[JFP in PA]

Originally Posted by pk2

JFP IN PA

Very interesting information. You inadvertanly answered 2 sticky questions I was trying diplomatically compose. so moot now. At this quick moment I have, I can recall two comparatively softball questions.

1) As I understand from you and maybe others on this thread, Porsche concocted this whole charade so they could burn up more oil with the extra heat. I thought it was for emission issues but, if it blows out the pipe it's going to hurt not help in this arena(No?) is it blow-by?

Or, Could it be just to mitigate that early morning start-up cloud syndrome that some people have and freak out about? In which case, no matter for me, it would be long gone by the time you get to the smog station.

Tell me they did not do this to try to keep the outside the motor cleaner> avoid build up to...keep the motor running cool? (To ironic)

Thanks as always, gotta run...

PK

Is blow by that going to become aprent or

The use of higher coolant temperatures is done purely for emissions purposes. Running the cooling system at very high temps has been a crutch used by the OEM’s since the late 1960’s when everyone ran carburetors. Running hot helps nearly any engine reduce emissions with the poorly controlled fuel delivery systems that existed at the time. Unfortunately, even though modern injected and ECU controlled systems do not need to run that hot, the band aid has persisted because it also helps extend the cat converter life, and as the cat is covered by the federally mandated 80,000 mile operational life warranty, they will do anything to prevent having to replace the cats.

Interestingly, jacking up the coolant temperatures also lowers the volumetric efficiency and increases the chances for fuel flame front propagation issues (knock, detonation, etc.), so decreases in ignition timing are needed when the engine runs hotter. Net result is poorer performance, worse fuel economy and shortened oil life.

As for coolant temps allowing the oil to “bun off” contaminants; that rationale has always been somewhat suspect as the oil always runs hotter than the coolant anyway, plus the two main contaminants (water and fuel) would still flash off at lower temperatures as well, so lowering the coolant temp 20-30 F should not be a factor.