Can someone settle an argument?

[ioni]

My friend thinks that you should periodically red line your car because engines don't get hit enough to burn off carbon build up in the engine in the 2-3k rpm range. Periodically meaning once a month for a minute or so. I think he just likes to red line.

 

[Vetterin]

Short answer: Your friend is an idiot! Run your car at redline for 1 minute and carbon buildup might just be the least of your problems. (Flame suit on)......

 

[Alienwho]

This is something that was true for older 2 stroke motorcycles which needed to be revved high to not only keep things moving inside the engine, but to stay in the powerband. Is it healthy to consistently redline your civic or accord? You already know the answer to that.

 

[monkeydelmagico]

used to be called the italian tune-up. Old school thinking for folks who couldn't tune carbs. For a fuel injected computer controlled system it's idiotic.

 

[tweakmonkey]

For 1 minute? Stupid.

But I think it's good and harmless to occasionally and regularly rev a car up. No reason to pussy foot all the time in a healthy car.

 

[dbcooper1]

This goes back to not only carburetors, but fuel that still contained lead.

 

[MiataNC]

Depends on the car...

The Mazda RX-8 needs to be warmed up properly and then redlined to keep carbon from building up. The RX-8 has a rotary engine, which makes it unique. The rotary burns a LOT of fuel and injects oil to protect the apex seals. So carbon build up can be an issue if the engine isn't run hard after a proper warm up.

Direct injection engines suffer from carbon build up on the valves, and redlining them will NOT prevent or remove carbon.

Back in the day when cars ran 4bbl carburators, you could often resolve a gummed up carb (clogged venturies etc) condition by taking the car to redline under load and forcing the secondaries to open. I think the "take it to redline to clean it out myth" comes from that.

 

[SpatiallyAware]

I doubt your friend meant he literally sits still and holds his throttle at redline.


Personally, I do feel like performance engines need to be 'run'. Blast up onramps, run the brakes hard now and then to heat them up and wear down pad material from rotors, that sort of thing.

The most problematic cars I've seen were driven by grandma and never ever driven hard. Seals/rubber parts failing, using oil, creaking suspension parts, etc

 

[jagec]

The (EFI) V8 "Northstar" engine was notorious for running poorly if it was pussyfooted too much for too long. Of course, that was the engine that went into a lot of land yachts driven by octogenarians. Yes, the solution was to let the youngest guy in the shop give it the ol' Italian tuneup, then charge them $200 and send them on their way.

That said, you certainly wouldn't want to let an engine sit at redline, and you don't need to go all the way to redline to keep an engine clean. Your average person probably keeps their engine plenty clean just by getting onto the freeway occasionally.

 

[JCH13]

Like others said, literally sitting at redline for 1 minute is a terrible idea.

Opening it up a little bit now and then? Great idea for some cars IMO. Hell, in these cold months I can feel my MS3 get faster after I open it up once or twice on a drive. Spark plugs might get cleaned off? Not sure why, I do know that it happens though.

A friend of mine, who was a mechanic at a BMW dealer for a while, saw several cases where carbon buildup caused issues because the cars were never driven hard.

 

[Zenmervolt]

I generally believe in running an engine hard (once it's warmed up, of course) a few times a month, but I don't think that bouncing off the rev limiter for a full minute is the way to go about it. A full-throttle run up an on-ramp every couple of weeks is plenty.

ZV

 

[ioni]

Interesting replies. Since I posted on my phone I was a bit lazy in describing exactly what I meant by redlining. I just meant getting the pin into the red, not bouncing off the rev limiter. Also maybe not for a solid straight minute, but flooring it up on ramps for more than just a few seconds, then slowing down, then flooring it again a few times.

I was out of town for a full month and my car wasn't driven at all. The speed limit is low with lots of traffic everywhere I drive around too, so I haven't driven my car very hard since I moved to this area a few years ago.

Anyway, my engine started bouncing around at idle and my check engine light came on. I took it in to a shop to get it fixed and after getting it back, it wasn't fixed. My friend thought it might be carbon build up since I don't rip on my car anymore. I didn't really think that was a thing.

 

[JCH13]

It is a thing. But you probably have IAC or EGR plumbing that's clogged.

 

[silicon]

My friend thinks that you should periodically red line your car because engines don't get hit enough to burn off carbon build up in the engine in the 2-3k rpm range. Periodically meaning once a month for a minute or so. I think he just likes to red line.

I would not reccommend anyone to redline their motor to burn the carbon from the cylinder. Carbon in a proper functioning motor takes many many thousands of miles to build up if at all. Even a motor with 150,000 km's on the clock will show little carbon buildup if, the aircleaner is changed once a year, the plugs are replaced once a year and good gas is used and the operator drives long enough at each outing to thoroughly warm the motor and accessories etc. Simply revving the motor to the redline is risky because its not made for this type of running. JMHO

 

[SpatiallyAware]

What... Yes a motor is certainly made to survive bursts up to redline.

And yes, it does burn off and clean up the sparkplugs, and it can help dislodge carbon on the valves.

And changing spark plugs once a year....???

 

[michal1980]

Like others said, literally sitting at redline for 1 minute is a terrible idea.
.

why? Whats going to happen to an unloaded engine bouncing of the rev limiter?

nothing.

 

[SpatiallyAware]

Engines are designed to function best under some sort of load. Rings seat better, less blow by, more evenly distributed forces on bearings.

 

[silicon]

What... Yes a motor is certainly made to survive bursts up to redline.

And yes, it does burn off and clean up the sparkplugs, and it can help dislodge carbon on the valves.

And changing spark plugs once a year....???

I disagree with your statement completely. Explain how the carbon is burned up by simply speeding the motor while running it at a normal speed will not. And once a year for the plugs is not too often.

 

[silicon]

Engines are designed to function best under some sort of load. Rings seat better, less blow by, more evenly distributed forces on bearings.

and at the design speed of the motor where they last the longest. And the type of oil used makes a difference too.

 

[SpatiallyAware]

I disagree with your statement completely. Explain how the carbon is burned up by simply speeding the motor while running it at a normal speed will not. And once a year for the plugs is not too often.

Running an engine hard once it's at full temperature introduces combustion chamber and valvetrain temps that can't be obtained otherwise.

It's not going to give you a spotless intake tract, but it will certainly help knock off excess carbon build up on valves and around the valve seats.


And yes, once a year is absolutely outrageous unless there's some extenuating circumstances.

 

[SpatiallyAware]

and at the design speed of the motor where they last the longest. And the type of oil used makes a difference too.

Fleabag, is that you?

 

[silicon]

Running an engine hard once it's at full temperature introduces combustion chamber and valvetrain temps that can't be obtained otherwise.

It's not going to give you a spotless intake tract, but it will certainly help knock off excess carbon build up on valves and around the valve seats.


And yes, once a year is absolutely outrageous unless there's some extenuating circumstances.

again i disagree with your statements and, no disrespect intended, you don't seem to know a lot about engines and mechanics. A course at a community college may help you a lot.

 

[silicon]

Fleabag, is that you?

this is not fleabag.

 

[SpatiallyAware]

again i disagree with your statements and, no disrespect intended, you don't seem to know a lot about engines and mechanics. A course at a community college may help you a lot.

Which statement do you disagree with? We can break them down one by one.

 

[Midwayman]

I doubt your friend meant he literally sits still and holds his throttle at redline.


Personally, I do feel like performance engines need to be 'run'. Blast up onramps, run the brakes hard now and then to heat them up and wear down pad material from rotors, that sort of thing.

The most problematic cars I've seen were driven by grandma and never ever driven hard. Seals/rubber parts failing, using oil, creaking suspension parts, etc

Exactly. Its a good idea to take every system to its max/min ratings once in awhile. Hold redline for 1min straight? Probably not. Blast it up an onramp once in awhile... probably good.