Rev Matching: What Is it And Why Should I Care?

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Heel-and-toe is a dying art, but the rev-match technique is very much alive.

Read in this article:

What is Rev Matching?

You've probably heard the term before, or perhaps watched a car video where the presenter says that "the pedals are perfectly placed for 'heel-and-toe'", but what is rev matching actually? Rev matching refers to adjusting the speed of the engine to match the speed of the gearbox in a manual vehicle, thus making for smoother shifts, better vehicle balance, and less wear. The technique is typically used when downshifting as the engine speed needs to be raised to match the gearbox speed in a lower gear. The act of rev matching is not to be confused with the effect that a manual gearbox's synchronizer rings have. These slow or speed up the input shaft during shifts to prevent grinding of the gears. However, there is a connection. In old cars without synchro rings, rev matching helps avoid the grinding of gears too. In these cases, a rev of the engine is just as important when shifting up a gear (timing the gear selection correctly) as it is when shifting down and blipping the throttle, but more on why rev matching helps with downshifts later.

How To Rev Match unsplash.com
Pedals unsplash.com

How to Rev-Match

For the purposes of this article, we're discussing manual cars as traditional automatics do not need to rev match as their fluid torque converter within the gearbox absorbs the harshness of a downshift and synchronizes the engine and gearbox speeds in a smooth manner already. The goal of a rev match is to ensure that every shift is smooth and that neither the gearbox nor the engine needs to speed up or slow down before delivering power. To achieve this while slowing down, you need to use the heel-and-toe technique, which involves using the ball of your foot and your big toe to depress the brake pedal while your heel blips the accelerator pedal. This keeps your left foot free to use the clutch and change gear. Sadly, there is no easy way to learn this skill, as every vehicle responds differently depending on powertrain (diesel or gasoline, turbo or naturally aspirated), throttle type (cable or by-wire), and of course, the time it takes to get the transmission into the correct gear. That being said, it's not as difficult as people think and poses little risk while you're practicing. We wouldn't practice in traffic, though, as the first few times you try it could be a little jerky.

Rev Matching Pexels.com
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Benefits of Rev Matching

Any modern car equipped with synchro rings has no significant mechanical use for rev matching, but especially in racing applications or for when you're driving a car spiritedly and need it to remain balanced, it remains a valuable skill. Besides that, it's helpful if your synchronizer rings should ever break and you can't get a tow. So how does it help in terms of racing or driving enthusiastically?

Racing benefits

  • The car is able to slow quicker with less braking force thanks to engine braking.
  • The chief reason, however, is that it keeps the car balanced with no sudden lurches or shifts of weight that can upset the handling.
  • In addition, the engine and clutch do not have to deal with sudden rev changes while under load and the gearbox is less heavily stressed too.
  • Once this skill is mastered, you will end up putting less strain on your powertrain components, be able to take corners faster and with better grip, and of course, cause the exhaust system to make you sound like a driving god.

Automatic Rev Matching

Some cars come standard with auto rev matching. Automatic rev matching happens when the car's ECU detects a downshift and automatically blips the throttle to suit. If you're inexperienced, this system does all the hard work of active rev matching for you without you having to learn the heel-and-toe technique. A good example is in sports cars like the Nissan 350Z and its successor, the 370Z. However, modern automatic gearboxes perform rev matching too, albeit in a manner that is imperceptible due to the speed of the shifts. The technology has even been implemented in a few modern muscle cars like the Ford Mustang Mach 1.

Examples of Cars With Automatic Rev Matching:

Other Useful Information

It is also important to note that rev matching does not guarantee the longevity of a gearbox or other drivetrain components. Incorrect revving techniques can actually cause more issues, and downshifting too soon can still damage your engine and gearbox by causing these to overspin. For immensely experienced drivers, rev matching near the redline is possible for maximum braking performance, but for everyone else, it's a huge risk - especially since it's only truly beneficial on a track.

Finally, it's worth remembering that too much practice without any learning (trying and repetitively failing) can eventually cause damage, and shifting to a gear that's too low for the engine speed can instantly cause engine damage (for example, going from third to first).

Gearbox Mercedes-Benz

FAQs

Is rev matching bad?

If done incorrectly, yes. However, the effects are minimal while you're learning and it takes a great number of bad attempts to cause any noticeable damage. If you rev-match on a regular basis for the sake of engine braking, this may put additional strain on the bearings within your engine in the long term.

Does rev matching burn your clutch?

No, the point of rev matching is partially to prevent wear on your clutch, making it do less work than usual. Done perfectly, there is no chance of damage.

Do I need to rev-match when downshifting?

No, but it does improve stability, reduce wear, and give a better overall driving experience.

How do I learn to rev match?

Practice makes perfect. When you're trying to learn how to rev match, we'd advise going somewhere quiet like a closed stretch of road or an empty parking lot where you can get up to speed in about third gear. The process involves placing the ball of your right foot on the brake and twisting your heel toward the accelerator. As you press the brake with your toes, depress the clutch with your left foot. Then use your heel to jab the accelerator while simultaneously downshifting. Lastly, release the clutch. It helps to have a good knowledge of how your car responds to throttle inputs to begin with so you know how quickly and how much to prod the throttle.

Should I rev match when upshifting?

No. When you shift into a higher gear, the engine speed automatically dips to a more suitable range for the next gear. However, you can make your shifts smoother by applying a very slight bit of pressure to the accelerator when upshifting to stop the engine speed from dropping too low.

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