Is it bad to redline your car?

[ffracer]

No... use the right oil, make sure the car is warm, and known how to shift gears.

My old 87 Honda Accord LXi had 270,000 mi on it and saw 6000 rpm daily, when I overrevved it. I was taking racing school students around Watkins Glen into the downhill 'boot' section (100 mph) when the brakes faded bad. Needed engine braking fast and floated it to 8000 rpm, milked the brakes, and back again down to 6000 rpm, a gurgle, full song again. A valve adjustment a week later - good as new!

Ran M1 5W-30 for most its life at 4000 mi intervals and it was solid at 305k when I sold it. Nearly no cam wear or consumption. Sold it due to body rust.

Same thing with my old 1995 Ford Ranger 2.3L pickup truck. 200K and revved hard and long. Used M1 5W-30 for a long time, then 0W-30.

 

[dailydriver]

Originally Posted By: swirlparanoid
Originally Posted By: dailydriver
Originally Posted By: swirlparanoid
ls1's dont count they were touched by the hand of God...


If you say so.

according to all the f-body boys thats always been the case lol at least it was when i had mine TOUCHED BY HAND OF GOD lol




I know it is kind of the sarcastic 'inside joke' on all of the various LSx forums I used to frequent- I was kidding in my response to you because of that (was not sure if you were on said forums

).

 

[CBR.worm]

I do not worry about the engines, I know RPM causes wear and worse fuel economy due to friction, etc, but I think they will still last long enough. I worry a bit about transmissions, but again, everything is so well managed now that they are dealing with much less torque during shifts, my experience is that they last about half as long as the engine.

What I wonder about is the A/C compressor. Is it OK for the AC compressor to run at or near redline? I regularly redline and/or top out my cars (at least the non-truck cars), but I turn off the A/C because I have this vision of exploding AC compressors. I typically turn off the AC if I am spending more than 20 seconds or so over 5K. Am I crazy? I don't worry about alternators or power steering pumps. I guess I don't have the option to turn them off.

I think one of the reasons I have this fear is that the A/C cuts out for max power for about 7 seconds, then clicks back on right at about 7,200 in each gear - which seems bad.

 

[hypervish]

I know that some cars turn the A/C compressor off at high rpms. I know my RX does that.

I redline regularly, and I drive my cars till 300k miles. None of them have had any major mechanical problems but then again they were all Japanese cars. But, as long as the car is fully warmed up, redlining should create no damage.

Redline for a good time!

 

[SteveSRT8]

For most cars it's a load thing not an rpm thing. The ac is switched off to lighten the load a bit so you get max power.

Our industrial equipment mounted in our vans uses a stuttering device to engage the electromagnetic clutches. This cycles the power to the clutch several times over a two second period to lessen the shock of a start event.

Why don't cars use this device?

 

[Papa Bear]

Is it bad to redline your car?

Certainly it is, if it wasn't they wouldn't need to put the RED line there...

 

[ueberooo]

I would think such a Max rpm driving would put much higher wear especially on the bearings on the rods. Even if I had great oil with tons of moly and zddp, I would want to avoid this. There's very little benefit in that area or driving and a large number of disadvantages.

I don't that often go more than a few hundred rpm above max torque because of fuel economy reasons, and pretty rarely go near peak hp. These points are 4400 and 5600 rpm on my car. In 1st gear it's a little hard to control exactly, but still I almost never get to 6000 and usually am below 5000.

I tend to under rev it and stay in the region of 40% wide open throttle to 90% wide open throttle; so, most of my driving is from 1200 to 3400, or good deal away from max motor torque rpm.

 

[mike7139]

I have seen people redline their cars on a daily basis and those people are the ones who usually get 200k+ miles out of their vehicles. Me I usually keep the RPM's around 2k just because I am cheap. I want to get the best gas mileage and keep my tires and brakes as long as possible.

 

[gathermewool]

Originally Posted By: SteveSRT8
For most cars it's a load thing not an rpm thing. The ac is switched off to lighten the load a bit so you get max power.



I always assumed that it had something to do with potential damage to the compressor at such high RPM, too.

Originally Posted By: Papa Bear
Is it bad to redline your car?

Certainly it is, if it wasn't they wouldn't need to put the RED line there...



I disagree. Driving AT redline all the time is just dumb, but driving TO redline, even regularly, isn't bad for the engine.

 

[chrome]

There was an article out a while back which describes "valve rotation" at high rpm operations. Apparently the engineers design the valves to actually rotate in-situ to keep the valve seats clean of carbon and seal properly.

I recall the article saying some engines require at least 5000 rpm and above for the valve rotation to take place.

Anyone heard of this before?

 

[ueberooo]

yes, rev'ing the engine is good for cleaning valves. But really; sparkly clean valves are overrated IMO; you only need to do this a few time a year at most. And I've yet to see 'dirty' valves and symptoms thereof.

Yes revving it to 5k once in a while is okay. I won't fear 5k but I do want to stay away from redline which is like 6k to 7k.

 

[BobFout]

Originally Posted By: ueberooo
yes, rev'ing the engine is good for cleaning valves. But really; sparkly clean valves are overrated IMO; you only need to do this a few time a year at most. And I've yet to see 'dirty' valves and symptoms thereof.

Yes revving it to 5k once in a while is okay. I won't fear 5k but I do want to stay away from redline which is like 6k to 7k.



Short is mis-shifting, you cannot rev an engine to damaging RPMs. The engine is designed to operate from idle to wherever the fuel cut-off is.

 

[ueberooo]

Originally Posted By: BobFout
Short is mis-shifting, you cannot rev an engine to damaging RPMs. The engine is designed to operate from idle to wherever the fuel cut-off is.


Bob, that's a little bit reassuring to hear given that shifting out of 1st into a higher gear at high acceleration is so difficult to time. But I sort of disagree that regularly and very frequently driving near redline is okay.

Wear rate at a given reasonable rpm is going to be a continuous function of rpm; engineers set the threshold level of what the acceptable wear rate is, and yes, it's going to be somewhat short of where wear rate goes hyperbolic (or discontinuous--i.e. where engine actually blows up and pieces start flying), but it still is a somewhat arbitrary number (it gets you in the right ballpark but isn't a precise number).

Anyways, my intuition also tells me wear is going to trend upwards and upwards fast the further you pass max HP rpm and into the redline (sort of roughly in an inverse fashion of the mpg).

So, driving below max HP is a no-brainer to me, and I actually really don't like going past the midway point of max HP and max torque (which in my case is 5000). Maybe the wear is still so low at 6k that from a wear standpoint my 5k preference isn't that practical, but when considering a fuel and wear I think my 5k limit is practical.

 

[BobFout]

Originally Posted By: ueberooo
Originally Posted By: BobFout
Short is mis-shifting, you cannot rev an engine to damaging RPMs. The engine is designed to operate from idle to wherever the fuel cut-off is.


Bob, that's a little bit reassuring to hear given that shifting out of 1st into a higher gear at high acceleration is so difficult to time. But I sort of disagree that regularly and very frequently driving near redline is okay.

Wear rate at a given reasonable rpm is going to be a continuous function of rpm; engineers set the threshold level of what the acceptable wear rate is, and yes, it's going to be somewhat short of where wear rate goes hyperbolic (or discontinuous--i.e. where engine actually blows up and pieces start flying), but it still is a somewhat arbitrary number (it gets you in the right ballpark but isn't a precise number).

Anyways, my intuition also tells me wear is going to trend upwards and upwards fast the further you pass max HP rpm and into the redline (sort of roughly in an inverse fashion of the mpg).

So, driving below max HP is a no-brainer to me, and I actually really don't like going past the midway point of max HP and max torque (which in my case is 5000). Maybe the wear is still so low at 6k that from a wear standpoint my 5k preference isn't that practical, but when considering a fuel and wear I think my 5k limit is practical.



We're talking about shifting RPMs, not cruising RPMs. Those fractions of a second spent near redline when shifting amount to nothing much.

If one chooses to *cruise* at 5K RPM, wear may increase, but not in a meaningful amount. At most they waste fuel.

Modern engines are (all hopefully) well overbuilt.

 

[ueberooo]

Quote:
We're talking about shifting RPMs, not cruising RPMs. Those fractions of a second spent near redline when shifting amount to nothing much.


Yes I realize that (and the engineers that set the redline also are accounting for this temporary rather than sustained time spent at those rpms to set their redline number).

 

[BobFout]

Originally Posted By: ueberooo
Quote:
We're talking about shifting RPMs, not cruising RPMs. Those fractions of a second spent near redline when shifting amount to nothing much.


Yes I realize that (and the engineers that set the redline also are accounting for this temporary rather than sustained time spent at those rpms to set their redline number).


You mean modern engines can't be run at top speed for hours on end for years and years? Pretty weak if they can't. The good ones can.

Redline is set well short of damaging RPMs. Cruise at 5K if you wish, not going to 'hurt' the engine.

 

[rslifkin]

^ I agree. I took the Jeep down to Watkins Glen for opening weekend last spring. On the 2nd set of 3 laps I did (about 15 mins total), it didn't get under 2500 rpm once, and it was sustaining 4k+ for 20 - 30 seconds sometimes (redline is 5250). Plus, most of that was at, or near WOT.

Didn't worry me a bit, and between the spirited drive down, running on the track, and a nice cruise home, it was running beautifully by the end of the day (smoothest idle it's ever had). Engines are designed to be worked, hence why marine engines last (outside of commercial use, they pretty much never wear out, something else always kills them first).

 

[lexus114]

red lines are probably harder on the auto trans, than on the motor.

 

[Dave424]

From what I understand engine wear depends more on the amount of load than it does on rpm. Look at most of the manual small engined cars. My ’04 Civic revved at 4000rpm at 80 mph, some older mazda miatas rev around 4500rpm at the same speed and many owners have gotten 200-300k miles out of them. My current car is geared the same so it revs at almost 4000k at 75 – peak 115 tq is at 4200. With so little power this little boxy Kia needs to be shifted at high revs when getting onto onramps... so the car sees 4-5k rpms daily. So did every other small engine car that I owned. My first car, 1984 civic wagon had 215k miles when I sold it and it was trouble free and burned 1qt/OCI. From my experience, short bursts of high rpm/load are no problem on a daily basis as long as your oil is at operating and engine is properly maintained. I also recommend that you use a good synthetic oil for those conditions.

 

[gathermewool]

Originally Posted By: lexus114
red lines are probably harder on the auto trans, than on the motor.


IMO, the torque being applied is more detrimental to the tranny than the actual speed, which would mean a peak-torque shift would cause more band wear than a redline shift, right?