Subframe / Suspension bushes

Discussion in 'Redish Motorsport' started by M3TOM, Dec 31, 2014.

  1. 31 Dec 2014 at 4:11 PM #1
    M3TOM

    M3TOM Rocking a new hat

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    Hi,

    Just wanted to know what bushes you fit where and why...

    Powerflex black or purple.. yellow etc

    Interested in doing an underside refresh to the car and after some info.

    Does fitting bushes with less flex benefit the boot floor in terms of less stress etc


    Cheers Tom
     
  2. 31 Dec 2014 at 8:43 PM #2
    James@Redish

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    Hi Tom, thanks for your message.

    It depends on the car's use. Is it a road car, coupe/conv, does it see trackdays many times a year, is it more of a dedicated track car, or even track only, is it used for competition are the questions we need to ask.

    Our main bush of choice is the Powerflex brand.

    The most common Powerflex we use (mainly road cars), are:
    Rear Trailing Arm Bushes = Black (shore 95 -the only compound they come in)
    Subframe Bushes = Yellow (shore 75)
    Rear Anti Roll Bar Bushes = Purple (shore 80)
    Diff Bushes we don't use from Powerflex as I'm afraid at the time of writing they don't fit 100% and could do with the design being reviewed
    Front Control Arm Bushes = Purple insert (shore 80)
    Front Anti Roll Bar Bushes = Purple (shore 80)
    Rear Shocker Top Mounts = Purple (shore 80)

    It's a tough question regarding the floor. Technically the stiffer bushes will mean a slight amount more torsional load and unload will be transmitted into the internal threaded platforms inside the Rear Axle Carrier Panel (subframe panel).
    Also increased NVH could be noticed (noise vibration harshness).

    The benefit is the flat top design and larger surface area of the subframe bushes spread that torsional loading and unloading energy into a larger surface area which technically disapates the load originally subjected to a small area. Plus it removed the OEM rubber bushes which have 2 small lips on top which the energy is concentrated into a small semi circle on the RACP and also directly onto 1 spot weld which always causes it to break and start 2 cracks in a fore and aft direction.

    If it's had a new BMW RACP, or a proven reinforcement system AND STRUCTURAL FOAM (which is a MUST), the positives above outweigh the negatives.

    Hope that helps.

    Best regards,
    James :)



     
  3. 2 Jan 2015 at 7:51 PM #3
    M3TOM

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    Thanks James.. very informative.

    What bushes do you use for the Diff? OEM ?

    Also what foam do you use to reinforce the subframe ? I think it's wurth but just wanted to know exact product

    Thanks Tom
     
  4. 5 Jan 2015 at 10:11 PM #4
    M3TOM

    M3TOM Rocking a new hat

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    Hi James, any thoughts on above?

    Thanks Tom
     
  5. 6 Jan 2015 at 7:04 AM #5
    Redish Motorsport

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    Thanks for the question Tom.

    For diff bushes we use OEM E36 bushes, if they require replacement. The E46 ones aren't a spareable part without buying the whole diff cover.

    With regards to the subframe foam/resin we use the OEM BMW resin purchased directly from them. We don't use a wurth product for that, but we do use wurth for undside protection (amoungst other products)

    Thanks Pete.
     
  6. 6 Jan 2015 at 4:45 PM #6
    M3TOM

    M3TOM Rocking a new hat

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    Thanks Pete,

    Think my posts got mixed up!

    Thanks to both of you for the info.

    Cheers Tom
     
  7. 17 Jan 2018 at 10:26 PM #7
    Jonnym3

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    Hi Pete just bringing this one back lol, what and where does the resin go pal ??
     
  8. 17 Jan 2018 at 10:28 PM #8
    E46CoupeM3

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