This past sunday, I went on a cruise held by the local import tuner scene. It was about a 250 mile round trip, mostly staying at legal speeds but at one point towards the end of the cruise after half the group made a wrong turn, it turned into a bit of a race. We all had turns passing each other at high rates of speed, I for one passed several Civic's in the group at about 170 km/h. My 92 Accord pulled right up to that speed in 5th and felt like it could have kept right on going past that. Anyway, over the length of the cruise, whenever the group pulled away from a stop, we all revved our engines pretty hard in gear, I usually shifted out of 1st and 2nd at 5000 or so. We stopped and started probably 15-20 times, and almost every time, I shifted at 5000. Now here's the thing, after doing that all day Sunday, the car doesn't seem any worse for it, in fact, it seems to be running maybe better. Maybe all that high revving freed up a sticky ring or something, or maybe sucking in all that oil smoke from the handful of Civic's made a difference? What do you think? Could repeated high revving make an engine run better?
Driving a car hard can make it run better?
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I've felt the same thing. They call this the "Italian Tune-Up". I do think it burns off some carbon buildup on rings, piston tops, and valves and that explains this phenomena. In contrast, engines that grandma has only ever driven 1 mile to and from church it's whole life always seem to be the unhealthy ones!
Runs better, but longevity suffers? I'm all for blowing the cobwebs out, but remember that you cannot escape that wear rate is proportional to the square of the relative speed of the parts. So higher rpm means higher squared wear. But don't let that put a damper on the fun: some cars are made for (even need?) driving hard, and normal wear can be controlled with normal maintenance.
Yes, blowing out the carbon does help the engine ECU to find a better operating point for the engine.
I find the engine in my Ferrari F355B only gets its mixture figured out after about 50 miles of running. This summer the wife and I took the car for an 8 day 2,346 drive out to 4 corners. After a day or so, the car was running better than it had in several years.
Some engine controlers try to tune the engine to the driving situation (and gas) at hand. As you drive, the ECU moves around the mixture and timing for each cylinder at each RPM and each throttle position, and makes adjustments to the Fuel and timing maps. The longer you can run at one throttle position and RPM, the easier it is for the computer to optimize the tablular entries. Long multi-day drives over varied terrain give the ECU time to optimize pretty much the whole operating envelope.
As to repeated high reving, this is part of the engine operating realm, and should be excercised rather regularly (post breakin). As long as the oil temperature does not get over 260dF (+/-) (and water temps stay in reason) there is little to worry about with using all of the redline limited rev band of the engine. And it is here that the thermodynamic and mechanical stresses are such that blowing the carbon out happens.
I find the engine in my Ferrari F355B only gets its mixture figured out after about 50 miles of running. This summer the wife and I took the car for an 8 day 2,346 drive out to 4 corners. After a day or so, the car was running better than it had in several years.
Some engine controlers try to tune the engine to the driving situation (and gas) at hand. As you drive, the ECU moves around the mixture and timing for each cylinder at each RPM and each throttle position, and makes adjustments to the Fuel and timing maps. The longer you can run at one throttle position and RPM, the easier it is for the computer to optimize the tablular entries. Long multi-day drives over varied terrain give the ECU time to optimize pretty much the whole operating envelope.
As to repeated high reving, this is part of the engine operating realm, and should be excercised rather regularly (post breakin). As long as the oil temperature does not get over 260dF (+/-) (and water temps stay in reason) there is little to worry about with using all of the redline limited rev band of the engine. And it is here that the thermodynamic and mechanical stresses are such that blowing the carbon out happens.
Wow! I just put a K&N FIPK on my 94 Corolla and have been taking the rpms higher than usual all day, and after doing that for a while, the car does seem to be running freer and better/snappier throttle response. Not just from the K&N (although it did give the car a significant power boost), but from romping on it frequently. I really think there is something to the italian tune up cause on my parents vehicles which are grandmaed as far as driving, they seem to have a snappier throttle after you give them a couple good high rpm romps. Think the ECU changes parameters or something like Mitch just indicated.
My '95 Accord always runs better if I wind it up on a regular basis.
Not just "drive hard", driving long trip helps a lot too.
When I was driving down to LA every other week, immediately after I got of the freeway the engine is alot smoother, and stay that way for at least 3 days. The drive was 5 hour non stop at 85-95mph.
When I was driving down to LA every other week, immediately after I got of the freeway the engine is alot smoother, and stay that way for at least 3 days. The drive was 5 hour non stop at 85-95mph.
I believe in it. I've actually heard of people that give their cars constant low RPM usage that end up having problems at the end. Like a Ford Taurus SHO with carbon buildup all over the pistons. My Focus gets a daily kick in the ***. Convincing people that their cars CAN actually rev past 2000 RPM's is a different stories. Freakin kills me!
Patman
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Even if it didn't work, it sure is fun!
I know I drive my car at lower RPM that I should, as it seems to help with the MPG and oil burning, however the owners manual actually states that for optimum emissions and fuel economy to keep the RPMs over 2500 and actually recommends AGAINST driving under that. With all the city driving that I do, I actually seem to rarely get over 2k, but it does get wound up on occasion.
Alan, I own an 84 533i, believe me, I completely understand!!! Did you know that alot of the older bimmers, dunno aout 3 series, but the old 5's have a completely separate fuel map for WOT? They basically run pig-rich, thast why they are so incredibly smooth at high rpm, but a lil rough on lower and idle. All old bimmers idle a lil funky, it's just what they do. They did it right off the showroom floor.
My '05 Subaru outback Sport's 2.5L N/A hits redline almost daily. I believe it's good for it. I've seen these engines with over 80k on them, with all the original crosshatching on the cylinder walls still, and not a bit of a lip in the cylinders from ring wear. Same for older BMW's, but I've opnly seen examples that had over 150k on them, with the exact same results.
My '05 Subaru outback Sport's 2.5L N/A hits redline almost daily. I believe it's good for it. I've seen these engines with over 80k on them, with all the original crosshatching on the cylinder walls still, and not a bit of a lip in the cylinders from ring wear. Same for older BMW's, but I've opnly seen examples that had over 150k on them, with the exact same results.
I thought it was common for fuel injected cars to richen the mixture at WOT. Ford vehicles do it.
>>>> "I've actually heard of people that give their cars constant low RPM >>>> usage that end up having problems at the end."
Actually, the worst consequence of consistent low rpm operation is cylinder wear pattern. In time, a ridge will form in the top of the cylinder at the top edge of top ring. Then, if the engine gets revved way beyond normal, the top ring will bang into that ridge because of the increased upward inertial force of the piston and rod at the top of its travel.
A ridge is going to eventually form in any case, but it'll be more "ramped" than abrupt if the engine rpm takes occasional excursions into the higher rpm range.
Regards, Gary in Sandy Eggo
Actually, the worst consequence of consistent low rpm operation is cylinder wear pattern. In time, a ridge will form in the top of the cylinder at the top edge of top ring. Then, if the engine gets revved way beyond normal, the top ring will bang into that ridge because of the increased upward inertial force of the piston and rod at the top of its travel.
A ridge is going to eventually form in any case, but it'll be more "ramped" than abrupt if the engine rpm takes occasional excursions into the higher rpm range.
Regards, Gary in Sandy Eggo
The best two reasons to drive it hard are:
1) It's more fun, and
2) The engine likely will live longer than the body anyway given the rust factor (at lest for us rust belt folks).
1) It's more fun, and
2) The engine likely will live longer than the body anyway given the rust factor (at lest for us rust belt folks).
Gary, sorry, what does your above post mean in layman terms?
Are you saying it's bad for a normal low rpm vehicle to make sudden climbs into high rpm?
Is there a shortened engine life from driving under 4k rpm's consistently?
Are you saying it's bad for a normal low rpm vehicle to make sudden climbs into high rpm?
Is there a shortened engine life from driving under 4k rpm's consistently?
Ramblin,
What I said was, an engine run for a long time at low rpm's will eventually form a sharp ridge that the upper ring could bang into if revved into a much higher rpm range.
What I can't tell you is how long it would take for the ridge to form to the point of being a barrier to higher rpm's OR, how much of a real problem it represents.
If you DO occasionally run your engine to a higher rpm for even a minute or so, that ridge would end up being tapered, and be of no serious consequence.
I personally do not believe you will have shortened engine life from driving under 4K rpm. In fact, the more time you can spend at or under 2K rpm, the longer your engine will last. It's simple math. All other things being equal, wear goes up with relative velocity.
Regards, Gary in Sandy Eggo
What I said was, an engine run for a long time at low rpm's will eventually form a sharp ridge that the upper ring could bang into if revved into a much higher rpm range.
What I can't tell you is how long it would take for the ridge to form to the point of being a barrier to higher rpm's OR, how much of a real problem it represents.
If you DO occasionally run your engine to a higher rpm for even a minute or so, that ridge would end up being tapered, and be of no serious consequence.
I personally do not believe you will have shortened engine life from driving under 4K rpm. In fact, the more time you can spend at or under 2K rpm, the longer your engine will last. It's simple math. All other things being equal, wear goes up with relative velocity.
Regards, Gary in Sandy Eggo
Indeed, Gary has a point.
However, we do have to remember hard driving can have a penalty. After all, with a lot of passes to redline, you are stressing the system repeatedly to its design limits. How much of a safety factor you have in there depends on the car and how it was maintained.
I had a good friend who always took his cars to the limits. Results? One blown headgasket, one connecting rod through the block, one siezed engine, two blown auto trannys and one completely fried manual trans clutch. All this over 20 years and probably 8 cars worth of driving. Worth it or not? Your choice.
However, we do have to remember hard driving can have a penalty. After all, with a lot of passes to redline, you are stressing the system repeatedly to its design limits. How much of a safety factor you have in there depends on the car and how it was maintained.
I had a good friend who always took his cars to the limits. Results? One blown headgasket, one connecting rod through the block, one siezed engine, two blown auto trannys and one completely fried manual trans clutch. All this over 20 years and probably 8 cars worth of driving. Worth it or not? Your choice.
I fail to see how a competent driver taking an engine to redline (repeatedly) could result in a fried clutch.
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