Rev matching - anyone else do it?

"Full of the sound of the Gran Fury, signifying nothing." (granfury) 10/07/2014 at 10:46 • Filed to: None

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I tend to do this almost instinctively, perhaps in an effort to minimize clutch and transmission wear. Not a full-on double-clutch maneuver, just a blip of the throttle whilst downshifting to get engine and transmission speeds closer together. Am I weird, or does anyone else do this?

(and now a gratuitous shot of a Mazda5 interior a little better equipped than mine, better than you can get in the US if you dare to be so weird as to want to shift for yourself)

quarterlifecrisis > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:47

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I do it. Often.

That Bastard Kurtis - An Attempt to Standardize My Username Across Platforms > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:48

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I do! I used to try to do it in my allroad, but it revved so lazily that I could never get it right. For some reason though it's super easy in my Corvair. Perfect blips every time.

Leon711 > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:49

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I do it, because MX-5 gearbox is nice for it.

spanfucker retire bitch > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:49

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My Mazda does it for me.

anothermiatafanboy > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:51

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There are people that don't?!?! And just clumsily let the driveline pick up the slack? This is amazing to me...I would never.

jariten1781 > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:51

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On the road I will on something like a 5th to 2nd downshift but not on something like a 6th to 5th.

Full of the sound of the Gran Fury, signifying nothing. > jariten1781 10/07/2014 at 10:54

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I'd tend to agree. I will if a corner is coming up or there is going to be huge discrepancy in revs, but 6th to 5th seems too small a rev change to require it.

McMike > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:57

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Every time I need a shorter gear. Doesn't matter what I'm driving.

Because it's smooth and reduces clutchwear.

macanamera > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:57

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Pretty sure like every person that drives a manual properly does this.

twochevrons > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:57

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Definitely. I learned to drive on a rather worn-out old Triumph whose gearbox was distinctly uncooperative if you didn't rev-match just right. My Dad's a stickler for such things, so it was actually one of the first things that he taught me. I'll do a full double-declutch if I'm downshifting at high RPM, too – I remember doing it on one of my driving tests for engine braking going down a steep hill, and the instructor was highly impressed! It just feels wrong having the clutch and synchromesh take up the speed differential.

edu-petrolhead > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:58

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Almost always! I don't know why they don't teach us those techniques on driving school.

IMO, a deep understanding of how an automobile works makes anyone a better driver. Rev matching, for example, extends the lifespan of many powertrain components, and consequently makes the cars and the traffic run more smoothly.

macanamera > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:58

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No such thing as too small! It's all about finesse, yo.

Bryan doesn't drive a 1M > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 10:58

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I do. Doesn't seem weird to me, but I haven't been shifting my own gears for very long, so what do I know?

Cé hé sin > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:00

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You need to do it yourself, both up and down, if you're driving one of these things, because non synchro box

Whereas one of these will do it for you (still a non synchro box but does it by smoke, mirrors and electrons)

505Turbeaux > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:01

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yeah I totally do. Practice on an 80's VW, you barely need to use the clutch once it is moving, down or up

crowmolly > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:06

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If I'm skipping gears then yea, usually. Or at lower speeds from 2-1.

Other than that, nah. Any argument for clutch life or driveline wear goes out the door when you powershift your car.

Full of the sound of the Gran Fury, signifying nothing. > 505Turbeaux 10/07/2014 at 11:08

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Funny you mention that, because I taught myself clutchless shifting on a '77 Dasher...

twochevrons > edu-petrolhead 10/07/2014 at 11:08

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This! I count myself really lucky to have been taught this way. My Dad is a mechanical engineer, and a true car enthusiast, and made a point of teaching me how everything worked at the same time as he taught me to drive. Before I even got behind the wheel, he sat me down and explained to me how the gearbox and clutch worked, so I could understand what I was doing. As I progressed, he did the same for steering and suspension geometry, to explain why a car handles the way it does.

His big point was, as he called it, driving 'sympathetically'. If you understand what's going on behind the scenes, you're much more aware of what can do damage and cause wear, as well as what the car's limits are. In my eyes, it also helps a lot when things go wrong, too – that same knowledge helps in those few seconds in which you have to decide whether to pull over right now, or try to limp it along. If I had things my way, everybody would be taught like that.

505Turbeaux > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:09

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yup! 86 scirocco for me!

RazoE > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:12

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I do this all the time in my IS300. I usually shift from 3rd straight to 5th, but when I want to go back to 3rd, I'll blip the throttle to 4th, then again to 3rd. Makes me feel like Takumi.

CAR_IS_MI > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:13

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I do this in pretty much whatever I am driving... Including the Jeep. It's hilarious to hear the jeep up-rev to match like it thinks its a race car...

Full of the sound of the Gran Fury, signifying nothing. > edu-petrolhead 10/07/2014 at 11:14

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Years ago I trained as a mechanic (although never practiced it as a career) and I think that experience taught me "mechanical sympathy", or in other words, how things wear and break and how to prevent it.

Watching how my parents drove also helped, as evidenced by 231,000 miles on the original clutch on my 525i before a friend destroyed it with a 5th to 1st downshift.

Being interested in racing also helped, and reading about proper technique as well as watching and listening to races gave me a good understanding of proper driving technique.

KusabiSensei - Captain of the Toronto Maple Leafs > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:14

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I generally double de-clutch. But that's because I'm weirder.

n54 & s38 > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:14

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Yup. Always. I usually double clutch as well, depending on whether I'm dropping more than one gear or not. I hate the lurch and lack of smoothness that comes with not matching revs

RazoE > jariten1781 10/07/2014 at 11:16

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What is this "6th" you speak of? I gots 5, and that's the ways I likes it...

...I need a 6th, rpms are too high at 65...=/

Full of the sound of the Gran Fury, signifying nothing. > RazoE 10/07/2014 at 11:19

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...and I occasionally find myself reaching for 7th.

Although in the 968 I kept forgetting about 6th for the first month or so since the 525i didn't have one. But with a torque-monster like that 3.0, it really didn't matter which gear you were in...

Izaerian > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:23

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Actually yes this is an everyday every drive occurrence for me. Granted I run my 1.6 Miata basically balls out every time I'm in it, so my rev matches are generally in the 5-6k rpm range. People stare, but I just can't help but giggle a lil'bit. Biggest benefit I have found so far is that my brake pads last longer, and my clutch which was mostly crap when I got it, is somehow still working.

jariten1781 > RazoE 10/07/2014 at 11:24

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It took me way too long to get used to having a 6th. I'd be cruising along at like 65 for an hour in fifth before I'd remember. Oops. I don't think my mind could comprehend a 7th gear.

Izaerian > 505Turbeaux 10/07/2014 at 11:24

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/raisehand 80 Scirocco YAY!!

Sir_Stig: and toxic masculinity ruins the party again. > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:26

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If I'm not actively heel-toeing I'm at least letting it get close.

With-a-G is back to not having anything written after his username > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:27

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Yup. And my gearbox makes it easy because the ratios are basically 54 = 5/4ths (blip it +25%); 43 = 4/3rds (blip it +33%); 32 = 3/2 (blip it about +50%). The only one that breaks the pattern is 21, which is a pretty rare one.

Full of the sound of the Gran Fury, signifying nothing. > jariten1781 10/07/2014 at 11:32

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The I6 (M20) in the 525i is wonderfully, deceptively smooth, and sounds great. I recall once driving along at normal freeway speeds with the windows and sunroof open and the radio blasting. I looked down at the tach and noticed the engine was spinning at over 5,000 RPM, but nothing felt or sounded strained or taxed. I upshifted two gears and continued the journey.

Twingo Tamer - About to descend into project car hell. > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:41

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I have to or my car rocks forward quite alarmingly when I shift from 3rd to 2nd. Mix of light car, heavy engine and decent torque.

BoulderZ > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:50

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This, exactly. I worked as service manager at a busy bike shop to put myself through grad school (couldn't even make rent on the RA pay, let alone groceries). I quickly noticed a pattern that you could give the same bike and components to a bunch of people, have them all ride the same amount of time and miles, and get vastly different wear and breakage rates. The ones that didn't last were always bringing in dirty machinery, usually under-lubed drivetrains, in a cross-chain gear, etc. It was obvious they didn't know how to properly use or maintain the machine, and it showed in drastically reduced lifespan of parts. I learned a lot about "mechanical sympathy" that way.

There was an interview with, I think, one of the Porsche teams from LeMans in the 90s (maybe?), where they mentioned the key to winning is getting your parts to last, particularly transmissions. When asked if it was a weak link, they said no, the transmission was fine as long as they kept one of the drivers to minimal seat time and constantly reminded him not to abuse the car. The weakest link in any system is always the user. It won't break just sitting there; someone has to force it. A system may be weak, and require so much user care as to be unreasonable babying, but it still won't break by itself.

Having rebuilt both my truck and my Z, I do my best to respect the machinery and use it properly. Sure, I go to the track in the Z, and haul max payloads with the truck, but I always double clutch and rev match (even on the street, in the truck), never cold-start and immediately launch, check all basics every first of the month, and stick to maintenance schedules. My Dad taught me, "Take care of your gear and your gear will take care of you."

Tapas > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:53

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Disclaimer: Noob here.

If I need to make a sharp turn and I have quite a bit of speed, I coast in neutral and brake on the turn, then shift into lower gear because that gear suits the lowers revs.

Alternatively, I brake + downshift on turn and release the clutch to engage lower gear at lower speed after turn.

Am I doing something wrong?

Full of the sound of the Gran Fury, signifying nothing. > spanfucker retire bitch 10/07/2014 at 11:54

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Your dog is named 'Mazda'? :P

spanfucker retire bitch > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:55

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I have no witty retort.

luvMeSome142 & some Lincoln! > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:57

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I am horrible to my clutch. I almost always downshift and let the clutch friction speed up the engine as I slow down. But at least my brakes aren't wearing out as fast!

OPPOsaurus WRX > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:58

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what else would you do? isn;t that just standard standard procedure?

sm70- why not Duesenberg? > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 11:59

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I drive an auto.

Full of the sound of the Gran Fury, signifying nothing. > luvMeSome142 & some Lincoln! 10/07/2014 at 12:00

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But brakes can be easily replaced; clutches are a tad more difficult. As long as you take your foot off the clutch quickly, even if it causes a little jolt or shudder, you're doing better than if you were to gently release the clutch, letting it slip in the name of smoothness.

ilostmypants > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 12:01

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Almost always rev match on down shifts, and when it's cold out (below freezing) I'll double clutch on up shifts for the first minute or two until the trans has a chance to warm up.

Full of the sound of the Gran Fury, signifying nothing. > sm70- why not Duesenberg? 10/07/2014 at 12:04

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That would tend to make this technique a tad more difficult, so I'm guessing that you don't do it.

It makes me wonder about some of the rev-matching systems, like those on the 370Z and Corvette, and how accurate they are. I'm assuming that they do a better job of getting the revs correct. Does anyone have any experience with those?

Full of the sound of the Gran Fury, signifying nothing. > OPPOsaurus WRX 10/07/2014 at 12:17

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It should be, but many people either don't know or don't bother. Since it's generally only enthusiasts buying manual transmission cars these days I would expect the percentage to be quite high.

sm70- why not Duesenberg? > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 12:19

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None whatsoever.

revrseat70 > Tapas 10/07/2014 at 12:19

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brake and downshift before a turn. you need to be in gear with enough torque if you need to modulate or request more power for any reason.. (miscalculated turn radius, surprise object, pedestrian, or fellow motorist that you might need to avoid.) In racing that torque is required to pull you out of a turn. On the streets, it is for safety and control. Downshifting and braking before a turn justifies the skill heel-n-toe downshifting for smoother and quicker decelerating.

OPPOsaurus WRX > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 12:23

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so whats the alternative? just letting the clutch out and it bringing the engine up to the right speed? sounds destructive

Tapas > revrseat70 10/07/2014 at 12:24

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I hear what you're saying.

The reason I don't engage the clutch till I'm past the turn and at a slower speed is because if I downshift at a higher speed, I get a jerk from the car because the revs are on the high side for said lower gear.

And this is why blipping the throttle never made sense to me. If I blip the throttle on a downshift, the revs would be even higher for the lower gear. Thats where I'm confused...

revrseat70 > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 12:24

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Every. single. time. I actually drove for ten years before I knew anyone else ever even tried downshifted without AT LEAST blipping.

Carl (@stuffcarlsays) > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 12:36

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All day, errday.

Full of the sound of the Gran Fury, signifying nothing. > OPPOsaurus WRX 10/07/2014 at 12:42

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It is destructive, but in teeny, tiny little increments. Most people let the synchronizers in the transmission take care of matching the revs, but those components should be considered wear items that only have a finite life and are rather expensive to replace. This is why on older cars you may find that matching the revs is more important due to the fact that the synchronizers are worn out and you no longer have a synchromesh gearbox. By rev matching manually you are saving wear and tear on those components thereby extending the useful life of your transmission.

Trevor Slattery, ACTOR > Tapas 10/07/2014 at 12:48

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That is why it is called rev matching. The skill is to match the revs of the engine to road speed so there is no jerkiness. Properly done, you can corner so much faster and smoother.

But it really depends on your pedal set up. Some cars make it SO easy to rev match/heel toe. Some do not.

revrseat70 > Tapas 10/07/2014 at 13:03

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Heel-n-toe, or anticipating/preparing for the corner a long way off come into play for that reason. As you brake the rpms fall to the low end or just bellow the powerband. When you blip and are in a lower gear, you'll be back in the powerband.

Textured Soy Protein > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 13:25

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I always rev match, and often heel-toe.

Textured Soy Protein > Tapas 10/07/2014 at 13:30

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Generally you want to do your braking and downshifting before your turning.

This is the situation in which you would heel-toe downshift.

Basically you brake with your right foot, hit the clutch with your left, then roll your right over to the gas to blip the throttle while downshifting, while keeping the right on the brake.

And unless you have super tiny feet, you're not actually using the heel and toe. More like ball of your foot and outer edge.

luvMeSome142 & some Lincoln! > Full of the sound of the Gran Fury, signifying nothing. 10/07/2014 at 13:32

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Weeelll, I was joking about the brakes, but if we're going to all technical I'll argue back. If you just pop the clutch out you might put less wear on the clutch, but it will put much higher stresses on the rest of the transmission. Those stresses are reversed from the stresses generated from accelerating in the forward direction. In engineering terms this reduces the fatigue life of whatever part we are considering. But that's all academic.

In my case a little clutch slippage during a downshift causes far less wear than your normal first gear start. BTW I am on my second clutch, but this one has at least 90k on it of mostly city driving. The first one I burned up towing stuff I shouldn't have.

Textured Soy Protein > Tapas 10/07/2014 at 13:38

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Think about what happens if you just downshifted with no attempt at rev matching: you put the clutch in, shift gears, let the clutch out, and the lower gear forces the engine to spin up to a higher RPM.

This happens because of the change to a shorter gear ratio. Let's say you're in 6th gear, which is typically an overdrive gear, which means it's a ratio of like 0.8:1. (i.e. 0.8 rotations of the engine for 1 rotation of the wheels).

Let's say you're downshifting to 4th, and it has a ratio of 1.5:1. As soon as you move the shifter into 4th, the clutch, which is connected to the transmission, spins up to a faster RPM. But the engine, and flywheel, is still at the RPM it'd be at if it were in 6th, or has actually gone to an even lower RPM while the clutch was out. So when you let the now-faster-spinning clutch out, it grabs on to the flywheel, and after some clutch slipping it forces the engine up to the higher RPM.

This generally doesn't happen entirely smoothly.

Blipping while downshifting is all about matching the speed of the engine & flywheel to the speed of the transmission & clutch created by shifting to the lower gear. If you do this ahead of letting the clutch out, and the clutch and flywheel are at roughly the same speed, the clutch/transmission doesn't have to force the engine/flywheel up to a higher RPM, and it's a much smoother downshift.

Make sense?

Takuro Spirit > anothermiatafanboy 10/07/2014 at 13:42

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The friend of mine with the 500AWHP STi that I talk about sometimes does this. With his high dollar 6-puck clutch. I was like REALLY DUDE?????

He just drops it a gear, lets out the clutch, and I can hear it crying from the force it has to endure speeding the engine up to speed to match the tranny.

I asked him if he knows how to heel and toe, and he replied with "Huh?"

*facepalm*

Tapas > Trevor Slattery, ACTOR 10/07/2014 at 13:44

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I see. So am I rev-matching correctly by engaging the clutch after braking, so the revs match the lower gear?

Yeah the throttle is farther away in my car than the brake and clutch. My feet are just large enough to place the heel on one and toe on the other pedal, but its very uncomfortable. This makes heel-toeing difficult.

Tapas > Textured Soy Protein 10/07/2014 at 13:49

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Oooohhhhhh so blipping would be applicable if I'm slowing down considerably and my next gear is higher so the slow speed revs don't match the gear I'm shifting into.

Gotcha.

When I take a turn on the road, I don't have to brake hard and slow down very much because I'm doing the speed limit lol So when I down shift, it just so happens that the lower gear's revs match my revs after turn exit. So I don't need to blip.

Cé hé sin > 505Turbeaux 10/07/2014 at 13:52

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Many years ago I had a work colleague who used to clutchless changes on his Beetle. We just thought he was weird.

Full of the sound of the Gran Fury, signifying nothing. > luvMeSome142 & some Lincoln! 10/07/2014 at 13:52

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I, too, was having a little fun regarding that scenario, and was just thinking back to my BIL who bought his first manual transmission car after my sister convinced him to do so. He managed to eek out 40K miles out of the clutch, all in the interest of driving smoothly. He should have been a lawyer; somehow he managed to talk the dealer into replacing it under warranty, even though it was clearly his fault.

Thankfully I've almost exclusively replaced clutches during engine swaps or other major changes like that. I figured that I might as well do it whilst I have the engine and transmission separated. The 525i went 231K, but given some of the hard launches I had done it wasn't going to make it to 250K.

Textured Soy Protein > Tapas 10/07/2014 at 14:26

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If you're slowing down a bunch to take a turn, you would be shifting to a lower, not higher, gear. A lower gear, also called a "shorter" gear ratio, means that you have a larger numerical gear ratio. So like, a 1st gear with a 3:1 ratio is shorter than a 6th gear with a 0.8:1 ratio. The 0.8:1 gear is considered "taller" than the 3:1 gear.

Anyway, the most common times you would blip are:

1. If you're slowing down to a turn, you should be shifting before the turn. Shifting in a turn is bad. This is where you would heel-toe, because you want to do both your braking and your downshifting before the turn. Or just brake some, then downshift. But do it before the turn.

2. If you're shifting to a lower gear so you can get more acceleration. Because your car is maintaining the same speed, but the lower gear (shorter gear ratio, more rotations of engine per rotation of wheels) first speeds up the transmission, and you want the engine's revs to match the transmission before letting out the clutch.

Tapas > Textured Soy Protein 10/07/2014 at 14:32

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Got it!

"If you're slowing down a bunch to take a turn, you would be shifting to a lower, not higher, gear. "

Yes, shorter / lower gear to make turn.

Luken10 > anothermiatafanboy 10/07/2014 at 16:25

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I had a friend who thought that is how engine braking worked. He also thought it was a smart idea to do that in order to save his brakes...

Evo155 > Full of the sound of the Gran Fury, signifying nothing. 10/08/2014 at 13:15

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I do it all the time, just because it's so much fun!

Bytemite > Tapas 10/08/2014 at 14:12

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I don't think you understand what rev-matching is?

If you are braking and and going into a lower gear afterwards, your speed might be low enough to not jerk the car since the RPMs would only jump from idle to 2k or so, but that is not rev-matching.

Tapas > Bytemite 10/08/2014 at 14:58

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So I blip the throttle to 1.5 - 2k rpm? Thats not easy to do.

My car idles at 1k rpm. The smallest blip will make the revs jump more than what I need...

space_captain_steve > Full of the sound of the Gran Fury, signifying nothing. 10/08/2014 at 16:33

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Yeah, I didn't realize there were manual drivers who *didn't* revmatch on downshifts. :|

KarmannA > Full of the sound of the Gran Fury, signifying nothing. 10/09/2014 at 00:42

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Forced to in the 31 Model A... Non-syncromesh gears are so fun.

Blitz207 > Tapas 08/17/2015 at 12:55

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You're doing everything wrong, before you reach the corner you have to be done with your braking and gearing. So it, brake, downshift (dont forget to revmatch) put it in the right gear with( one wi enough torque) accelerate out of the corner.