How much damage does running higher in the RPM range cause?

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bk7794
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How much damage does running higher in the RPM range cause?

Post by bk7794 »

My car reaches optimum torque at about 4k. I do not have a tach but based off of the manual's optimum shifting speed I am guessing what those are around 3k. Sometimes while driving backroads I stay in a lower gear to get up the hill rather then choking it. I always wondered, how much damage does that really cause. The engine is fully warmed up so it's viscosity is optimum.

So what do you think?
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Re: How much damage does running higher in the RPM range cau

Post by theholycow »

No "damage".

Unnecessarily high RPM is unnecessary revolutions, each revolution with one revolution's worth of wear. It's also likely to produce more heat, more exhaust, etc.

Downshifting to climb a hill gracefully is the right thing to do. No need to make it struggle.
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Re: How much damage does running higher in the RPM range cau

Post by Shadow »

Engines are designed to spin at any speed up to their redline. You're not "damaging" anything as long as you stay within that range. Running higher RPMs can accelerate engine wear though...but in the context you're talking about, you really have nothing to worry about.
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Re: How much damage does running higher in the RPM range cau

Post by bk7794 »

Interesting, I probably shouldn't have said "damage" I know once I was watching the youtube channel "davidsfarm" and he had a v6 camry. He used to rev the crap out of that thing and he had to get rid of it because of lost compression and all that. Was that due to him probably doing it because it was cold and bouncing off the rev limiter all the time? Probably something I shouldn't be comparing to..

Also what will cause more engine wear, bogging the engine at a lower rpm at 100% throttle up a hill, or less throttle at a higher rpm.

Also mis-shifts, the sudden spike in RPMs, does that do damage as long as you are below red line?
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Re: How much damage does running higher in the RPM range cau

Post by Shadow »

bk7794 wrote:Interesting, I probably shouldn't have said "damage" I know once I was watching the youtube channel "davidsfarm" and he had a v6 camry. He used to rev the crap out of that thing and he had to get rid of it because of lost compression and all that. Was that due to him probably doing it because it was cold and bouncing off the rev limiter all the time? Probably something I shouldn't be comparing to..
I've watched his videos before...those guys are pretty crazy. Did you ever see the ones where he drives the cars from way up high in the air? Funny stuff. Anyway, I'd say he was probably abusing the Camry and he definitely contributed to its death.
Also what will cause more engine wear, bogging the engine at a lower rpm at 100% throttle up a hill, or less throttle at a higher rpm.
That goes back to our old debate about lugging the engine. In my opinion, it's not good practice to lug the engine. It makes far more sense to just downshift and allow the engine to accelerate from a more favorable RPM. Even so, at 100% throttle, the engine RPM will still climb and not be at low RPM for long, even in a higher gear.
Also mis-shifts, the sudden spike in RPMs, does that do damage as long as you are below red line?
There's no harm in spiking the RPM because of a missed shift. And If your car has a rev limiter, you can miss a shift quite badly and never exceed the redline, even if you kept your right foot to the floor. But even with a rev limiter, there is a situation where you can overrev your engine.....Imagine you downshift from, say, 5th gear into 4th, at high speed on the highway. But as you release the clutch, you suddenly realize that you selected 2nd gear instead of 4th. Even with a rev limiter, you can mechanically overrev the engine and cause some damage if your road speed means the engine will be beyond redline in 2nd gear.
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Re: How much damage does running higher in the RPM range cau

Post by bk7794 »

Shadow wrote: I've watched his videos before...those guys are pretty crazy. Did you ever see the ones where he drives the cars from way up high in the air? Funny stuff. Anyway, I'd say he was probably abusing the Camry and he definitely contributed to its death.
Oh yeah, haha the sky hill or something. Yeah he came back on Youtube, he made a diesel caravan which is kinda cool.

I was thinking that too, revving the crap out of the enigne cold is probably not good for your tranny, along with all the idiots that would probably drive the car and bounce off the rev limiter, it was probably beaten..
That goes back to our old debate about lugging the engine. In my opinion, it's not good practice to lug the engine. It makes far more sense to just downshift and allow the engine to accelerate from a more favorable RPM. Even so, at 100% throttle, the engine RPM will still climb and not be at low RPM for long, even in a higher gear.
Sometimes in a higher gear I still lose speed...even at full throttle.
So I started making the practice of downshifting before the hill, just in case it can't make it. I would also assume the lower oil pressure is probably not as good for it as lets say a higher pressure

Also I get paranoid sometimes keeping my enigne at that high of an RPM because I burn oil and it just makes me feel weird when I have to add oil..not sure why it does. Sometimes if I smell my car burning oil I will purposely back off on speed.
There's no harm in spiking the RPM because of a missed shift. And If your car has a rev limiter, you can miss a shift quite badly and never exceed the redline, even if you kept your right foot to the floor. But even with a rev limiter, there is a situation where you can overrev your engine.....Imagine you downshift from, say, 5th gear into 4th, at high speed on the highway. But as you release the clutch, you suddenly realize that you selected 2nd gear instead of 4th. Even with a rev limiter, you can mechanically overrev the engine and cause some damage if your road speed means the engine will be beyond redline in 2nd gear.
[/quote] That's good, puts my mind at ease when I am tired and botched a downshift. I have heard of the over rev, infact I have seen it destroy engines sometimes. Not good, I am afraid of hitting 3rd sometimes instead of 5th when I am quickly shifting.
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Re: How much damage does running higher in the RPM range cau

Post by Shadow »

bk7794 wrote: Sometimes in a higher gear I still lose speed...even at full throttle.
So I started making the practice of downshifting before the hill, just in case it can't make it. I would also assume the lower oil pressure is probably not as good for it as lets say a higher pressure
By all means, go ahead and downshift as you approach a hill. I do that too if it's a long and/or steep hill that I know I'd be better off in a lower gear. As for your oil pressure, there shouldn't be any concern unless your RPM drops below idle speed. Only then will your engine really be in any kind of danger of insufficient oil pressure. And if you think about it, that's not really even a serious concern because you'd end up downshifting anyway if your RPMs dropped that low.
Also I get paranoid sometimes keeping my enigne at that high of an RPM because I burn oil and it just makes me feel weird when I have to add oil..not sure why it does. Sometimes if I smell my car burning oil I will purposely back off on speed.
My car burns oil too. It's actually considered normal for my car. It doesn't consume a lot of oil, but I normally have to add a quart between oil changes (which I do at a 5,000 interval). Still though, that doesn't stop me from running the engine at high RPM. I don't know if the oil consumption would change much between running high RPM or running low RPM.

BTW, are you sure you're really able to smell the oil burning? Are you sure you're not smelling the catalytic converter? Is the smell more of a sulfur smell?
That's good, puts my mind at ease when I am tired and botched a downshift. I have heard of the over rev, infact I have seen it destroy engines sometimes. Not good, I am afraid of hitting 3rd sometimes instead of 5th when I am quickly shifting.
Are you sure your car has a rev limiter? Most cars do, but not all of them.

BTW, the primary danger when overrevving an engine is usually to the valvetrain and related components (rockers, lifters, etc..) depending upon your engine set-up. A short overrev usually won't cause any serious or permanent damage to an otherwise healthy engine.
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Re: How much damage does running higher in the RPM range cau

Post by bk7794 »

Shadow wrote:
By all means, go ahead and downshift as you approach a hill. I do that too if it's a long and/or steep hill that I know I'd be better off in a lower gear. As for your oil pressure, there shouldn't be any concern unless your RPM drops below idle speed. Only then will your engine really be in any kind of danger of insufficient oil pressure. And if you think about it, that's not really even a serious concern because you'd end up downshifting anyway if your RPMs dropped that low.
That is true, I just know that sometimes the idle drops below idle on an uphill start. So hopefully even then it won't be too bad.


My car burns oil too. It's actually considered normal for my car. It doesn't consume a lot of oil, but I normally have to add a quart between oil changes (which I do at a 5,000 interval). Still though, that doesn't stop me from running the engine at high RPM. I don't know if the oil consumption would change much between running high RPM or running low RPM
You burn oil aswell? You have a 4, 6 or an 8 cylinder. I forgot. That makes me feel much better about revving it a bit higher then. Even though I probably have more then 240k miles less then you.
BTW, are you sure you're really able to smell the oil burning? Are you sure you're not smelling the catalytic converter? Is the smell more of a sulfur smell?
It might be that, but I thought I was smelling the distinct smell of oil. This is only at very high rpms.
Are you sure your car has a rev limiter? Most cars do, but not all of them.
I have a fuel cutoff at around 6800 rpms.
BTW, the primary danger when overrevving an engine is usually to the valvetrain and related components (rockers, lifters, etc..) depending upon your engine set-up. A short overrev usually won't cause any serious or permanent damage to an otherwise healthy engine.
Yeah I know sometimes valve's could bend and break. I remember seeing a BMW M series motor having a broken valve due to an over rev.
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Re: How much damage does running higher in the RPM range cau

Post by Shadow »

bk7794 wrote: That is true, I just know that sometimes the idle drops below idle on an uphill start. So hopefully even then it won't be too bad.
You can control that by slipping the clutch and keeping the RPM higher than idle speed. Either way, you're not going to cause any kind of damage if you're talking about the RPM dropping down momentarily as you first get moving. What I'm talking about is more extreme. Think running in your top gear at 20 MPH up a long steep hill. Chances are good that your engine will not be able to gain RPM in a situation like that and might actually lose RPM instead. That's kind of extreme and it's not something too common because most people will just downshift.
You burn oil aswell? You have a 4, 6 or an 8 cylinder. I forgot. That makes me feel much better about revving it a bit higher then. Even though I probably have more then 240k miles less then you.
All cars consume oil. Some cars just consume more than others. On my particular car (2.0 turbo), it's completely normal to consume a quart of oil between oil changes. The vast majority of guys with my car on the Audi forums have to add oil on occasion. It's not an issue. Like I said, I don't think revving the engine higher will have much (if any) impact on the amount of oil consumed. I just don't think it makes an appreciable difference either way...

It might be that, but I thought I was smelling the distinct smell of oil. This is only at very high rpms.
How much oil are we talking about? Do you need to add a quart of oil every few days? Do you see blue smoke out of the exhaust when you accelerate?
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Re: How much damage does running higher in the RPM range cau

Post by bk7794 »

Shadow wrote: You can control that by slipping the clutch and keeping the RPM higher than idle speed. Either way, you're not going to cause any kind of damage if you're talking about the RPM dropping down momentarily as you first get moving. What I'm talking about is more extreme. Think running in your top gear at 20 MPH up a long steep hill. Chances are good that your engine will not be able to gain RPM in a situation like that and might actually lose RPM instead. That's kind of extreme and it's not something too common because most people will just downshift.
That is basically what I do..the slipping of the clutch, not going up a grade in top gear at 20mph. I would have figured that aswell, plus probably not saving much gas doing that either, your dumping more fuel into the combustion chamber.
All cars consume oil. Some cars just consume more than others. On my particular car (2.0 turbo), it's completely normal to consume a quart of oil between oil changes. The vast majority of guys with my car on the Audi forums have to add oil on occasion. It's not an issue. Like I said, I don't think revving the engine higher will have much (if any) impact on the amount of oil consumed. I just don't think it makes an appreciable difference either way...
I guess its not that bad, but my family owned a car that would burn probably a quart of oil every 1000 miles if not more and when I would change the oil it made me wonder if I should just start putting the old stuff back in and just replace the filter...I start to think that it is a waste of money.

How much oil are we talking about? Do you need to add a quart of oil every few days? Do you see blue smoke out of the exhaust when you accelerate?
Um, generally its like 3/4 of a quart to ever 3500 miles. Sometimes more sometimes less. I am not really doing well this run because I have been trashing it up hill lately and I had a friend drive the car that likes to rev it high in the rpm range...Also I do not see any blue smoke when I accelerate hard. Even when I think I am smelling it.
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Re: How much damage does running higher in the RPM range cau

Post by potownrob »

bk7794 wrote:...my family owned a car that would burn probably a quart of oil every 1000 miles if not more and when I would change the oil it made me wonder if I should just start putting the old stuff back in and just replace the filter...I start to think that it is a waste of money...
i know what you mean, but i truly hope you didn't actually resort to doing this :shock:
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Re: How much damage does running higher in the RPM range cau

Post by bk7794 »

potownrob wrote:
bk7794 wrote:...my family owned a car that would burn probably a quart of oil every 1000 miles if not more and when I would change the oil it made me wonder if I should just start putting the old stuff back in and just replace the filter...I start to think that it is a waste of money...
i know what you mean, but i truly hope you didn't actually resort to doing this :shock:
No I never resorted to doing that, but it was just annoying that I would have to add oil just to go on a 50 mile trip and then comeback and dump the new oil that I put in there...atleast the civic isn't that bad in doing that, but still.
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