ErnestSw

Supercharging causes head gasket failure.
Discuss.

AO

Awwww... c'mon now Ernie. You, as a medical professional, should know not to jump to cause and effect conclusions.

That's like saying since some guy died while having sex, ALL SEX CAUSES DEATH! Stop having sex if you want to live! Paaaauuuullllleeeesssssee!

FlyingDog

Without sex, there is no procreation. Without procreation there is no new life. Without new life, new deaths are prevented.

Therefore...


Without superchargers we could all live long happy lives with turbochargers.

killav

The intocixating effect of more thrust due to boost is no doubt addictive. So much so that it affects the way we drive our cars me thinks. Even if you think you are not hard on your car more often, wouldn't the times that you are having a little fun with the go pedal not be harder on the car? Car meaning drive train. I floor my car 318 times during a run down the tail of the dragon (not possible by the way). A boosted car does the same. Who's car do you think is worse for wear?

It's a curve. The more power you make, the harder it is on the parts. There is no escaping this fact.

I can't wait for the day that I can afford to boost my car. The gaskets are original and are 20 years old. If one lets go, I'll replace them. If its something more catostrophic, I'll probably just cry.

leperboy

My mother told me that head gasket failures were caused by masturbation.

Matt

hacker-pschorr

Nope - not even close

There are over 50 (might be 60) supercharged 928's around the world.

Detonation will kill a head gasket. Even N/A cars detonate.
On the dyno we (Murph, Z, etc..) have logged knock on a 100% stock 928's.

Andrew's car was / is a pre-production prototype for DR's kit. Andrew has stated multiple times his car was knocking during various stages of testing / development.

Gretch

Mine still runs fine, 3+ years later.............

ErnestSw

Interesting responses. Let me point out a few obvious facts:
1 Supercharging increases the strength of the air/fuel mixture explosion in the combustion chamber therefore increasing the pressure on the head gasket.
2 Supercharging increases the PROBABILITY of detination therefore increasing the stress on the head gasket.
3 Engine designers have universally reduced the compression ratios in supercharged cars to deal with these facts.
4 Andrew's is the SECOND supercharged car to experience head gasket failure in the last year (the other one was in Australia). That's 2 out of 60 or 3.3%.
5 I said DISCUSS, not defend.
5 Everything has its price, including supercharging. I'm NOT saying supercharging is bad, just that there are known and predictable risks and that ignoring them is stupid.

AO

Exactly! It knocked like a **** for a year before I finally got the STer on it to adjsut the timing. Whereas I would record 700 knocks on a 2nd gear pull to redline before I tuned it, I was getting 30-ish afterward.

I was oblivious to the destruction I was causing to my car for the 1-yesr I ran the stock EZK chip.

See below how much timing I had to take out to get the knock down (under WOT).

SwayBar

I say, let's 'discuss' instead how stupid and idiotic that statement is.

I mean, WTF???

928saregreat

I agree, boosting when done right is not the problem, but an overlean condition caused by some fuel-metering error will blow up a boosted engine pretty quick. Thats not unique to superchargers, turbos and NOS have the same problems. It has to be done correctly.

Detonation will ruin any engine, I guess when boosting the problem is more acute due to the pressures involved. If its a modification from stock then its got to be a good system where the fuel system pressure/computer mapping/ injector size is all worked out. If you've got knock on a stock 928 using decent gas I'd guess its got some carbon buildup issues.

Mark

Rob Roy

I've had some scares, but my head gaskets seem intact.

I did a compression test recently and got some nice, high, consistent numbers - this is with over 190,000 mles (not all supercharged mind you).

I do drive diffferently though - much harder - and I think my biggest cost is going to be replacing the 295s out back as I often see some very expensive smoke behind me.

If I get a decent bonus this year, I am thinking about buying a second motor to build up to increase the boost even further and yet remain relaibale (Stage III plus?)

928saregreat

Wow, you guys replied pretty quick, I meant I agreed with Enzo...

ErnestSw

Andrew,
was the kit marketed as a "preproduction prototype" with a discount? Were you warned that it would blow your head gasket unless it was Sharktuned? Was detonation measured in the test car?
Seems to me that your post confirms the proposition that your supercharger caused detonation and therefore your head gasket failure.
Speed Racer,
Shooting the messenger has not, historically, been an effective solution to any problem.

leperboy

Two known head gasket failures out of 60 cars is hardly a significant sample. I think other questions have to be asked, such as:

What were the driving characteristics of those drivers versus other drivers?
What was the condition and miles of the heads and gasklets prior to the events?
What was the boost on both cars?
What type or brand of head gasket?
What other events were occurring along with supercharging? Andrew says he had bad detonation, which I think would cause more destruction than increased pressure.
What is the rate of failure at different elevations? Here in Denver, a supercharger may only normalize my pressure compared to a sea level car...
What is the head gasket failure rate for 928s in general?
Is the head gasket the most likely trouble point for supercharged cars?
What other types of failure are we seeing in supercharged cars? More bent rods, more broken timing belts, more cracked cylinders, more overheating?
What is the operating temp of a supercharged car versus a non super?

I don't think we can get close to knowing the affect of superchargers on our engines given the very small number of supercharged cars out there. I do think the potential risk is worth it for those want to do it. It's just making sure the engine is up for it and you can tune for it.

Matt