The dangers of hitting redline

[rationull]

How bad is it really to occasionally hit redline in a controlled manner? Is it practically detrimental at all? I'm not talking about revving in neutral, or cruising at redline -- just hitting it (at WOT) during acceleration and/or during passing maneuvers after everything is warmed up. To me, logic would dictate that the redline is set to an engine speed that's safe to hit occasionally (or else it would've been set lower), and that this is true whether you're talking about an engine in a sporty car or in a car with less of a sporty focus (be it a 6000 RPM V8, an 8000 RPM I4, or even a 4500 RPM diesel I4). In fact while sporty cars are probably more likely to be redlined recreationally, economy cars may be in general more likely to be in situations where the full engine speed range is actually needed and used given they have less power on tap and will need to take advantage of all of it from time to time. I don't see why higher revs would be safe in one but not in the other.

However, despite this logic, plenty of people seem afraid to hit redline or seem to think it's bad for the car. Generally the truth is somewhere in the middle -- where is the truth here? Has anyone actually experienced or heard of engine problems that could be attributed to too much revving? Ever redlined a car all the time and still had no issues after many miles?

 

[addyguy]

Absolutely no harm at all.

In fact, probably pretty darn good for the engine.

 

[SteveSRT8]

In a modern car the rev limiter is set to protect the motor.

You can't hurt it if you tried.

And I agree with addyguy, probably good for most engines.

 

[chubbs1]

Just make sure she's warmed up good and nail it!

 

[IndyIan]

Most fuel cut offs are set low enough that, unless the engine is very sick already, no damage occurs. For autocross the odd time the gearing won't work out for a car and its not worth shifting, so someone will run the car on the limiter for a second or two.
An extreme case is an old Festiva a guy in my club runs, he just runs it off the limiter for fun, and nothing happens. In some races there are 3 guys running it, each of them bouncing off the limiter often and the car loves it...

 

[hate2work]

Originally Posted By: addyguy
Absolutely no harm at all.

In fact, probably pretty darn good for the engine.


How can redlining the engine all the time be good for it?

That goes against most everything I thought I knew, but I try to keep an open mind

 

[HTSS_TR]

The redline of '94 S2000 is 8k and the limiter is 8200-8250, I hit the limiter/fuel cut off once in a while.

 

[tinmanSC]

If the engine has had a very gentle life, it can be a problem. But in general, I don't think it hurts it. The problem with giving an engine a very gentle life then red lining (i.e. new owner) is that over time a lip develops at the top of the combustion chamber. This is where the piston/piston rings stop and start to go back down again. The cylinder lining is made longer than the piston will normally travel. At red line, the connecting rod and wrist pin will have some give, and the crank can flex. Sometimes this is just a few microns, but it's enough for the piston rings to go beyond their normal throw and hit that little lip in the lining. This can cause cracking and all sorts of angry things. I've seen a few family cars that have this problem. Engine runs like a top, then the 16 year old kid gets it and it starts burning oil and has lowered compression. So, long story short, revving it up from time to time won't hurt it, unless you have gone 100K miles driving like a soccer mom.

 

[ABerns]

Thanks, tinmanSC! I've heard a babied engine shouldn't be redlined late in its life. Now it makes sense why!

 

[Shannow]

+1 to tinman.

When we first started buying cars (late 60s, early 70s holden 6', that would sometimes happen, parrticularly if it had been operated without a thermostat at some time in it's early life.

Other than that, there shouldn't be a problem.

Parent's R16 manual allowed for limited operation past the redline in overtaking and emergency.

 

[01rangerxl]

I've redlined my truck countless times since new and it still runs like new at 104K miles. It burns less than a quart every 6000 miles.

 

[Scienceman]

Everynow and again it can't be bad!

 

[GenSan]

Life's too short not to redline.

2002 Sequoia was redlined with less than 10 miles on odometer off the lot, and I would say that I hit redline(5200rpm) at least once every time I drive it.

8 years, 110,000 miles later and no detrimental effects that I'm aware of. The 4.7 V8 does not use any appreciable amount of oil during its once a year oil changes ranging from 10-15,000 miles yearly.

 

[rationull]

Even more positive response than I expected. Excellent. I guess I won't feel bad for my poor car, then!

 

[rjundi]

My cars are both well powered Subaru WRX and Legacy GT(turbo) wagons.

In 5+ yrs of ownership I can count on one hand the amount times hitting red line. The car is well powered so I don't see the point. I do use 4000 RPM (torque peak) as shift point though on my WRX.

 

[JHZR2]

Originally Posted By: GenSan
Life's too short not to redline.

2002 Sequoia was redlined with less than 10 miles on odometer off the lot, and I would say that I hit redline(5200rpm) at least once every time I drive it.

8 years, 110,000 miles later and no detrimental effects that I'm aware of. The 4.7 V8 does not use any appreciable amount of oil during its once a year oil changes ranging from 10-15,000 miles yearly.


The thing that gets forgotten is the true long-term effect. 110k is like nothing. What is interesting is the effect on terminal mileage, which I doubt anyone knows.

Letting the car breathe, generating max power, etc. is all great... But redline isnt necessarily any of those.

 

[ls1mike]

I had my 01 Z28 on the Dyno with 48 miles on it. Never had a problem.
The Trans Am? A day without redline is like a day without sunshine

 

[Audi Junkie]

The redline on my tach turns red 1000rpm before the real redline, that was actually raised by my ecu flash. In a warmed healthy engine, hitting redline under load is no problem.

 

[GenSan]

Originally Posted By: JHZR2

The thing that gets forgotten is the true long-term effect. 110k is like nothing. What is interesting is the effect on terminal mileage, which I doubt anyone knows.



Only time will tell my friend. I plan on keeping the vehicle for a very long time so I'll let you know every 100,000 miles how it's holding up.

From a native South Jerseyan, who knew your neck of the woods well....say hi to Mr. Columbus for me at the Cooper River Park and have some pancakes for me at the Pop Shop and tuna jaw at Sagami

 

[Hokiefyd]

Especially for an automatic, I think a redline run is more detrimental to the transmission than the engine. I'm sure the engine could care less (for the most part). It's the transmission that has to handle that WOT/redline upshift. With a 3-pedal car, you can better manage the load on the transmission during an upshift. But most modern vehicles have engine torque management programs that softens engine power during upshifts anyway, to protect the transmission.

Bottom line: wring it out!