MFGJR

I'll see if i can steal a few holiday minutes to post up a pressure vs. rpm comparison. It'll probably be April before I'm on track again, with some sort of aftermarket solution. We'll see what the data says then.

PPo

This is an interesting thread.

Is anybody able to correlate the drop in oil pressure to eventual or acute engine issues?

How many of the 996 engine failures are a direct result of oil starvation?

I understand that many 996 engines end up with scored cylinders, and scored cylinders can be attributed to poor oiling. Other things can cause oiling issues that result in scored cylinders besides oil pressure. What I am really trying to understand:

Is the oil pressure dropping to 2 bar a concern?

I race and have tracked 944 based cars for many many years. Last year I was told by somebody who "knew everything about these cars" that you cannot track a 944 reliably because the #2 rod bearing WILL fail. They where so adamant that they said a 944 would never finish a ChumpCar race. Well after 4 ChumpCar races in 2016 (and many many other years of driving a 944), I have yet to experience a rod bearing failure. I know people that have, and I believe I know the mistake that leads to it, but that's not the point I am trying to make. If the oil pressure drop is known to be the problem, then it needs to be addressed, but you should have seen the signs of a problem already if it is indeed the problem. Keep your oil fresh, use quality oil, keep the level properly adjusted, and even at 2 bar (28PSI!) you have adequate oiling IMHO.

PPo

Please do... I am very interested in seeing the data.

MFGJR

Oil pressure on the top, rpm on the bottom.





That's the important question--is 2 bar/28psi too low? And that prompts another question, possibly impacting the data I've presented: My gauge typically reads 5 bar at decent rpm, which would be, what, ~72psi? In its data protocol, Aim expresses oil pressure in psi, and it's topping out at 45 psi where you'd expect 72... is Aim's calibration off? Does anyone else have reliable ool pressure readings in psi?

MFGJR

Interesting thread here, especially post #23, re: location of the sensor.
https://rennlist.com/forums/racing-a...weepers-2.html

And, I'm beginning to suspect that even though Aim labels oil pressure as psi, it's really bar without the decimal, i.e., what looks like 45 psi might well be 4.5 bar (see that graph at the aforementioned post in the other thread). I'll post in the data acquisition subforum about that, and will edit this thread if I can nail that issue down.

Slakker

Great data. There does appear to be an RPM correlation though which actually makes a whole lot more sense.

91K-Man

Aim data can be in either PSI or bar. User defined

Frank 993 C4S

Good observation - this is typical for engine driven oil pumps.

MFGJR

At first glace, it appears so, as the pressure drops generally occur at the slower turns which are inherently (at least for me) lower rpm. But take a closer look and check if you still see it. The drops are often happening where rpm is rising (e.g., T5) and you'll see max oil pressure elsewhere at similar rpm to where some of the drops occur.

I have it set to psi in the protocol, but a max pressure of 45psi on the logger vs. 5 bar on the gauge doesn't make sense, whereas 4.5 bar does. When I get back home, I can do a comparison using both the bar and psi setting, and see if that sheds any light.

DeanClevername

When you install the Mantis deep sump on a 996, do you cut holes in the windage tray to clear the swirl pots or do you upgrade to the 997 style oil return tubes that don't require changes to the tray?

Aspen Autosports

We have installed it both ways. Upgrading to the 997 part is more cost effective if I remember correctly it's about $25 for each part. Cutting the windage tray is a bit of a pain but it does work well.

Slakker

You might look at this one. Easy to install and works well.

http://www.fvd.de/us/en/Porsche-0/91...otorsport.html

NYoutftr

That FVD unit looks like about the best built unit.

A lot more $$ than just going with the X51 baffle, but probably comes down to penny wise and dollar foolish

Thanks for link, now I have to add that to my wish list.