Rev match ruins the A-spec

[RAM]

I have driven the 2023 A-spec w/ tech for the last year now, put 30k miles on it and have gritted my teeth the entire time because of the rev hang and overall clunky shifting. I have driven manual vehicles my whole life and I have never struggled so much. I posted the car for sale a while back and test drove a mustang and I was instantly reassured that I didn't suck at driving a manual. After realizing that i wasn't comfortable taking a depreciation hit after just a year of ownership I decided to hang on to the car a bit longer and hope that tuning and mods would make this car worth driving.
Recently i saw a post on a 11th gen Si forum that said rev hang was reduced when rev match was disabled. I have been driving with rev match this whole time because it is a luxury that I paid for when I bought the car, something I have never had before.
Now, after a week of driving with rev match disabled, I am pleased to say that this car is the driver's car that everyone said it would be. I can now climb over 4000 rpm without being punished. I can now more easily pass people on backroads (a daily occurrence with my commute). I can now even cruise around in the city while pulling off shifts as smooth as butter.
I can't fathom why rev match would have such a huge impact on both up and downshifting, but I wanted to post this novel in case there was any other poor souls out there that have been suffering from horrible shifts induced by rev match. I would say that the problem is now 50% fixed and hope that the phearable 1.5r tune will be even more help.

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[UWU-mancer]

Interesting take

on the type s at least. Turning it off doesn’t seem to offer any advantages. I could be wrong tho. I’ve only been driving stick about 29-30 years

UWU

 

[bullitt]

I've noticed on the Mustang it does add a little rev hang, but not a lot that I really notice it regularly. It also makes it add more RPM's to resist stalling on an incline even if Hill Assist is off.

I hate Hill Assist so much, I have never stalled a car so much in my life till i turned that off on my Mustang.

 

[akoza]

Interesting take

on the type s at least. Turning it off doesn’t seem to offer any advantages. I could be wrong tho. I’ve only been driving stick about 29-30 years

UWU

I had mine on in my Type S for about 2 years and decided to turn it off about 5 months ago. While the rev-match is nice, I do think there was a little bit of noticeable rev hang. I'd have to wait a half second or so for the computer to do its thing, before letting off the clutch. With it off, I don't feel that delay. Maybe my mind fills in the gap because I'm blipping the throttle myself, who knows. But either way it's more satisfying with it off.

I've been driving stick for 20 years.

 

[UWU-mancer]

I had mine on in my Type S for about 2 years and decided to turn it off about 5 months ago. While the rev-match is nice, I do think there was a little bit of noticeable rev hang. I'd have to wait a half second or so for the computer to do its thing, before letting off the clutch. With it off, I don't feel that delay. Maybe my mind fills in the gap because I'm blipping the throttle myself, who knows. But either way it's more satisfying with it off.

I've been driving stick for 20 years.

Can confirm actually

when engaging an auto rev matched down shift I do wait about a second before I begin to let out the clutch

you’re right!

 

[Victorofhavoc]

What's weird for me is that on track it feels faster/better than it does around town. Makes me think they're using more than position logic to determine how quickly and when to match, probably brake input or G. It's only bad coming down from 3rd into 2nd where under 100—95% brake I always chirp the tires (probably from the gearing difference).

I wish there was a button to quickly turn it on and off, or that it could be selectable per drive mode. The rev match system in my Z was flawless. I've had a lot of experience with heel toe and there's no way I could be faster than it, but it also worked very differently because it would start matching as you move the shifter out of the gate and not wait until you're fully in the next gate to match.

 

[UWU-mancer]

What's weird for me is that on track it feels faster/better than it does around town. Makes me think they're using more than position logic to determine how quickly and when to match, probably brake input or G. It's only bad coming down from 3rd into 2nd where under 100—95% brake I always chirp the tires (probably from the gearing difference).

I wish there was a button to quickly turn it on and off, or that it could be selectable per drive mode. The rev match system in my Z was flawless. I've had a lot of experience with heel toe and there's no way I could be faster than it, but it also worked very differently because it would start matching as you move the shifter out of the gate and not wait until you're fully in the next gate to match.

Can also confirm this to be true

when pushing hard. I can make use of the previous gear instantly after an auto rev matched downshift

maybe rpm is a factor when determining how instantaneous the rev match will be?

 

[Victorofhavoc]

Can also confirm this to be true

when pushing hard. I can make use of the previous gear instantly after an auto rev matched downshift

maybe rpm is a factor when determining how instantaneous the rev match will be?

I thought that too, so I tried doing a high rpm downshift while cruising along, and my car was not much faster at the match. Curious if yours might be?

Definitely, the weight of the flywheel is the biggest impact to speed of the match. The tune, rpm, and grabbiness of the clutch also have an impact, but not anywhere near what the flywheel does.

 

[UWU-mancer]

I thought that too, so I tried doing a high rpm downshift while cruising along, and my car was not much faster at the match. Curious if yours might be?

Definitely, the weight of the flywheel is the biggest impact to speed of the match. The tune, rpm, and grabbiness of the clutch also have an impact, but not anywhere near what the flywheel does.

No not at all. At least not on my end. Might need high throttle position too?

 

[Victorofhavoc]

No not at all. At least not on my end. Might need high throttle position too?

I can see that on upshift since being turbo 4 you have to be on the throttle sooner to keep torque up.

The downshift, it certainly could be brake position and/or G.

We do know the suspension reaction is based on many factors feeding the ecu and ads, so I don't see why the rev match rate would be different. Hard to know what they've done with the coding underneath though. The Bosch ecu is incredibly capable, but I know Honda only uses a miniscule amount of its full functionality.

 

[Frenzal]

If you want to have a more direct clutch, you can also remove the clutch damper and slave cylinder delay valve.

It helps a lot.

But does nothing about rev hang though.

 

[Spart]

If you want to have a more direct clutch, you can also remove the clutch damper and slave cylinder delay valve.

It helps a lot.

But does nothing about rev hang though.

Indeed, I just posted a how-to on this yesterday.

Regarding rev-hang in general, there are a few ways to drive "around" it.

One thing to be aware of is that your car has a sensor on the clutch pedal that tells it when the pedal is all the way to the floor. On some cars at least, this sensor is used to tell the ECU to stop doing rev hang. So the longer you hold the pedal to the floor, the more rev hang you get. Solution? Tap the pedal on the floor (in cadence with your shifting) and immediately start bringing it back up.

The other thing to do is to stop dumping the clutch on upshifts. Tap the pedal to the floor like I mentioned, and pause briefly at the bite point. Far less than you would talking off in first, but enough that there's a "hitch" in your pedal travel on the release.

I have driven quite a few cars where rev-hang is a common complaint and I've never really had a problem with it due to my driving style. I think the crutch that some people lean on (and that gets them into trouble) is that rather than actively match the engine speed to the road speed with a minor amount of clutch slip and throttle, they instead learn to just time the point at which they release the clutch on upshifts and they don't use any finesse with the clutch pedal. This works until it doesn't, like when rev hang is keeping your revs higher than the road speed.

 

[RAM]

Indeed, I just posted a how-to on this yesterday.

Regarding rev-hang in general, there are a few ways to drive "around" it.

One thing to be aware of is that your car has a sensor on the clutch pedal that tells it when the pedal is all the way to the floor. On some cars at least, this sensor is used to tell the ECU to stop doing rev hang. So the longer you hold the pedal to the floor, the more rev hang you get. Solution? Tap the pedal on the floor (in cadence with your shifting) and immediately start bringing it back up.

The other thing to do is to stop dumping the clutch on upshifts. Tap the pedal to the floor like I mentioned, and pause briefly at the bite point. Far less than you would talking off in first, but enough that there's a "hitch" in your pedal travel on the release.

I have driven quite a few cars where rev-hang is a common complaint and I've never really had a problem with it due to my driving style. I think the crutch that some people lean on (and that gets them into trouble) is that rather than actively match the engine speed to the road speed with a minor amount of clutch slip and throttle, they instead learn to just time the point at which they release the clutch on upshifts and they don't use any finesse with the clutch pedal. This works until it doesn't, like when rev hang is keeping your revs higher than the road speed.

Thank you, I'll focus on these tips while driving and see if I can make a difference. I'd love to get more information on the risks associated with deleting the clutch delay valves. I've heard that they sacrificed the clutch to save the transmission and that deleting them puts more stress on the transmission. I'm not familiar with how much these transmissions can take or how much extra wear deleting the valves puts on the transmission.

 

[Spart]

Thank you, I'll focus on these tips while driving and see if I can make a difference. I'd love to get more information on the risks associated with deleting the clutch delay valves. I've heard that they sacrificed the clutch to save the transmission and that deleting them puts more stress on the transmission. I'm not familiar with how much these transmissions can take or how much extra wear deleting the valves puts on the transmission.

They are intended to stop novice or abusive drivers (but I repeat myself) from causing damage to warrantied parts.

They do this by making the driving experience much worse for experienced drivers.

The process is reversible, I would highly recommend buying a spare clutch slave cylinder and bench modifying it before attempting the swap. My video has instructions on how to do so, or you could purchase one that has already had the CDV deleted from JSR or @ashmostro has one for sale on here.

 

[RAM]

They are intended to stop novice or abusive drivers (but I repeat myself) from causing damage to warrantied parts.

They do this by making the driving experience much worse for experienced drivers.

The process is reversible, I would highly recommend buying a spare clutch slave cylinder and bench modifying it before attempting the swap. My video has instructions on how to do so, or you could purchase one that has already had the CDV deleted from JSR or @ashmostro has one for sale on here.

I may have watched your video in the past and I'll check it out again. I appreciate the relative info!

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