler won't hurt her, it's not like im trying to run her at 100 degrees.
It will just reduce fuel mileage a bit and increase engine wear a tad.
From what I've read and such with the lower temp stat the computer will want to add fuel to help it warm up to normal temp. That is why you see all those chip companys also making cooler stat's for the cars the make the tunners for. Never know my work fine for you but may also drive you nuts. Never know try it and see.
If the info is to be believed in the Probst EEC manuals, with good o2 sensors the system will go into closed loop at far less than 180* degrees... While he doesn't give exact figures, I'm guessing it's some where around 100*-120*... Thats the reason for the heated o2 sensors(that and to maintain closed loop at idle)...
I've run KOER EEC scans on a barely warm engine(just warm enough not to get a temp code) and come up with no faults... The O2 sensors must be switching(operating) to not throw codes... Plus I had a 4cyl Stang that always stalled after approx two minutes on cold start... At that point the temp was barely off the "C"... Changing the o2 sensor was the final fix... If o2 was unplugged so it couldn't try to go closed loop, it never stalled...
How does running the engine abit cooler add on the wear factor?
You have your points, but why don't you elaborate?
You can look at the GUFB and see the computer logic. There is an absolute minimum temperature scalar, I think it is 120 degrees on A9L EECs. (It may not have that scalar - I have the luxury of owning two CFI 3.8s, so I can't do any EEC tuning). Other than that computer goes into closed loop based on several timers related to the ECT temperature at startup. IIRC, there is a hot, warm, and cold timer. Each being progressively longer.
I haven't had time to find it as of yet, but there is a graph of piston wear versus coolant temperature for a given run time. There is less wear for a 195 coolant temp verus 180.
A large difference? No
Enough to be concerned about for a high-powered engine that will see a lot of WOT? No
However, if it's going to be a DD powerplant that is going to die from high mileage, just run the proper stat. OEM's don't run 195+ temps just for emissions.
Regarding the mpg, a cooler engine will be more pr0ne to puddling in the intake ports, and less able to vaporize all the fuel before it enters the combustion chamber. Also, the denser air will increase mass flow and increase pumping losses.
So I take it the OE stat is rated at 195.
I'm only looking for a slight decrease since it will be replaced no matter what, to be on the safe side.
In which case I would only look for a 185-190
i have a 180 AND I THINK IT RUNS WELL I DID 160 AND IT DIDNT LIKE IT
If you're running a bigger cam or more potent heads it would be helpful as those things tend to make the engine temp rise. The SD computer won't have an issue with it.
Jeremy, see my other thread in the electrical section please. You may be able to answer my question!:D