camaroguy1997

Good evening my fellow LT1 heads. After digging through the old archives of the forums in regards to engine idle temp, tstat, etc. I've come to the conclusion I'd like some updated advice.

My 97 Z28 is going to be heading into the shop next week to find out where my coolant is leaking. I thought while this was being done I would take a look into replace the stock thermostat. I've read that the stock Thermostat on the LT1 was a 180*, and that the first fan kicks on at 226* and the second kicks on at 235*. Most of the recommendations at the time said to get a 160*tstat and a tune from PCMforless to get the fans corrected for the thermostat swap. Is there anyone who recently has done this modification and if so, which Tstat are you running and what does the tune from PCMforless run?

Formula313

I ran 160 in my old firebird with no tune. Ran just fine. Never went over about 175, But the one I have now already had a 160 in it when I bought purchased it. Difference is I noticed is the fans come on almost as soon as I start it & takes longer to warm up. I can sit in idle for a hour on a summer day, I never get past about 163! So putting 2 n 2 together, I think it might have a tune, & it would certainly help keep it cool.

cardo0

At the time for the PCM4less tune i ran a 180* t-stat. But u have to fill out their check list for the tune and u can select any t-stat u want.

My PCM4less tune was just shy of $200 with shipping.

nitrous2fast

iTrader: (2)

I put a 160* stat in my bird and set the fans to kick on at 185* and 200*. Having done that... I should have just lowered the stock fan kick on temp lower to 190* and 210*. I think there might have been a bit of loss in mileage with the lower temps. Maybe just my right foot though. lol

moehorsepower

iTrader: (3)

Running too cool is not good either, 160 is too cold, a running temp of around 180 or so is better. more complete combustion, less contamination of the oil ect.

bowtienut

iTrader: (1)

Because of the reverse cooling, an LT1 sees low 190's ECT with the stock 180 deg tstat, and low 170's with a 160 tstat.
I put a 160 tstat in mine before I did any tuning, and fuel mileage change was zero. With the mailorder PCMforLess tune (for the 160 tstat), mileage increased just shy of 1 mpg.

nitrous2fast

iTrader: (2)

Do you think that the better tune with more timing advance gave more power at lower rpms making it more efficient thus giving better mileage? Or do you contribute the increase in fuel economy solely on the reduce engine temps?

bowtienut

iTrader: (1)

"I put a 160 tstat in mine before I did any tuning, and fuel mileage change was zero."
So, reduced temp alone did NOTHING. But it permitted more aggressive high MAP / low rpm timing, which perked the engine up and improved efficiency.

Catmaigne

iTrader: (6)

Your motor needs to warm up fully so moisture and condensation in your oil can be burned off. My EWP, a tune with low fan temps, and short trips in the winter time made things in the valve covers and oil fill a little foamy. I increased my fan temps to 100/107*C to prevent this. The EWP keeps things cool as is and the temp takes a while to climb sitting in traffic. My gauge usually sits around 185-190*F with the stock thermostat. I wouldn't run a 160 in my car but maybe if my water pump was stock.