Keep her above 4000rpm and she'll thank you for it every day.

[Paul]

Once it's good and warmed up, I always look for safe opportunities to floor it and shift above 6000. This happens every time I take it out.

[RandallNeighbour]

While keeping our engines above 4k does keep carbon from building up, it does wear the engine out sooner too. Brucelee stated this elsewhere on the forum a while back when asked this same question. Good logic.

I don't keep my motor above 4k at all times, that's for sure. But I do run it up to redline most every time I drive it though to blow out any cobwebs that might have accumulated in the car between drives

I went through the Tail of the Dragon 6 times last Spring, never shifted out of 2 gear. Kept the RPM's above 4,000 the entire distance, about 12 miles each way.

[Paul]

You left out the best part: Both you and your car were SMILING!

Originally Posted by Paul

You left out the best part: Both you and your car were SMILING!

Still am, Paul!

[Paul]

Is your car smiling or is it sitting in a cold dark place shivering?

My car was smiling big time today!

Two words my fellow white Boxster friend:

H E A T E D G A R A G E !!!!!


I did wax the front bumper today. Like it needs another coat of wax!

Did you drink the '92 Hess yet?

[RandallNeighbour]

Originally Posted by bmussatti

I went through the Tail of the Dragon 6 times last Spring, never shifted out of 2 gear. Kept the RPM's above 4,000 the entire distance, about 12 miles each way.

Ditto here, Bill!

I was in 2nd gear the whole time and well above 4k too while driving the dragon.

However, I don't drive the dragon exclusively with the car and while I move past the 4k mark with most shifts, I don't keep it up there all the time.

Chock it up to $3.50 per gallon fuel I guess

[blue2000s]

Originally Posted by RandallNeighbour

While keeping our engines above 4k does keep carbon from building up, it does wear the engine out sooner too. Brucelee stated this elsewhere on the forum a while back when asked this same question. Good logic.

I don't keep my motor above 4k at all times, that's for sure. But I do run it up to redline most every time I drive it though to blow out any cobwebs that might have accumulated in the car between drives

I read an SAE paper a while ago that measured engine wear by oil analysis if metal particulate. They found that engine wear was not, in fact, related to engine speed at all. It was directly related to load. The higher the engine load, the higher the wear.

Particulate count was consistent no matter what the RPM of the engine for a given load, essentially stating the higher the RPM, they found the lower the wear per stroke.

[Brucelee]

Originally Posted by blue2000s

I read an SAE paper a while ago that measured engine wear by oil analysis if metal particulate. They found that engine wear was not, in fact, related to engine speed at all. It was directly related to load. The higher the engine load, the higher the wear.

Particulate count was consistent no matter what the RPM of the engine for a given load, essentially stating the higher the RPM, they found the lower the wear per stroke.

Love to see this. they have repealed the law of physics here if that is what they are saying. Load and stress on all metal structures within an engine increases as RPM increases. Again, if high RPMS were GOOD for an engine, race car engines would last forever. They don't, not even for weeks.


BTW-wear is measured by things other than particulates in the oil.

[Paul]

Unless you are going to keep your car for 150,000 to 200,000 miles, who cares?

With just the Porsche recommended maintenance you can drive these cars hard for at least that long.

It's a toy, enjoy it!

[rule1]

Should you run your car over 4000 rpm before its warmed up?

[Frodo]

I'd venture a "Negative" on that one.

Don't know a heck of a lot on the matter, but my gut tells me (and I follow it!) to keep her down at not much (if any) over 3000 RPM until warmed up (180 on the temp gauge). So far so good.

[blue2000s]

Originally Posted by rule1

Should you run your car over 4000 rpm before its warmed up?

Check out my link above, there is a strong relationship between engine wear and oil temperature. Warm up that engine before loading it!

[RandallNeighbour]

Originally Posted by Paul

Unless you are going to keep your car for 150,000 to 200,000 miles, who cares?

Please remind me never to buy a used Porsche from you

I am planning to keep my car well past 200,000 miles as I cannot afford a newer or new one. So this attitude doesn't work for me from any angle.

Originally Posted by Paul

With just the Porsche recommended maintenance you can drive these cars hard for at least that long... It's a toy, enjoy it!

My 2.5 motor only lasted 79k, and measuring the condition of the car when I got it at 82k, those were 79k hard miles. It appears that all the maintenance was done on the car too from records I've come across. The new motor (not reconditioned) that was put in the car and only had a couple of thousand miles on it now has 25k after three years of spirited weekend driving.

I replaced the tranny two years ago for suspect noises in 1st and 2nd gear at low rpm.

I would not be surprised if during my ownership of this car, with meticulous maintenance and replacement of every single thing I can find that is wearing or worn, I will have to put a third motor in it. Of course, it will be a 3.4 or 3.6, but nevertheless, I might not get 200k out of this new motor with the intermediate shaft failures that still occur in newer Porsche engines.

Paul, you have a good attitude about your car... it is indeed a rich man's toy for sure!
I drive my car like I stole it a lot of the time and run it up to redline most every time I put the key in the ignition. I just don't keep it above 4,000 rpm all the time because I want to keep my existing motor running for at least another 100,000 miles.

I think there's two schools of thought about sports car ownership. Those like yourself who enjoy the car to its full limits and might be harder on the motor than one who buys a car to own for 20+ years. I'm that second kind of guy by virtue of my personal financial situation and my growing satisfaction of fixing up an old car that has my fingerprints on most every part of the car as the years go by.

I guess my take on this thread is this: The motor is designed to be revved right up to redline and it does blow carbon out of the motor ... and the sound is glorious at redline. Conversely, if one keeps the revs up all the time, he or she will be replacing the motor sooner than later.

[Paul]

Originally Posted by RandallNeighbour

Paul, you have a good attitude about your car... it is indeed a rich man's toy for sure!

I drive my car like I stole it a lot of the time and run it up to redline most every time I put the key in the ignition. I just don't keep it above 4,000 rpm all the time because I want to keep my existing motor running for at least another 100,000 miles.

I agree and do the same except I see no issue with running the car above 4000 rpms IF IT"S IN TOP GEAR (in my case 5th).

[blue2000s]

Originally Posted by Brucelee

Love to see this. they have repealed the law of physics here if that is what they are saying. Load and stress on all metal structures within an engine increases as RPM increases. Again, if high RPMS were GOOD for an engine, race car engines would last forever. They don't, not even for weeks.


BTW-wear is measured by things other than particulates in the oil.

It may challenge YOUR understanding of the laws of physics, but rest assured, it's not breaking them.

It's not the RPMs that wear out racing engines, it's the constant WOT and related engine load.

Here's the article review:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=923479#Post923479

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=923866#Post923866

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=924463#Post924463

[Brucelee]

Originally Posted by blue2000s

It may challenge YOUR understanding of the laws of physics, but rest assured, it's not breaking them.

It's not the RPMs that wear out racing engines, it's the constant WOT and related engine load.

Here's the article review:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=923479#Post923479

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=923866#Post923866

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=924463#Post924463

Well. what you posted is a post from a guy who says he read a report by SAE on engine wear, which was measured by metal part. in the oil. Lets start there.

I agree that wear is greater while the engine is getting to operating temps. I would also agree that wear would be greater under load. ie. hammering the throttle and putting the engine under load. Of course, that is one way and likely the most frequent way that most of us GET TO THOSE HIGH RPMS!

Are you suggesting that we drive our Boxes very gingerly on our way to 6000 RPMS and they leave them there on cruise control? If that is the case, wear would be lower than the classic jack rabbit start. However, at 6000 stress and wear would still be higher than 3000 RPM, all things being equal.

Moreover, the measurement of particulates in the oil is not a very rigorous way to measure "wear" in a classic sense. In fact, one way you can generate more metal in the oil is to change it too frequently (source: Bob is the oil guy).

Lastly, if you search this thread, you will find reference to a study on piston ring wear and RPMs. There is a correlation, hard to imagine how there could not be.

Really, the last point. In a reciprocating piston engine, what happens to the forces of stopping and starting a piston throug the cycle as the RPMs increase?

Do the forces increase or not as RPMs increase or decrease or stay the same?

Is "wear" and stress, metal fatigue, bearing wear, reduced at 6000 RPMs or increased vs say at 3000 RPM?

Unless something happened in the universe last night to change physics, I would say that forces are increased at higher RPMs.

Do increased stresses and increased friction rates on metal parts, bearings etc. improve their useful life or decrease it?

PS-Those racing engines are designed to last, ie enhanced casting techniques, allowy metals, six main bearings etc.

They simply grenade anyway. Don't you think the guys would LIKE to get two races out of an engine?

Just a thought.

[blue2000s]

Originally Posted by Brucelee

Well. what you posted is a post from a guy who says he read a report by SAE on engine wear, which was measured by metal part. in the oil. Lets start there.

I agree that wear is greater while the engine is getting to operating temps. I would also agree that wear would be greater under load. ie. hammering the throttle and putting the engine under load. Of course, that is one way and likely the most frequent way that most of us GET TO THOSE HIGH RPMS!

Are you suggesting that we drive our Boxes very gingerly on our way to 6000 RPMS and they leave them there on cruise control? If that is the case, wear would be lower than the classic jack rabbit start. However, at 6000 stress and wear would still be higher than 3000 RPM, all things being equal.

You said you'd like to see the article, I have provided you with the means to find it. Go to SAE.org and buy it if you're not an SAE member.

I'm not sure that you understand what high load means. It's very easy to accelerate a car to 6000 RPM at light/medium load. If you've ever monitored an engine with a MAP sensor, it's very easy to see.

Originally Posted by Brucelee

Moreover, the measurement of particulates in the oil is not a very rigorous way to measure "wear" in a classic sense. In fact, one way you can generate more metal in the oil is to change it too frequently (source: Bob is the oil guy).

What's your more rigorous method alternative?

Originally Posted by Brucelee

Lastly, if you search this thread, you will find reference to a study on piston ring wear and RPMs. There is a correlation, hard to imagine how there could not be.

You're not talking about simply rubbing two pieces of metal against each other. There's a non-Newtonian fluid in between the two that has characteristics that can be very counter-intuitive. The viscosity a non-Newtonian fluid changes non-linearly with shear stress, meaning that the faster the two metal parts move relative to each-other, the thicker and more protective it becomes.

There are some very complicated physics going on that are not immediately apparent and often counter-intuitive.

Originally Posted by Brucelee

Really, the last point. In a reciprocating piston engine, what happens to the forces of stopping and starting a piston throug the cycle as the RPMs increase?

Do the forces increase or not as RPMs increase or decrease or stay the same?

Is "wear" and stress, metal fatigue, bearing wear, reduced at 6000 RPMs or increased vs say at 3000 RPM?

Again, there is a lubricant at work here that doesn't act as you appear to expect it to.

Originally Posted by Brucelee

Unless something happened in the universe last night to change physics, I would say that forces are increased at higher RPMs.

Do increased stresses and increased friction rates on metal parts, bearings etc. improve their useful life or decrease it?

PS-Those racing engines are designed to last, ie enhanced casting techniques, allowy metals, six main bearings etc.

They simply grenade anyway. Don't you think the guys would LIKE to get two races out of an engine?

Just a thought.

Again, engines under high stress wear out faster. It's not RPM related, it's stress related.