Quote:
Originally Posted by Dzmitry
Typical data has shown that somewhere before 200-210F, you see fairly consistent pressure increase with an increase in RPM. Somewhere after these temps, you start to see a loss in pressure somewhere past 5-6K RPM.
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So we know a couple of things about the FA engines that are different from previous Suby engines. One is that the ECU is tied into oil temps. So, to the tuners out there, how is the oil temp feedback affecting output variables? We also know AVCS changes ~5,000 RPMs and it causes a pressure drop. Pressure
should stay relatively flat to slight decrease under WOT load through the upper RPMs. Visualization credit here to Nissanfanatic. Not looking at the pressure numbers, that plot is normal for pretty much all Suby AVCS engines.
Quote:
Originally Posted by Dzmitry
This type of data is what started the oil battles on this forum that have been repeatedly discussed. Ideas of cavitation and other theories came about to try and explain what is going on. I recall you mentioning cavitation being unlikely/impossible to be the case on our pumps.
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Thanks so much for the data!
Correct, I have said that. The pump itself will NOT cavitate, it's not one of the characteristics of a positive displacement pump design. Same design is used on much higher reving engines, including motorcycle engines; some that rev to 16,000 RPMs. The problem that CAN occur is aeration from the pump's bypass valve. Given the design, pump output/RPMs, I don't see this as a possibility, especially below 7,000 RPMs. Another indicator that there's not cavitation is that the higher weight oils, and lower temp data, would have feedback that is misaligned from the others, and that posted data doesn't show that. That data looks proportionally correct across the board.
Quote:
Originally Posted by Dzmitry
Since you're quite experienced with Subarus and their oiling systems, I like to keep a close eye at your insight and thoughts on the meaning of all this.  |
Thanks! We are certainly Subay oiling nerds and have collected far more data than anyone else out there that I know of. Knowledge is a never-ending battle!