Rev Jump When Upshifting under Hard Acceleration

[egxflash]

FInally stretching my car's legs after break-in and noticed something peculiar under hard acceleration.

When upshifting 1 ->2 and 2 -> 3 , I noticed the revs jump ~500 rpm in between shifts. I thought maybe I was a little late to take my foot off the throttle but even after being mindful of that, it still jumps up a bit.

I'm finding I have to shift around that so as not to bang on the rev limiter. I been reading around and I've seen mention of rev matching but that doesn't make much sense to me. Also, this phenomenon happens even as I have the rev match feature off.

Is this rev hang? I'm not very familiar with it and never had this experience in any other manual car I've had. Granted, all my other cars have been N/A.

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[optronix]

It's rev hang. You get used to it. I'll let others chime in on the ability to get rid of it with a tune.

Don't worry about banging off the rev limiter; that's what it's there for (but do worry if you "bang off the rev limiter as a result of a missed shift...!).

 

[Fred 930]

I'm new to modern Japanese cars, but also have noted the exact same problem as you have described. When shifting during aggressive acceleration, the engine will over-rev (they call it rev-hang). I was worried about this, having experienced it once on another Japanese car, and again when test driving an A-Spec. At this point, I'm considering it a "design flaw". Will discuss with the Dealer during first service, but I'm betting the only way to fix it will be some sort of aftermarket tune - which is a bad idea from a warranty standpoint.

Hope someone has a better solution to this very annoying problem.

 

[mugendc4]

as mention, it's rev-hang. I had it on my 8thgen civic and had to get a tune to fix it but flashing the ECU was easier since didn't require an unlock like the DE5.

Post#28 explains it better
https://www.civicxi.com/forum/threads/revving-issue-during-upshifts.52138/page-2

 

[optronix]

The only "solution" is to get a tune, because it is an intentional implementation. I stole this image from that linked thread.

Yes, it's probably different from most other manual cars out there (but is it really though? My brother's WRX has done this since he bought it in 2015). You can throw a fit about it, or you can get used to it. It isn't hurting anything and some would argue it's actually beneficial. Let it be known I'm not here to make that argument, but if I can get over it, so can the rest of you.

This is a good example of mild psychosis. It's only "annoying" because you let it be.

 

[Integra23]

It's also part of an emissions thing. Tune removes it

 

[Fred 930]

I will argue with your about this rev-hang problem. It really is hurting something.

When up-shifting during spirited acceleration, one wants engine RPM to drop a suitable amount to match what is necessary for smooth engagement of the next gear - probably dropping about 500 RPM. But my ITS does the opposite and increases RPM about 500. So when you re-engage the clutch the RPM is about 1000 higher than it should be. Done often, this will cause unnecessary clutch and drive-train wear. Perhaps Honda does it for some emissions related reason, but I've not seen it occur on any German cars.

 

[Frenzal]

It really is annoying. Like I'm not able to shift correctly... I hate it when the car does it.

 

[optronix]

I will argue with your about this rev-hang problem. It really is hurting something.

When up-shifting during spirited acceleration, one wants engine RPM to drop a suitable amount to match what is necessary for smooth engagement of the next gear - probably dropping about 500 RPM. But my ITS does the opposite and increases RPM about 500. So when you re-engage the clutch the RPM is about 1000 higher than it should be. Done often, this will cause unnecessary clutch and drive-train wear. Perhaps Honda does it for some emissions related reason, but I've not seen it occur on any German cars.

Personally I don't have this issue to the degree you're describing it. Maybe if you're drag racing?

Have you tried disabling VSA (i.e. the "pedal dance")? Maybe that's causing it? Personally I don't think slamming gears on a race track is the best approach.

See this clip starting here from Savagegeese's on-track review. This is how I try to shift on track, and as you can see there's not an egregious amount of noticeable rev hang.



If it bothers you that much, I'd suggest getting a tune. Otherwise I'm not sure what else you're looking for.

 

[Clayman]

This is actually a consequence of the rev-match system. Unfortunately it holds revs while you upshift, causing that rev hang. Try disabling it and driving. Your revs will drop much faster.

 

[SlippyFist]

yeah it's pretty annoying. so a question i have now- does disabling the rev-match feature only disable rev-matching while downshifting, but not while upshifting?

 

[egxflash]

This is actually a consequence of the rev-match system. Unfortunately it holds revs while you upshift, causing that rev hang. Try disabling it and driving. Your revs will drop much faster.

My rev match is disabled already and still getting a jump under hard acceleration.

I've learned to live with it since I'm not drag racing anybody but it does feel weird shifting a tad earlier than what I'm used to.

yeah it's pretty annoying. so a question i have now- does disabling the rev-match feature only disable rev-matching while downshifting, but not while upshifting?

that's what it seems like. No rev matching on the downshift for me (which is fine) but still jumping on upshifts during hard acceleration. I notice it mostly for 1 -> 2

 

[SlippyFist]

My rev match is disabled already and still getting a jump under hard acceleration.

I've learned to live with it since I'm not drag racing anybody but it does feel weird shifting a tad earlier than what I'm used to.



that's what it seems like. No rev matching on the downshift for me (which is fine) but still jumping on upshifts during hard acceleration. I notice it mostly for 1 -> 2

is it happening every time you upshift? i can live with the "normal" rev-hang (well not like we really have a choice if we don't want to tune) but every once in a while i get a really bizarre spike in revs in-between gears. as far as i can tell it's only happened when i was getting on it pretty hard while merging onto the interstate, usually going from 3rd to 4th, but i mean the engine sound significantly ramps up as if the accelerator is pushed flat to the floor despite giving no input to the throttle at all. i haven't been able to catch exactly how many RPM it jumps up but it definitely sounds like its more than just 500rpms.

 

[egxflash]

is it happening every time you upshift? i can live with the "normal" rev-hang (well not like we really have a choice if we don't want to tune) but every once in a while i get a really bizarre spike in revs in-between gears. as far as i can tell it's only happened when i was getting on it pretty hard while merging onto the interstate, usually going from 3rd to 4th, but i mean the engine sound significantly ramps up as if the accelerator is pushed flat to the floor despite giving no input to the throttle at all. i haven't been able to catch exactly how many RPM it jumps up but it definitely sounds like its more than just 500rpms.

no, i don't think so. I notice it when WOT upshifts 1 -> 2 and 2 -> 3

Being more focused on my upshifts when I was trying to isolate the issue, I made sure my foot wasn't late on the liftoff and it still jumped ~500rpm.

I shift about 500rpm short of redline now and I just barely bang redline.

 

[Clayman]

My rev match is disabled already and still getting a jump under hard acceleration.

I've learned to live with it since I'm not drag racing anybody but it does feel weird shifting a tad earlier than what I'm used to.



that's what it seems like. No rev matching on the downshift for me (which is fine) but still jumping on upshifts during hard acceleration. I notice it mostly for 1 -> 2

Yeah unfortunately it doesn’t seem to totally get rid of it. It’s definitely a noticeable difference though. Like others said, you probably have to tune it to make it fully go away.

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