What is "Rev Matching"?

[Old Guard]

Have a 2016 GT Manual on order. Should arrive about the time the 2019's start production (just kidding).

I have been hearing the term, "Rev Matching", and assume it involves down-shifting at certain RPM's. The term was unfamiliar to me in the early 70's when I drove a Challenger RT 383 manual 4-speed.

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[garagelogic]

An electronic gimmick for those who are manual-shifting challenged.

 

[NvrFinished]

Rev matching is when you blip the throttle on a downshift in order for the RPM's of the engine to match up close with the RPM's of the gear you are downshifting to.

Common when racing, this will prevent the rear end and overall balance of the car from getting upset by sudden compression braking caused when the engine RPM's are increased after the clutch is let out when you don't rev match.

If you like to downshift when slowing down, it also saves wear on your clutch.

 

[GT Pony]

Lots of videos on YouTube showing how to rev-match: https://www.youtube.com/results?search_query=rev+matching

[ame]

 

[Nazgul]

Take note that when Rev matching you input shaft speed is different than the engine speed. To correctly match the two you should double clutch. Rev matching in my opinion is the lazy man's double clutch.

 

[evanescent03]

rev matching, like others have said, is when you blip the throttle when you downshift and called "heel-toe downshifting" or some variation of that when you combine it with braking ... some cars will blip the throttle (rev match) for you. yes it's lazy, but it's also really awesome (pure opinion, of course ;))

 

[Horse]

For 2015/2016 Mustang auto, rev-match is done for you. For manual Mustang thou, you have to do it yourself.

 

[GT Pony]

Take note that when Rev matching you input shaft speed is different than the engine speed. To correctly match the two you should double clutch. Rev matching in my opinion is the lazy man's double clutch.

Not really, because as soon as you shift the transmission into the lower gear the input shaft will change speed according to the what gear you are in. Going into a lower gear will make the input shaft and clutch disk spin faster. Then you just have to blip the engine to match the flywheel speed to the clutch (which is on the input shaft) speed. "Double clutching" doesn't get you any better speed matching.

 

[Horse]

But how, at lower gear, does the clutch/counter shaft etc. get to higher speed? It is the synchro that brings the speed up (if you don't double clutch). Double clutch (if done right) will relieve the synchro from its duty (thus makes it last longer).

Yes, I am aware that the synchro will likely outlast the car doing what it is designed to be doing (matching the output shaft to the counter-shaft/clutch). But it is pure fun to double clutch.

 

[GT Pony]

But how, at lower gear, does the clutch/counter shaft etc. get to higher speed?

By shifting the transmission into a lower gear, it will force the clutch disk to increase in speed since the rear wheels are spinning the whole drive line from the wheels all the way up to the clutch disk. The clutch disk is connected by splines to the input shaft of the transmission

The transmission is shifted while the clutch is disengaged, therefore a quick blip of the throttle at the same time brings the flywheel to near the same speed as the sped up clutch disk . So when the clutch is re-engaged, they the flywheel speed and the clutch disk speed should be pretty matched.

 

[Nazgul]

Not really, because as soon as you shift the transmission into the lower gear the input shaft will change speed according to the what gear you are in. Going into a lower gear will make the input shaft and clutch disk spin faster. Then you just have to blip the engine to match the flywheel speed to the clutch (which is on the input shaft) speed. "Double clutching" doesn't get you any better speed matching.

The point of a double clutch is to match the engine speed, input shaft speed with intermediate shaft speed. Rev matching matches engine speed and speeds up input shaft but doesn't match intermediate shaft speed. By letting out the clutch and blipping the gas you use the clutch's rotational inertia to spin up the intermediate shaft so that the synchros match the next gear closer. Simply picking a new gear and reving doesn't match all three. You match engine and Imput, but still used a slower moving intermediate shaft to select the gear (slow wear on synchros) If you properly double clutch the input/output shaft perfectly aligns with the intermediate shaft and there is almost 0 resistance when picking a new gear. The shifter almost falls into the next gear.

My mistake in not initially explaining the link between the engine/input shaft and intermediate. Intermediate and Input are always closely linked in my mind.

 

[Horse]

But how, at lower gear, does the clutch/counter shaft etc. get to higher speed? It is the synchro that brings the speed up (if you don't double clutch). Double clutch (if done right) will relieve the synchro from its duty (thus makes it last longer).

Yes, I am aware that the synchro will likely outlast the car doing what it is designed to be doing (matching the output shaft to the counter-shaft/clutch). But it is pure fun to double clutch.

By shifting the transmission into a lower gear, IT will force the clutch disk to increase in speed since the rear wheels are spinning the whole drive line from the wheels all the way up to the clutch disk. The clutch disk is connected by splines to the input shaft of the transmission

The transmission is shifted while the clutch is disengaged, therefore a quick blip of the throttle at the same time brings the flywheel to near the same speed as the sped up clutch disk . So when the clutch is re-engaged, they the flywheel speed and the clutch disk speed should be pretty matched.

What is IT? If you think about IT, you will get IT. :cheers:

 

[Horse]

The point of a double clutch is to match the engine speed, input shaft speed with intermediate shaft speed. Rev matching matches engine speed and speeds up input shaft but doesn't match intermediate shaft speed. By letting out the clutch and blipping the gas you use the clutch's rotational inertia to spin up the intermediate shaft so that the synchros match the next gear closer. Simply picking a new gear and reving doesn't match all three. You match engine and Imput, but still used a slower moving intermediate shaft to select the gear (slow wear on synchros) If you properly double clutch the input/output shaft perfectly aligns with the intermediate shaft and there is almost 0 resistance when picking a new gear. The shifter almost falls into the next gear.

My mistake in not initially explaining the link between the engine/input shaft and intermediate. Intermediate and Input are always closely linked in my mind.

As far as I know, it is the following (sorry I could not help :cheers:

By letting out the clutch and blipbing the gas you use the engine to spin up the clutch and the intermediate shaft so that the synchros match the next gear closer.

 

[Double]

For 2015/2016 Mustang auto, rev-match is done for you. For manual Mustang thou, you have to do it yourself.

That's something I never really understood about the "Rev matching" for the Automatic. While it makes all the sense in the world to have it for the Manual.

I mean doesn't it always have "Rev matching" when its an auto ? how else are you going to down shift with an auto ? Or does it just make it quicker and smoother ?

 

[Lowrider]

That's something I never really understood about the "Rev matching" for the Automatic. While it makes all the sense in the world to have it for the Manual.

I mean doesn't it always have "Rev matching" when its an auto ? how else are you going to down shift with an auto ? Or does it just make it quicker and smoother ?

The average passenger car auto trannies do not rev match. Actually even some sport sedans like the new WRX do not have rev match. And autos downshift whenever the brake pedal is pressed as the car slows down.

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