ThetaTau87

I plan on tracking my '89 928 GT at PCA HPDE events at Waterford Hill about 4 times a year. With all this talk about unmodified S4 engines failing due to oil starvation at anywhere upwards of 1 hour of track time I'm very concerned for the health of my engine on the track.

Sessions are 20-30 minutes. I'll be running street tires (Michelin Pilot Super Sport) 225 front 245 rear. My skill level is decent, but I'm far from being able to sustain maximum g's that the chassis or tires are capable of. What do I need to make sure that this occasional track use doesn't kill my engine?

OB pan?
3/8" spacer?
Accusump?
All of the above?

hacker-pschorr

We might hit a record in 2014 for how many times this topic is brought up.

In my opinion, tracking a 928 without a larger oil cooler (with associated gauges to keep an eye on temp) and a properly installed accusump is irresponsible. I would even go as far as rigging up a warning light every time the knock sensors go off.

There are threads in the 996, Boxster, Corvette, Mustang, Camaro, Suburu, Acura....... forums talking about the best way to install oil coolers and accusumps on those cars to make them last at the track.

Why people in the 928 world think our engines are so "special" when it comes to oiling is beyond me.
Honestly I'm starting to think it's all Kibort's fault.

A good friend of mine who spends most of his day job preparing Corvettes for track use recommends an oil cooler and accusump (along with trans and diff coolers) on any Corvette that will see regular track time.

This isn't rocket science, keep oil that isn't broken down (cooler) fed to the bearings at all times (accusump).

Modifying the breather system to avoid sucking gobs of oil down the throttle is a whole different thread. Bare minimum a good size catch can drained to the pan vented to atmosphere is a good place to start.


Locally we have a 16V EuroS that is flogged like a rented mule when at the track (Jean-Louis driving ability is known by a few around here...) Not only has he never lost an engine due to oiling issues, the last 3-4 seasons his 10.4:1 compression EuroS motor has been supercharged.....
He has never run without a huge oil cooler and an accusump.
He did spend a considerable amount of time perfecting the oil breather system, it's rather ingenious and I will be copying it on my track car.

Yes in a perfect world we would all have dry sumps, that isn't happening.

I'm starting to think anyone who wants to track a 928 should just go out and buy a dedicated Corvette track car so we stop wasting away so many good 928 parts.

GregBBRD

^^^^^^Great information!

I'd add a pan spacer, an early oil pick-up, and a breather system to keep the oil out of the intake. Add some race fuel 25% to keep the car from maxing out the knock sensors and pounding out the rod bearings.

WallyP

Greg - Do you suggest limiting the oil flow to the heads?

mickster

^^^^That (and what Hacker worte) should be added to the main FAQ thread-or a new sticky on "tracking" a 928 might be of use.

Curious: Does the belly pan fit an S4 with the spacer for the oil pan installed?

linderpat

Are you guys suggesting that our cars, in pure stock form, can't handle the odd PCA DE day a few times a year? I call pure BS on that.

Casper, Kibort, Carl, those guys race, and put some serious stress on their cars. An occasional club weekend warrior with 3 morning sessions at 20 mins per shouldn't harm anything in any stock performance car they bring absent a crash into a wall. I never had issue one with my Mustang (other than the ****ty brake rotors and fade). I have to think my Porsche engine is at least as robust as my Ford engine.
Flame suit on

GregBBRD

Wally:

I do not, because of the terrible problems with all of the 944 engines so equipped. I'm literally afraid that I would create another problem trying to solve one....much like the vacuum pump idea for the GTS engines currently being talked about, on another thread.

GregBBRD

I would not run my own car through a DE without some alterations.

Keep in mind that the 32 valve engines had huge survival problems, going down relatively straight high speed roads, in Germany!

GregBBRD

You really need a different starter motor and some good motor mounts for the spacer to fit, but everything else works. If you have a 5 speed car, getting rid of that silly steel clutch line that runs over the top of the starter is a virtual must....but that is a virtual must without a pan spacer! Not the best thing that Porsche designed, on the 928.....

hacker-pschorr

That depends on many factors, driving style and tires is the biggest. If you drive on 5 year old street tires and shift at 5,500 all day long, you should be fine. But then, what's the point of being on the track???
It only takes one corner of oil starvation to ruin an engine. How lucky are you feeling today?

Compare the cost of basic oil modifications to a new engine and let me know which one is the better idea.

Take my Corvette friend when you ask him about the LS3: "If you track a stock one with sticky tires you will lose an engine".
He's very adamant about that, he really dislikes people blowing stuff up.
He's not the best business man with that regard, but he does build some very fast Corvette's (multiple track records in three NASA classes and a championship or two).


On that note, you don't need to wear a condom when banging a $5 hooker in the red light district at 4AM either.

James Bailey

Over 20 years ago when Kim Crumb (the then PCNA 928 specialist) first started talking about "944 disease" he figured you normally could get about 10 hours of track time before 2-6 let go. Little has changed in the last 20 years except with better tires it can happen more quickly. Kim by the way blew up 2 1/2 engines the half being his Project 928 Euro which blew the first day for the new owner...when he tried big Willow.
That 10 hours was probably about how long it took for new drivers to get comfortable and mount a better set of "track tires" but there is quite a delta about how many hours. The old very brown 1980 obviously a two valve and on good oil plus shifting below 6,000 it only makes more noise above 5,000 has way more hours but almost all on short technical many cornered tracks. It has only seen big Willow twice, Auto club speedway roval once...now how close to ten hours is that ????

IcemanG17

don't let my issues jdiscourage you.....on street tires things are MUCH different...for example my old lemons racer.....using only an OB sump and 3/8th spacer with crankcase vented to atmosphere through a K&N it ran for about 125 hours on track why I owned plus another 50 for current owner....under race conditions, BUT shifted at most 6000rpm (I usually told the guys 5500 for the whole 1st day) and was on STREET TIRES.....maybe 1.2g.....not the spikes of 1.9g and constant 1.5g plus our racers see on slicks...

Hacker is rightf, its not just us....lots of track junkies smoke engines....that is why there is such a huge market for accusumps because they WORK....Joe Fan has the oldest race stroker around thats over 500whp....he runs an accusump, no dry sump....why because it works....that engine is years an years old.....

Keep in mind the stresses race engines go through....brand new GT3 cups figure an engine lifespan of maybe 25 hours between rebuilds.... I got 27.5 on casper since I bought it...it ran THREE SEASONS before that and was a street engine before that....built in 1991.....I would say it was a good motor!!!!

At a minimum for your S4 given your goals....OB pan and 3/8th spacer and carefully watch the temp of the oil...only run quality RACE oil.... a real outboard oil cooler and accusump is ideal....

This is what will be on Casper V2.0 in the next couple weeks....

redpathtribe

Greg, just wanting to confirm your comment, based on the OP's question...
when you say "Great information", are you saying IN ADDITION to Hacker's comment re: adding a larger oil cooler and accusump, you should ALSO add a pan spacer, early oil pick-up and a breather system (and the 25% race fuel) for the occasional DE, or do you mean JUST add the items you listed and you don't need the oil cooler and accusump for DE?

I've got to say I'm in linderpat's camp a bit on this. I've tracked my GT (DE type events only) at local tracks here in AZ, fastest/longest being the old PIR road course, and while I may not be as fast as Kibort , I've done my share of passing Caymans, Boxters and 911's while running on "track tires" (DOT Victoracers, NOT slicks) and even occasionally accidentally hit the rev limiter

Maybe my expectations are too high for the highest priced Porsche in it's day, but I'm a little surprised a 928 shouldn't be expected to be able to go out and run in a DE and not be expected to blow up. If I'm out of line on this, please let me know because I'd like to be able to get back out to the track and occasionally run my GT on street or DOT tires, and be able to get back home again. I understand some of these mods are cheaper than a new engine, and I'm willing to make updates if needed, but just want to make sure and understand IF they are really needed, again back in line with the OP's question. I really do appreciate your input on this.

RKD in OKC

996 manual warns specifically against DOT tires and the track due to oiling issues.

GregBBRD

Definitely in addition to. I hate blowing up engines and always want to error on the "safe" side.

I do not think that an Accusump is required for the occasional DE event, on street tires.

However, I also completely agree with Hacker's post #10 and think he's got a very good handle on this and is offering very sage advice. It's one hell of a lot cheaper to error on the safe side than to ruin an engine.

The one problem with the GT engines is the increased rpm limits. I believe these engines have crossed over the rpm limits where a cross drilled crankshaft works well. (For more information on this....you can read the thread about Casper's demise, that is running concurrent with this thread.

I'd be really careful about rpms in these engines and would definitely spend a few extra dollars to run some race fuel.....or remove some timing with the Sharktuner system. Never run one of the available "generic chips" with increased timing and increased rpm limits. That's like hiring a hit man to kill yourself! As few knocks on the knock counter as you can make is very important. It may also be wise to do some "decarbonization" before any track events....it is easy and cheap. I would make some serious efforts to keep oil out of the intake....there are several ideas on this subject being debated concurrently with this thread. (I think my system is the best. It retains the closed crankcase and is "passive", with zero risk or downside.....and it works.) Oil in the intake system has some very serious consequences....but reducing the effective octane of the fuel is probably the most significant for your DE events.