roadie13

Last week I had a chance for a first evaluation of my new LN deep sump kit, driving at Watkins Glen. As is well documented here,
for a 997.1 with the stock oil sump there will be some level of oil starvation/aeration at prolonged turns, especially right-handers. This is detectable on the
oil pressure gauge, which can drop to 2 or 3 bar even at high revs during such turns. The effect gets worse with high temperatures. Overall, this is the reason why Porsche does not allow the use of
slick tires on the car, but this also happens with modern performance street tires. Basically, any prolonged turn with about 1g lateral pull or more will lead to an oil pressure drop.

The LN deep sump is meant to fix that, but as far as I can tell there have been mixed experiences with it on the forum. Well, I was happy to see that at Watkins Glen the pressure remained pegged at 5bars through all turns, which is what I wanted to see. This was still just on street tires, so about 1g lateral pull, but it was a marked difference from the situation before. So far so good!

Now, the little problem is the additional NVH created by the LN skid plate that covers the deep sump. It's actually engine bay noise transmitted into the cabin, dominated by high-frequency squealing from the accessories between 2-3k rpm. It does not matter on the track, but it is very annoying/grating on the street.

The skid plate does not come with any noise reducing hardware, though LN engineering are aware of the problem.
For those who have installed the LN skid plate, did you use any method to dampen the noise?

rtl5009

Which kit capacity did you go with?

roadie13

The 2qt one. Bigger is better in this application, I thought.

rtl5009

It is. I was just curious.

Matthew Scott

Great to hear feedback that the kit works as promised. Bummer about the skid plate.

cwheeler

My experience was the same with the BILT (LN) 2 quart deep sump. Windage tray I think is particularly important. Didn't get the skid plate tho, sorry to hear about the issue there.

roadie13

Yes, I remember that your positive experience with the LN sump encouraged me to try it!

I'd be worried about hitting something without the skid plate, not on track but on the road.

Petza914

Make sure the skid plate isn't touching the motor. I even have mine with some dynamic tension in the plate so it's flexed downward or outward.

I cut the rear mounting hole slots so they would extend all the way to the edge of the piece. That was so I could install it without removing the muffler hanging bracket. Maybe that let me pick a lower rear height position than is possible with the holes the way they're drilled. My deep sump is also the MantiSport one, but doubt that matters.

Iceter

Jeezus, its no wonder that thing vibrates and makes noise. Its just a flat piece of sheet.

I'd take it to a metal shop and ask them to roll some beads in that--maybe along the perimeter and an X through the middle of it. It will make it stronger and less-likely to vibrate at speed. Whoever "designed" that should have foreseen that issue.

What's it vibrating against? If it is against the sump, then I can't see how much protection it is providing. A good hit would just transfer to the sump anyway. Or is it vibrating against something else?

roadie13

I don't think it's touching anything, but it's rear support picks up noises from the engine bay and the front support transmits them into the cabin. The preferred eigenfrequencies of the plate seem to amplify accessory whine, some folks have compared it to the sound of a straight teeth gearbox

Petza914

Those are my pictures, not rhe OPs. Mine doesn't make any noise or touch anything. It's been installed for years. We have the same skid plate, but different deep sump kits - his is LN and mine MantiSport. The LN skid plate is very thick and mine is installed under tension bowed outward so it doesn't vibrate and that tension will also add to the protection and help the car ride up over anything it would hit if it's large, like a dead animal.