Lower Temp Thermostat
01-09-2015, 10:08 PM
#31
Rennlist Member
one could argue it as a regional or seasonal thing
in warmer climates or in heavy stop and go traffic, prefer the lower LTS
here in the north where temps rarely break 100, the stock would make more sense
mine is slow to warm anyway, taking 6-8 minutes to reach full temp
in warmer climates or in heavy stop and go traffic, prefer the lower LTS
here in the north where temps rarely break 100, the stock would make more sense
mine is slow to warm anyway, taking 6-8 minutes to reach full temp
01-09-2015, 10:49 PM
#32
Of course no consensus 
Other dead horses: I*S failure (5% or 10%?), best IMS solution, engine oil, transmission oil, n-spec tires, short shifters, anti-seize on spark plug or not, brake vibration dampers or not, clutch helper spring or not,...
All have very little to no scientific proof to convince people one way or the other.
Other dead horses: I*S failure (5% or 10%?), best IMS solution, engine oil, transmission oil, n-spec tires, short shifters, anti-seize on spark plug or not, brake vibration dampers or not, clutch helper spring or not,...
All have very little to no scientific proof to convince people one way or the other.
Never heard so much bickering between guys honestly before I came here. People should use what works best for them and what they believe in but don't bash others for doing so. Kinda like Religion...
01-10-2015, 12:53 AM
#33
01-10-2015, 10:43 AM
#34
Rennlist Member
On other news, OP, did you get your question answered?
01-10-2015, 11:13 PM
#35
Rennlist Member
"Actually, I'm not passionate about one way or another. I'm simply challenging so I can gain knowledge. Actually based on all the info Ahsai has graciously supplied in this thread I'm leaning toward an LTTS."
Information? Really? More like anecdotes at best... Not that I don't like anecdotes... I've been thinking about this issue today (while building my workbench) and the only possible theory/possibility/explanation I can come up with is that - due to the low temp thermostat opening sooner, there is less thermal shock to the crankcase/heads due to the cold coolant rushing into the (less) hot passages. I suppose it's possible that in extreme cases this could cause very thin sections in the heads to crack.
Information? Really? More like anecdotes at best... Not that I don't like anecdotes... I've been thinking about this issue today (while building my workbench) and the only possible theory/possibility/explanation I can come up with is that - due to the low temp thermostat opening sooner, there is less thermal shock to the crankcase/heads due to the cold coolant rushing into the (less) hot passages. I suppose it's possible that in extreme cases this could cause very thin sections in the heads to crack.
01-11-2015, 12:09 AM
#36
From reading this entire thread, my main observation is:
No one has any evidence, statement, etc. that a low-temp thermostat OR a regular thermostat will brick and engine. Maybe some evidence that one may or may not have the potential to do so.. but ultimately, it sounds like no matter what avenue you go with, as long as your thermostat operates properly - your engine will be fine.
Maybe I'm over simplifying.
No one has any evidence, statement, etc. that a low-temp thermostat OR a regular thermostat will brick and engine. Maybe some evidence that one may or may not have the potential to do so.. but ultimately, it sounds like no matter what avenue you go with, as long as your thermostat operates properly - your engine will be fine.
Maybe I'm over simplifying.
01-11-2015, 12:12 AM
#37
Burning Brakes
Tests have found as engine temperature goes down wear increased dramatically.
Wear isn't the reason why we developed the low temp T stat, it was to directly attack cylinder deformation issues that plague these engines.
Macster, ever installed a thermostat in a Porsche engine before? Ever carried out a single comparative valuation with the same engine and two different T stats, back to back before?
01-11-2015, 10:08 AM
#38
Race Director
So you truly believe that these vendors are trying to get rich by selling this $100 part? And JR is risking all his reputation by putting in a part that will create MORE wear and no benefits in all the M96 engine he builds/rebuilds?
And Porsche must be dumb too because they went with a lower temp thermostat for 997s?
And Porsche must be dumb too because they went with a lower temp thermostat for 997s?
As for the 997, the lower temp T-stat is in place to open sooner not because Porsche decided colder was better but to allow the other DME controlled T-stats in the engine control the coolant temperature of the various regions of the engine/cooling system they control.
The word I get is Porsche will implement this change in coolant temperature control in all engines over time.
Porsche is aiming towards more precise control of the coolant temperature during all phases of engine operation.
As such, I expect at some point Porsche will do away with the old fashioned T-stat entirely and just let the DME and its population of T-stats manage coolant temperature.
The old fashioned T-stat is just there in case there's a problem and Porsche can install a higher opening T-stat and disable the DME control of the other T-stats leaving then in their fully open position.
01-11-2015, 10:21 AM
#39
Jake thanks for chiming in on this. Does your low temp t stat operate only as full open or full closed? What is the theory behind its operation and ability to curb cylinder deformation?
01-11-2015, 10:22 AM
#40
Race Director
Thats assuming your cylinders aren't compromised from the factory.
Wear isn't the reason why we developed the low temp T stat, it was to directly attack cylinder deformation issues that plague these engines.
Macster, ever installed a thermostat in a Porsche engine before? Ever carried out a single comparative valuation with the same engine and two different T stats, back to back before?
Wear isn't the reason why we developed the low temp T stat, it was to directly attack cylinder deformation issues that plague these engines.
Macster, ever installed a thermostat in a Porsche engine before? Ever carried out a single comparative valuation with the same engine and two different T stats, back to back before?
Might mention that even then there were a few who would recommend installing a low temp T-stat. It never really caught on and I note automakers could have at any time elected to install one as matter of course, but have chosen not too.
My recommendation to stay the factory T-stat is based on Porsche's testing, not my own testing. My info is Porsche runs a number of test mules thousands of miles in all kinds of climate conditions, from the heat of the desert in the USA southwest (or in South Africa where the local government gives Porsche -- and other cars makers -- carte blanche to drive at high speeds with impunity), to the sub-freezing temperatures of northern Norway in the winter and all temperatures in between. These test mules are heavily instrumented and carefully monitored and checked by a team of Porsche techs for any issues at all.
By overruling Porsche on this matter, then it is your testing that comes in for consideration.
Has your testing even approached the level of testing Porsche does prior to one model's release?
01-11-2015, 10:26 AM
#41
Rennlist Member
Jake,
I'm glad you weighed in on this, as you're one of the "experts" I hoped would comment. Please explain in layman's terms via cause/effect, what the advantage to the low(er) temp thermostat is. Thanks in advance!
I'm glad you weighed in on this, as you're one of the "experts" I hoped would comment. Please explain in layman's terms via cause/effect, what the advantage to the low(er) temp thermostat is. Thanks in advance!
01-11-2015, 10:42 AM
#42
Race Director
Thats assuming your cylinders aren't compromised from the factory.
Wear isn't the reason why we developed the low temp T stat, it was to directly attack cylinder deformation issues that plague these engines.
Macster, ever installed a thermostat in a Porsche engine before? Ever carried out a single comparative valuation with the same engine and two different T stats, back to back before?
Wear isn't the reason why we developed the low temp T stat, it was to directly attack cylinder deformation issues that plague these engines.
Macster, ever installed a thermostat in a Porsche engine before? Ever carried out a single comparative valuation with the same engine and two different T stats, back to back before?
Well, lets consider this then. The low temp T-stat affects of course the coolant temperature. It does not affect the combustion temperature. Thus the surfaces exposed to combustion still get exposed to the same high temperatures.
With a low temp T-stat in place with the resulting slower warm up and the engine being slower reaching temperature equilibrium and this temperature being lower than it would be with the proper T-stat installed the cylinders run cooler then they would otherwise. Yet the piston crown still gets exposed to the same heat of combustion as before.
So the cooler cylinder remains smaller in diameter while the piston still grows in size from its exposure to the heat of combustion.
This works to decrease the clearance between the piston and the cylinder wall, which is already quite small to begin with.
Couple this with cooler oil there is the real concern, at least on my part, about the cooler cylinder with the hot piston being subjected to marginal lubrication. Oil is not pressure fed to the cylinder wall/piston interface so any oil that gets there does so by splash and flow on its own.
But now the oil is faced with flowing into a smaller gap and with the oil at a lower temperature than it would have otherwise.
I note Porsche has a caution to avoid high RPM (>4K) operation until the engine is warmed up. However, with the low temp T-stat in place the engine doesn't obtain the operating temperature Porsche expected when it set this cold engine RPM limit, yet as far as I know no recommendation to use a lower temperature T-stat has come with any change in this RPM limit to take into account the colder oil arising from the lower temp T-stat.
Someone driving around with the colder engine now decides to use a lot of throttle. Of course combustion temperature goes up as then does the temperature of the piston and naturally the piston grows in size. But the cylinder wall already cooler than it would be otherwise has less margin of clearance so my concern would be the piston grows larger and reduces the clearance between the piston and the cylinder even further possibly to the point of oil film break down and metal to metal contact.
It would appear then to address some cylinder deformation one is accepting whether he realizes it or not the increased risk of cylinder wall/piston and ring clearance lubrication issues.
01-11-2015, 01:21 PM
#43
You truly believe all automakers are clueless about engine coolant temperature and the role it plays in all phases of engine operating and all have opted to run T-stats that subject the engine to the wrong operating temperature and two indy engine rebuilders have uncovered this?
As for the 997, the lower temp T-stat is in place to open sooner not because Porsche decided colder was better but to allow the other DME controlled T-stats in the engine control the coolant temperature of the various regions of the engine/cooling system they control.
The word I get is Porsche will implement this change in coolant temperature control in all engines over time.
Porsche is aiming towards more precise control of the coolant temperature during all phases of engine operation.
As such, I expect at some point Porsche will do away with the old fashioned T-stat entirely and just let the DME and its population of T-stats manage coolant temperature.
The old fashioned T-stat is just there in case there's a problem and Porsche can install a higher opening T-stat and disable the DME control of the other T-stats leaving then in their fully open position.
As for the 997, the lower temp T-stat is in place to open sooner not because Porsche decided colder was better but to allow the other DME controlled T-stats in the engine control the coolant temperature of the various regions of the engine/cooling system they control.
The word I get is Porsche will implement this change in coolant temperature control in all engines over time.
Porsche is aiming towards more precise control of the coolant temperature during all phases of engine operation.
As such, I expect at some point Porsche will do away with the old fashioned T-stat entirely and just let the DME and its population of T-stats manage coolant temperature.
The old fashioned T-stat is just there in case there's a problem and Porsche can install a higher opening T-stat and disable the DME control of the other T-stats leaving then in their fully open position.
Hottter running is not best for engine longevity, but engine longevity is not first on Porsche's list, emmisions are since engine longevity doesn't prevent Porsche from putting a car on the market, but emmisions will.
So its all a question of priorities. Porsche rocket surgeons have designed a fantastic cooling system that assures it complies with emmision standards, not necessarily engine longevity. The first thing Porsche has to do is get a car to market, they can deal with longevity problems later.
01-11-2015, 02:35 PM
#44
You truly believe all automakers are clueless about engine coolant temperature and the role it plays in all phases of engine operating and all have opted to run T-stats that subject the engine to the wrong operating temperature and two indy engine rebuilders have uncovered this?
As for the 997, the lower temp T-stat is in place to open sooner not because Porsche decided colder was better but to allow the other DME controlled T-stats in the engine control the coolant temperature of the various regions of the engine/cooling system they control.
The word I get is Porsche will implement this change in coolant temperature control in all engines over time.
Porsche is aiming towards more precise control of the coolant temperature during all phases of engine operation.
As such, I expect at some point Porsche will do away with the old fashioned T-stat entirely and just let the DME and its population of T-stats manage coolant temperature.
The old fashioned T-stat is just there in case there's a problem and Porsche can install a higher opening T-stat and disable the DME control of the other T-stats leaving then in their fully open position.
If your theory was true, we should see all the engines with the low temp T-stat throwing rods and blowing up left and right. The UOA metal should also shoot up the roof. Sorry but I didn't see either.
Re the 997, the fact that the engine uses a low temp T-stat means there a region where the low temp makes sense. Otherwise, they couldd have just reused the regular t-stat.
01-11-2015, 04:55 PM
#45
I know that the first priority of the car companies has to be to meet the emission regulations set by various governments, not engine longevity. I went with the low temp thermostat because I believe Jake and some other experts that have devoted a good portion of their lives to improving the longevity and reliability of these engines and said its the better way to go. Thats their opinion and I'm going with it, they didn't have to meet any government regulations and were concerned only with the other issues that affect the 996 motors.