Quadcammer

thats so odd that it was fine at shenendoah given the carousel and the crazy elevation changes.

What turns were causing your pressure drop? I'm guessing the light bulb.

I have the Tune RS sump spacer and I got that one specifically for the horizontal baffle. I don't think the FVD has that.

Unless you are just developing higher Gs as you get more experienced.

Did you use the pressure sender from your old motor? would be interesting to see if you don't and then put the old one back on whether the drop goes away.

TonyTwoBags

Fair enough, I figured it was worth mentioning to keep it halfway between high & low. Never had mine smoke under hard driving or at HPDE, but have read Slakker's thread where he worked through some smoking issues by keeping a lower oil level.

Kris Murphy

At lightning, it was every turn. I am using the pressure sensor from the new motor. I think I am going to swap it out with either the one from my old motor or a new one. It's a cheap enough thing to experiment with.

fpb111

Accusump?
http://www.accusump.com/

Picture 4 in pelican track prep

http://www.pelicanparts.com/techarti...Track_Prep.htm

Mike Murphy

Does your RPMs drop below a normal idle when you come in off the highway? If not, and a blip fixes the issue, that seems a bit strange to me. The oil pressure should be a function of RPM, and if the blip then settles down to the same RPM, the oil pressure should fall back down to the same too.

Kris Murphy

Yes, looks like an accusump is in my future. It's just so odd that I had no issues last year and no issues the first event this year. It is possible that that I am just driving the car harder. I am still running street tires though. Was about to make the jump, but am waiting until I have the oil issue taken care of.

My order of preparing a car is:
1. SAFETY
2. Reliability
3. Performance

2002C2

Thanks murphyslaw. RPM's drop at the stop sign to ~800 or so when I get the warning. Seems like the sudden drop in engine speed causes it. I'll keep a closer eye on it on the way home today. It does stabilize and only happens after 30 plus minutes of sometimes spirited highway driving.

Mike Murphy

What are the differences in your lap times if that were the case?

Did you switch oil brands from then until now?

AWDGuy

haven't read the whole thread but have you tried a new sensor?

Kris Murphy

Been using the same oil Joe Gibbs XP9. I have never timed myself, but this year I am catching people I was never able to catch before.

Last year was the first year in the 911 (was E36 M3 before that), that it took me most of the season to feel comfortable in the car.

Porschetech3

Ok I just stumbled onto some facts about oil foaming that may or may not contribute to the oil pressure drop/ oil foaming problem on the m96 engine.

I discovered that the Ford PowerStroke engine had suffered problems with oil foaming due to a chemical reaction with the RTV silicone used on the oil pan. Certain year models of the PowerStroke uses oil pressure to activate the injectors and the oil foaming after @3k miles would cause lose of power or missfire(no main oil pressure problems apparently the oil level of un-aerated oil was still satisfactory to supply the main oil pump).

The cure was to add anti-foaming additives or change oil early to eliminate the foaming, The reaction of the RTV with the oil would lessen after time and ageing of the RTV.

The "special" RTV that was designed that would NOT react with the oil is a Alkoxy cure type of RTV.(( part # Ford- F5TZ-19G204-AB, Motorcraft TA-31, IH- 1830858C1,Wacker (pronounced vahker) - T-442))

. According to my research there are 5 common types of RTV silicone that are categorized by the by-products of the curing process, namely Alkoxy, Acetic , Oxime, Acetone, Amine. See attached link for more info on RTV types.[URL=http://www.intertronics.co.uk/articles/tb008.htm

Just for reference the Loctite 5900 is of the Oxime type, the Permatex Ultra Grey, Blue, Black, Copper is also of the Oxime type.

According to what I found the only type that does NOT react with the metal or oil is the Alkoxy type.

I had just happen to use the Permatex Ultra Grey on my 1999 Cab recently for the oil pan and head covers. I normally always use Loctite 5900 (which is still an Oxime type) but since I have been retired it would take a special trip to get it so I used what was handy. It would be interesting to know if some of you that have this issue were using the Permatex RTV or recently used Locktite 5900?

There needs to be more data to see if this has any effect on the oil foaming issue that we have on the m96, but it sure did cause a fuss in the PowerStroke World. The PowerStroke placed unusual demands on the oil for anti-foaming and our m96 engine with the high revs and 2 scavenge pumps place an unusual demand on it.

We know that different brands of oil have different anti-foaming abilities ( more silicone for anti-foamng). I will know if my choice of RTV has contributed to this IF my oil pressure problem returns. Thoughts??

Mike Murphy

^^ Interesting. My car, to my knowledge, has not had anything removed or replaced, so if foaming is due to silicon or other adhesives, it must be what the factory used.

There was one other person here on this forum that continued to have loss of oil pressure in turns and they finally got rid of it with a specific brand of oil.

Kris Murphy

A data point for you. I am having the issue while using 5900. New pan install and new oil install and it is happening.

rockhouse66

Ditto

Mike Murphy

It's quite simply that the oil pump is sucking air because there is no dry sump system in place, along with enough proper scavenging, combined with g-force loading and aeration of the oil. Putting in a better oil pan, with a better pickup, changing the scavenging in the heads, Accusump, and running different oil can all help, but nothing is guaranteed to fix the problem.

I'm guessing 95% of Porsche 996 owners (and this affects some Boxsters too) don't drive on the track, and the ones that do, probably have some symptoms or issues, but don't notice it or don't have a failure because of it.

That leaves less than 1%, which means that track folks are already doing all sorts of upgrades to thier cars to make them dutifully track proper. In the old days, oil and cooling systems were part of the car that would almost certainly need to be upgraded for serious track duty, even when using a sports car that was well built. I think we have come to expect more from a 996 than it was really meant for. For the track duty 911s, Porsche wanted us to buy GT3s and such.

The old days of carrying over a dry-sump oiling system from a race car to the production version of the car was meant to actually save money by not having multiple designs for relatively low-production numbers. Now the Porsche made several tens of hundreds of 986/996 models, the opposite is true - it saves more money to make street versions that don't need to be robust on the track due to scale.