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Boostez

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Hondata also said the clutch needs miles to bed in.
That may be true, but you have past experience with 10th gen Si. That clutch was weak also. It's not a stretch to assume the bedding in process won't make a big difference.
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LBP

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That may be true, but you have past experience with 10th gen Si. That clutch was weak also. It's not a stretch to assume the bedding in process won't make a big difference.
I really don't disagree with you that the stock Si clutch is "weak" but I believe it's awfully funny if you really think about it. I mean, before my Si, I owned a Fiesta ST. For all the flaws that car had, the ST's stock clutch really spoiled me. IIRC the Fiesta ST's OEM clutch was produced by AP Racing and it could easily hold big turbo power levels (mid-400s for hp, high 300s for tq) without issue. The stock 10th gen Si clutch doesn't usually slip until you're producing 40% or more torque over the factory output, assuming you haven't abused it. That's a decent amount of overhead! To compare the two, I wouldn't really say that the Si clutch is particularly weak as the ST clutch was tremendously overbuilt. Given the amount of overhead apparent here, the stock clutch is more than adequate for stock and mildly tuned power levels. Others might, but I can't really throw stones at Honda over this. The car is designed to meet a certain specification and cost.

Although the flywheel is now a lighter single-mass unit and the engine has obviously had updates, Hondata's report of clutch slippage at ~270lbft means it may not be a stretch to assume that the 11th gen clutch disc design has not had a major overhaul of any kind over the 10th gen. I also have a feeling that the 11th gen's transmission is also identical or near-identical to the one found in the 2020 Si. The published gear ratios for the 2022 are all identical to the 2020, including the final drive (which was updated for the 10th gen 2020MY). From a volume/cost standpoint it makes sense to continue using the updated design from the previous-gen's final year instead of killing it off so soon. The marketing blurbs and press releases spoke of an "improved transmission" for the 11th gen but would go on to only mention shorter shift throws, rev-match, stiffer shifter bushings/mounts, and a lighter flywheel. All of these are great but are technically outside the actual transmission. It's very likely that the 11th gen transmission/clutch will have all the same weak points as the 10th gen. I won't be surprised to hear of turboswapped/ethanol-tuned 11th gens shearing teeth off of gears. Disappointing, but at least these are familiar problems that already have solutions.
 

fenix-silver

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I really don't disagree with you that the stock Si clutch is "weak" but I believe it's awfully funny if you really think about it. I mean, before my Si, I owned a Fiesta ST. For all the flaws that car had, the ST's stock clutch really spoiled me. IIRC the Fiesta ST's OEM clutch was produced by AP Racing and it could easily hold big turbo power levels (mid-400s for hp, high 300s for tq) without issue. The stock 10th gen Si clutch doesn't usually slip until you're producing 40% or more torque over the factory output, assuming you haven't abused it. That's a decent amount of overhead! To compare the two, I wouldn't really say that the Si clutch is particularly weak as the ST clutch was tremendously overbuilt. Given the amount of overhead apparent here, the stock clutch is more than adequate for stock and mildly tuned power levels. Others might, but I can't really throw stones at Honda over this. The car is designed to meet a certain specification and cost.

Although the flywheel is now a lighter single-mass unit and the engine has obviously had updates, Hondata's report of clutch slippage at ~270lbft means it may not be a stretch to assume that the 11th gen clutch disc design has not had a major overhaul of any kind over the 10th gen. I also have a feeling that the 11th gen's transmission is also identical or near-identical to the one found in the 2020 Si. The published gear ratios for the 2022 are all identical to the 2020, including the final drive (which was updated for the 10th gen 2020MY). From a volume/cost standpoint it makes sense to continue using the updated design from the previous-gen's final year instead of killing it off so soon. The marketing blurbs and press releases spoke of an "improved transmission" for the 11th gen but would go on to only mention shorter shift throws, rev-match, stiffer shifter bushings/mounts, and a lighter flywheel. All of these are great but are technically outside the actual transmission. It's very likely that the 11th gen transmission/clutch will have all the same weak points as the 10th gen. I won't be surprised to hear of turboswapped/ethanol-tuned 11th gens shearing teeth off of gears. Disappointing, but at least these are familiar problems that already have solutions.
I MIGHT be able to forgive Honda for putting in a weak-ass clutch for the 10th gen seeing as how it was an all new drivetrain for them, but considering that they went with a whole new SMF (and I assume a sprung friction disc), to not upgrade the torque handling ability of it in the 11th gen is a big letdown. I know people say, "but it's fine at stock power levels", but it's not like this is just a run of the mill commuter car. Honda knows that these cars get tuned and pretty much encourages it to a point. Just put in a slightly strong clutch from the factory and save your customers the pain of having a clutch start slipping on even a base tune.
 

LBP

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I MIGHT be able to forgive Honda for putting in a weak-ass clutch for the 10th gen seeing as how it was an all new drivetrain for them, but considering that they went with a whole new SMF (and I assume a sprung friction disc), to not upgrade the torque handling ability of it in the 11th gen is a big letdown. I know people say, "but it's fine at stock power levels", but it's not like this is just a run of the mill commuter car. Honda knows that these cars get tuned and pretty much encourages it to a point. Just put in a slightly strong clutch from the factory and save your customers the pain of having a clutch start slipping on even a base tune.
Valid opinion. I think you are correct about changing the clutch to a sprung disc. I had absentmindedly forgotten that changing to a sprung disc would be "required" with a SMF to keep the car easy to live with, so it's a safe assumption that the clutch has received a fairly substantial design change. Perhaps they kept the same friction material specification because of the comparable power profile. Anyway, I'm going to argue both for and against your point here...

Arguing in favor of your stance, we already know that the new Si shares several components and features with the upcoming Type R, mostly in the suspension components. So, outside of purely the performance and marketing benefits we should consider that this also means they have reduced component variation and therefore gained production cost savings through increased volume on these parts. It is already known that within the 10th gen the Type R clutch and flywheel assembly are compatible with the Si with modifications to the parts (sup eman!). So, why not commonize whatever is necessary and share the clutch/flywheel/pressure plate assembly for the 11th gen Si and Type R?

Arguing against it, perhaps the per-unit cost for a Type R clutch assembly is simply too high to be made up by volume savings, and to keep the Si profitable at the price point they have aimed for it was seen as a necessary concession. Another consideration could be that they have designed the Si to meet not only a certain price point, but to meet a particular specification in order to keep the Si within its designated place in the hierarchy. Make no mistake, the Type R is THE flagship sports model for Honda USA. Designing a car with certain components that will fail or otherwise not perform at just below the flagship's factory spec can be seen as a calculated decision to prevent sales cannibalization. It was a similar story in the 80s with the Ford Thunderbird Turbo Coupe and Mustang GT - as the story goes, Ford intentionally made the Turbo Coupe nerf boost at higher gears in order to prevent it from outrunning the big daddy 'Stang. Why spend on a Type R if a Si with a few simple and inexpensive mods equals or beats a Type R?

All of this isn't to tell you that you're right or wrong. I'd love to see a bulletproof factory clutch in a Si the way my old ST had an overbuilt OEM clutch. I'm currently sitting on a clutch & flywheel upgrade for my Si, and it's a project I'd rather not have to do and a thousand dollars I'd rather have not spent. But, basically, any unutilized overhead on the stock parts that we do get is a bonus. Anything beyond stock-as-advertised is not within the scope of Honda's responsibility. They'd probably tell you themselves, though in much more diplomatic terms, "If you don't like it, buy a Type R!"

Anyway, I'm still eagerly awaiting more of Hondata's test results for the new Si to see what has and hasn't improved.
 


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Hondata

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Rev Hang is emissions related. The technical description is injector overrun cutoff delay. The injectors keep firing for a short time after throttle closure to reduce the oxides of nitrous pollution.

Switching this off is illegal for any CARB / EPA tune and for any road vehicle. This is switched off for our race FlashPro and was tested by Team Honda Research West in their two 2022 Civics this past weekend at the ThunderHill 25 hour race. We will fold these race calibrations info our software.

We will have two 22 Civics on track at Buttonwillow next Friday to gather and share data.

We intend to do is gather data on hard driving over time in a safe location to :
  • improve our product
  • to share the data to
  • educate you, the reader, so that you make the best decisions for your car
  • To fold this data into this road legal CARB calibration
Our testing to date suggests we will offering the CARB tune with slightly less peak torque, but with similar power. Clutch slip is a function of torque, not power.

You can have clean, green, fast and legal.
 
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OGGsr

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Rev Hang is emissions related. The technical description is injector overrun cutoff delay cutoff. The injectors keep firing for a short time after throttle closure to reduce the oxides of nitrous pollution.

Switching this off is illegal for any CARB / EPA tune and for any road vehicle. This is switched off for our race FlashPro and was tested by Team Honda Research West in their two 2022 Civics this past weekend at the ThunderHill 25 hour race. We will fold these race calibrations info our software.

We will have two 22 Civics on track at Buttonwillow next Friday to gather and share data.

We intend to do is gather data on hard driving over time in a safe location to :
  • improve our product
  • to share the data to
  • educate you, the reader, so that you make the best decisions for your car
  • To fold this data into this road legal CARB calibration
Our testing to date suggests we will offering the CARB tune with slightly less peak torque, but with similar power. Clutch slip is a function of torque, not power.

You can have clean, green, fast and legal.
Thank you for your detailed response and explanation of why rev hang is a product of emissions/injector function. As a 2022 Civic Si owner, I'm looking forward to further updates from you all as you gather data. Any rough timeline when you plan on offering a tune?
Thanks!
Jamie
 
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Hondata

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We re-visit the dyno Monday/Tuesday next week to incorporate what we have learned into release calibrations. Our calibrations are driven and tested daily in our own car with our own experienced staff. Expected release about 2 weeks.
 

Kullervo

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Rev Hang is emissions related. The technical description is injector overrun cutoff delay. The injectors keep firing for a short time after throttle closure to reduce the oxides of nitrous pollution.

Switching this off is illegal for any CARB / EPA tune and for any road vehicle. This is switched off for our race FlashPro and was tested by Team Honda Research West in their two 2022 Civics this past weekend at the ThunderHill 25 hour race. We will fold these race calibrations info our software.

We will have two 22 Civics on track at Buttonwillow next Friday to gather and share data.

We intend to do is gather data on hard driving over time in a safe location to :
  • improve our product
  • to share the data to
  • educate you, the reader, so that you make the best decisions for your car
  • To fold this data into this road legal CARB calibration
Our testing to date suggests we will offering the CARB tune with slightly less peak torque, but with similar power. Clutch slip is a function of torque, not power.

You can have clean, green, fast and legal.
Can the rev hang be reduced in the CARB compliant version, or is it on/off?
 


alex4515

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Rev Hang is emissions related. The technical description is injector overrun cutoff delay. The injectors keep firing for a short time after throttle closure to reduce the oxides of nitrous pollution.

Switching this off is illegal for any CARB / EPA tune and for any road vehicle.
I don't find the rev hang in my '23 Si all that offensive when driving normally. When getting on it/revving it out, it's a bit more noticeable, but no worse than my '09 Si, if memory serves.

Getting to my actual question - if it's required for emissions, how does the Type R or other cars from other manufacturers get away without rev hang? Are they just choosing to make those models a little less "clean"?
 
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Hondata

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I don't find the rev hang in my '23 Si all that offensive when driving normally. When getting on it/revving it out, it's a bit more noticeable, but no worse than my '09 Si, if memory serves.

Getting to my actual question - if it's required for emissions, how does the Type R or other cars from other manufacturers get away without rev hang? Are they just choosing to make those models a little less "clean"?
Each Honda model has different emissions levels - some cars are cleaner than others. Automatics are usually cleaner than manuals
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