Rev matching: opinions?

[Norm Peterson]

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".

These days, those GD software engineers think they need to be involved in every little thing we do. A simple switch that controls something directly is no good because it isn't telling a computer what you want it to do for you.

It just might be more satisfying to be less than perfect on our own merit than appear to be perfect according to somebody else.


Norm

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[Norm Peterson]

... 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.

I'm pretty sure that "use it or lose it" applies here . . . and that constant practice is what it takes to "keep you current".


Norm

 

[Michael_vroomvroom]

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.

Well, that video was more intended as a reply to whether what Herrin said implies he engages the clutch when downshifting llike that or not. I don't know who the rider in the video is (though it's obviously not Herrin), and if he was a professional racer I guess he'd say it. I think one can not question that he's very, very good however, and from the video it's clear he engages the gears as he's downshifting from e.g. 5 to 4, 3, 2 at the segment starting where I linked it in.

The rest will be subjective of course, so one can say I'm only hearing what I want to hear, but to me, starting at the segment I linked in, that's the sound of someone downshifting leisurely (relatively to his very impressive skills) and using the engine for much of required braking. An amazing rider and the video is a joy to watch.

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.

Good guess. The bike in the video is a Ducati Panigale V4. If I calculate the spacing correctly based on the specs listed at
https://www.motorcyclespecs.co.za/model/ducati/Ducati_Panigale_V4R_19.html, the spacing is about 20% apart between first/second (22%), and
second/third (18%), and even less for the subsequent gears (12%, 10%, 8%). 20% seems like a really educated guess.

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).

Possibly. It does not feel good whatever it is.

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

Norm

Thank you. It was a nice clear day and it was a joyful drive, though slightly shorter than hoped. Still got about 100 miles to go, but when back home tomorrow evening that should be complete.

 

[Michael_vroomvroom]

First off, welcome to the club. Hope other than rev match, you're enjoying your stang! Nice to see another super sport rider in here as well, I have an 07 Kawsaki ZX-10R SE and a 15 Kawasaki ZX-10R ABS.

With that said, I just got my GT 2 months ago and it took me a while to get used to the rev matching but I absolutely love it now. I've only ever had manual shift mustangs, outside from my very first car which was a ford escort and an inbetween car which was a mistake (Infiniti G37). You really appreciate it when spirited driving or track driving (which I am getting ready to do with this stang soon). It really does rev match near perfectly for that.

Many thanks. Apart from my 50cc Kawasaki AE moped a century and a half ago, I've never had the pleasure of riding a Kawasaki.
The first bike I had was a small VFR 400. In 2008 or 2009 I rented an R6 for two track days. The second day they had a double booking so I was given an 750 GSX-R instead, which promptly landed me on my ass as I spun the rear wheel upon exiting the corner on I think the second lap, possibly even the first. As I got up I remember thinking: hmm, this is a bit different from the R6. ;-) R6 was my favourite, while the Suzuki felt too aggressive for my skills. :-/

The Mustang is great. Makes me smile from the moment I'm seeing it parked outside, walking towards it, turning on the engine and hearing the rumble, till I'm parked again. The rev matching is starting to grow a bit on me, though I've yet to do any spirited driving so far. There's a nice windy road going through the mountains to Ronda not too far from here. I've twice struggled up that road in my old 20 year old Audi A3 (it was on that road I also discovered the automatic in that car gonna blow sooner than later, sans a complete rebuild, as after a while it refuses to up-shift anymore until it's cooled down), so I'm sure it will be a real pleasure going up that road in the Mustang. It seemed to be really popular with bikers also, as I don't see many bikers here normally, but that road was full of them.

Really like the "track mode" display on the Mustang too. Wanting to keep the rpm below 4,000 as I'm doing my first 1,000 miles, and the track mode display makes it really easy to quickly see the rpm. Just 100 miles left to go now. . Vroom vroom.

 

[Silver Bullitt]

Many thanks. Apart from my 50cc Kawasaki AE moped a century and a half ago, I've never had the pleasure of riding a Kawasaki.
The first bike I had was a small VFR 400. In 2008 or 2009 I rented an R6 for two track days. The second day they had a double booking so I was given an 750 GSX-R instead, which promptly landed me on my ass as I spun the rear wheel upon exiting the corner on I think the second lap, possibly even the first. As I got up I remember thinking: hmm, this is a bit different from the R6. ;-) R6 was my favourite, while the Suzuki felt too aggressive for my skills. :-/

The Mustang is great. Makes me smile from the moment I'm seeing it parked outside, walking towards it, turning on the engine and hearing the rumble, till I'm parked again. The rev matching is starting to grow a bit on me, though I've yet to do any spirited driving so far. There's a nice windy road going through the mountains to Ronda not too far from here. I've twice struggled up that road in my old 20 year old Audi A3 (it was on that road I also discovered the automatic in that car gonna blow sooner than later, sans a complete rebuild, as after a while it refuses to up-shift anymore until it's cooled down), so I'm sure it will be a real pleasure going up that road in the Mustang. It seemed to be really popular with bikers also, as I don't see many bikers here normally, but that road was full of them.

Really like the "track mode" display on the Mustang too. Wanting to keep the rpm below 4,000 as I'm doing my first 1,000 miles, and the track mode display makes it really easy to quickly see the rpm. Just 100 miles left to go now. . Vroom vroom.

I've got an older oil cooled GSXR750 mounted sideways in my midget sprint car. It's got bigger 40mm Mikuni's and runs on minimum 100 octane. It's definitely got a little attitude.

 

[shogun32]

The R6 is a gutless wonder. The like-year GSXR750 has some actual torque. It's not at all surprising he got spat off getting too greedy with the happy stick, on a likely cold tire to boot.

 

[Cdshivers]

Does anyone know if this feature can be added to a 15-17?

 

[Michael_vroomvroom]

I've got an older oil cooled GSXR750 mounted sideways in my midget sprint car. It's got bigger 40mm Mikuni's and runs on minimum 100 octane. It's definitely got a little attitude.

Hehe. Looks like something straight out of the ancient movie "Flåklypa Grand Prix," also known as "Pinchcliffe Grand Prix" .

 

[Spart]

OP, you're driving a V8, not a liter bike.

The difference in rotational inertia is quite large. Large enough in fact that if you bork a downshift sufficiently enough, you'll briefly "lock up" the rear wheels and hear tire squeal. (They're not actually locked, just rotating slower than the road surface, but that's neither here nor there.) Worse, if you do this during the winter on an icy road you could put the car into a skid.

None of that is good for your drivetrain or clutch.

The Ford engineers know what they're doing. It's best for the longevity of all involved driveline components if the engine speed matches the input shaft speed when you let out the clutch. That goes for upshifts and downshifts. You don't let off the gas for five seconds, select the next highest gear, and then let out the clutch? No, you'd look like a huge idiot as the car bucked and you'd cause unnecessary wear. You instead shift with a cadence that lets the engine RPM fall to match the speed of the input shaft on the trans for the next highest gear... hopefully. Rev-matching is the equivalent of this for downshifting.

You've been driving manual transmissions wrong. Lots of people do this, no reason to be defensive. I used to do it. My parents didn't teach me the right way. That's fine.

Rev-matched downshifting is the way, whether you do it yourself or the car does it for you. Clutch-slipped downshifts are wrong. Again, the Ford engineers know what they're doing. If you think it's obnoxious to other drivers, you've bought the wrong car.

To anyone else reading this looking for justification of their bad habit: just fix yourself. It's easy and your car will thank you.

 

[shogun32]

What's funny is some Class 8 truck drivers use engine braking but you'll notice there is no "dragging the engine back up to road speed". The reason is that the transmission won't even go into gear unless the 2 shafts are within a narrow band so the driver MUST revmatch when selecting the next lower gear.

 

[Spart]

What's funny is some Class 8 truck drivers use engine braking but you'll notice there is no "dragging the engine back up to road speed". The reason is that the transmission won't even go into gear unless the 2 shafts are within a narrow band so the driver MUST revmatch when selecting the next lower gear.

By "some" you mean "essentially all, especially those that make it out of the mountains alive."

Vast majority of those trucks are unsynchronized, which makes them well-suited to floating gears if you know what you're doing with your right foot.

 

[Michael_vroomvroom]

OP, you're driving a V8, not a liter bike.

The difference in rotational inertia is quite large. Large enough in fact that if you bork a downshift sufficiently enough, you'll briefly "lock up" the rear wheels and hear tire squeal. (They're not actually locked, just rotating slower than the road surface, but that's neither here nor there.) Worse, if you do this during the winter on an icy road you could put the car into a skid.

None of that is good for your drivetrain or clutch.

The Ford engineers know what they're doing. It's best for the longevity of all involved driveline components if the engine speed matches the input shaft speed when you let out the clutch. That goes for upshifts and downshifts. You don't let off the gas for five seconds, select the next highest gear, and then let out the clutch? No, you'd look like a huge idiot as the car bucked and you'd cause unnecessary wear. You instead shift with a cadence that lets the engine RPM fall to match the speed of the input shaft on the trans for the next highest gear... hopefully. Rev-matching is the equivalent of this for downshifting.

You've been driving manual transmissions wrong. Lots of people do this, no reason to be defensive. I used to do it. My parents didn't teach me the right way. That's fine.

Rev-matched downshifting is the way, whether you do it yourself or the car does it for you. Clutch-slipped downshifts are wrong. Again, the Ford engineers know what they're doing. If you think it's obnoxious to other drivers, you've bought the wrong car.

To anyone else reading this looking for justification of their bad habit: just fix yourself. It's easy and your car will thank you.

Thanks. I've fixed myself I think and are only intentionally using the brakes for slowing down now. This also means the slight rev'ing from the automatic rev-match while downshifting to stop/slow down is quite light too. Now that I better understand why it's there I've also grown to like it.

Ok? ;-)

 

[Spart]

Thanks. I've fixed myself I think and are only intentionally using the brakes for slowing down now. This also means the slight rev'ing from the automatic rev-match while downshifting to stop/slow down is quite light too. Now that I better understand why it's there I've also grown to like it.

Ok? ;-)

Braking actually isn't the issue - engine braking doesn't cause any real wear on your vehicle as long as you're not slipping the clutch.

I engine brake all the time. If you keep the engine in the torque band, you're going to get some engine braking effect and the car will slow down very gradually. If I'm going from a 55mph zone to a 45mph zone, I don't usually touch the brakes. I just do a rev matched downshift to the gear I'd normally be in for cruising at 45mph (4th) and let compression braking get me down to that speed.

Same for 45 to 35, 35 to 25. It's a good habit because if you need to accelerate, you aren't trying to do it in 5th gear at 25mph.

This is also good for fuel economy, since your PCM actually cuts the injectors off when you're engine braking. Typically referred to by tuners and hypermilers as Deceleration Fuel Cut-Off or DFCO.

 

[Michael_vroomvroom]

Braking actually isn't the issue - engine braking doesn't cause any real wear on your vehicle as long as you're not slipping the clutch.

I engine brake all the time. If you keep the engine in the torque band, you're going to get some engine braking effect and the car will slow down very gradually. If I'm going from a 55mph zone to a 45mph zone, I don't usually touch the brakes. I just do a rev matched downshift to the gear I'd normally be in for cruising at 45mph (4th) and let compression braking get me down to that speed.

Same for 45 to 35, 35 to 25. It's a good habit because if you need to accelerate, you aren't trying to do it in 5th gear at 25mph.

This is also good for fuel economy, since your PCM actually cuts the injectors off when you're engine braking. Typically referred to by tuners and hypermilers as Deceleration Fuel Cut-Off or DFCO.

Ok, thank you. That makes a lot of sense to me and is also what I would like to do if that's ok for the car. Thanks again.

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