Quote:
Originally Posted by nemo
So then an oil pan warmer might produce better fe than a block warmer. I wonder if this is in part caused by oil viscosity? The 212 oil temp is that the spec for your car? I know this is a general rule for block temp.
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Yes I think it is actually entirely caused by oil viscosity. I've been reading bobistheoilguy and apparently the difference in oil pressure at startup is as much as 20 psi
between different 0W-20 rated oils, with Toyota's 0W-20 having the highest viscosity index. Maybe I read it wrong, but someone definitely posted saying that their oil pressure dropped 20psi when switching to Toyota 0W-20, and I don't think they were going from a 40 or 50 weight oil either. In fact Toyota's 0W-20 is so good that some people there apparently recommend adding some as "viscosity index improver". Seems like a thinner oil is the easiest way to get better gas mileage on shorter trips.
100C is a typical temperature for listing the oil viscosity at, I think it's considered the "correct" temperature.
Perhaps a good fuel economy addition could be an oil to water oil cooler. "Coolers" are usually used to reduce oil temp on the track, but obviously if the water is hotter than the oil, then the water will heat the oil up
