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thstone · 01-30-2012, 05:24 PM

Ok, I'll bite.

I'm not sure that it works as described. When driving down the interstate at 75mph and then jumping on the throttle, the coolent continues to flow at the full rate. The closed thermostat does not slow or hinder coolent flow, it only redirects it (to the first order of operation).

Thus, the theoretical instantaneous spike in coolent temp that happens when the throttle opens isn't real because relatively cool coolent is circulating continuously at full flow at all times and is maintained at a constant temp as the thermostat incrementally opens to divert the some of the now warmer coolent to the radiators to maintain it.

If (and that is a big IF) there is a local hot spot within the engine, then that is a result of poor flow design and is unlikely to be fully mitigated by using a lower temp thermostat (will help under some conditions but not help under other conditions).

The fact that the temp sensor is on the "cold" side of the cooling system is a red herring (meaning irrelevant) because the thermostat operates entirely independent of the gauge reading, i.e., the stock thermostat starts to open at 180F regardless of what the coolent temp gauge reads. Moving the gauge to anywhere else in the coolent system will not change the cooling system performance.

With all of that being said, I definitely agree that heat is the enemy of an engine and better engine heat management is always a good thing!

Shouldn't we also be talking about the benefits of adding the center radiator to the non-S cars that don't have it?

01-30-2012, 05:24 PM	#8
thstone Certified Boxster Addict Join Date: Nov 2010 Location: Los Angeles Posts: 7,669	Ok, I'll bite. I'm not sure that it works as described. When driving down the interstate at 75mph and then jumping on the throttle, the coolent continues to flow at the full rate. The closed thermostat does not slow or hinder coolent flow, it only redirects it (to the first order of operation). Thus, the theoretical instantaneous spike in coolent temp that happens when the throttle opens isn't real because relatively cool coolent is circulating continuously at full flow at all times and is maintained at a constant temp as the thermostat incrementally opens to divert the some of the now warmer coolent to the radiators to maintain it. If (and that is a big IF) there is a local hot spot within the engine, then that is a result of poor flow design and is unlikely to be fully mitigated by using a lower temp thermostat (will help under some conditions but not help under other conditions). The fact that the temp sensor is on the "cold" side of the cooling system is a red herring (meaning irrelevant) because the thermostat operates entirely independent of the gauge reading, i.e., the stock thermostat starts to open at 180F regardless of what the coolent temp gauge reads. Moving the gauge to anywhere else in the coolent system will not change the cooling system performance. With all of that being said, I definitely agree that heat is the enemy of an engine and better engine heat management is always a good thing! Shouldn't we also be talking about the benefits of adding the center radiator to the non-S cars that don't have it? __________________ 1999 996 C2 - sold - bought back - sold for more 1997 Spec Boxster BSR #254 1979 911 SC POC Licensed DE/TT Instructor Last edited by thstone; 01-30-2012 at 05:35 PM.