For the MT owners: how do you downshift?

[Norm Peterson]

Your left foot can correct this too...

Sounds about right, or at least consistent . . . just use sloppy (slippy) clutch technique to cover for poor right-foot-vs-left foot coordination and hope that nobody notices how many things are being done wrong.

Any time the revs aren't going to match when I'm about to downshift, I will rev-match that particular downshift. In actual practice, that's most of them going into 2nd, 3rd, 4th, or 5th (depending on which car I'm driving). On the street this is almost always a full double-clutch operation. On a road course/HPDE day it's not quite as clear-cut as that, being somewhere in between a simple rev-match with only one clutch pedal disengagement and two complete clutch disengagements. How do I know the revs won't match any given time? Dunno, but I guess after 40+ years of owning only MT cars it's like knowing how far you have to turn the steering wheel to stay in your lane around a curve or how hard to step on the brake pedal to get stopped - something you just develop a feel for.

Even if you don't care one way or the other about synchro life (which is finite, and they do wear more rapidly when asked to cover for greater amounts of rev mismatch inside the gearbox), it is smoother and less upsetting to the car if you make the rev-matching happen going down as well as up. Just for that reason, it's a good skill to have in your driving toolkit.

Doesn't hurt the car at all. Nobody rev matches anymore lol

You need to find some real MT drivers to talk to, not just converted AT drivers who never had to even know about this stuff when they were learning to drive.

Norm

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[Horse]

Sounds about right, or at least consistent . . . just use sloppy (slippy) clutch technique to cover for poor right-foot-vs-left foot coordination and hope that nobody notices how many things are being done wrong.

Any time the revs aren't going to match when I'm about to downshift, I will rev-match that particular downshift. In actual practice, that's most of them going into 2nd, 3rd, 4th, or 5th (depending on which car I'm driving). On the street this is almost always a full double-clutch operation. On a road course/HPDE day it's not quite as clear-cut as that, being somewhere in between a simple rev-match with only one clutch pedal disengagement and two complete clutch disengagements. How do I know the revs won't match any given time? Dunno, but I guess after 40+ years of owning only MT cars it's like knowing how far you have to turn the steering wheel to stay in your lane around a curve or how hard to step on the brake pedal to get stopped - something you just develop a feel for.

Even if you don't care one way or the other about synchro life (which is finite, and they do wear more rapidly when asked to cover for greater amounts of rev mismatch inside the gearbox), it is smoother and less upsetting to the car if you make the rev-matching happen going down as well as up. Just for that reason, it's a good skill to have in your driving toolkit.



You need to find some real MT drivers to talk to, not just converted AT drivers who never had to even know about this stuff when they were learning to drive.

Norm

^This

 

[dgc333]

You need to find some real MT drivers to talk to, not just converted AT drivers who never had to even know about this stuff when they were learning to drive.

I am a real MT driver. My first field car when I was 12 was a manual, got my license at 16 on a manual and have owned at least one manual transmission for the past 40 years. I have never felt the need to rev match in normal driving conditions. I did spend a fair amount of time as a teenager practicing rev matching so I could impress my friends by shifting up and down through the gears without using the clutch but that certainly was the fast way to shift through the gears.

As I previously posted I have only worn out one clutch in all those years and that was at 190,000 miles and have never worn out syncros. I typically put over 200,000 mostly non-highway miles on a vehicle before retiring it.

Whether you choose to rev match or not is not going to have any real world impact on the longevity of the clutch or syncros and you can be just as smooth with your down shifting whether you rev match or not.

 

[Norm Peterson]

I am a real MT driver. My first field car when I was 12 was a manual, got my license at 16 on a manual and have owned at least one manual transmission for the past 40 years. I have never felt the need to rev match in normal driving conditions. I did spend a fair amount of time as a teenager practicing rev matching so I could impress my friends by shifting up and down through the gears without using the clutch but that certainly was the fast way to shift through the gears.

I'd really aimed my comment at awr90, but anyway, if you got that good at rev-matching why wouldn't you stick with it? I suppose if you're willing to let the engine lug a bit from time to time it may not matter as much, but I think we should try to do better than that.

FWIW, smoother shifts not only means less upset between the tires and the pavement . . . it also means less head toss for the occupants.


Norm

 

[SkapeGote]

i still don't get why people engine brake in a dd environment. replacing brake pads is alot cheaper than replacing something else from engine brake high rpm assistance. really only reason why people do it is to hear their exhaust lol

and for double clutching, why do it?! it's 2015!

Driving a stick shift in the winter, I engine brake to avoid using the brakes and locking up the wheels. As for rev matching, no need. I have driven several cars into high 200k and never had a mechanical issues.

Skape

 

[fionic]

lol at all these people not rev-matching to downshift.

 

[Lightsaber]

If the person who does not rev-match when downshift drives your car gently, like in low RPM range all the time and engaging the clutch smoothly, the drivetrain should be fine. There is simply not enough torque in the system to hurt anything.

However, if the person drives your car hard and does not rev-match, it could at the very least wear your clutch. If he also drops the clutch harshly, it can drastically reduce the life of your transmission gears and rings as well. Therefore, proper stick shift skills are important and you want to choose carefully about who can have the privilege to drive your car.

 

[Socalmustang]

I don't get how people don't rev-match? For example, sometimes I'm on the freeway going 65+ on 6th gear, then I might hit some slight traffic and need to drop to 4th or 5th gear, if you just drop it either gear, without rev-matching, the car is gonna lug and slow you way down until it catches up to the correct RPM's.

 

[Horse]

Driving a stick shift in the winter, I engine brake to avoid using the brakes and locking up the wheels. As for rev matching, no need. I have driven several cars into high 200k and never had a mechanical issues.

Skape

Yes, engine braking in winter is the way to go. As you mentioned, this reduces the chance of locking up wheels. But this could/should also be a reason for rev match. When slower engine mates with higher rpm clutch (which would be the case when down shifting without rev match), the engine could lock up the wheels (via clutch).

One of the reasons the professional drivers rev match (likely heel toe) at curve is to prevent wheel lock-up. This is important to them (race drivers) since they are at/near the limits of things.

In everyday driving (low speed), this might not be as big of a deal. But, in theory at least, rev-match makes everything smooth (hence no lock up), which is crucial when driving on snow. Just my 2 cents. :cheers:

 

[SnoopisTDI]

Yes, engine braking in winter is the way to go. As you mentioned, this reduces the chance of locking up wheels. But this could/should also be a reason for rev match. When slower engine mates with higher rpm clutch (which would be the case when down shifting without rev match), the engine could lock up the wheels (via clutch).

One of the reasons the professional drivers rev match (likely heel toe) at curve is to prevent wheel lock-up. This is important to them (race drivers) since they are at/near the limits of things.

Yep. I almost wrecked a 4x2 truck once because I was driving in snow on crappy tires, and if I touched the gas the rear tires would spin, and if I lifted they would skid. A downshift without rev matching would have been disastrous. Stepping on the clutch pedal solved all my problems (except ignorance, only experience cured that!).

 

[Danger]

I always rev match

When I down shift the amout of gas I give it when I rev is based on the speed and gear I'm in, for example. If I'm in 4th gear and going about 30 MPH and downshifting into 3rd gear, I will give it a low rev about 500 RPMs. If I'm in 6th gear going about 50 MPH and downshifting into 5th gear I will give it a medium rev about 1000 RPMs. If I'm driving in 3rd gear doing about 20MPH and downshift into second (aggressive driving, passing another car) I will give it about 1500 RPMs. Remember its better to give it just a bit more of gas when downshifting at higher speeds, read the info above, you don't want to loose control when that slow moving engine RPMs hit that high RPM clutch disc. Once you get good you will know how much to rev and just the right amount.

 

[Supa LA]

So many good points and mixed feelings/info in here. Seems like the thread has done it's job rather well. Thanks to everyone whom chimed in. I'll continue driving the way I do (rev - matching a mid to higher rpm downshift) and not matching when I'm below 2k rpms in a higher gear.

 

[Old 5 Oh]

might be boring but it's sensible

Double-clutching and rev matching smooths out the drive in a manual, it keeps the rear wheels where they belong on slick pavement. It's also a skill that, once developed, is completely second nature and a lot of fun.

Don't diss it until you master it.

 

[Carzzi]

Clutchless, pop unto neutral, blip, downshift clutchlessly. Buttery smooth. Indulgently satisfying.

 

[Supa LA]

Clutchless, pop unto neutral, blip, downshift clutchlessly. Buttery smooth. Indulgently satisfying.

What? Lol.

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