driving below 2800 RPM = trouble?

[Brucelee]

Lets try this.

Yes, one should avoid lugging the engine. There is no exact RPM rule for this, as in first gear, you should not be able to LUG the engine, and in 6th gear, it is quite easy.

Second. The engine should be able to run safely between just above lugging and to just about red line. So, any exact RPM rule is clearly not appropriate for the issue of grenading the engine. The engine SHOULD NOT grenade.

Re: The IMS, Porsche should just fix the issue if it has not already.

Regarding wear: Higher RPMS cause greater wear than lower RPMs. Any auto engineer will tell you that, assuming you are NOT lugging the engine.

The whole drive it like you stole it advice is purely infantile, if you are talking about engine wear.

Having said that, if you want to trash your engine, be my guest. Just go to the track and beat it until it dies.

[blue2000s]

Originally Posted by Brucelee

Regarding wear: Higher RPMS cause greater wear than lower RPMs. Any auto engineer will tell you that, assuming you are NOT lugging the engine.

Have you actually talked to an auto engineer who told you this? Different parts wear for different reasons, load is the leader in wear, not speed. Any mechanical engineer will tell you that.

[Brucelee]

Both lead to wear on the engine. As I said, if you are not lugging the engine, you are not loading it unduly with low RPMs. If you are flooring the accelerator all the time, you ARE loading the engine unduly. Would you want to take you car to the drag races every day? Would it comfort you to know that you are not lugging the engine?

If you are running at 6000 RPMS all the time, you are elevating friction, heat. and wear. Pistons have to reciprocate. When you move them at 6000 rpms rather than 3000 RPMs, and they have to reverse direction, at which RPM do you think there is more stress on the cranshaft and the pistons?

Think about it.

[blue2000s]

Originally Posted by Brucelee

Both lead to wear on the engine. As I said, if you are not lugging the engine, you are not loading it unduly with low RPMs. If you are flooring the accelerator all the time, you ARE loading the engine unduly. Would you want to take you car to the drag races every day? Would it comfort you to know that you are not lugging the engine?

If you are running at 6000 RPMS all the time, you are elevating friction, heat. and wear. Pistons have to reciprocate. When you move them at 6000 rpms rather than 3000 RPMs, and they have to reverse direction, at which RPM do you think there is more stress on the cranshaft and the pistons?

Think about it.

Ah Bruce, we've had this discussion before, I've shown you data, and you still ask the same questions. There's nothing else I can do for you.

[Brucelee]

Originally Posted by blue2000s

Ah Bruce, we've had this discussion before, I've shown you data, and you still ask the same questions. There's nothing else I can do for you.

Repost the data. I don't recall. Again, explain please how load, friction, heat, are all lower at higher rpms. Explain why running your engine at near redline reduces wear than say at 3000 rpms. Are you suggesting that if I drive 90 MPH that the load on the engine is lower than if I drive at 65? If my MPG is lower at the higher speed, does that not reflect the extra energy consumed by the engine to push the air away to attain that speed? Does the extra load lead to extra wear?

If the laws of physics have been changed, I would like to know.

BTW-I too have posted information from engineers on this topic before.

[Brucelee]

Have you actually talked to an auto engineer who told you this? Different parts wear for different reasons, load is the leader in wear, not speed. Any mechanical engineer will tell you that.


Are you suggesting that load is lower at higher speeds?? How can that happen in normal aggressive driving?

[CaptainObvious]

Is the concept of "lugging" an engine even relevant with fuel injection? I mean in the good ole days, you could feed the car too much fuel. Now, the car will only feed what it knows it can burn.

What exactly is stressed more at low RPM? The engine has less torque.

Is driving a BMW 135i at 1500 RPM lugging the engine... when it is near the peak torque there?

[dennis]

I drive a manual by sound more than watching the RPMs....if it feels the engine is ready, I shift. If I'm getting on it, I wind out the gears more, if I am driving casually I shift through the gears quicker and soem times around 2k, if downshifting around a turn, sometimes at 1700