Riddle me this

[Willfulone]

Why do some tuners ask that you install a 160 degree T-Stat when you do certain mods.

I was always under the impression that when the T-Stat opens, it opens.

So if it opens at 160 or 180, the car still goes to 194-210ish when running.

Why the 160 T-Stat?

Peace
Chip

[Y2Kvert4me]

Why do some tuners ask that you install a 160 degree T-Stat when you do certain mods.

I was always under the impression that when the T-Stat opens, it opens.

So if it opens at 160 or 180, the car still goes to 194-210ish when running.

Why the 160 T-Stat?

Peace
ChipThat's a common myth that many people think.

With an adequately efficient radiator, when the car is moving, coolant temp should run at or near the thermostat rating. The Tstat is actually starting to close, or remaining in a partially closed state. It is doing it's job of keeping the temperature warm enough by controlling the flow through the radiator.

Now, when the car comes to a stop, and there is no airflow through the radiator, the Tstat fully opens, but despite that, the temperatures continue to climb, until such a time the fans turn on and bring some air through the radiator.

Now, here's where the two components tie together. We've been told by many engineers and experts that the LS engines have a "sweet spot" of optimum coolant temps in the 180-195° range.

With the stock thermostat, you probably find your temps while moving hover right around 192°, right in the range you want to keep it at. But what about the fans....they don't trigger on until at least 219° (depending on year of car). So we want to reprogram the fans to come on sooner, and not let it get so hot, that's easy...but you cannot cool it down more than what your normal moving temps are, because the Tstat will begin to close, and the fans will never reach thei turn off setpoint, and thus, never shut off.
So with the stock Tstat, you can probably set the fans to cool down to maybe 195° at best. (I prefer to have them turn off at least 10° higher than normal moving temps, but this can be pushed.

So, now with a tune, and perhaps some changes to the timing, lets say you want to keep it even cooler to prevent any knock retard from occurring, and run the fans down even more. This is where the lower temp Tstat is needed.


I have a 160 stat in mine. With it, I find my normal moving temps run about 176-178°...kinda tells me it's not really a 160 stat, but that's ok, I really don't desire it to run at 160 anyways.
I have my fans turning on at 195°, and turning off at 185°. My total window of operating temp is now 176-195°....right where I want it to be at all times. That would not be possible with the stock thermostat.


Hope that makes sense.

:cheers:

[Sneaks]

That's a common myth that many people think.

With an adequately efficient radiator, when the car is moving, coolant temp should run at or near the thermostat rating. The Tstat is actually starting to close, or remaining in a partially closed state. It is doing it's job of keeping the temperature warm enough by controlling the flow through the radiator.

Now, when the car comes to a stop, and there is no airflow through the radiator, the Tstat fully opens, but despite that, the temperatures continue to climb, until such a time the fans turn on and bring some air through the radiator.

Now, here's where the two components tie together. We've been told by many engineers and experts that the LS engines have a "sweet spot" of optimum coolant temps in the 180-195° range.

With the stock thermostat, you probably find your temps while moving hover right around 192°, right in the range you want to keep it at. But what about the fans....they don't trigger on until at least 219° (depending on year of car). So we want to reprogram the fans to come on sooner, and not let it get so hot, that's easy...but you cannot cool it down more than what your normal moving temps are, because the Tstat will begin to close, and the fans will never reach thei turn off setpoint, and thus, never shut off.
So with the stock Tstat, you can probably set the fans to cool down to maybe 195° at best. (I prefer to have them turn off at least 10° higher than normal moving temps, but this can be pushed.

So, now with a tune, and perhaps some changes to the timing, lets say you want to keep it even cooler to prevent any knock retard from occurring, and run the fans down even more. This is where the lower temp Tstat is needed.


I have a 160 stat in mine. With it, I find my normal moving temps run about 176-178°...kinda tells me it's not really a 160 stat, but that's ok, I really don't desire it to run at 160 anyways.
I have my fans turning on at 195°, and turning off at 185°. My total window of operating temp is now 176-195°....right where I want it to be at all times. That would not be possible with the stock thermostat.


Hope that makes sense.

:cheers:

Couldn't have said it better myself. And glad I didn't have to. That's a lot of typing! :lol:

[DropTheTop]

Great info, Thanks! :cheers:

[WKMCD]

:iagree: Consider yourself riddled.

[Neutron]

Wow, Tom you know your stuff. Thanks for the info. :cheers:

[C5 BEARSFAN]

Great bit of info there Tom

[Bluezey]

[QUOTE]Wow, Tom you know your stuff. Thanks for the info. QUOTE]
:iagree:[/

Well put ! :yesnod:


Bluezey

[DaveK88]

I have a question. If the sweet spot is 185 - 195 and with a 160 t-stat you are only reaching 175 ish. Aren't you missing the ultimate running temp?

[Y2Kvert4me]

I have a question. If the sweet spot is 185 - 195 and with a 160 t-stat you are only reaching 175 ish. Aren't you missing the ultimate running temp?I guess I see it like this...Holding ECT within a 10° window at all times is a bit tough to pull off. With a good aftermarket radiator, and a 180 Tstat, you could probably do it, as more efficiency in heat removal will inherently stabilize the moving temps better.

So to answer the question I guess I'd prefer it to run it a little cooler, rather than a little hotter, if forced to run outside that window.

I also said that "sweet spot" statement had been made by GM engineers, which assume a stock engine....not quite as applicable to the guy running boost or a 12:1 compression engine.

Coolant temp affects the cylinder heads and combustion chamber more than anything else. Oil temperature is important, but not in that area so much.

The argument of running the engine (coolant temp) "too cold", is because you may not get the oil temp hot enough to burn off contaminants and allow for planned expansion and fit between moving components. Even running at 175, I never have troubles getting oil temp up over 200, so that logic doesn't seem to apply.

The bottom line is you want cool heads, and a hot engine for the best of all worlds. There's nothing wrong with running coolant temp too low, if the engine itself (oil) is getting hot enough.


:cheers:

[Junkman2008]

Just so I'm clear with your description, you are NOT saying that the thermostat can regulate the final engine temperature, correct?

[Y2Kvert4me]

Just so I'm clear with your description, you are NOT saying that the thermostat can regulate the final engine temperature, correct?The thermostat regulates the lower end of the normal operating temperature spectrum.

While moving (abundant airflow through the radiator), you should find your coolant temp hovering near the rating of the thermostat. In this case, yes, the thermostat is regulating the temperature - it is doing it's job of keeping the coolant hot enough by controlling coolant flow through the radiator.

On a stock C5, this temperature will be right around 192°. As stated, mine normally runs about 176° when moving. That is the difference in Tstat only. My normal operating temperature definitely did drop.


The thermostat can NOT limit the maximum temperature the coolant reaches.
If you find it running hotter than say 200° while moving, it suggests blockage or reduced airflow through the radiator, or in extremely hot climates, the capacity of the stock radiator might be exceeded.

If the car is idling, or not moving, then it is the job of the fans to introduce airflow and control the maximum temps.


:cheers:

[Junkman2008]

Okay, I'll say this and see if you agree with me because I'm still a liitle unclear with your description. The thermostat does not regulate engine temperature. It only dictates at what temperature coolant begans to flow througout the engine. Actual regulation of engine temperature is dependent on all of the components of the cooling system (radiator, tstat, cooling fans, water pump and air flow).

[Y2Kvert4me]

Actual regulation of engine temperature is dependent on all of the components of the cooling system (radiator, tstat, cooling fans, water pump and air flow).That is correct.

I just defined in what area the tstat does contribute to the regulation.

:cheers:

[Junkman2008]

That is correct.

I just defined in what area the tstat does contribute to the regulation.

:cheers:

Okay, we're on the same page then. You just use bigger words than I do. :lolsmile:

[Sneaks]

Okay, we're on the same page then. You just use bigger words than I do. :lolsmile:

I speak Kentuckian: That thar temp thingamajig heps keep it from boilin over.
Better now AJ? :D
:lol:

[Junkman2008]

I speak Kentuckian: That thar temp thingamajig heps keep it from boilin over.
Better now AJ? :D
:lol:

Your mom said to come home. She said bring a switch with you too. :lolsmile: