DreamCarrera

Cool story!!!

A good friend of mine has an '84 911(Turbo look) and I absolutely love that car. In fact it was the first P-car I have ever driven and I will never forget that experience.

Shark Attack

Who the hell names thier daughter Rev Limiter?

DaveSpeed

I've only seen the TC light one time and not when I hit the rev limiter. Althougth is was the say day.

Quadcammer

So how do you know it hasn't hurt the car at all? What are your compression and leakdown numbers? have you test the valve springs (they love it when you bounce it off the rev limiter).

Furthermore, your anecdotal evidence, plus the fact that your only proof its not harmful is that the engine hasn't blown up yet doesn't amount to much.

fhp911

Follow-up to Quadcammer:


I did have a leakdown test done. The results (at the 120,000 mile mark) were within factory spec for a brand new engine.

So, yes, this is just one data point from one guy, but it implies that hitting the rev limiter does not harm the engine. I sure did it a lot, and so far at least the engine does not seem to have suffered.

BruceP

I'm not sure where all this heat is coming from, Quadcammer. The rev limiter is an ECU function, not a physical barrier. These engines are made for high rpms; they suffer much more from the opposite kind of use, it seems to me. And I have trouble imagining that Porsche would go to the trouble of programming the engine to cut fuel at a certain rpm, and then choose an rpm that produces engine damage.

This runs the risk of becoming one of those debates in which the absence of evidence just serves to dial up the rhetoric. Me, in the absence of evidence, I just default to common sense...

Quadcammer

Of course its an electronic barrier. Just like getting the correct a/f ratio in a 996 is an electronic function. Electronics have a very serious effect on engine longevity. The engines can tolerate high rpm, they aren't built for high rpm. Furthermore, its not the rpm that causes the damage.

Obviously tapping this thing on occasion is not a big deal. Thats why its there. Holding the car on the limiter is simply not a good idea. Thinking about the harmonic issues alone caused by cylinders essentially misfiring at max rpm for 20 seconds at a time makes me not want to do it, but use whatever common sense you want.

drive your car in 1st gear banging off the rev limiter for the next 20 years if it makes you happy...but I sure won't.

Quadcammer

so less than 2% in all holes?

rwiii

Quadcammer, Is there a data based reason to not hit the rev limiter on a regular basis or just your best practice?

BruceP

Um, not really what I had in mind. I just sometimes want to upshift so that the revs drop into the meat of the power band. With this motor, that's sometimes going to mean the redline.

Quadcammer

I think you may be misunderstanding what I'm getting at. Let me try to clarify.

Scenario 1:

You are an enthusiast. You regularly accelerate briskly and hit the rev limiter for a millisecond before shifting (i.e. you do not hold the car on the limiter)

Scenario 2:

You are on the track. Your gearing is not optimized for the track. You decide to let the car bang against the rev limiter for 10 seconds/lap (i.e. literally keeping your foot to the floor while the rev limiter limits the rpm for 10 seconds).

The first scenario is absolutely fine and will not cause any damage. hit the thing momentarily as often as you want.

The 2nd scenario, while probably not resulting in immediate damage, is not doing your engine ANY favors.

Quadcammer

Bruce, like I've said several times, thats perfectly fine. Its the act of holding the car against the limiter that is the problem.