Rev matching: opinions?

[Laserbrain]

I think OP has made up his mind and there's nothing anyone can say that will change it. He believes that slipping the clutch to slow down the car is proper technique, and he doesn't like the "rather impolite "vrooom" sound" the Mustang makes when rev matching. Four pages of discussion hasn't moved him one bit.

Am I wrong, Michael? Is there something that would change your mind? If so, what?

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[Norm Peterson]

It's not at all clear from Herrin's presentation whether he's re-engaging the clutch on every step of the way down or not.

Though he clearly does not mention using the bike's momentum to drag engine rpms up, ever. I suspect you've over-interpreted what he did say into what you wanted to hear.

But if he's braking at the end of a long straight into a fairly slow corner he's probably on the verge of doing a stoppie where momentary lockup of the rear tire would be stupid-easy to come by if he was counting on compression braking for much. Just like he mentions for braking in the rain, where he's further away from a stoppie but has less grip to work with.

He is very clear about being smooth getting onto/into the brakes. Obviously, he's not slow about ramping up his brake action, but he's definitely not 'spiking' them like most car drivers do in a panic stop..

You'd need some datalogging to know for sure exactly what he's doing.

I really need to watch the whole thing, rather than just a little snippet.


Norm

 

[shogun32]

It's not at all clear from Herrin's presentation whether he's re-engaging the clutch on every step of the way down or not.

he's not. He's maintaining just barely enough friction on the clutch plates for the rear wheel to drive the engine RPM upward but not enough to disrupt rear tire traction. This frees him from having to manipulate the throttle while also trying to threshold brake. Unlike cars, motorcycles put nearly all weight (>95%) on the front wheel when braking hard.

When I watch the in-car videos at the track I cringe at how late and "sudden" throttle application appears to be in many cases.

 

[Michael_vroomvroom]

I think OP has made up his mind and there's nothing anyone can say that will change it. He believes that slipping the clutch to slow down the car is proper technique, and he doesn't like the "rather impolite "vrooom" sound" the Mustang makes when rev matching. Four pages of discussion hasn't moved him one bit.

Am I wrong, Michael? Is there something that would change your mind? If so, what?

Mmm. The many posts here by people with experience, you included, coupled with my first week of driving have changed my mind. I can feel the enormous (relative to a bike) weight of the Mustang pushing down on the engine when I try to use the engine to slowdown more than just a tiny bit and it feels uncontrolled to me. With time and practice I could get much better at it I'm sure, but since everyone here is saying it's so bad I'm thinking it's not a good idea anyway, and it does not really feel good.

The "vrooom" sound as I downshift while slowing down is growing on me a bit too. If nothing else, it's reminding my of what a beautiful car I'm in. I still find it a impolite to have the engine rev up as I'm coming to a complete stop so e.g., my kids can get into the car at school though. Already my car gets enough attention in the local forrest of the butt ugly other cars stopping outside there (including a few cars that cost considerably more than mine), so I don't need my car to make some extra "look at me" sounds ;-). As some other members here have mentioned however, it's easy enough to avoid by slowing down more before downshifting, or possibly changing the exhaust mode (it's selectable on my model) to quiet temporarily (not tried that yet, but think I'm too lazy to do that).

300 miles left now before I've completed the 1,000 drive-in miles recommended by Ford, so hoping a Sunday road trip tomorrow will do it. Just need to find somewhere half-sensible to drive.

 

[Michael_vroomvroom]

It's not at all clear from Herrin's presentation whether he's re-engaging the clutch on every step of the way down or not.
Norm

I started to google for some videos of Herrin where one can hear what he does, but while googling I saw this one, by someone else. Don't know who, but he rides well. If you look at the video, from e.g. here:

You can hear him going through each gear as he's downshifting from fifth gear at 130 mph down to second gear at 40 mph while going through the turn, before accelerating out of it.

 

[shogun32]

You can hear him going through each gear as he's downshifting from fifth gear at 130 mph down to second gear at 40 mph

I thought I recognized the sound of a Panigale. That bike has auto-blip in track mode and depending on trim has a 'slipper' clutch as well so the rider doesn't have to be all that good with the clutch.

 

[Michael_vroomvroom]

I thought I recognized the sound of a Panigale. That bike has auto-blip in track mode and depending on trim has a 'slipper' clutch as well so the rider doesn't have to be all that good with the clutch.

He's not riding it in track mode. Look more closely and you see it's in street mode.

 

[Norm Peterson]

he's not. He's maintaining just barely enough friction on the clutch plates for the rear wheel to drive the engine RPM upward but not enough to disrupt rear tire traction.

That's why I'd like to see some datalogging. A bike rider has no option but to hit every gear on the way down, but nothing says he has to re-engage the clutch on every step except the last one.

This frees him from having to manipulate the throttle while also trying to threshold brake. Unlike cars, motorcycles put nearly all weight (>95%) on the front wheel when braking hard.

I know. Seems to me that having only 30 lbs or so on the rear tire would make it a lot more difficult to keep a varying amount of engine braking constant than holding the foot brake constant.

When I watch the in-car videos at the track I cringe at how late and "sudden" throttle application appears to be in many cases.

Over-slowing?


Norm

 

[Norm Peterson]

I started to google for some videos of Herrin where one can hear what he does, but while googling I saw this one, by someone else. Don't know who, but he rides well. If you look at the video, from e.g. here:

You can hear him going through each gear as he's downshifting from fifth gear at 130 mph down to second gear at 40 mph while going through the turn, before accelerating out of it.

Thanks for the link.

It's still awfully hard to tell exactly what he's doing, though he may well be doing it both ways. Sometimes a throttle blip is clearly evident. other times it does sound like he's not. One thing I did pick up on was the closeness of the gear spacing in that particular gearbox (around 20% apart, near as I could tell from the tach and speed readouts), so either way the revs don't need to vary very much. In comparison, gear spacing in your MT82-D4 is more than 40% until you hit the overdrive gears.

I haven't chased any slipper clutch information down yet, so I don't have a solid idea how that would affect things here compared to a normal automotive clutch.


Norm

 

[ktp1598]

Well, I love my rev-match if it still matters! Been driving manuals since I was 18 or so and I'm 50 now. Of course I've slowed down quite a bit so it works well for me.

 

[torqued]

Well, I love my rev-match if it still matters! Been driving manuals since I was 18 or so and I'm 50 now. Of course I've slowed down quite a bit so it works well for me.

I generally love it too but wonder if the doodads on this car is causing some of my skills to atrophy. Like what if I had to drive someone's older stick shift vehicle for some reason. I might look like an idiot doing it, now that I'm used to auto rev matching, hill assist, and automatic throttle on easing out the clutch.

 

[shogun32]

but wonder if the doodads on this car is causing some of my skills to atrophy. Like what if I had to drive someone's older stick shift vehicle for some reason. I might look like an idiot doing it,

amen to that. That's why I leave rev match off. I really dislike the auto-brake that prevents rolling backwards. If you don't have the skills to drive a manual, then don't drive one, or learn! GD software engineers thinking they exist to "help".

 

[JCFoster]

I think it’s all gimmicky.

 

[Laserbrain]

I find hill assist to be awful. I turned that off the day I bought the car, before I left the dealer's parking lot.

 

[Norm Peterson]

Mmm. The many posts here by people with experience, you included, coupled with my first week of driving have changed my mind. I can feel the enormous (relative to a bike) weight of the Mustang pushing down on the engine when I try to use the engine to slowdown more than just a tiny bit and it feels uncontrolled to me. With time and practice I could get much better at it I'm sure, but since everyone here is saying it's so bad I'm thinking it's not a good idea anyway, and it does not really feel good.

I suspect what you're feeling is the rotational inertia of the flywheel and pressure plate, which probably runs more than a hundred times as much as a motorcycle's clutch assembly (I'm guessing ten or more times the weight on more than three times the diameter, which gets squared, here).

I still find it a impolite to have the engine rev up as I'm coming to a complete stop so e.g., my kids can get into the car at school though. Already my car gets enough attention in the local forrest of the butt ugly other cars stopping outside there (including a few cars that cost considerably more than mine), so I don't need my car to make some extra "look at me" sounds ;-).

I absolutely get this, even though I'm well past that stage myself (my youngest grandchild is 14).

As some other members here have mentioned however, it's easy enough to avoid by slowing down more before downshifting, or possibly changing the exhaust mode (it's selectable on my model) to quiet temporarily (not tried that yet, but think I'm too lazy to do that).

I think that changing the exhaust mode, or ARM, or any of the other settings that cars now give you some on-the-fly control over would soon become a PITA to keep changing as your surroundings and the driving conditions change.

300 miles left now before I've completed the 1,000 drive-in miles recommended by Ford, so hoping a Sunday road trip tomorrow will do it. Just need to find somewhere half-sensible to drive.

Hope you enjoyed the drive. Must be mid-afternoon for you as I type this.


Norm

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