REV-Matching

[ZULU]

Hello guys,

Can anyone explain teh process in which you REV match when downshifting from say 4th to 3rd to race rollling....

I hear people talk about it but I could never get a concrete answer as to why its done and more importantly HOW it is done !

Thanks everyone

[Fenvy]

say if you are in 4th gear around 40mph 2500rpm, and you know that it will be 3000rpm when if you are in 3rd gear at the same speed of 40mph then you shift and rev the engine to around 3.2 k so when you let go of the clutch you will be at the same speed with the matching rpm

[Cyberkreig]

what this does is reduce driveline shock. this is much better for your clutch over the long run. additionaly, when entering a corner at medium to high speed (grip race style), you know you will have to downshift to power out on the other side. Rev matching places the car in a different gear without tailhappyness

[hannibal]

...and you use the heel-toe technique to match revs while braking...

[Hijacker]

it's mainly used to keep the car from getting unsettled during racing. Any form of racing (grip or drift), it's essential to keep the car from getting unsettled, or else you could find yourself in the grass very quickly.

[Fenvy]

mannn I learned that **** on my own after 2 months of driving stick haha

hate it when I down shift and the car jerk in a unpleasanyt way

[[Zero-S]]

it's mainly used to keep the car from getting unsettled during racing. Any form of racing (grip or drift), it's essential to keep the car from getting unsettled, or else you could find yourself in the grass very quickly.

Or kissing lightpoles:rolleyes

[Drill_Sergeant]

lets just say the gears are 1K rpms apart...

4th gear at 3K rpmslet off gas and press clutch at same timeput the stick into 3rd while on the clutchblip the throttle to rev quickly to 4K rpmslet the clutch goengagement should be SMOOTH with no jerkinessget on the gas

but the rpms arent always going to be 1K apart. you have to learn the car.

[Drill_Sergeant]

oh and as for why....

say you are in the middle of a turn and if for some reason you feel like downshifting, rev matching eliminates sudden weight shifting and shocking of the drivetrain which ultimately shifts weight.

shocking the drivetrain in the middle of a turn will cause your car to sort of leap forward like mashing down on the brakes. this puts all the weight in the front and none in the rear. that will make the rear come out. and then you have loss of control unless that was what you were trying to do in the first place.

comprende?

[PhaneSoul]

si, si

[whiterps13]

oh and as for why....

say you are in the middle of a turn and if for some reason you feel like downshifting, rev matching eliminates sudden weight shifting and shocking of the drivetrain which ultimately shifts weight.

shocking the drivetrain in the middle of a turn will cause your car to sort of leap forward like mashing down on the brakes. this puts all the weight in the front and none in the rear. that will make the rear come out. and then you have loss of control unless that was what you were trying to do in the first place.

comprende?

yo comprende, but it doesnt move the center of gravity if you downshift without heel/toe, rather it will lock up your rear tires sending you into one hell of a spin.

[Zyphar]

what about if you downshift heading torwards a stop sign ?

if you dont rev-match then u dont slow down (well not as much as if your RPM is lower) but if u have the RPM lower and slowly let out the clutch i will slow u down faster.

but will rev-matching help with your clutch when down-shifting or should u just not downshift at all ?

[C-Kwik]

Rev-matching itself is just a matter of keeping things smooth. I highly recommend against using clutch slip to slow down your car. Engine braking is fine, but if you use the engine's lack of speed to slow down the car through slutch slip, you are placing a lot of heat into the clutch. It can absorb some of it and probably won't be an issue on the street other than excess wear, but add it up and that's a lot of wear. Not to mention, your brakes are designed to slow down the car and can do a much better job of it. On a track, you can be sure your clutch will overheat if you do this in every braking zone.

As far as heel-toe downshifting, this is done before entering a turn in preparation for the exit of that turn. Basically you are minimizing the amount of time it takes to transition from turning to accelerating and consequently allowing you to focus on maximizing your turning grip and acceleration grip. It's kind of a version of multitasking in a car. doing this during braking is best as you will not be smooth at doing this all the time, especially with a heavy flywheel and it may lengthen your stopping distance slightly, that's easier to adjust for and much safer. You do NOT want to use this technique mid turn if at all possible. If you are maxing out your lateral grip and you suddenly jerk the drivetrain(as I said, you won't be 100% smooth everytime doing this) you can upset the balance. In most cases you may not end up off the track, but you can be sure, you will have to slowdown slightly to let the car regain it's composure. The time loss will be small, but add this up ofer several turns and then several laps. Races are won by adding up very small increments of time over many laps. Also, being in a lower gear during a turn gives you better throttle response. It becomes much easier to throttle steer.