Hella-Buggin'

I was at Sonoma today and noticed that on some of the tight hairpins I was having pressure drop to about 2PSI. Both are hard right turns, T7 & T11. At what point should I be concerned with getting too low?

I'm in an 06 997.1 S pretty much stock running Yokohama AD08-R street tires.

the_vetman

2 psi, if accurate, is already way way way too low. You need at least extended pan and baffles, it appears. Accusump should also be considered.

For comparison, 9A1 engines don't get below 45 psi on the track even with sticky R compounds driven aggressively.

M96 and M97 engines were built for only up to 0.8 G before oil starvation (info from Panorama interview with one of top Porsche engineers).

Rob996

Oil starvation is serious business, there are tons of articles and posts covering the topic very well.. You will easily find many types of fixes, from deeper oil pans with baffles that help keep the oil from sloshing around on heavy corners.. The worst kind are long carousel type corners where the oil starvation lasts longer to your poor engine.

Good luck..

ProCoach

10 lbs per 1000 rpm was the rule of thumb, not P-car specific...

Hella-Buggin'

Sorry, I guess the gauge is a x10 so it would be 20psi.
On the "carousel" i was getting about 35psi at about 5000 rpm.

I've looked into Accusump as well as deep sumps. I just can't seem to find enough info to make up my mind. I'd probably rather do an Accusump system to avoid ground clearance issues but maybe that's just an ill informed notion.

If deep sump, which one... Mantis, LNE, others?

Bill Lehman

I have had good results with the Mantis +2 liter pan on a 987.1 engine. You might also look at a Motorsport AOS.

CCA

Consider also your brake and return to throttle technique for the corners you noticed the low pressure. If you carried you braking a little longer than typical or followed the braking with any non-throttle coasting, you can often see drops in pressure. However, if you were on throttle when they occurred than oil pick-up is big concern.

Spinout

If you're reading the '2' on the oil pressure gauge, wouldn't that actually be 2 bar, or 29.4 psi? I had always thought that increment was bar or atmospheres, not psi.

Hella-Buggin'

Very Interesting.... in both of the corners T7 & T11, I'm going from over 100mph
hard braking and shifting down to second to speeds around 30mph. It totally makes sense that I would be carrying my braking longer and coasting if not giving just subtle maintenance throttle to settle the rear around the corner. I've only driven Sonoma a few times and getting the braking right on those two straights to
more than 180 degree hairpins is tricky, especially if I was passing someone.

Hella-Buggin'

Just looked at the manual, yep the gauge is measuring bar not PSI.

Thanks, that moves this issue from need to fix it tomorrow to taking it easy and coming up with a suitable long term plan. It's mainly a street car that sees about 8 events a year so I have to be careful with a deep sump. I don't want to catch it on a curb. Accusump seems like a great idea but it also seems like more of an after the fact bandaid. I could be wrong.

LostSouth

There are numerous threads on this. LN Engineering has a good write up on in somewhere on various solutions. I have been running a 996 with R888 for a year, Hoosiers for a year and now slicks for the past year. I have the FVD deep sump, a motorsports AOS and use a quality racing oil. I have my oil test fairly regularly with no issues.

The longer turns will push the oil to the left or right of the sump. The extended oil pan with baffles keeps more oil centered under the pickup tube. The extended right hand turns tend to load the oil up in the heads and also overwhelm the regular AOS. The deep sump is an easy DIY. The motorsports AOS is a bit tougher due to it's location (I opted to pay to have this done).

I know of at least one heavy racer on slicks that only used the deep sump with good results. My car is lowered, but with stiff suspensions and I have not had any clearance issues.