ACCUSUMP - Discuss please (oil starvation)
 

sounds compelling..

Preventing oil starvation on the track in your Boxster, Cayman, or 911 model Porsche.

For those people wanting protection that is streamline and transparent, adding a 2 QT Deep Sump that is fully baffled to prevent sloshing of oil, in addition to the two extra quarts of oil, is a step in the right direction, as mentioned previously. Adding Dual Tandem Scavenge Pumps to the cylinder heads adds one additional scavenge stage to each head, allowing the engine to suck oil that would otherwise be trapped in the cylinder head under high G-forces, improving oil pressure in turns under high G-forces by at least 15-20 psi, based on data reported by others using the factory pumps.



Completed installation on one cylinder head bank (looks pretty much the same on the other side). Note we supply non-descript black hose and fittings to make the installation look as factory as possible


http://www.lnengineering.com/pumpsinstalled2.JPG

Not cheap.

2 Qt Deep Sump Kit: $727
Dual Oil Scavnger Pump Kit: $2900 plus custom professional installation

Might be hard to justify unless you are going professional racing or have actually blown an engine due to oil starvation and want to avoid a repeat.

I'm not a fan.
One of my good friends and TT competitors added the accusump after he tossed his 3.2L at Auto Club Speedway. Well, in April we were back at AAA and one of the hoses to the accusump let go, sprayed oil all over the exhaust manifold, ignited into a 6' high ball of flame, and attempted to burn down his car with him in it. The end result was driver and car survived the fire but the nice 320hp 3.4L motor was tossed from zero oil pressure when the hose blew. :(

With 7 years of track experience my car still has dodged that bullet. I added the X51 pan a few years ago when I went to R-comp tires, and I make sure my oil level is topped before each run session. I also avoid redline unless I am on a long straight in higher gears. If coolant temps rise too high (220?) I end my session early. My car burns little or no oil between changes. Fingers crossed.

If the hose failed, it was either the wrong spec, or installed/assembled incorrectly, which is no fault of the accusump. Whether one is required, or the best solution, is another issue.

3.2's require more oil pressure than 2.5's to overcome the centrifical force of longer stroke crank & higher rpm redline.

Yes and yes. It just seems like a very complex and sometimes unreliable solution to a problem that can be solved in much simpler ways.

Same for me. I installed the EBS baffle when I went to r-comps and just keep my fingers crossed. Same for IMS. Same for... well, you get the idea, I hope for the best in a lot of different ways!

On the other hand, I haven't heard of very many engine oil starvation failures so this might not be as big of a worry as it sounds.

The starvation isn't directly related to G forces, it is aggrevated by G forces. The Gs are just the straw that breaks the camels back.. I just finished the chapter of my book that explains the chain of events leading up to failure and used a timeline to illustrate it.

We run engines in Grand Am with zero oil devices employed and they live all season.. It took years to figure it all out.

Bingo! :cheers:

I'm guessing an oil cooler, and higher viscosity oils?

how do you (accurately) gauge this?

Long answer:
When I first got the car I used the dip stick exclusively. I had no faith in the dash gauge. One of my friends was a long time Porsche owner and suggested that the dash gauge was actually quite good. I did some tests over a period of time comparing the dash gauge to the dip stick. Hmmmm, on level ground the dash gauge is right on. Ok then, on my car it does actually work as designed.

Short answer:
Dash gauge at start-up.

70+ track days, 100k miles and counting...

So what is the root cause of oil starvation?

so assuming the ground is flat (do you use a level?), the oil is cold and well settled, how much oil do you add per bar? and do you stop until all bars are full?
Is there a certain level that is problematic for autox/track?

I've lost count at how many wacky readings I've gotten from the dash. And that dip stick...forget it. That seems like checking the space shuttle for leaks with a garden hose.

Level? The car doesn't roll away in neutral. :) Most cold pits at a track are pretty level to allow for jacking up the car/changing tires/changing sway settings etc.

Adding oil? 3oz and re-check.

The oil is never cold at a race track but when the timer on the dash allows you to check it, it's ready. I can't speak for others dash gauge but mine and my brother's seem to work just fine. I check it every time I get gas also. Just using the tools at hand to continue playing the game. No dead motors due to oil starvation. No replacement AOS due to overfilling. Seven years and counting...