engine temp.
03-26-2017, 01:32 PM
#1
Registered User
Thread Starter
Join Date: Sep 2015
Posts: 87
engine temp.
Hey Members,
My transplanted Lt1 always runs between 180 and 190 degrees. My radiator fan kicks in at 185. Car runs really great with a stock exhaust, no
cats. Checks out fine from open loop to closed loop. Should I be running a bit hotter? I heard that it sometimes helps improve gas mileage? Thanks.
My transplanted Lt1 always runs between 180 and 190 degrees. My radiator fan kicks in at 185. Car runs really great with a stock exhaust, no
cats. Checks out fine from open loop to closed loop. Should I be running a bit hotter? I heard that it sometimes helps improve gas mileage? Thanks.
03-26-2017, 02:14 PM
#2
Registered User
Join Date: Jun 2003
Posts: 1,083
Re: engine temp.
stock T stat is 185
is the PCM programming stock?
your operating temps are fine. If your pcm is controlling the radiator electric fan the on temp sounds about right. It may be on a little lower than stock programming
someone should be able to reply when fan temps are commanded on with stock pcm tuning. The donor car would have had two fans which come on at different temps. If you have a single fan it is likely seeing the primary fan on command from the pcm...
will you see better MPG running a little hotter...maybe 1
is the PCM programming stock?
your operating temps are fine. If your pcm is controlling the radiator electric fan the on temp sounds about right. It may be on a little lower than stock programming
someone should be able to reply when fan temps are commanded on with stock pcm tuning. The donor car would have had two fans which come on at different temps. If you have a single fan it is likely seeing the primary fan on command from the pcm...
will you see better MPG running a little hotter...maybe 1
03-26-2017, 04:56 PM
#3
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: engine temp.
Stock t'stat is 180°F. Stock fan on temps are 226°F first fan (early 94) or both on low speed (late 94); 235°F second fan on (early 94) or both on high speed (late 94). Popular mod is a 160°F t'stat and reprogram the fan on in the range of 180-195°F.
Lower coolant temp reduces the completeness of combustion, and reduces fuel economy, which increases emissions. I doubt you would notice the change in fuel economy. Easy to test, just reset the fan temps higher. Probably a good idea to run the numbers (miles driven / gallons pumped) for at least 10 tanks or so for each condition. Just the difference in weather conditions will still probably mask any meaningful results.
Power gains w/ 160° t'stat.
Drivetrain Modifications #3
Lower coolant temp reduces the completeness of combustion, and reduces fuel economy, which increases emissions. I doubt you would notice the change in fuel economy. Easy to test, just reset the fan temps higher. Probably a good idea to run the numbers (miles driven / gallons pumped) for at least 10 tanks or so for each condition. Just the difference in weather conditions will still probably mask any meaningful results.
Power gains w/ 160° t'stat.
Drivetrain Modifications #3
03-27-2017, 08:52 AM
#4
Registered User
Thread Starter
Join Date: Sep 2015
Posts: 87
Re: engine temp.
Stock t'stat is 180°F. Stock fan on temps are 226°F first fan (early 94) or both on low speed (late 94); 235°F second fan on (early 94) or both on high speed (late 94). Popular mod is a 160°F t'stat and reprogram the fan on in the range of 180-195°F.
Lower coolant temp reduces the completeness of combustion, and reduces fuel economy, which increases emissions. I doubt you would notice the change in fuel economy. Easy to test, just reset the fan temps higher. Probably a good idea to run the numbers (miles driven / gallons pumped) for at least 10 tanks or so for each condition. Just the difference in weather conditions will still probably mask any meaningful results.
Power gains w/ 160° t'stat.
Drivetrain Modifications #3
Lower coolant temp reduces the completeness of combustion, and reduces fuel economy, which increases emissions. I doubt you would notice the change in fuel economy. Easy to test, just reset the fan temps higher. Probably a good idea to run the numbers (miles driven / gallons pumped) for at least 10 tanks or so for each condition. Just the difference in weather conditions will still probably mask any meaningful results.
Power gains w/ 160° t'stat.
Drivetrain Modifications #3
03-27-2017, 09:58 AM
#5
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: engine temp.
Why not just let the stock PCM control the fans? GM designed the engine to run at 210°F, for a decent balance of low emissions and good gas mileage. Oil stays warm enough to boil off harmful condensates. Absolutely no down side to running that way, except for the 5 HP you could gain with lower temps.
Seriously doubt you could measure or notice any difference in fuel economy running a bit warmer. Right now, your 185°F fan on is fighting the t'stat. A 180° t'stat only starts to open at that temp, not fully open until ~200°. You are putting unnecessary wear on the fan, and making the water pump work harder against a partially closed t'stat.
Seriously doubt you could measure or notice any difference in fuel economy running a bit warmer. Right now, your 185°F fan on is fighting the t'stat. A 180° t'stat only starts to open at that temp, not fully open until ~200°. You are putting unnecessary wear on the fan, and making the water pump work harder against a partially closed t'stat.
03-27-2017, 06:52 PM
#6
Registered User
Thread Starter
Join Date: Sep 2015
Posts: 87
Re: engine temp.
Why not just let the stock PCM control the fans? GM designed the engine to run at 210°F, for a decent balance of low emissions and good gas mileage. Oil stays warm enough to boil off harmful condensates. Absolutely no down side to running that way, except for the 5 HP you could gain with lower temps.
Seriously doubt you could measure or notice any difference in fuel economy running a bit warmer. Right now, your 185°F fan on is fighting the t'stat. A 180° t'stat only starts to open at that temp, not fully open until ~200°. You are putting unnecessary wear on the fan, and making the water pump work harder against a partially closed t'stat.
Seriously doubt you could measure or notice any difference in fuel economy running a bit warmer. Right now, your 185°F fan on is fighting the t'stat. A 180° t'stat only starts to open at that temp, not fully open until ~200°. You are putting unnecessary wear on the fan, and making the water pump work harder against a partially closed t'stat.
Thinking about going to a 160 stat so my water pump and fan do not have to work so hard. Any part numbers available for the 160 stat.?
