The bad part of Super Charging

I have been following some threads on other forums and have found some detrimental effects of Super Charging your 928 Engine.

PLEASE add your Ideas to this thread

It comes down to the blow by past the rings causes pressure in the crankcase.

This pressure and "windage" impedes the oil flow from the heads back to the pan.

The end result is;

The cam covers fill with oil and the oil pump runs dry.

Before you freak

This only happens during long extended high rpm runs around 6000 + rpm, and
normally while racing or tracking your 928 in corners.

only a few on the street (LA hills and corners for example) have experienced a lose of oil pressure due to this issue.
as far as I have heard

There are many Ideas and the 928 wizards are working on a fix.
So don't worry.

Some of the fixes are;

Full length windage tray, crank scraper and deflectors.


This is a picture of the bottom of Sterling"s engine and the way he is going.
His page and really good read and pictures can be found here.
www.928sg.com/

Of course Sterling is NOT S/C-ing his car... It is a bore/stroke and ITB car... NO FORCED INDUCTION on that system, but the oiling is still important and that is a good idea that he is doing there...

The debate over the 928s oiling issues will probably be never ending. Experts dispute both the cause and the solution all of the time. For anyone wishing to learn more on the matter, search the Rennlist forums. There is an infinite number of forums concerning oiling issues. It would take a week or two to read every last post. Perhaps those of you desiring a forced induction system and/or racing your 928 on the track would find the dialogue most beneficial.

It seems clear that the stock oiling system WILL NOT keep up with the demands that a race track puts on a 928. Don't be tempted to switch to Amsoil without making any other modifications like one Rennlist member has had success with and proudly advertises . Lightning doesn't strike twice in the same place.

Well, I disagree to a point... The folks who rev their cars above 6500 and in particular when G loaded are going to have an engine failure. Simple as that. Then they will do various things like dry sumps or whatever when they rebuild the car and then it will last better, but not indefinitely.

The auto cars will run good for MUCH longer as it is more unusual to rev them as high as the 5spd guys do, but if you don't change the tranny fluid REGULARLY and I am talking every 10ish DE/race weekends then you will have a tranny failure (thankfully that is about 1/10th the cost of an engine failure though...ask me how I know!)

Having tracked 928's for more than 14 years now I can tell you that I have also seen more 928 GT failures than any other type of 928. Think about it this way, there were damn few 90/91 GT's built (way more 5spd S4's from '87-'89) and I can think of THREE GT failures and not ONE S4 5spd failure. I am not saying they are not out there, I am just saying that I have not seen any while I HAVE seen several GT's fail... one more than once!

James..............do you believe the GTs fail because they're solely being revved higher? what about street driven cars?

As far as Amsoil goes I've no opinion other than when I use Mobil 1 it stays clean for much longer than dino oil.

Oh God this is getting interesting and I have to get in here.

I agree with Austin that a moderately driven car, even sometimes hard, should have no worries.

I need clarification on the Amsoil please Austin because I was going to use it to reduce cam ware.
Its ZD factor

I am also curies James as to the GT failures that you are talking about.
Is it main bearing, rod, wrist pin or piston failure and why you heard they fail.

Guys I drive this car like I stoled it and so I am trying to head some of these issues off because I don't want to blow it up.

hmm I asked more then I told