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Thread: 540iT - Coilovers and Spring Rates

  1. #1
    Join Date
    Jul 2007
    Location
    Dallas, TX
    Posts
    14
    My Cars
    2000 540iT

    540iT - Coilovers and Spring Rates

    Hi, (540iT on 18" style 65's)

    Goal: Street comfort ride on coilovers. Budget not a problem.

    Background: Currently BC Racing 540iT coilovers are installed, can't say I love them. (8K front / 8K rear spring rates with dampener adjustment currently set to "15 clicks" in the middle. Should have kept the rear bags but I don't want to talk about that.

    Issue: Car too bouncy (floaty?), the passenger rear tire will loudly rub at highway speeds when going over fluctuations in the road that cause the car to float and then bouncy. I suspect the ride height is uneven and ever so slightly lower on this side causing that issue. Really though, I want to fix this ride quality.

    Solution(s): Gathering input here, I'm thinking about scrapping the BC Racing coilovers and going with Swift Springs + Koni Shocks (KW v1?). Now for the questions.

    Springs: Swift Springs front and rear spring rates for a V8 wagon? 10K front/12K rear? 12K front/10K rear? 10K front/10K rear? No idea. Anyone have any experience on this? I'm just confused on ideal rates and spring set up here.

    Shocks: Koni yellows fronts (8741 1372SPORT) and rears (1157SPORT). Anyone use these in their touring coilover set up with success?

    Bonus: Einhorn Adjustable perch, because why not?


    -Thanks, Tyler

  2. #2
    Join Date
    Apr 2017
    Location
    London, UK
    Posts
    134
    My Cars
    E30 Turbo, E39 530d Tour
    Quote Originally Posted by TylerTheToaster View Post
    Hi, (540iT on 18" style 65's)

    Goal: Street comfort ride on coilovers. Budget not a problem.

    Background: Currently BC Racing 540iT coilovers are installed, can't say I love them. (8K front / 8K rear spring rates with dampener adjustment currently set to "15 clicks" in the middle. Should have kept the rear bags but I don't want to talk about that.

    Issue: Car too bouncy (floaty?), the passenger rear tire will loudly rub at highway speeds when going over fluctuations in the road that cause the car to float and then bouncy. I suspect the ride height is uneven and ever so slightly lower on this side causing that issue. Really though, I want to fix this ride quality.

    Solution(s): Gathering input here, I'm thinking about scrapping the BC Racing coilovers and going with Swift Springs + Koni Shocks (KW v1?). Now for the questions.

    Springs: Swift Springs front and rear spring rates for a V8 wagon? 10K front/12K rear? 12K front/10K rear? 10K front/10K rear? No idea. Anyone have any experience on this? I'm just confused on ideal rates and spring set up here.

    Shocks: Koni yellows fronts (8741 1372SPORT) and rears (1157SPORT). Anyone use these in their touring coilover set up with success?

    Bonus: Einhorn Adjustable perch, because why not?


    -Thanks, Tyler
    Keep the BC’s and speak to “OnlyChargedDubs” and look at their “bagsbyocd” conversion kits. Convert BC coil overs to air ride.

    Mention I recommended you.

    NF aka Deepan


    Sent from my iPhone using Tapatalk

  3. #3
    Join Date
    Jul 2007
    Location
    Dallas, TX
    Posts
    14
    My Cars
    2000 540iT
    That's awesome, thanks for pointing it out. I had no idea they made those.

    Having pulled the compressor and eventually intending to eventually cut/weld the spare tire well for true dual exhaust, I'm not sure that's the direction I'll end up going though.

  4. #4
    Join Date
    Apr 2017
    Location
    London, UK
    Posts
    134
    My Cars
    E30 Turbo, E39 530d Tour
    Quote Originally Posted by TylerTheToaster View Post
    That's awesome, thanks for pointing it out. I had no idea they made those.

    Having pulled the compressor and eventually intending to eventually cut/weld the spare tire well for true dual exhaust, I'm not sure that's the direction I'll end up going though.
    If you look at the above method, there’s ways and means to incorporate a new tank and compressor in the new sized spare wheel well, or even elsewhere like the side cubby holes for the cd changer, above the battery or a combination.

    Worth asking them to begin with anyway. They’re in the uk, so if you’re on the other side of the pond, you can ask a local installer to design a boot/trunk “build” considering the space you have.

    I’m going for a potential quad exhaust but due to LPG tank in my spare wheel well, my existing oem compressor is above the battery in my touring, and I’ll end up with dual pipes on one side and single on the other as I can’t cut my spare wheel well at all.

    Can’t loose anything but time by asking.

    Best of luck!


    Sent from my iPhone using Tapatalk

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