So I've upgraded .... pressure valve/spring, x51 pan, and added 996 gauges. The car is lowered with bilsteins.

While going through a sweeping turn around 68mph with track tires, the oil pressure would drop to 2. I could still see the pressure drop every time in that turn.

What is the best solution to avoid this?? I've read deeper pan... accusump .. and some Cervelli dry sump (but cannot find).

Thanks in advance

 

A problem with the 986/996 engine is under some conditions: I forget the exact particulars but it involves a long high speed corner in I forget which direction (and the direction is I think different depending upon the engine) and with some braking. The higher than normal and persistent for longer period of time than normal G-forces can have the oil under one of the camshaft covers piled up at the end opposite from where the scavenge oil pump is located. This can result in a considerable volume of oil (quart or quarts...) being under the camshaft cover rather than in the sump.

Are you sure you have the "right" or good X51 oil pan. I vaguely recall that not all "X51" oil pans/baffling are the same. One is deeper, and has better baffling. And with the deeper pan it is imperative that the oil pump pick up tube either be longer or a spacer (supplied with the pan I believe) is installed to get the oil pump pick up down deeper in the oil.

The deeper pan of course adds more oil volume so the temporary loss of oil due to high g force cornering is compensated by the fact there is more oil volume to begin with. But there is a limit. Stickier tires often result in higher track speeds and higher G-forces and this can require more oil volume margin that even a deeper sump can provide.

Additionally better baffling helps keep what oil there is in the pan around the oil pick up tube. What can happen is the oil level does not get so low the oil pump sucks up air, but under high RPMs the oil gets a bit frothy and because of the high volume of oil being circulated the oil doesn't have time to shed all the air. If the pump ingests this frothy oil this can result in a drop of oil pressure. (In some cases at near red line the engine output falls off because the frothy oil results in partial hydraulic lifter collapse which reduces valve lift and affects valve timing.)

To reduce the tendency of the oil to froth/foam fresh oil should be used and a proper (read approved) oil. Some oils are worse when it comes to frothing and foaming under extreme operating conditions and you have to be concerned that one of the frothy oils is *not* being used. Approved oils are selected because of among other things they are not as likely to froth and foam. Overhead cam engines, and these engines have 2 cams per bank, and nearly a mile (it seems) of cam chains, all of which tend to aerate the oil and oils that are not noted "foamers" are preferred. The defoamers are pretty good but they are not necessarily capable to removing all the air under extreme operating conditions.

 

I have an oem X51 oil pan.

While oil type and viscosity might help, I don't think it's a solution.

In reading others that track, they all have it.

 

The oil type and viscosity is not offered as a solution, but as part of the solution.

The OEM X51 oil pan doesn't offer extra volume. It offers better baffling. Also, the engines fitted with this at the factory have an extra oil pump with suction pipes to keep oil from building up under the camshaft covers.

What you want is something like this:

https://www.suncoastparts.com/produc...yABEgI5PPD_BwE

The above oil pan increases oil capacity by about 3/4 quart. The above might suffice if one was running street tires on the track.

For cars fitted with track tires or cars modified for more speed and thus subject to higher g-forces, the following oil pan might be the better choice.

https://lnengineering.com/2qt-deep-s...51-baffle.html

This offers 2 extra quarts of volume and better baffling. This will certainly help oiling but it may not eliminate low oil pressure under all circumstances. The oil piling up under the camshaft covers is the real problem.

For dealing with this, somebody (LN Engineering?) offered a kit that came with a better baffled oil pan, maybe even a deeper oil pan, and with the extra oil pump but this requires some machining which I believe requires some partial engine tear down. But it I believe mimics what Porsche did for the X51 engines in that it better scavenges the oil from under the camshaft covers.

As some kind of a fail safe device, one can also fit an Accusump system which under low oil pressure conditions can provide a temporary emergency supply of oil and at pressure.

 

I'm talking to a few places about a 2qt pan to work with the x51. I'll try that then add the accusump.

Honestly... I'm pondering selling it and getting an s2000. I'm a porsche guy, but this is ridiculous. This car with street tires on the track wouldn't be fun.