Why not just remove thermostat?

[Dynomite]

Originally Posted by Hog

I agree with everything Dyno, makes sense. Just a tidbit, lets say your max. temp is going to be 210º no matter the temp of therostat used. If you have a 180º stat, and I have a 160º stat, my car will take longer to reach that 210º max than your 180º stat. Why? Because my stat has started to open at 160º and has been removong heat from teh system, while your car has NOT been removing heat from the system. Assuming all else equal of course.

Your arguements come across as sound to me, but whenever I have swapped from a stock OEM stat to a 160º stat, the engine coolant gauge has always been lower. SO much so, that I swap between my 160º stat for warm weather and the OEM stat for Winter as the interior heat is lacking with the lower rated stat.

There has to be something else at play here. (my experience with stats is not LT5 related-if that matters?)

I concur with you on a non steady state (warming up or cooling down) but after driving for say 30 minutes we have a steady state which I compare.

Now on the experience part where many suggest a 160 deg Stat will run cooler in steady state.....I have no explanation

I am assuming a 160 deg Stat has the same flow rate as a 180 deg Stat when fully open.
I also assume both the 160 deg Stat and 180 deg Stat fully open relatively quickly as I experienced when placing them in a pot of water on the stove with thermometer. At least I thought they were fully opened

[Schrade]

Originally Posted by Bob Eyres

True enough. But as I mentioned before, though the 160deg. thermostat is designed to OPEN at that temp, that doesn't mean that it keeps the engine at that temp.Do we know if there is an average temp. differential between these thermostats? Not just during the warmup cycle.

Do we know what the average engine temp, (on a 70deg day), would be on two identical ZR-1's that had 160, and 180 deg. thermostats, after warm up?
And, what is the ideal engine temp, for performance, on the ZR-1.

This question does not apply to the intake plenum, where I think the ideal temp would be as cool as possible.

These questions are important on the LT5 because it seems to respond very noticeably to changes in temp. On a rare cool day here in Florida, after a short warm-up mine runs much stronger for a while until the plenum gets hot.

That should always be the end of discussions about lower-temp rated thermostats.

And if you have a 160', and LT5 Closed Loop starts @ 167 [?], or 176, that means your mill is going to spend more time in OL. MUCH longer in fact, because MUCH more of coolant is now cycling...


ed.:
Now if your chip was coded to make the fans come on @ 160, or 165, then the fans would do a pretty good job of staying neat that.

[Dynomite]

Originally Posted by Schrade

That should always be the end of discussions about lower-temp rated thermostats.

And if you have a 160', and LT5 Closed Loop starts @ 167 [?], or 176, that means your mill is going to spend more time in OL. MUCH longer in fact, because MUCH more of coolant is now cycling...

ed.:
Now if your chip was coded to make the fans come on @ 160, or 165, then the fans would do a pretty good job of staying neat that.

What did you just say
Did you say your fans (or someones fans) come on at 160 deg F?

Seems to me I recall Secondary fan turns on at 228 deg F and Primary fan turns on at 219 deg F.
I also recall fans turn off with a drop of 11 deg F more or less.
With a chip....Marc sets the fans on at 205 deg F and off at 200 deg F.

I think lower temperature thermostats are a cheap way of trying to lower engine temperatures without having to spend money were it counts (get a Ron Davis Aluminum Radiator)
Or....blow more air through the radiator you have.

[Tyler Townsley]

Originally Posted by Dynomite

I concur with you on a non steady state (warming up or cooling down) but after driving for say 30 minutes we have a steady state which I compare.

Now on the experience part where many suggest a 160 deg Stat will run cooler in steady state.....I have no explanation

I am assuming a 160 deg Stat has the same flow rate as a 180 deg Stat when fully open.
I also assume both the 160 deg Stat and 180 deg Stat fully open relatively quickly as I experienced when placing them in a pot of water on the stove with thermometer. At least I thought they were fully opened

Check the code for fueling, it runs richer at the lower temp which will contribute to some cooling. I once asked Graham why they did not calibrate the car to run at the lower temps and the answer was emissions not power. The car can make more power at 165-175 than it can at 195-205 but it could not be made to comply with all EPA emission constraints at the lower temps.

Tyler

[KILLSHOTS]

Originally Posted by Tyler Townsley

Check the code for fueling, it runs richer at the lower temp which will contribute to some cooling. I once asked Graham why they did not calibrate the car to run at the lower temps and the answer was emissions not power. The car can make more power at 165-175 than it can at 195-205 but it could not be made to comply with all EPA emission constraints at the lower temps.

Originally Posted by Tyler Townsley

Tyler

This is exactly what I thought. My car is emissions-exempt anyway, and I don't care about that. Obviously, a better radiator is the way to go but a cooler stat would help, too. And I don't understand the assertion that a 160-degree stat isn't meant to KEEP it at that temp; I think that's generally understood. The point is that it opens the coolant flow and STARTS the cooling 20 degrees earlier, which will keep the LT-5 from achieving such lofty temperatures in the first place. This is crucial, unless you like your ZR-1 feeling as though you'd misplaced its power key.

Took my car for a drive on surface streets in the 108-degree heat with the A/C on yesterday and it didn't like it one bit. Need to do something soon. A lot of you guys have to "put your cars up" for the winter. I don't want to have to "put mine up" for the summer!

[We Gone]

I run a stock thermostat with marc's chip and with AC on I see temps of 200-210 stopped and as soon as I start moving it stays 193-195. Outside temps 90s

[PhillipsLT5]

GC had luck running a stock radiator in Phx as a daily driver
With his new motor he went to a different radiator & fans
I have luck but running Marcs chip with fluidyne radiator, it really helped over stock radiator, but these cars need to be moving to keep cool in Phx
You can open it @ 160 or 180, but you will be lucky to run at 190-200
Sounds like you may have the typical blocked radiator due to fans sucking air thru along with dirt and blocking flow after years
Ron Davis is local/buy a new stocker/remove & clean 20yr old rad/Dewitts
You do not want to overheat & blow head gasket

[Schrade]

Originally Posted by Hog

I agree with everything Dyno, makes sense. Just a tidbit, lets say your max. temp is going to be 210º no matter the temp of therostat used. If you have a 180º stat, and I have a 160º stat, my car will take longer to reach that 210º max than your 180º stat. Why? Because my stat has started to open at 160º and has been removong heat from teh system, while your car has NOT been removing heat from the system. Assuming all else equal of course.

Your arguements come across as sound to me, but whenever I have swapped from a stock OEM stat to a 160º stat, the engine coolant gauge has always been lower. SO much so, that I swap between my 160º stat for warm weather and the OEM stat for Winter as the interior heat is lacking with the lower rated stat.

There has to be something else at play here. (my experience with stats is not LT5 related-if that matters?)

Where is the guage temp signal coming from??? Is the temp sensor located where out-of-block [cooler] coolant is coming INTO the CTS???

Originally Posted by Jim Nolan

I have a 160 thermostat in mine and the fans programmed to come on at 185 and off at 180. In the summer months it normally runs 190, some times 200 in slow traffic. I never liked it stock running at 220-230 and on a really hot day in traffic 235.

It's surprising to me that the fans don't take coolant temps back down to your shutoff temp...

Originally Posted by KILLSHOTS

This is exactly what I thought. My car is emissions-exempt anyway, and I don't care about that. Obviously, a better radiator is the way to go but a cooler stat would help, too. And I don't understand the assertion that a 160-degree stat isn't meant to KEEP it at that temp; I think that's generally understood. The point is that it opens the coolant flow and STARTS the cooling 20 degrees earlier, which will keep the LT-5 from achieving such lofty temperatures in the first place. This is crucial, unless you like your ZR-1 feeling as though you'd misplaced its power key.

Took my car for a drive on surface streets in the 108-degree heat with the A/C on yesterday and it didn't like it one bit. Need to do something soon. A lot of you guys have to "put your cars up" for the winter. I don't want to have to "put mine up" for the summer!

I disagree with this.

And it seems that Jim Nolan's ECM coding, above, points this out - he still had his fans coded to come on at a lower temp, because the coolant still will exceed the rated temperature of the stat - 160, and even then, his fans don't take temps down to that fan shutoff temp that he coded. THAT part is surprising to me...

Originally Posted by Dynomite

What did you just say
Did you say your fans (or someones fans) come on at 160 deg F?

Seems to me I recall Secondary fan turns on at 228 deg F and Primary fan turns on at 219 deg F.
I also recall fans turn off with a drop of 11 deg F more or less.
With a chip....Marc sets the fans on at 205 deg F and off at 200 deg F.

I think lower temperature thermostats are a cheap way of trying to lower engine temperatures without having to spend money were it counts (get a Ron Davis Aluminum Radiator)
Or....blow more air through the radiator you have.

I said IF...

ME
Now if your chip was coded to make the fans come on @ 160, or 165, then the fans would do a pretty good job of staying neat that.

And JN's chip is coded CLOSE to that...

[Dynomite]

Originally Posted by Schrade

I said IF...

OK

Now if anyone has a stock radiator with stock engine and say a 160 deg - 165 deg thermostat and fans coming on whenever.......and running stop and go with ambient temperature 100 deg F.....tell me what the temperature gauge reads.....and then go and read the temperature digitally using HVAC to confirm.

Press both Fan Up and Fan Down together waiting 3 seconds to enter HVAC diagnostics. Then press Fan Up to parameter #16 and then press Auto (between the two Fan Buttons) to read the Engine Coolant Temperature in deg C which Engine Coolant Temperature will be a real time continuous reading.

See Using HVAC Display for Engine Coolant Temperature

Just interested

[Schrade]

Originally Posted by Dynomite

OK

Ain't ya' got 20/20 hearing?

Now if anyone has a stock radiator with stock engine and say a 160 deg thermostat and fans coming on whenever.......and running stop and go with ambient temperature 100 deg F.....tell me what the temperature gauge reads.....and then go and read the temperature digitally using HVAC to confirm.

Press both Fan Up and Fan Down together waiting 3 seconds to enter HVAC diagnostics. Then press Fan Up to parameter #16 and then press Auto (between the two Fan Buttons) to read the Engine Coolant Temperature in deg C which Engine Coolant Temperature will be a real time continuous reading.

See Using HVAC Display for Engine Coolant Temperature

Just interested

Me too here. Why does JN's temps not go back down with his lower fans kick-on temp coding???

And why does Hog's run a little cooler, with only a lower temp stat????????????