Rev matching downshifts... good or bad?

[Loki]

My friend and I are having a debate and he won't budge cause his "friend with a Roush Mustang" agrees with him. He never rev matches when he downshifts, he just lets the clutch right out. I do rev match, and lately I've been teaching myself to "big-toe/little-toe" on downshifts, keeping most of my foot on the edge of the brake and just tapping the accelerator with the side of my shoe. My friend says this is bad for the clutch and you shouldn't rev the engine with the clutch depressed but I have a feeling he's wrong.

So, NICO Mythbusters, who's right in this regard? What is best for the transmission and clutch when downshifting?

[Tyler]

i always rev-match.

plus nissan is designing cars that do it for you, now think about it, would they design it to do something that causes extra wear and tear on the clutch and drivetrain components? i think not, though i have no real evidence to back up my statements

[flohtingPoint]

Nothing wrong with just shifting, it's all part of normal wear and tear.

[zer0c123]

Rev Match!!! heal toe or whatever, so you don't screw up the transmission and clutch. When it comes time to fork over the $$$ for a premature clutch change, then your friend will learn.

But then again i've got tons of friends that do this. You would need to constantly downshift at high speeds for something really bad to happen. The other thought is do your passengers mind the huge jolt from just literally dropping a geaR?

[Loki]

I brought up how the 370Z rev matches but he just said some BS about certain car set-ups. I've always been under the impression that letting out the clutch without giving it some gas is bad for it. It FEELS bad everytime I do it.

[Dattebayo]

It all depends really on how heavy the flywheel is in said car...

If you have an aluminum flywheel or some kind of aftermarket lightened deal (again, depends on the car), you're gonna have to keep up the momentum in a downshift like you were doing. But a regular flywheel should hold momentum enough unless you're really slow.

[flohtingPoint]

Rev Match!!! heal toe or whatever, so you don't screw up the transmission and clutch. When it comes time to fork over the $$$ for a premature clutch change, then your friend will learn.

Transmissions and clutches have been working fine for decades w/out having to rev match. Unless you're driving like a total toolbag, your drivetrain components will be fine.

[Axel Grungy]

Its fine. Just dont rev match it from 70mph down into 2nd. LOL

[Bubba1]

Transmissions and clutches have been working fine for decades w/out having to rev match. Unless you're driving like a total toolbag, your drivetrain components will be fine.

Right. modern technology has taken away much of the drama about downshifting and made driving manuals much easier. The Synchronizers have replaced the need to rev match downshifts (or double clutch for that matter), And Nissan took it one step further with the auto-blip),so your Friend with the mustang is not doing any real harm by making the synchros work by not rev matching.

With a modern manual transmission car on a race track, the rev matching/heel-toe downshifts will make you quicker, with smoother transitions (if done right), and it is less stressful on the clutch and synchronizers, but we're not talking major differences in longevity here.

I always rev match, but that's out of habit as I learned to drive on non-synchro cars/trucks. I kinda miss the days of non-synchronized transmissions, which not only required rev matching for downshifts, but double clutching too. To do that on race track takes some finesse (and practice), and is regretfully becoming a lost art.

[krimsonviper]

Nothing wrong with just shifting, it's all part of normal wear and tear.

^This.
Motor companies know that the normal Joe these days don't rev match, so they design them to withstand it.

My question is, is it bad to be a tad over the next RPM when rev-matching downshift? I tend to do this, thank you ETB, sometimes and go over by about 300-500RPMS.

[Koshin]

I rev match in any manual transmission. Im just used to doing it

but I dont think it matters if you do. It becomes more of a MUST on bikes in my mind

[Razi]

Some people plop down into a lower gear without matching revs?
wtf y0?

[MinisterofDOOM]

With a modern manual transmission car on a race track, the rev matching/heel-toe downshifts will make you quicker, with smoother transitions (if done right), and it is less stressful on the clutch and synchronizers, but we're not talking major differences in longevity here.

Also (and correct me if I'm wrong...I'm not track guru, but I understand the physics of cars) part of the reason for rev-matching on a track is to maintain traction. You don't want an abrupt gear engagement as it'll "shock" the tires, potentially breaking loose. Any time the tires aren't moving at the same speed as the surface they're supposed to be sticking to, you lose traction. And much of the time you're going to be downshifting, at least if you're driving well, will be in traction-critical situations, like setting up for an apex.

[EvoTyler]

Its fine. Just dont rev match it from 70mph down into 2nd. LOL

I rev match in any manual transmission. Im just used to doing it

but I dont think it matters if you do. It becomes more of a MUST on bikes in my mind

^agree with both. not necessarily a necessity in newer cars but definitely helps make for a smoother ride (or quicker if you're on track)

[Red coupe]

Either way is fine.
No rev match may TECHNICALLY be a little more wear, but transmissions & drive trains are designed for this.

My question is, is it bad to be a tad over the next RPM when rev-matching downshift? I tend to do this, thank you ETB, sometimes and go over by about 300-500RPMS.

Can't make a promise either way... but having your engine spinning a few hundred rpm too fast has got to be MUCH easier on things then spinning a few thousand RPM two slow when the clutch engages.

[Razi]

Plus, the car dives forward when you downshift without revmatching, that doesn't sound like a comfy drive around town...
To me, tapping the gas a little is far better than getting jerked forward by the car because you didn't match the revs.

Can't make a promise either way... but having your engine spinning a few hundred rpm too fast has got to be MUCH easier on things then spinning a few thousand RPM two slow when the clutch engages.

That's what I think, and is one of the reasons why I revmatch, even if it's somewhat halfassed.

[frapjap]

I've always rev-matched. Even before I found out it was the "cool" thing to do. Just made sense mechanically I guess. That, and it made for a MUCH smoother ride for me and occupants. I've had people think its weird, and others who are surprised that I can do it. Either way, I don't think I'll quit.

[Loki]

Plus, the car dives forward when you downshift without revmatching, that doesn't sound like a comfy drive around town...
To me, tapping the gas a little is far better than getting jerked forward by the car because you didn't match the revs.

Exactly that for me. It's quite funny to watch him drive his Saturn, as he has a stock long-throw transmission and dumps the clutch. So it takes him at least 2 seconds to actually change gears and the car lurches bad when it does. And yet he says my smooth short shifts are bad lol

[Razi]

My friend's Hyundai Accent was the first manual transmission car I got driven around in , and he always revmatched and that thing doesn't even have a tachometer.

[s0m3th1ngAZ]

Please tell me you guys aren't matching revs coming to a stop. If so...smack your selves.

[krash]

I thought that "rev-matching" was the normal thing to do?

[C-Kwik]

Right. modern technology has taken away much of the drama about downshifting and made driving manuals much easier. The Synchronizers have replaced the need to rev match downshifts (or double clutch for that matter), And Nissan took it one step further with the auto-blip),so your Friend with the mustang is not doing any real harm by making the synchros work by not rev matching.

With a modern manual transmission car on a race track, the rev matching/heel-toe downshifts will make you quicker, with smoother transitions (if done right), and it is less stressful on the clutch and synchronizers, but we're not talking major differences in longevity here.

I always rev match, but that's out of habit as I learned to drive on non-synchro cars/trucks. I kinda miss the days of non-synchronized transmissions, which not only required rev matching for downshifts, but double clutching too. To do that on race track takes some finesse (and practice), and is regretfully becoming a lost art.

In theory, rev-matching will result is less wear on the clutch as there will be less slip between the surfaces and thus, less wear. However, not every match will be perfect and there could be some additional wear on the motor. Regardless, its not likely to be a significant factor either way.

As for the syncros though, they do nothing with regards to elimiinating the need for rev-matching. The only function syncros serve is to match the speeds of the dogs with the gears. This only replaced the need to double clutch as that was what helped match the speed of the dogs to the gears. Not rev-matching will not do anything to the syncros since you will already be in gear.

[Red coupe]

Please tell me you guys aren't matching revs coming to a stop. If so...smack your selves.

I do sometimes, I don't sometimes.

I know there is no real need to... but why not.

[Urabus GodofTraction]

Please tell me you guys aren't matching revs coming to a stop. If so...smack your selves.

We agree.

Brake pads are cheap. Transmissions aren't. If I'm coming to a stop, I generally don't shift until stopped.

As for rev-matching, only if I'm driving spiritedly. Normal commuting? No, that would make me a tool.

Well, I am a tool, but not THAT sort of tool. That sort of tool has things dangling from their towhooks, and talks about "apexes" and "hitting the twisties" in mixed company trying to impress people.

[Red coupe]

Brake pads are cheap. Transmissions aren't

Transmission are reasonably cheap for my car... The extra 2 shifts REALLY are not going to put noticeable wear on it and if you really wanna get into wear on one component vs another I bet you could make a pretty good case that the number of brake pads and rotors you will change over the life of one transmission will be WAY more then picking up a replacement for a worn out trans.

But who cares either way? You may as well say your a tool if you downshift ANY time your not on a track, because you never really need to.

But I enjoy driving my car, and I don't need to be on a track or going 100mph to do so... Sure I don't have to downshift when I am not driving hard... But I don't need to shift at all.
Why not just daily an auto? After all, ATF is cheap, clutches are not.
In the end its something I don't have to even think about. It takes no extra concentration or skill, and it produces no significant wear on the car (if anything, not slipping the clutch to spin the engine up to speed when you is gonna wear less). Why not?

[krimsonviper]

Please tell me you guys aren't matching revs coming to a stop. If so...smack your selves.

I don't see a problem with doing it on your daily commute/city driving. I don't like sitting on the clutch and adding extra stress on the throwout bearing while coasting. I don't like coasting in neutral.

[Urabus GodofTraction]

Brake pads are cheap. Transmissions aren't

Transmission are reasonably cheap for my car... The extra 2 shifts REALLY are not going to put noticeable wear on it and if you really wanna get into wear on one component vs another I bet you could make a pretty good case that the number of brake pads and rotors you will change over the life of one transmission will be WAY more then picking up a replacement for a worn out trans.

But who cares either way? You may as well say your a tool if you downshift ANY time your not on a track, because you never really need to.

But I enjoy driving my car, and I don't need to be on a track or going 100mph to do so... Sure I don't have to downshift when I am not driving hard... But I don't need to shift at all.
Why not just daily an auto? After all, ATF is cheap, clutches are not.
In the end its something I don't have to even think about. It takes no extra concentration or skill, and it produces no significant wear on the car (if anything, not slipping the clutch to spin the engine up to speed when you is gonna wear less). Why not?

I guess pickup truck-derived transmissions are going to be pretty cheap...

[Red coupe]

I guess pickup truck-derived transmissions are going to be pretty cheap...

I heard you know people who race mazdas... Willing to bet you could find a transmission for your car fairly cheap too.

[PEZi]

i rev match everything everywhere i drive it.... now, in town i find myself shifting to neutral to come to a stop... but whenever else i downshift it is rev matched

[krash]

Well, I am a tool, but not THAT sort of tool. That sort of tool has things dangling from their towhooks, and talks about "apexes" and "hitting the twisties" in mixed company trying to impress people.

Man, people like you make me laugh, and I love it.