Jake951

I'm learning the hard way that the first generation Cayman engines are failure-prone on the track. They suffer oil starvation in sustained high-g corners and eventually go kaput. So, the question is whether anyone has converted their 987.1 engine to a dry sump engine? I know it's been done on Boxsters but I couldn't find any info on Caymans.

jdistefa

Call Chris Cervelli.

Likely an 8-10k USD investment.

Other approach is do the following...
- deep sump
- latest generation swirl pots
- motorsports AOS
- overfill by 0.5 liter
- coated rod bearings and ARP rod bolts
- don't overrev the motor

Jake951

Yes, I'm aware that Chris Cervelli had done dry sump kits but last I heard, there was nothing available for the Cayman. I've done almost everything else on your list. The last engine was rebuilt by Vision Motorsports with forged internals but that doesn't solve the oil starvation problem.
I think the answer is to abandon the M97 engine for track use. I don't race the car so there is no issue of spec compliance. I'll probably go in the direction of a DFI engine.

CTS

Vision has installed one of my dry sumps in a Cayman. Others have as well.

Chris Cervelli
Cervelli Technical Service

Olemiss540

Have you tried an oil accumulator?

jscott82

Accumulator does help. The key for me was to control it electronically rather than the simple pressure switch that they come with.

Its not perfect, but its brought the floor up from 6psi to 20.

Jake951

I'm seeing oil pressure drop to 7 psi in the sustained high g corners, very similar to the 6 psi you saw. The oil pressure varies all over the place, from around 50 psi down to 7. It drops a lot in every corner.

De Jeeper

I may want to spend some time and read this.

https://rennlist.com/forums/996-foru...stability.html

We have been discussing technical solutions to the oil starvation issue with a bunch of vendors. Chris does have a solution for your car and Hartech accross the pond has some very intense reads available and unavailable solutions for us (he doent currently sell in the us). He has figured out how to feed the car pressure with an accusump that works.

Nickshu

+1 for talk to Chris Cervelli.

Jake951

Vision Motorsports built the engine so it's going back to them for a teardown and evaluation. Assuming the engine is rebuildable, I'm going to ask them about adding the Chris Cervelli dry sump kit. It turns out that changing to a DFI engine is not straightforward in this car. It requires custom ECU tuning.

This is the second M97 engine in two years that has blown on the track. One of the precursors to the engine failure was what I call "hiccups" or engine cutouts in the middle of high-g corners. This season I added an oil pressure sensor and fuel pressure sensor to the engine. I have an AIM MXP dash for datalogging engine parameters. The fuel pressure sensor was installed to see if the hiccups were related to fuel.

During the session where the engine died, I logged the following data during a portion of one of the laps:

From top to bottom, the plots are: vehicle speed, fuel pressure, inline acceleration, lateral acceleration, and oil pressure. The fuel pressure is very steady, so that's not an issue. However, you can see the hiccups as sharp but short drops in the inline acceleration. The hiccups coincide exactly with low points in oil pressure, which bottoms out at 7.5 psi in the high-g corners. For those of you who know the Club Motorsports track in Tamworth, NH, this portion of the data is taken in turns 7-8-9a-9b, which are a series of fast sweeping left-handers. I'm running Hankook Z214 tires (the spec tire for Spec Caymans).

Frank 993 C4S

Plot speed, GSum, RPM and oil pressure over an entire lap. I've had oil pressure go into the single digits momentarily on some tracks in one or two high g corners. What's the over-rev situation? These motors hate to be over/reved.