Does hitting redline help or hurt your car?


There’s an old tale that Ferrari mechanics would often run their clients’ cars up to redline for extended periods after servicing to break loose the carbon deposits within the engine—a process that became known as the “Italian tuneup.” But just how effective is this technique at removing carbon buildup? Engineering Explained’s Jason Fenske explores three key areas to determine if there would be any benefit to periodically redlining your engine.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/10/15/does-hitting-redline-help-or-hurt-your-car


Beware of high RPM on older worn engines! Timing gears, chains and belts can slip or fail which is catastrophic for interference engines. Worn bearings can spin, lifters can float and stick and loosing carbon can rattle around and sound like a rock is in the intake.


My dad had a 1977 Fiat 131. Was actually a great little car. He’d frequently take it to redline in second gear after it was warmed up. At 150,000 miles the Fiat dealership asked what the heck he was doing for the car as it still had perfect compression. Never had a problem with the car. Pretty amazing for a 70’s car of any make.


This topic comes up frequently with the rotary engine crowd. A high rev’ing engine burning a small amount of oil and with a combustion chamber that has a lot of surface area. Opinions vary. While it can be a good rationale for having alot of fun, it’s still added stress with little effect. And IMO carbon control should be a gradual process. A water-injection systems, especially on a forced-induction car is usually more effective and comes with cooling and knock suppression too.


Jim - It’s interesting you bring up a rotary engine. Back on the late '90s, I had a 1983 RX 7 and used it as a daily driver. My commute was all of 7 miles each way. It began to run rough, so at about 1am on a weekday I got onto I-95. No traffic, I downshifted , punched the gas and ran her to the redline. I slowed down and repeated several times. As I looked in my rear view mirror, I saw a cloud of carbon coming out of the tailpipe when I hit the gas hard. So, I repeated my Italian Tuneup until I saw no more carbon coming from the rear. From that point forward, the car ran beautifully. So, it definitely worked for the RX 7. Was great fun too. Dang - now I miss her!


I entirely agree with Mr. McFrederic’s cautionary note. There is absolutely nothing to be gained by red lining a modern car engine, and a whole lot of potential downsides for all of the accessory drive elements such as water pumps, alternators, air conditioners, as well as the internal engine parts that, over time, can simply not tolerate even momentary full throttle operation. Standard American Engineers has technical data on just how long one can expect a gasoline engine to operate BEFORE it needs to rebuilt. I would refer these engineering experts words of wisdom to any one who is reading this article and whose idea of extending the life an expensive car requires red lining.


I am not a mechanic but I can maintain my fleet of old vehicles and a tractor. It seems to me that myths are formed for various reasons, some valid, others are passe, but I have a difficult time believing that stressing moving parts will be good for them. The easiest way to keep a car healthy with proper tuning and fresh oil, new plugs, wires,. seems to get lost with a lot of daily drivers.

But back to myths, I cringe when I hear a person rev their engine right before shutting down. I guess they’re thinking that they’re blowing out the bad particles but it seems to me is they’re burning off cylinder lubrication that the engine could make good use of with the next start… ?

Another cringe-worthy moment is when drivers rev their engine immediately after starting. I don’t know but it seems like waiting for the oil pressure to rise by idle first (plus being a cold engine) would be the healthiest thing for any engine…


Today’s engines run so good and so clean that I can’t see ever having to blow out the engine. However, that was not the case back in the sixties. I bought a new 1969 Chevy Nova SS with the 300HP engine and a four speed. After driving it around town for a couple weeks, it would take a couple miles of wide open running to get it to clear up and run like it was supposed to.


I am from tbe era where you would do one of two things, you either floored the gas pedal when the light turned green and held it there until it shifted into second, then let off, or you went to your favorite long entrance ramp to the highway and ran the car with the gas pedal to the floor from 10mph to the speed limit, or to the end of second gear if you were sure of your surroundings. The light brown clouds coming out the exhaust were what was desired. You were pretty safe with automatics if you let them do the shifting. Generally top speed in first was about 40mph. Safe speed in the city. I found that the longer run in 2nd gear got more carbon smoke. Nasty stuff to breath if you were following. Never found it to hurt any car I did it on, both customers or my own. I would do this run on the pre-tune up road test with the customer in the car. Once they saw the crap that came out, they would either do it themselves or insist on going on the test drive to watch.


With modern fuel injection engines, modern unleaded gas, and today’s catalytic converter exhaust systems, “blowing the carbon out” is a myth. However, I recall a sustained 110 mph drive on a moonless night a 1967 Austin Healey 3000 that shocked me when a glance in the rear view mirror showed large sparks & flashes (obviously carbon) streaming out the tailpipe. I backed off the speed but must admit, the old girl ran better for several weeks after that.


Years ago, I owned a '67 Opal GT that developed the notorious rattle somewhere around the valve cover, at around 60k miles. Took it to an older man who owned a junk yard, and who also fiddled with foreign cars. (My first, being a TR3.) He suggested I take it out onto the nearby Interstate, slowly build up speed in 4th gear, until the speed maxed out, hold it there for about 5 minutes, and then slowly bring the speed down to normal. Said it would either blow it out, or blow it up. I was young and stupid, so I did what he instructed. At 90 mph the sound resembled a jack hammer, black smoke was pouring from the exhaust, and I couldn’t hear my self think. It top ended at just over 100 mph, then began quieting down. After completing the process, the engine purred like a kitten for the remaining years that I owned her. Absolute truth.


Is there any other way to drive an MG? Mine wants to redline, and more, in every gear. I have to cajole her to remain sane and sober, and not annoy the neighbors. But she just keeps redlining, especially in the downshifts around the corners. She’s just so happy to do it!
Of course, after driving her that way for the last fifty years, I may be doing it wrong…?


Running your car had once on a while does seem to help it run better, however running your car hard for 10 to 20 miles before a Smog test seems to help the vehicle pass the emissions test. I had a 1989 jeep grand Wagoneer that would just pass the test after a hard run, but would not pass with just a normal drive to the test center. In fact I’ve been told that heating your catalytic converter with a blow torch will help a recalcitrant car get a passing grade. Any way hope that contributes


This reminds me of the stand up comedian Bill Cosby, 200 mph recorded many years ago he talks with his mechanic, Bob, about engine not running. Bob tells him the repair for a engine in his car. To go 200 MPH in second gear to blow the Gunk out of the engine. So to get the gunk out? Listen to the red line blowing out the gunk or 200 mph in second gear. https://youtu.be/BHbOrHG65uo


I’m pretty certain the Italian tune up was only necessary back when we used carburetors and unleaded fuel. There were significant deposits in the combustion chambers and on the spark plugs that would just get worse under mild driving. About 1975, I was employed as a mechanic in a British Leyland dealer. When the Jaguar V12’s came in for a tune up, I’d change the plugs and filters, etc, then take it out and repeatedly run it up to red line, second gear, foot to the floor, until it stopped misfiring. They usually needed half a dozen acceleration runs before they would run smooth. I don’t think this is needed on newer cars. Then again, my cars get regular use of WOT, so carbon isn’t an issue.


When I was LOT younger back in the early 70’s and just learning about cars, my elderly neighbor used to drop off his carbureted small block powered Chevy Nova with my brother and me for a “tune up” about once a season. He only drove the car to the Post Office, his doctor’s office in town, and to the grocery store - all of which were only about a mile away. He never drove the car faster than about 25 mph either, and it never ran long enough for the choke to come off all the way (especially in suburban Pittsburgh in the winter where this all took place). Our “tune up” (based entirely on my car-guy Dad’s recommendations, by the way) was to take the car and to run it at full throttle for as much as we possibly could for about a half hour or so around the roads that ran through the farms and fields in Washington County. When we’d drop it back off, it’d be purring like a kitten. When he’d offer to pay us for our “hard work” we’d politely refuse and say that the pleasure was all ours!