Shifting with rev hang

Vrruumm

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Rev hang seems to only be an issue when leaving it in gear and braking after accelerating hard. I will accelerate in 1st to 20mph, let off and brake and the engine still wants to keep the car from slowing down. It is about my only issue with it. I still think sport mode from the factory should disable rev hang.
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Chief 08

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I just drive and shift normally. I have never had an issue with it to the point that I don't even notice it.
 

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I have my car for 8 months driving it stock, and one day I tried to turn off my traction control (VSA). I can feel the rev hang is almost killed, and with the Sport mode on it's really day and night different. For now every time I getting in the car I always turn off VSA.
 

REBELXSi

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Can someone explain this problem? I don't seem to be experiencing anything like this... Is it a problem for everyone? Is it for all SIs? I have an '18 if that makes a difference
 

Chief 08

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Can someone explain this problem? I don't seem to be experiencing anything like this... Is it a problem for everyone? Is it for all SIs? I have an '18 if that makes a difference
Basically, when you let off the accelerator and push in the clutch to shift, the engine RPM's don't drop immediately. This can cause an issue with quickly shifting through the gears because It makes it difficult to rev match and for the synchros in the transmission. The purpose of the rev hang is an emissions function.
 


turbo dragon

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Ill be deleting my cdv soon, hopefully Ill like it better, if not, Ill put it back in and live with it.
 

NHCivicGuy

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Ill be deleting my cdv soon, hopefully Ill like it better, if not, Ill put it back in and live with it.
I have read that this does not help with the hang. The only thing that seems to fix it is disabling it via a tune (ktuner or hondata).
 

JoYu

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Removing the clutch delay valve does nothing for rev hang. It may help you shift smoother, but rev hang is when the rpm doesn't come down as quickly as it should.

Rev hang:
When you are flooring the gas and then let go of the gas pedal, the car is still giving it a little gas even though you are not pressing the pedal.

So to shift smooth you have to wait a little longer for the rpms to come down. Or as some have said you can wear your clutch a bit by releasing the clutch pedal even though the rpm hasn't dropped yet.
 
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MuffinMcFluffin

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So to shift smooth you have to wait a little longer for the rpms to come down. Or as some have said you can wear your clutch a bit by releasing the clutch even though the rpm hasn't dropped yet.
See, I'm bad with car terms. When you say "releasing the clutch" in my head I'm thinking of taking the foot off the clutch pedal, but I'm assuming you're talking about the actual clutch part disengaging with the gear, in which case that means "put your foot on the clutch pedal."

If that is the case, are we wearing our clutches when we blip RPM's for rev-matching as we downshift? If not, how is that different from doing this as a result of rev hang instead?
 

JoYu

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Releasing the clutch means taking your foot off the clutch pedal :)

I guess I should have said releasing the clutch pedal.
 


captlwr

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Personally - my experience in driving Manuals for over 50 years is that you will never "get used to" the Honda Rev Hang Program. I had it much more in my 2012 Civic Si than I do in my 2018 Civic HB Sport. In the 2018 it seems to be programmed in at a much higher RPM and you really have to "snap" your foot OFF the gas when shifting above 4500 RPM to control it, at least in MY current car. I spent the $650+ for a Hondata Tool and Reflash on my 2012 and it DID work...........for a time - but reality is that the ECU will "learn back" it's initial Programming and you'll have to keep doing a Reflash every few months of driving - today's Manufacturers do not LIKE Manuals because of CAFE Standards and try to do anything they can to "burn off" excess Fuel, hence the Honda Rev-hang..............Larry
 

FK7_ASM

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Took my civic to the local drag strip our in Ennis, Texas. I'm 100% stock on everything and you can feel it for sure. Now it's only a 1/4 mile strip but you can 100% feel boost threshold and the rev hang. I was racing a '92 MR2 that was boosted and I did beat him but not by a big margin. Every time I shifted, between rev hang and the boost threshold he would catch up to me about 1/2 to 1/4 car lengths every time. Daily driving you usually don't feel anything unless your WOT. This is just from my first hand experience.
 
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MuffinMcFluffin

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I was driving on 35 MPH streets on my test runs and I experienced rev hang. Didn't go a single RPM above 3500 (doubt I even went that high), and I was deliberate in my shifts given that it was not my car.
 

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I get the whole emissions thing, but there are new manual cars out there that do not have rev hang. Honda should at least attempt to get rid of it on the more sportier models. I don't know how an engineer can get in and drive the car spiritedly and think that it's not an issue.
 

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the rev hang for me is definitely the worst in the 2 - 3 shift, especially at high rpm/redline.

like another poster, the 9th gen si the rev hang was even worse, if you can imagine that.

one thing i really miss of the old hondas - em1 gsr prelude etc. is the no rev hang. once honda introduced rev hang shifting has been a bitch.

i did use the flashpro to eliminate the rev hang, but imo it eliminates too mich of it, and made the car very jerky.
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