Every driver has asked himself at least once will over-revving the engine damage it.
Whether it’s an overtaking, driving on the highway, or just some showing off, sooner or later the pedal will meet the metal.
When it does, having some prior knowledge may mean the difference between the engine serving you for years to come or being prematurely destroyed.
This article has the purpose of shedding some light on the whole topic as well as answering some of the most common questions.
IS REVVING THE ENGINE BAD?
There is a difference between revving and over-revving the engine.
Revving the engine within the normal parameters, predicted by the manufacturer is not bad. On the contrary, an occasional revving up is desirable since bogging the engine down is equally harmful.
On the other hand, over-revving the engine is bad and can seriously damage it, especially if it’s done on a regular basis. It causes stress to the engine and significantly reduces its life span.
Damages that may occur may even mean a partial or complete engine overhaul.
So best stay within the normal values specified by the manufacturer and avoid over-revving as much as possible.
DOES REVVING YOUR ENGINE DAMAGE IT?
Some of the most common situations when revving can damage the engine is:
- When it’s done during a cold start and during low temperatures (more on this topic in a separate article which you can read by clicking here).
- Revving the engine for a prolonged period of time while the car is parked. Among else, this may cause overheating, especially during the summer.
- Having bad driving habits. Not paying attention to the rev counter and not listening to the engine will lead to constant over-revving which will over time cause damage.
- When the engine burns oil. Revving it all the time will increase oil consumption and reduce the oil level which can lead to major engine damage.
DOES REVVING THE ENGINE CHARGE THE BATTERY?
Yes, it does. Although the alternator charges the battery immediately after starting the car, revving up the engine will produce a higher amperage output.
This means a faster charge which is especially convenient if your battery is completely depleted.
For instance, you’ve accidentally left your lights on or some other electric appliance. If you’ve managed to jump-start the car, a few good engine revvings should revive the battery to the point that you can start the engine again. This is under the circumstance that the battery is in good condition.
Just make sure to keep the revs within the allowed limit. Don’t think that over-revving the engine will charge the battery any faster.
DOES REVVING THE ENGINE HELP JUMP-START A CAR?
Yes, it does but sometimes it’s not necessary. This again depends on the circumstances.
If the car that’s supposed to be jump-started has a completely dead car battery, then it’s best, once the jumper cables are connected, to start the engine and rev it up.
As told in the previous part of the article, higher revs mean higher amperage and easier jump-starting.
Again, over-revving the engine will not lead to easier jump-starting. The revs should be kept within the normal limits.
HIGH REVVING OF A DIESEL ENGINE
More experienced drivers will know that diesel engines are not a big fan of revving.
Unlike gas (petrol) engines where the rev limit starts as far as 7000 RPMs, on most diesel engines the red mark starts usually at 5000 RPMs.
In a nutshell, this is due to the engine construction and at what point is the main power output achieved.
Cars with gasoline engines reach their peak at higher revs while the diesel engine gives its best at lower revs.
Gasoline cars are more inclined to higher revs although this has changed to some extent thanks to newer technologies in the diesel realm.
New fuel injection technologies, turbo’s, intercoolers, and else have made the diesel engine a serious and formidable powerhouse.
Nevertheless, over-revving a diesel engine is still not recommended nor needed. In most diesel engines, the main power output is at 3000 to 4000 RPMs, and exceeding that may only cause problems.
If you get tempted, remember that today’s diesel engines are a technology marvel but a complicated one at that. Over revving the engine for a prolonged period of time may cause serious and expensive repairs.
For more information about the differences between a gasoline and diesel engine, click here for a separate article on that topic.
When sitting behind the wheel, always remember that the rev counter isn’t there for nothing.
The main reason why it was invented is to protect the engine while getting the most from it.
Revving the engine normally will not damage it and is considered normal exploitation. On the other hand, constantly over-revving the engine will send it to the scrapyard before it’s time.
If you don’t have a rev counter, listen to the engine. This goes double for stick-shift drivers. Don’t let the engine roar and scream until you engage a higher gear.
There will be situations where you’ll have to do some serious revving, but let’s be honest these are pretty rare. Added to that, most engines have a certain level of tolerance so an occasional over-revving should not be a problem.
Constant over-revving is meant for cars that have specially made and tuned engines that can withstand that kind of treatment.
For the common driver, the best thing to do is keep the revs well before the red limit.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com