Lower thermostats, really needed?

[Jennabear]

A common belief is that a cooler running engine will reduce intake air temperature. The reality is that outside of idle, there is very little heat transferred from the engine to the intake charge. The mass of air moving across the incredibly small surface area of the intake ports is too large and too fast to allow for any large temperature transferance.

As a vehicle sits out overnight, you may notice condensation on the windows, hood, etc from moisture in the air. That same moisture ends up in the crank case as well. An engine that does not reach the manufacturers operating temperature will not as easily boil off that condensation, especially if only short trips are taken.

Here is some info to further whet your palate: http://www.tuneruniversity.com/blog/2012/04/low-temp-thermostats-whats-the-advantage/

With a 160* thermostat, the average operating temperature of a GM engine is approximately 180*. With the OEM thermostat, it is around 199*. A few minutes on the dyno can quickly show temps above 210-220*, regardless of the thermostat. As long as intake air temperatures remain static, power output is static and sometimes even BETTER under the 210-220* range.

In short, keep your stock tstat.

[kstruckcountry]

Thanks for the info!

[TJay74]

Jenna the lower stat is not for IAT temps, it is to help reduce engine temps to avoid detonation. I never installed a 160° stat for an intake charge reason. The cooler the engine and heads run the more consistant the power will be and the less the chance for detonation to sneak up on you.

[yukon25008.1]

Your basing your post on people puting lower stats in for pwr gain and/or lower intake temps..

I chose to go with 180 because when im towing or hauling up hills,etc.. I simply do not want them temp over 200 or near boiling, And for the fact that on a big block It does help reduce oil usage! Everyone has different reasons for what they choose to run, Not just what most assume! I would agree that for the proper fuel burning/effeiciency the motor should be near designed operating temp.

But yea..Thanks for the info,

[00Silverado4x4]

Your basing your post on people puting lower stats in for pwr gain and/or lower intake temps..

I chose to go with 180... And for the fact that on a big block It does help reduce oil usage!

Can you explain that one? I don't understand how lower temps reduces oil usage. Curiousity question.

[Jennabear]

The exceptions to this would be the 8.1Ls and the 2500HD 6.0Ls under heavy towing; they have design flaws.

[Jennabear]

Jenna the lower stat is not for IAT temps, it is to help reduce engine temps to avoid detonation. I never installed a 160° stat for an intake charge reason. The cooler the engine and heads run the more consistant the power will be and the less the chance for detonation to sneak up on you.

You are correct, intake air temperature is different than coolant/engine temp, I am not referring to the IATs. I stated that this applies when "inlet temperature are constant". With 99.9% of the vehicles out now having a dry intake manifold, heat soak within the engine effectively does not occur. Any engine bay temperature variation is negligible (exhaust manifolds being the great equalizer). Remember a thermostat is not a cooling device, it is a regulating device. It merely sets the minimum, not a maximum for the regulator to open.

 

Here is an example I used for someone else:

 

If you have two identical candles that you would like to burn out at the same exact time, one in an oven at 150* and one in a freezer at 10*, should you light one earlier? The candle in the freezer would need to be ignited earlier to overcome ambient air temperatures to achieve the same completion time, just like colder air (with density CONSTANT for the sake of discussion) needs to be ignited earlier, hence the timing reduction at higher temperatures. If coolant temps were so critical, you wouldn't see NASCAR running 240-250 for an entire race or 300 during the Bud Shoot out.

[oldscsc]

Your basing your post on people puting lower stats in for pwr gain and/or lower intake temps..

I chose to go with 180 because when im towing or hauling up hills,etc.. I simply do not want them temp over 200 or near boiling, And for the fact that on a big block It does help reduce oil usage! Everyone has different reasons for what they choose to run, Not just what most assume! I would agree that for the proper fuel burning/effeiciency the motor should be near designed operating temp.

But yea..Thanks for the info,

Near 200℉ isn't even close to boiling. Between the increased boiling point of coolant as opposed to water, and the fact that your cooling system is pressurized (1 PSI of pressure further increases the boiling point by 3℉).

 

Also, what temperature does the engine coolant have to reach for the PCM to enter closed loop mode?

[TJay74]

NASCAR doesnt even run a coolant if memory serves me right, so that is not really a good comparison. I have always ran the 160° as they put you at 180° temps once the stat opens.

 

This is one of those mods that are like CAI and UDP. I do it as the car runs more consistant and it is not always the single mod that makes the differance and all of these are mods that always have a ton of input that they work/dont work. Once the weather warms up my truck is getting a 160° and if I find a deal on one a UDP. I installed a 160° in my vette right after I bought it, car runs very well for only putting down 390rwhp with only a CAI and the stat as the mod.

[Jennabear]

NASCAR engines absolutely run coolant. The numbers I posted were from an individual that deals with tuning on them.

 

With proper tuning to deal with the unnecessary timing retardation at higher temps, the t-stat will show no difference in consistency than OEM. Put your car on the dyno and provide it fresh air. You'll find that at 180*, 200* or 220*, power will remain relatively constant or might even increase. We've seen many vehicles make their most power on the dyno at 220-230* ECT.

[MikeNH]

There was a long, long thread back when I first signed up about some guy who ran a cooler t-stat in his truck and the whole slew of codes and other errors it caused, the money he blew trying to fix it, refusing to believe the cooler t-stat was the source of the issues.

 

 

And I'm not trying to be a jerk, but to those who are trying to argue the points the BlackBear folks are making (benefits to big block and HD trucks aside), how much engine tuning experience do you have?

[demech23]

And I'm not trying to be a jerk, but to those who are trying to argue the points the BlackBear folks are making (benefits to big block and HD trucks aside), how much engine tuning experience do you have?

 

[Badass69]

But how much cooler are most of you going. 160 even in a tow pig is too cold most of the time unless you live in a southern US state or something. The stock thermostat temp in the LS powered GMT800's I play with is 186 F........ When I add e fans I just adjust accordingly to that and have no issues.

[kstruckcountry]

I think the point is, if the truck is that hot, the thermostat will be open whether it's a lower or higher thermostat.

 

My truck stays at 193 in town and 191 highway, just about all the time.

[Badass69]

If it's getting too hot towing, loaded, wide open or whatever that is not the fault of the thermostat.... your cooling system at that point is somehow inadequate.

 

Lot's of people try and bandaid that by making the engine run cold in a hope maybe that it will be enough of a buffer to keep it from overheating.