MT-82 Question 2019+

[K4fxd]

LOL

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[m3incorp]

I don't see what all the fuss is about. The rev hang doesn't affect how I shift and for me, the gear changes tend to be smooth. Sometimes I drive really aggressive and sometimes I don't and I have no complaints when doing either.........mostly

 

[WD Pro]

Well I got the chance to have a little test and I can confirm that the 'rev hang' is actually present on my UK 2020.

However ... Under normal driving when is this feature intrusive or even noticeable ? The only conditions I can see this becoming apparent to the driver are :

A) Shifting into neutral and letting the car coast from speed (Why would you do that ? )

B) During very (very) slow gear changes (Like plan your gear changes using a calendar and apply three days prior in writing kind of slow ... )

Just my opinion - I appreciate other opinions may vary

WD

 

[Vlad Soare]

I once drove a car with no rev hang at all. As soon as you disconnected the clutch and let go of the throttle, the revs would immediately drop to idle. It was very unpleasant and caused a jerk when the clutch was engaged again. In order to drive smoothly you had to continue pressing the throttle a little. But exactly how much throttle you needed was tricky to determine. You just kept your foot there and hoped for the best.
Now, I'm sure an experienced driver can feel exactly how much throttle to use when shifting and doesn't need any assistance, in the same way as some prefer to rev match themselves and don't care for the auto rev-matching feature. But for the rest of us a bit of help is nice.

 

[WD Pro]

The mustang is the first car I have had with rev match.

Perhaps the other cars have taught me how to drive without it, hence the reason I didn't even think the mustang did it (until I tested) ?

WD

 

[Vlad Soare]

All the manual cars I've driven during the past twenty years had some degree of rev hang. I'm sure all of yours had it (unless they had a carburetted engine from the eighties), you just probably never noticed it.
Automatic rev matching on downshifts is another story.
Power and torque are also important factors. You can afford not to rev match in a puny Golf diesel, but a 450 HP RWD is another story.

One test we could do would be to disable the auto rev-match and see if there's a change in the way the revs hang on upshifts. This will tell us whether the auto rev-match feature works both ways - i.e. if it also has an influence on the amount of rev hang.

 

[WD Pro]

Works both ways according to some of the above posts

My experiences - Kit cars (no ecu), XR2 (no ECU), old sierra's (no rev hang), Cosworth (no rev hang) + tuned (again no rev hang). Sequential SMG's and old school autos don't count.

I got a yet to be mapped (long way off) Cosworth kit car, that defo wont have it.

I will check my diesel Kia but I'm pretty sure that doesn't do it (its probably not got the intelligence to do it)

WD

 

[K4fxd]

I suppose it is what you learned on. I learned on high horsepower carbureted engines. Roadrunners, Chevelle's Nova SS, Sunbeam Tiger, 63 Impala SS409 and on and on.

It is simple clutch in, gas off, move gear, gas on, clutch out. When I do that in a rev hang car it does not work.

Old habits.

I borrowed my Son's Scion TC for a few weeks, and even after that amount of time I still had trouble shifting gears. I got better, but when I didn't think about how to shift, I reverted to the old way.

 

[Jordan @ Lethal]

I don't think what you're asking is how it works. The computer isn't helping the car shift, it basically just has a sensor for when you start going into a specific gear, and the computer does the calibration on what speed to rev the engine to. It's not assisting the shift any other way.

So no, I don't think this would help at all with grinding or lockout.

+1

 

[WD Pro]

All the manual cars I've driven during the past twenty years had some degree of rev hang. I'm sure all of yours had it (unless they had a carburetted engine from the eighties), you just probably never noticed it.
Automatic rev matching on downshifts is another story.
Power and torque are also important factors. You can afford not to rev match in a puny Golf diesel, but a 450 HP RWD is another story.

One test we could do would be to disable the auto rev-match and see if there's a change in the way the revs hang on upshifts. This will tell us whether the auto rev-match feature works both ways - i.e. if it also has an influence on the amount of rev hang.

Ref rev HANG : I got a chance to mess around with the sportage on the way home and to confirm - zero rev hang function on that either.

On the motorway, dip the clutch and the revs drop immediately to idle.

Put the selector in 6th, 5th, 4th and 3rd and nothing, idle rpm only.

I’m also struggling to see what horsepower has got to do with this. If the rpm is dropping (what it seems people want it to do) then the throttle is (mostly) closed and hp will be minimal. If the clutch / throttle relationship is mismatched, engine inertia / engine braking will have a far greater influence on the smoothness of the shift than the amount of horsepower that is (potentially) available.

In my opinion rev hang is only a substitute for pedal control issues and will only make itself noticed in the instance of poor clutch / throttle synchronisation.

For changing up the box, only two pedals and two feet are needed, get the relationship / timing between them correct and a (correctly programmed) rev hang will go completely unnoticed.

Again, just my opinion and not intended to offend anyone

WD

 

[Vlad Soare]

It all depends on what you're used to. Like Dan said above, if you're used to doing it yourself every time, then rev hang will get in your way. But when most of your previous cars used to have it, then not having it will result in jerky shifts until you learn how to compensate yourself for its absence.
Driving with rev hang is easy - just don't touch the throttle while you're lifting the clutch. But I can understand why it may be unpleasant if you're not used to it. Incidentally all the fuel-injected engines I've driven had it to some degree (some more than others; most noticeable was in a Renault Clio). Might have been just my luck, who knows...

I’m also struggling to see what horsepower has got to do with this.

What I meant was that the more powerful a car is, the more badly it tends to jerk when you get it wrong. It's one thing up-shifting at 2500 rpm in a small diesel, when you can just drop the clutch without giving it too much thought, and another to shift at 6500 rpm in a Mustang, where not matching the revs correctly would cause a strong jolt.

 

[WildHorse]

If you grinding into third, you're probably trying to ram the shifter between 1st & third. Adjust your shifting habits. As for high RPM lockout, you're probably revving the clutch way past what it's designed for. Not sure on the twin disc set up, but on my 17 with the factory clutch you'll get lock out past 7500 rpm about half the time. I shift for 7000 rpm, so I start to engage the clutch around 6500, and by the time it reaches 7K I shift. Happens very quick.

 

[DickR]

FYI "rev hang" can also be needed for emissions reduction. Sudden closing of the throttle can cause spikes in emissions. One of the solutions in the 70's was the use of dashpots to slow throttle closing. The delay in some cars was very annoying to skilled drivers. I'm pretty sure that I've read that delayed throttle closing (i.e. "rev hang") is still used and, of course, is more noticeable with manual transmissions. I've also read that dashpots were also used to reduce stalling as someone noted above.

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