Quote:
Originally Posted by mikefocke
JFP.
Great response.
But the evidence based on immediate max power and racing revs is somewhat different than the 3500 RPM limit until 12 miles and warm I was describing in an every day car. Or is it? How much is enough? In racing every HP counts. But do I care if I lose 2 or 3. I'll still make it to the grocery store.
Is there any system in our cars that pumps/sprays the oil and delays the start for a few seconds to get the oil flowing? You would think there should be given what you describe.
The thermostat limits the water cooling until warm. The oil/water exchange helps warm the oil. The side air exchange fan doesn't come on till the engine compartment is hot. All show Porsche thinks quick orderly warmups are important. Is there any other system?
Sisu. Agreed. I'm just trying to establish the degree.
I used a rev limit until warm and even then I didn't hammer it. Is that enough or do we need heated garages and to what temp? Block heaters? Fluid heaters?
(Lets limit the discussion to moderate (28f to 100f) temperature climates with 0w-40 oils. Alaska is just different.)
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Mike, the entire point is about component wear due to dimensional shifts as the engine heats up. All alloy engines move around quite a bit as they warm up, enough that astute machine shops actually do their work on the major engine components only when they are at normal operating temperatures, which is where they spend most of their lives. And the dimensional differences between running temp and normal room temp are considerable, enough that engines prepped this way actually make more power because everything is where it is supposed to be at temp. Add in the high thrust angle inherent in the flat six design, plus the poor film strengths inherent in 0W oils, and you get excessive piston and cylinder wear (scuffing), which becomes even worse on DFI versions.
Coolant heaters, which are often used on race engines, greatly reduce the wear caused by dimensional stress induced wear that cold starts result in. Heated storage is always a plus for any vehicle, even for components outside the engines or drivelines, but normal storage temps (55-60F in our storage facility) is not warm enough to dramatically alter the engine warm up wear patterns. The coolant needs to be 150-170F to make a real difference.
Because of the differences in wear patterns we have seen, if a customer asks our recommendation, I would tell them to let the car sit and warm up at least until the heater starts to blow warm before moving the car, and then take it easy until the car is up to temp.