2020+ Rev Hang lean spike/buck issue solution?

[RedeyeRalleye]

I'd really like to hear if anyone has a 2020+ SI running hondata and how/if they dealt with revhang

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[Boosted_01_R]

Ktuner emailed me the beta a couple of months ago, and they said it is what they use on the 11th gen MTs for that platforms rev hang issues.

The 'reduced' setting It only works with rev hang still ENABLED, and I'd say it's slightly less hang than factory. No lean spike/bucking with this setup so far, just not nearly as snappy as it fully disabled.

Not trying to defend anyone, but they did say they 'won't remove the emissions code on the 2020+s'. It sounds like they're legally bound to keep it (rev hang) there to avoid violating some emissions laws, but I'm just speculating here. Im hoping they find a way around it soon

Hmmm, wonder if it's more "can't" than "won't". Ktuner is an "off-road" product. It already has the ability to disable secondary O2 codes, and rev hang on 17-19 10th gens etc. When it comes to emissions, EPA will look at this product the same way they do Hondata (referencing PFI's issues with the EPA), regardless of that code. I'm glad the 11th gen's have this issue so they will hopefully put some effort into resolving this. It's been a long time since they added any value to the software, would be nice to get a update with refined revhang, etc.

 

[geeeek]

I have 70a rmm, fk8 retrofit, and rev hang disabled. On TSP stage 1 which I'm not sure exactly how aggressive the throttle padding and other general settings are.

I'm not sure if you're referring to jerkiness/bucking within gear or when engaging the clutch into another gear but I still experience both. I assume this is caused by the massively increased throttle response of any tune over the stock tune. I learned that you can avoid this by "taking the slack out of the drivetrain" like feathering the throttle lightly before any further input whether in gear or going into gear. Obviously in daily driving situations it's not possible to do this 100% of the time given how many inputs you make going down even one block of traffic.

The bucking going into 2nd especially can get pretty bad if I don't shift correctly. I haven't really seen this talked about much except for this guy on reddit who drives a 6mt acura TL and he brings it up all the time.

When you say lean spike are you talking about the positive stft spike? I always as that was normal when you open/close throttle

 

[RedeyeRalleye]

Hmmm, wonder if it's more "can't" than "won't". Ktuner is an "off-road" product. It already has the ability to disable secondary O2 codes, and rev hang on 17-19 10th gens etc. When it comes to emissions, EPA will look at this product the same way they do Hondata (referencing PFI's issues with the EPA), regardless of that code. I'm glad the 11th gen's have this issue so they will hopefully put some effort into resolving this. It's been a long time since they added any value to the software, would be nice to get a update with refined revhang, etc.

It's not ideal and this is worst case, but has the topic of using a 17-19 ecu been discussed somewhere? I'm still pretty new on the forum and can't seem to find anything definitive on if can be done or not yet

 

[RedeyeRalleye]

I have 70a rmm, fk8 retrofit, and rev hang disabled. On TSP stage 1 which I'm not sure exactly how aggressive the throttle padding and other general settings are.

I'm not sure if you're referring to jerkiness/bucking within gear or when engaging the clutch into another gear but I still experience both. I assume this is caused by the massively increased throttle response of any tune over the stock tune. I learned that you can avoid this by "taking the slack out of the drivetrain" like feathering the throttle lightly before any further input whether in gear or going into gear. Obviously in daily driving situations it's not possible to do this 100% of the time given how many inputs you make going down even one block of traffic.

The bucking going into 2nd especially can get pretty bad if I don't shift correctly. I haven't really seen this talked about much except for this guy on reddit who drives a 6mt acura TL and he brings it up all the time.

When you say lean spike are you talking about the positive stft spike? I always as that was normal when you open/close throttle

Yea the 1-2 shift is tough to perfrct on this Gen, but it's more of that in-gear buck. So do you get that 1 second delay with high + stft (like the throttle is open but not spraying fuel), then the injectors kick back on? For me, this Happens regardless of what the sensitivity/padding is set to on both the ktuner base maps and P1.5. Adapting to it feels like we're just accepting a flaw.

In my testing, The stock and reduced throttle/revhang settings only have a split second on-throttle delay and stft only flickers pos/Neg slightly by comparison, so I'm not really sure what's considered normal or why the ecu reacts that way

 

[Crakzor]

I have a 2020. I remember seeing this when I switched to phearable 1.5R in the initial email. I was on tsp1+ with revhang disabled. So I just kept it on since running 1.5R and learned to drive with it.

Revhang:
On 2020 civic si's using any tune on ktuner having revhang turned off can cause an intermittent throttle response issue between shifts.
Revhang is enabled by default on our stage 1.5 calibration without god mode for 2020 civics.
Revhang is disabled on 2017-2019 stage 1.5 calibrations.

 

[FaceNachos]

I also have a 2020. Pherable 1.5 and I leave the rev hang on. It sucks but I haven't seen anyone say they can find a way around it. Rev hang seems like the lesser of two evils.

 

[Boosted_01_R]

It's not ideal and this is worst case, but has the topic of using a 17-19 ecu been discussed somewhere? I'm still pretty new on the forum and can't seem to find anything definitive on if can be done or not yet

Probably more hassle than it's worth, and other computers expecting to see a 2020 ecu could create a nightmare. Not something I would ever do.

I have a 2020. I remember seeing this when I switched to phearable 1.5R in the initial email. I was on tsp1+ with revhang disabled. So I just kept it on since running 1.5R and learned to drive with it.

Yeah it's in his tune notes. I tried it for a bit but the no throttle response when pulling away was fustrating. Had enough and flashed back with revhang enabled. Phearable tune is great, this a purely a Ktuner issue.

 

[geeeek]

Yea the 1-2 shift is tough to perfrct on this Gen, but it's more of that in-gear buck. So do you get that 1 second delay with high + stft (like the throttle is open but not spraying fuel), then the injectors kick back on? For me, this Happens regardless of what the sensitivity/padding is set to on both the ktuner base maps and P1.5. Adapting to it feels like we're just accepting a flaw.

In my testing, The stock and reduced throttle/revhang settings only have a split second on-throttle delay and stft only flickers pos/Neg slightly by comparison, so I'm not really sure what's considered normal or why the ecu reacts that way

I have a 2019 hatch so you can probably ignore my feedback. I know the delay-buck you're talking about but it's never ever 1 second long, it's at most half second and a stft spike that doesn't exceed +30%. I assumed it was within normal operation but it seems ktuner makes that interaction far worse on your ecus so I really hope it gets fixed for you guys, I can imagine it really puts down the driving experience.

 

[Montana Miner]

I'd really like to hear if anyone has a 2020+ SI running hondata and how/if they dealt with revhang

simple, spend alittle cash and have E-tunez custom tune it. Problem solved.

 

[fg2kid]

I'm really glad to see a thread on this. To be clear, are we talking about the buck/lean spike when getting back on the throttle?

To reproduce:

• Disable rev hang and make sure cruise main is OFF
• Coast in gear, say 3rd at 50 mph
• Step on the gas
• Throttle opens but engine doesn't produce any power
• About 1/2 second later, the engine jerks somewhat violently and then makes power.

 

[waterudoing]

I'm really glad to see a thread on this. To be clear, are we talking about the buck/lean spike when getting back on the throttle?

To reproduce:

• Disable rev hang and make sure cruise main is OFF
• Coast in gear, say 3rd at 50 mph
• Step on the gas
• Throttle opens but engine doesn't produce any power
• About 1/2 second later, the engine jerks somewhat violently and then makes power.

That's exactly what happens in my car. Only, I have a 2018, not a 2020. I wonder why lol

 

[fg2kid]

That's exactly what happens in my car. Only, I have a 2018, not a 2020. I wonder why lol

Are y'all running an aftermarket intake or MAF housing?

Today I tried testing to duplicate the issue:

• Flashed dual factory/19.5 PSI tune with rev hang disabled
• Turned off cruise main
• Coasted in 2nd gear and tried light and heavy throttle inputs from ~3,000 and ~5,000 RPM

Of course the car ran beautifully and didn't hesitate/buck even once

One major change is that I used to have the PRL Cobra intake with race MAF housing. So maybe the issue is related to the OTS tune for that system? Or it will come back after the ECU has time to adjust to the reflash. I'll update the post if it does.

 

[waterudoing]

Are y'all running an aftermarket intake or MAF housing?

Today I tried testing to duplicate the issue:

• Flashed dual factory/19.5 PSI tune with rev hang disabled
• Turned off cruise main
• Coasted in 2nd gear and tried light and heavy throttle inputs from ~3,000 and ~5,000 RPM

Of course the car ran beautifully and didn't hesitate/buck even once

One major change is that I used to have the PRL Cobra intake with race MAF housing. So maybe the issue is related to the OTS tune for that system? Or it will come back after the ECU has time to adjust to the reflash. I'll update the post if it does.

Yes, I have a K&N short ram. I did switch back to the stock intake last year, and it was a little better, but the hesitation was still there (switched back to the K&N for the spoolsss lol). So I do think it has to do with the intake. Mind you my fuel trims with both intakes are within a few percent.

Also from my tunerview, it's actually a rich spike on throttle tip in; STFT will go between -20% to -25% for a very split second while the car hesitates. It pretty much sounds like this when it happens. Admittedly, it sounds pretty cool and sometimes will pop really loud.

 

[fg2kid]

Yes, I have a K&N short ram. I did switch back to the stock intake last year, and it was a little better, but the hesitation was still there (switched back to the K&N for the spoolsss lol). So I do think it has to do with the intake. Mind you my fuel trims with both intakes are within a few percent.

Also from my tunerview, it's actually a rich spike on throttle tip in; STFT will go between -20% to -25% for a very split second while the car hesitates. It pretty much sounds like this when it happens. Admittedly, it sounds pretty cool and sometimes will pop really loud.

That video is a great example of the noise! I was always worried something terrible would happen to the engine though haha.

I tried data logging again today and came to no real conclusion aside from driver error on my part, and that I need to install the PRL intake to get the aggressive bucking to happen. As things stand, it looks like the acceleration is making me lift my foot off the gas pedal slightly during part throttle application. Oops

Here's a clip of the only "bucking" I could induce:




And the accompanying data log:

RPM (blue) is the only line to scale.

Throttle position (orange) shows me lifting off the pedal right as RPMs begin to rise, which I assume is happening due to acceleration.

AFR (purple) is hitting 16.8 on initial throttle tip-in, before settling to 14.5, then 13.7 during acceleration. So I guess there is a "lean spike" but I need a cleaner pull with the PRL intake to be sure of that.

This was a fun experiment either way. I'd be curious to see data logs from someone else that is having the issue with an intake installed.

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