Quote:
Originally Posted by Hags86
This is a scatter plot of my car of oil pressures (Y axis) vs revs (X axis) where the colour is oil temp. The data is a shakedown run on my turbo setup, maybe 5 or 6 laps with just two hot laps. Stock bottom end, 10W-40 synthetic oil, 240rwkW on e85 with an oil cooler.
What this data tells me is 10W-40 is barely thick enough. The cross is showing sample of 52.9psi at 7335rpm with oil temps of 115C. This is too low a pressure.
|
This graph is quite interesting.
One thing I see is that in addition to the pressures at high RPM/high temp being too low (under the target of 10psi/1K RPM) the pressures at lower RPMs with lower oil temps seem to be excessively high.
From what I've read, my guess is that dropping to a 0W-40 oil (that has a comparable 100 deg C viscosity) will drop the low temp data points to a more acceptable level.
I'm also a bit shocked that pressures were recorded in the 75-90 psi range. I figured the stock oiling system would have a bypass valve that limited excess pressures, but perhaps it doesn't?
In reality, these excess low temp pressures (on their own) would likely only be a concern on a street-driven or dual-use car. And even that could be mitigated by letting the car thoroughly warm up before driving.
HOWEVER, changing oil weight to drop these pressures could also work in concert with a new gear/oil pump drive designed to provide greater oil flow, and therefore oil pressure.
Hmmmm.