Quote:
Originally Posted by Jordo!
Anything empirical I can find on modern oils basically points to anything below 300* as acceptable for short periods of time. Running over that on an enduro race could present a problem...
I've found less clear info on how cool is too cool, but if memory serves, ol' A.G. Bell (another plug by me for he  ) notes in several engine building and tuning texts that anything below about 160* F is insufficient for optimal lubing. Technical papers by SAE and whatnot may yield more specific values...
I usually aim for about 175* - 180* as a good lower bound for high load, with about 200* - 210* as ideal, based in part on evidence that the OEM Nissan tune tends to pull a little ignition timing above as you creep above 200* F.
Any water or fuel that may be in the oil is almost certainly not a significant factor at that point (and ideally those values began close to zero anyway...), as another poster noted.
Nissan's 260* F (is it 280*F?) limp mode threshold is undoubtedly tied as much to minimizing warranty claims as anything.
Otherwise I am unaware of any clear data on the point at which the VQ37HR components will begin to fail based on over-heated oil providing insufficient lubrication.
That's all assuming, of course, that the OEM gauge data and what the ECU responds to is consistent with the values obtained from empirical testing... |
Stage 1 limp is at 260F with a rev limit of 5000 rpm I believe and then a stage 2 limp at 280F with a rev limit of 3000 (or 2000?) rpm.
I was just trying to point out that the gauge is reading the coldest point. The oil will be hotter once it enters and cycles through the engine back into the pan, according to the temp sensor placement found out by z1.
Edit. I do remember reading a claim by some one on here that said that the bearings in the motor are of a softer metal (not lead based) and anything over 240F was not good. I think they had taken apart and engine or something. I'll see if I can dig up the thread.
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