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Civic Si in GS

Discussion in 'Tracking / Autocross / HPDE' started by grantsjc, Sep 22, 2017.




  1. grantsjc Senior Member

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    Anyone developing GS class Civic Si? I have 20 mm rear bar coming. Starting to look at wheels and tires .
     
  2. BarracksSi

    BarracksSi Senior Member

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    Can you change the rear bar and stay in G Stock?
     
  3. 5inn

    5inn Senior Member

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    You can change (which means replace OR remove one) and stay in G-Street.

    I've ordered the TypeR bar, but it is currently backordered. I'm considering going GS-lite, meaning 17x8 wheels, and 255 RE-71/Rival-S + rear sway bar.

    There's been some discussion of it in the main Si forum here http://www.civicx.com/threads/civic-si-for-autocross.11226/
     
  4. BarracksSi

    BarracksSi Senior Member

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    Thanks for the thread link. Looks like I've got some reading to do.

    All I remember from auto-x'ing ten years ago is that I had to run in STX because I had a brake swap. I kinda glossed over the details of other classes once I learned which one mine was, and I haven't even looked at what's changed since then.
     
  5. 5inn

    5inn Senior Member

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    The TL;DR version of what you can change in GS is:
    Wheels but must be same width and +/- 7mm offset and +/- 1" in diameter
    Cat-back exhaust
    Shocks (but not springs)
    One sway bar
    Tires 200tw or above (current hotness = RE71R or Rival S 1.5)

    Although I'm not sure how you would change the shocks without pissing off the computer.
     
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  6. BarracksSi

    BarracksSi Senior Member

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    Sometimes I wished I had stayed Stock so I could run R-comps. ;)

    The variable shocks are why I would not recommend the Si (or Type-R) to a heavy-duty, hardcore autocrosser who wants to mod and tweak the car 'til the cows come home. It seems like a waste to have all that gadgetry built into the suspension from the factory if the plan is to change it out for something that won't talk to the onboard computer.
     
  7. 5inn

    5inn Senior Member

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    If these cars are anything like other ones with adjustable suspension from inside the cabin, there will be third party defoulers that will keep the computer happy even if you put on non-electronically adjustable dampers.
     
  8. exyia Senior Member

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    Yup. Such a wasted technology. They should gone far more aggressive on the OEM suspension setup, and used "normal" to revert ride quality back to tolerable levels - or just not bothered with it at all and use the budget elsewhere.

    Between that and a stock clutch that barely holds up as-is, the 2017 Si doesn't look worth going in anything above GS just off cost alone.

    Someone posted recently that even just changing springs on an Si threw warnings in the dash and disabled "Sport" mode, so it's not a one-way data stream. Have a bad feeling you might not be able to feed dummy information/cutoff to bypass the system.

    Continuously adaptive dampers, so the car is very likely reading for shock travel every second and expecting feedback values. Unless some aftermarket companies are willing to replicate that to talk to the car (highly doubt it for a Civic platform, let alone any platform), the car will probably reject anything non-OEM...and disabling Sport disables a lot more than a shock setting unfortunately.
     
  9. 5inn

    5inn Senior Member

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    I don't agree that they should have gone far more aggressive on suspension. They have the Type-R for that. The Civic Si is currently not worth going above GS for now because it would probably be dead in whatever ST * Class it's in. It MAY stand a chance in STH (if it's classed there), since it has a diff but even then, I'm not so sure. Keep in mind that you can't use an upgraded clutch in ST*.

    The Si does not use continuously adaptive dampers, like magride. When you switch modes the dampers are adjusted. They are not adjusted again until the driver changes mode.

    As I said, this technology already exists for other cars like the Focus RS. Here's a link to a write-up on KW's kit.
    http://www.motoiq.com/MagazineArtic...lug-Play-Coilovers-for-the-Ford-Focus-RS.aspx
     
  10. exyia Senior Member

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    Sorry, that's just wrong.

    The Civic Si uses a continuously adaptive damper based on the ZF CDC system, mostly handled electronically. It is NOT just a basic two mode damper like that found on the Focus RS, mostly handled mechanically.

    The technology for the Focus RS and KW's aftermarket offering are nothing alike nor remotely compatible with what Honda uses on the Si.
     
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  11. baldheadracing

    baldheadracing Senior Member

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  12. 5inn

    5inn Senior Member

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    The only thing I can find about the Si having this continuously adaptive damper system is in a CivicX thread here: http://www.civicx.com/threads/honda...an-205-hp-192-lb-ft.10248/page-54#post-205989 where this youtube video is linked which begins the talk about it at 17:25

    I can't seem to find any other mention of it anywhere, which is why I believe he mispoke. There's a clear difference between adaptive and continuously adaptive suspension.
     
  13. exyia Senior Member

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    That's clearly not a mistake, I'm trying to be nice about it, but I'm still baffled at how you think he mispoke that.

    He specifically says "continuously adaptive".

    He explains how there is still a "full range adaptive" of damping force, how changing sport mode changes a minimum damping force value.

    The shock chart clearly shows a damping range, not a damping plot.

    In that very same thread, we find it's the ZF CDC system.

    In Honda's R&D publications, it has a whole article on adaptive damper development.

    pVQLiYX.png

    It is an adaptive damper.
     
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  14. Design Senior Member

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    Very interested to know your impressions on the rear bar. Although I don't plan to compete with the Si, I'm considering for weekend scoots without upsetting the rest of the chassis for daily duty.
     
  15. Design Senior Member

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    I don't think the actuators can be removed easily. I took a peak under the rear. Looks like a fused assembly from the plug forward. And Honda sells them as part of the shock/strut unit, IIRC.

    Not sure? :dunno:

    BaXdw17JEy88ypBnXv3f2JrgBK0098Tu5C5NDdEzFWzc0TZQjJ5OM_q_Gwd1lf2N1Rw2cTm9KFzAyKpxBnU=w659-h878-no.jpg

    krrso1aO2NbZh__LzmCuNnAGCoRk9LkKfPecFiwGNYvLqwj71cZzMLnwTspIWSkysHn8KbQoKEI7ign72XE=w659-h878-no.jpg
     
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