rockhouse66

I guess I skipped a step in my description. I meant that the scavenge pump supplies an air/oil mix to the sump where the main oil pump picks it up and pumps this air/oil mixture to the bearings (and pressure sender). I understand that the pressure sender is after the main oil pump, not the scavenge pump. Thanks for clarifying this.

jandackson

Way back when, I had an air cooled beetle as my first car. I beat hell out of that car, doing donuts in wet parking lots, catching air over RR tracks etc.
then I built a bigger motor for it. As part of the build, I installed aVDO oil pressure gage to supplement the stock low oil pressure light. The sender was the same VDO unit that is used in the 996. Around sweeping on ramps, the oil pressure went to zero. Never did that with the stock engine. I pulled the sender and went back to the standard sender (without the second output for gage) and the oil light never came on.

My my buddy had the same experience in his beetle with a bored out engine and VDO sender.

Bottom line, the sender seemed to be the culprit. It could not handle even moderate g's without reading incorrectly. I wonder if that is contributing to the issue on the 996? Is the sender reacting to the g forces and malfunctioning? How can guys drive on track for extended miles with this problem and not have evidence of low oil pressure damage in their engines?

rockhouse66

Well that's an interesting angle on this. I did replace the sender and only noticed this oil pressure drop afterwards. Hmmmm....

Kris Murphy

Wow. That is great insight. I wonder how that can be tested? Has anyone ever hooked up another oil pressure sensor?

As I noted earlier in the thread, this just started happening to me this year, after an engine swap. Never happened before. In my case, it starts happening after about 10 minutes on the track, after the oil is nice and hot. I have a deeper pan, and am running XP9.

The last track event, when it was happening, as soon as I was out of the turn, it would go back up to between 4-5bar This past weekend, even when I was out of the turn, the needle would bounce up and down before it would go back to 4-5bar in the straight, kind of acting like a broken gauge.

These cars are fun! To top it off, all of my oil pressure trouble shooting was rewarded with a blown AOS. This AOS made it 1600 miles, a factory Porsche part.

MoeMonney

This is what LN recommends.

Mike Murphy

I disagree on the ring compressor. I use photo paper with a bunch of rubber bands.

2002C2

So I have a related question. Driving home from work I get off the highway after normal driving and when I get to a stop sign I occasionally get a low oil pressure warning. Oil is topped up and recently changed. Warmer weather but not scorching up here in the NE. A quick blip makes it go away. Normal? Thanks.

Quadcammer

AOS is the bain of my existence. I should bill NJMP for my mosquito killing services. At least its easier to change on my boxster. very frustrating.

Kris Murphy

Yeah, I kept hearing your car/number called over the radio for your clouds. I stopped driving mine after it started. Now just need to figure out if I have time to change it before the Glen or if I need to pay someone to do it.

At least it was under warranty.

Quadcammer

same here, mine was new as well. I have a new one on the way.

have you checked your scavenge pumps for the proper orientation? I was hoping that was my problem but I pulled it last night and it was oriented correctly and undamaged.

Kris Murphy

I haven't yet, although it is a remanufactured motor from Porsche, that I do not think has ever been apart so they would have had to have been having a pretty bad day at the factory.

I really do not want to have to add an accusump, but I really would like to be able to go out for more than 10 minutes for each run session. I know there are a ton of people that just ignore the drop in oil pressure, I'm just not willing to.

Quadcammer

what sump/sump mods do you have?

TonyTwoBags

How high are your oil levels with the AOS smoking?

Kris Murphy

The FVD Brombacher one: https://www.fvd.net/us-en/FVD2079880...otorsport.html

What's so odd is that I had no issue last year on the old motor with this pan, and no issues at Shennandoah with the new motor and this pan (and I was watching everything like a hawk at Shennandoah since it was my first event since replacing the motor).

I have changed nothing (other than changing the oil, but the oil type was the same Joe Gibbs XP9).

Kris Murphy

Using the electronic level, I started out between 1 bar above low, and one bar below half. I added a bit more (so it was 1-2 bars above half) to see if to would clear up the oil pressure issue. It did not, but the AOS went the session after adding more oil.

I will never run it with it over the half mark again.