Engine operating temps
02-02-2007, 11:15 PM
#1
Rennlist Member
Thread Starter
Engine operating temps
My 997TT is my first "wet" turbo. My previous, air-cooled car (930) came with advice to avoid hard boost levels unti the engine reached a suitable operating temp as indicated by the engine temp gauge. Assuming the same kind of general precaution is resonable for the wet cars, what temp should be used as a guide for engine operating temp safe for full boost? Coolant temp? or oil temp? The owner's manual doesn't address this and I'm hoping some of you seasoned 996TT owners might know. Seems like oil temp would be the one to use. Any opinions? TIA
02-03-2007, 02:13 AM
#2
Burning Brakes
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Hello,
to kick this off, it is relatively unknown that the main anti-wear (AW) additives in the oils we use (synthetics) typically start to become most effective above about 55C. Most of "our" lubricants are comfortable operating in a "sump" temperature of around 90-120C
It is common to have oil return temperatures from turbochargers in the 140-180C range. An IR temperature reader makes such readings quite easy
It is common for the oil's temeprature to lag behind the coolant's for up to about 20 minutes or more at cold startup depending on ambient/use etc. - until the "normal" operating equilibrium is reached
It is also common - depending on the lubricant's formulation (Viscosity Index) - to have a huge disparity in Approved lubricants with only small viscosity variations as they warm up.
As an example, at an oil temeprature of 40C, Mobil 1 0w-40 has a viscosity around 30% thinner than a 5w-40 version
I hope this helps - IMHO in answering your query, the lubricant's temperature is the best guideline
Regards
to kick this off, it is relatively unknown that the main anti-wear (AW) additives in the oils we use (synthetics) typically start to become most effective above about 55C. Most of "our" lubricants are comfortable operating in a "sump" temperature of around 90-120C
It is common to have oil return temperatures from turbochargers in the 140-180C range. An IR temperature reader makes such readings quite easy
It is common for the oil's temeprature to lag behind the coolant's for up to about 20 minutes or more at cold startup depending on ambient/use etc. - until the "normal" operating equilibrium is reached
It is also common - depending on the lubricant's formulation (Viscosity Index) - to have a huge disparity in Approved lubricants with only small viscosity variations as they warm up.
As an example, at an oil temeprature of 40C, Mobil 1 0w-40 has a viscosity around 30% thinner than a 5w-40 version
I hope this helps - IMHO in answering your query, the lubricant's temperature is the best guideline
Regards