Hit the Rev Limiter

[Brucelee]

"No, I am not convinced that hitting the Rev Limiter, even on a consistent basis is much to worry about so long as you look after the car's Tune and Fluids. Every Engine I've ver seen Blow-up was from some other type of abuse, usually neglect."

I understand that you are not convinced and that is not my intention. You can drive your car off the rev limiter everyday and that is fine with me. However, it is factual that heat, friction and mechanical stress all act to increase wear in ANY engine, not matter how well maintained. Same applies to the drivetrain. So, all of these increase greatly as revs climb and the gas pedal goes rapidly to the floor.

As long as you understand that you are shortening your engine life, that is fine as it is your car.

Don't delude yourself into thinking that keeping your oil clean and plugs new is going to eliminate this "cost" as it will not. It will help but there is not cheating the man!

Also keep in mind that blowing up an engine and decreasing useful life are not necessarily the same thing. However, I would bet more engines "blow up" at red line than at 2500 rpms.

Lastly, if I understand your point about engine warm up correctly, it conflicts with every professional's advice that I have seen, which is to allow your cold engine to run about 10 seconds, drive off slowly and allow the engine to warm up quickly under light load.

AFTER the engine is fully warm, one can get more aggressive with driving.

If I understand what you are advocating, you would sit in the driveway until the temp gauges moves. Did I get that right?

If so, this theory went out with the 60s I believe.

[limoncello]

Continuing the debate -
Rail, IMHO, bouncing the rev limiter did no damage to your car.
Warm-up: Not as critical as it used to be, for starting and driving normally. I think the manual even says you can turn the key and go. As an old-schooler, I still let my cars idle for 5-10 seconds before I pull away - it's just habit. Here's the distinction: I never drive hard (aggressive throttle, or above 3500 RPM) until the car is FULLY warmed. If the car has been sitting for 3 weeks, I warm it up carefully.
High RPMs: Yes, continuous high RPMs (the race car) will burn up a motor quicker than all gentle driving. But sports cars, like Porsches, should be able to take 100,000 miles of driving by Porsche owners. Running the revs up smoothly on a regular basis should not burn the car up prematurely.
Smooth is a key word. Slamming the drivetrain wears out parts. (Many an SUV'er does damage to the soccer van by rolling backwards and dropping the automatic into drive while still moving backwards. That's bad.)
Porsche and the Economics of Warranty Work: The rev limiter is an easy target because it's measurable. It's easy to say that high RPMs = abuse. Sometimes that's correct, and sometimes it's not. Running the revs up smoothly is a joy, and personally, I don't think that alone should blow my motor early. (Track time might, however, which I do. Explains why I have a car that's out of warranty - no one would touch it after repeated trips to the track. If it breaks I'll fix it.) But Porsche is erring on their safe side - not surprising, they are a business enterprise. It's probably true that some drivers lose some deserved warranty work solely because they rev'd out a few times, but equally true that other owners wring the crap out of the cars and then take it to the dealer to fix it under warranty. And the SUV owner that puts it in drive while rolling backward gets their car fixed under warranty, simply because there is no strain gage on the driveshaft. Yet.
Back to Rail: IMO, no mechanical damage done, but your dealer may try to convince you otherwise at some future moment.

[Brucelee]

Lemon

As usual all good points.

According to my service shop, the computer tracks all overrevs.

This is not an automatic warranty no no.

However, if they see 50 or so of them,

Well........................

Good stuff.

[eslai]

Correlation versus causation, the usual logical fallacy! High engine revs can't be shown to *cause* premature engine failure, but there are other htings to take into account. If you're the type of driver that likes to drive the car hard, there's a lot of other stress factors involved than just how many times you revved the engine.

But even if there is a correlation, that doesn't make me comfortable with Porsche using computer data that states how many times you've hit [whatever] RPM as a tool for denying warranty claims. It is not proof of any sort that you've mistreated the car... well, except for really obvious over-revving of course...

[Brucelee]

Lets try this.

Does racing a car lengthen or shorten its useful life?

Do you want to buy a car that has been raced?

Does racing involve high revs and tremendous internal stresses?

Does daily trips to the redline lengthen or shorten an engines useful life?

Do manufacturer's in general have a qarranty disclaimer for racing or other forms of abuse?

Originally Posted by eslai

Correlation versus causation, the usual logical fallacy! High engine revs can't be shown to *cause* premature engine failure, but there are other htings to take into account. If you're the type of driver that likes to drive the car hard, there's a lot of other stress factors involved than just how many times you revved the engine.

But even if there is a correlation, that doesn't make me comfortable with Porsche using computer data that states how many times you've hit [whatever] RPM as a tool for denying warranty claims. It is not proof of any sort that you've mistreated the car... well, except for really obvious over-revving of course...

OK, let's say you were interested in buying a used Boxster from a Porsche dealer. And you wanted to see how many times, if any, the previous owner bounced off the Rev Limiter. If the dealer actually gave you the data (you could make the final sale conditional on this data) off the ECU (DME) how could you decifer the codes? Could you tell how many times they bounced off, if they gave you the data off the ECU??

[Tool Pants]

I am not going to study all the messages.

The question was from a 987 owner.

There are now 7 ranges, at least with the 997.

[lexuspilot]

When we say life or premature here are we talking in Miles, RPM's, or Years.


I think everyone is using a different yardstick for engine life.

Miles, hours, revolutions, years,?

You could also take into account engine acceleration. Is bouncing off the rev limiter in fifth different than bouncing it in first or nuetral?


What I don't know is what happens to an engine when you stall it. This has to happen at a much higher rate than rev limiter bounces.

[Brucelee]

"So long as the engine is in good tune and overall good shape, and your oil & coolant levels are good, you can bounce off the Rev Limiter all day."

This was the one statement that I addressed. I think you made it.

My assertion is, if you "bounce off the Rev Limiter all day long" you are shortening your engine life.

I stand by that statement and I think any prudent, knowledgable person would.

Here is a test:

Next time you try to sell a car, tell the prospective buyer that you "bounce off the rev limiter all day long."

Tell him its OK though as you keep the oil clean and topped off and the coolant too!

See how many prospects end up walking away.

Off course, infrequent trips to Red Line are fine and I never said otherwise.

Keep bouncing the limiter if you want. Simply don't delude yourself that this is a cost free strategy.

As I indicated in one of my post, this issue was addressed in Panorama by the tech guy there. I think the article backs up my statements.

No one is attacking you, I simply think your assertion is not supported by fact.

[MNBoxster]

Originally Posted by Brucelee

Lets try this.

Does racing a car lengthen or shorten its useful life?

Do you want to buy a car that has been raced?

Does racing involve high revs and tremendous internal stresses?

Does daily trips to the redline lengthen or shorten an engines useful life?

Do manufacturer's in general have a qarranty disclaimer for racing or other forms of abuse?

Hi,

Wait a minute here. You are carrying your examples to extremes to justify your arguments. NO ONE said anything about Racing. This was an example you brought up.

The Lister simply inquired about the Damage Potential of hitting the Rev Limiter ONE time. I said that this wasn't a problem and all of a sudden, we're talking about Racing and Warranty Claims.

Realize that Porsche has the ability to set the Rev Limiter to whatever Threshold they choose. This isn't some arbitrary number (although I would probably concede that there are more factors than merely Engine Preservation factored into their decision, such as the Marketing Potential of achieving certain Performance Parameters such as HP and Torque). I suspect that the Power Curve trails off at or just before RedLine. This means if you want to derive the maximum potential the car has to offer (and don't forget this is a Sports Car, driven largely by Enthusiasts) you're going to enter these Nether Reaches of the Tach. Porsche knows this too.

I further concede that I would not drive My car in a manner which hit the Limiter on every shift, or even every day (as you allude to), or week. But, when I'm out to take a Run or in any Competition, I want the car to Deliver the Goods, this means exceeding 6k Revs when appropriate.

I have developed a good deal of Mechanic Skill through the years and keep my cars in top shape. I have somewhat of a reputation among the Formula Vee crowd with whom I compete as having one of the most reliable cars, very few Mechanical Failures and DNFs by comparison to the rest of the field. Yet, I am one of the most Competitive and beat the P*ss out of the car on the Track. Where's your Cause and Effect here? As pointedly mentioned by another contributor, it's how you drive the car, over at what RPM range which will, to a great part, determine the car's longevity. I am smooth and very easy on my cars, despite pushing them to their limits. This is why they last. Most FV engines require a rebuild annually or every other season. Mine has averaged every 3-4 over the 14 years I've owned it. In large part, the Rules see to it that all the engines are basically the same, so how do you explain this if not for the effect of the Driver and proper maintenance?

Further, I realize that at some point in each of my cars that a rebuild will be necessary at some point, this is part of the Pkg. when owning Performance Cars longterm - you gotta Pay to Play. I try to hold that day off until absolutely necessary, but not if it means I have to drive like an Old Lady. If that's your point, those people would be much better off in a SunFire.

The 987S develops 276 bhp and 236 lb-ft of Torque respectively and this is often one of the arguments made to queeries about which model to buy - Base or 'S'. But, these numbers are only achieved at 6,200RPM and 4,700RPM respectively. If you are one of those guys who never exceeds 5k RPM, you're never gonna see this performance anyway, so buying the 'S' is a waste of time, if buying it solely for it's greater performance potential. On the other hand, a Base model driven to it's Max can realize more performance than the aforementioned 'S'.

Of course manufacturers build-in the Caveat of denying Warranty Claims against Racing or other Competition. Not usually because the cars can't take it, rather because all Drivers, or Owners are not the same. My cars are driven Hard, but, they are not abused. They are driven and maintained properly. Every car I've ever sold was sold for usually more than I paid for it, despite being very forthcoming to the Buyer about how the car was used. Their Test Drive, PPI, and complete Service Records (incl. every fill-up and Oil Change) tells them that the car is in excellent shape regardless of it's past use. Further, I have never had a Buyer come back to me with any complaints about a car I sold them. I have owned 43 cars in my life and currently own 5, so I've sold a few of them through the years.

So, to conclude, how you drive your car and maintain it is much more important in preserving it's life than an occaisional run to Red Line. If you want to keep bringing these extreme examples into the discussion, I suggest you start another thread on these topics, because they are not really germane to the discussion here. In that context, you may find that we're not so much in disagreement as you think.

Happy Motoring!...Jim'99