mobil onay değerli oranlar Betboo yeni adresi izmir escort antalya escort izmir escort porno porno izle bursa escort escort mobil porno havalandirma sistemleri metin2 pvp serverler saha betonu izmir escort bursa escort izmir escort izmir escort istanbul escort
coilover grievances -- rear axle version
500 Madness
   
 

KONI Shock Value Sale

 
Page 1 of 6 1 2 3 ... LastLast
Results 1 to 10 of 51

Thread: coilover grievances -- rear axle version

  1. #1
    Banned
    Join Date
    Mar 2013
    Posts
    348
    Thanks
    32
    Thanked 35 Times in 31 Posts

    coilover grievances -- rear axle version

    as we all know, the rear axle of our cars is a fantastic effort on the part of the mopar engineers, but it's a bit of a mess regardless (not their fault!). how can we improve it?

    things we need: suspension stroke measurements. standard mounting point measurements. spring ID for stock mounts. diameter of spring lower perch and upper mounts (for poly replacements?) more? ryephile feel free to chime in

    keep in mind that there is likely a drop-in replacement axle available from the assetto corse car that significantly improves some of these things. my italian contact is working on finding an abarth engineer that can tell us more about this and other corse parts.

  2. #2
    Senior Member Ryephile's Avatar
    Join Date
    Feb 2013
    Location
    Metro Detroit
    Posts
    1,055
    Thanks
    159
    Thanked 528 Times in 279 Posts
    Thanks The whole point of this will be to retain or improve the geometry of the rear axle, mainly at a lower ride height where there isn't feet of unnecessary ground clearance and a California rake stance, which isn't appropriate on a front-drive car.

    The main things that impact rear torsion beam performance are:
    *Its pivot plane [for lack of a better term]. This is the "kick-up" of the axle versus ground level, or the delta between the pivot and the axle centerline. Having the axle above the pivot axis creates awful bump absorption and a bucking of the chassis. We don't want this, but it's what happens when we over-lower the car
    *Torsion beam twist design. Yes, the beam flexes a lot. During both corners and bumps, the beam is designed to give each wheel a specific path of travel in 3 dimensions. This flex may be OK for straightline ride quality but sub-optimal for high-g cornering. This motion is unknown at this time, whether the beam has aggressive bump-toe, etc. all has to be determined. The Assetto Corse beam that mkawa mentions will likely have different flex characteristics.
    *Bushing location and design. The bushings impact the toe changes, ride quality, and ride height range. More to look at.


    To improve the rear axle, I'm envisioning a couple things, not all will be good ideas:

    *Design a "drop-spindle" to retain stock ride height geometry at a lower ride height
    *Damper bracket on the axle to install a longer rear damper if practical
    *Relocate bump-stop to damper if necessary
    *build a database of alignment shims to give a solid idea of which shim sizes and location instill what toe and camber changes

  3. #3
    Banned
    Join Date
    Mar 2013
    Posts
    348
    Thanks
    32
    Thanked 35 Times in 31 Posts
    the corse beam is extremely interesting. while we have a traditional torsion beam with a reinforcement tuning bar underneath, the corse axle has a three-sided open torsion pillar with the reinforcement bar through the center. in other documents they call this an "interlocking arm" design rather than a torsion beam.

    also this is completely the wrong place to put this, but i can't stop looking at the front subframe of the corse. it's truly a beautiful piece of metal.

    https://docs.google.com/viewer?url=h...parts-list.pdf

    general question re: non-IRS rear suspensions. what is the rationale for separating the perches for the damper and spring anyway? a coilover spring over damper has the advantage of the damper applying compression and rebound directly to the action of the spring. in all these torsion rears i've seen, you lose damping response, both phase and force, to the flex of the axle assembly. this just seems dumb. is there a rationale to this other than a cost-cutting measure during assembly?
    Last edited by mkawa; 04-15-2013 at 10:59 AM.

  4. #4
    shagghie's Avatar
    Join Date
    Aug 2011
    Location
    San Diego, California, United States
    Posts
    3,900
    Thanks
    485
    Thanked 1,163 Times in 774 Posts
    Dayum, the modified front grille looks awesome:

    5741319 Front Lower Grille €150.00

    Wonder if you need to buy the entire front bumper though for it to fit... €300.00 more. Sorry getting back on track...all I can say is the Neu-F bar on the rear just changed everything as far as I'm concerned... the rear feels, you know, like it's actually THERE now and contributing. Turn-in is better, but even more so is post apex turn-in once suspension is fully loaded.. seems there's no limit on how much you can tuck back in. Doesn't fix the above issues, but sure does mitigate the way the car handles!
    http://www.fiat500usaforum.com/image.php?type=sigpic&userid=509&dateline=14328366  62
    RAW Big Turbo, tuned to 250+whp on p93
    LSD, FX400, Okadas, 550cc, ported t-mani
    NightOwl Racing BC Racing with SWIFT Spring Suspension set up
    ATM FMIC, ATM Fenderwell Intake
    VanHook CF Rear Diff, doorhandles, hood vents and duct covers
    Advan RSII 17x7.5, rally stud conversion

  5. #5
    Banned
    Join Date
    Mar 2013
    Posts
    348
    Thanks
    32
    Thanked 35 Times in 31 Posts
    followup question: is there any reason we can't just ignore the dumb spring perches on the rear axle completely and mount a coilover at the damper points? (say, an 8212 series?)

  6. #6
    shagghie's Avatar
    Join Date
    Aug 2011
    Location
    San Diego, California, United States
    Posts
    3,900
    Thanks
    485
    Thanked 1,163 Times in 774 Posts
    Quote Originally Posted by mkawa View Post
    followup question: is there any reason we can't just ignore the dumb spring perches on the rear axle completely and mount a coilover at the damper points? (say, an 8212 series?)
    Probably because the geometry has the springs holding up a portion of the rear at a specific angle that is complementary to the shocks. Although, the shocks shouldn't be supporting any weight so I'm probably wrong. But even as far as pure dampening function goes, they may be at that angle by design as far as the whole geometry goes of the entire rear end. A shock's angle and mount points affect it's relative dampening performance against the two pieces it is providing dampening between. (more angle = lower effective rates?).
    http://www.fiat500usaforum.com/image.php?type=sigpic&userid=509&dateline=14328366  62
    RAW Big Turbo, tuned to 250+whp on p93
    LSD, FX400, Okadas, 550cc, ported t-mani
    NightOwl Racing BC Racing with SWIFT Spring Suspension set up
    ATM FMIC, ATM Fenderwell Intake
    VanHook CF Rear Diff, doorhandles, hood vents and duct covers
    Advan RSII 17x7.5, rally stud conversion

  7. #7
    Banned
    Join Date
    Mar 2013
    Posts
    348
    Thanks
    32
    Thanked 35 Times in 31 Posts
    the only reason i can think of for the dampers to be at that angle is to produce more cargo room in the rear of the car. it destroys the rear's motion ratio to have the dampers at such an odd angle

    BUT if we moved the springs to the dampers, at least we could fit longer springs and get rid of spring binding issues

    another possibility is to fit the dampers with bolt ends instead of eyelets and move the dampers into the spring perches/mounts

    FINALLY, does anyone have a picture of the upper spring mounts from inside the chassis? is there a way to extend a whole coilover whole assembly into the trunk?
    Last edited by mkawa; 04-15-2013 at 01:08 PM.

  8. #8
    Banned
    Join Date
    Mar 2013
    Posts
    348
    Thanks
    32
    Thanked 35 Times in 31 Posts
    big picture of the rear axle http://www.factorychryslerparts.com/...ssembly=639971

    big picture of the rear spindles http://www.factorychryslerparts.com/...ssembly=583723

    notice a few things: the corse rear axle effective drops the axle below the spindle. the spindles themselves look identical (in terms of mount-points at least). must stiffer looking bushings (probably sphericals) on the corse axle.

    conclusion: i want that axle. NAO
    Last edited by mkawa; 04-15-2013 at 01:38 PM.

  9. #9
    Senior Member
    Join Date
    Jan 2012
    Posts
    1,387
    Thanks
    446
    Thanked 309 Times in 204 Posts
    Quote Originally Posted by shagghie View Post
    Dayum, the modified front grille looks awesome:

    5741319 Front Lower Grille €150.00

    Wonder if you need to buy the entire front bumper though for it to fit... €300.00 more. Sorry getting back on track...all I can say is the Neu-F bar on the rear just changed everything as far as I'm concerned... the rear feels, you know, like it's actually THERE now and contributing. Turn-in is better, but even more so is post apex turn-in once suspension is fully loaded.. seems there's no limit on how much you can tuck back in. Doesn't fix the above issues, but sure does mitigate the way the car handles!
    I have gone through numerous contacts who continue to tell me the AC Grill will not work on the North American Cars .
    however its a pretty simple piece and I will have a spare stock grill to work off of for a possible prototype soon.

  10. #10
    Senior Member
    Join Date
    Jan 2012
    Posts
    1,387
    Thanks
    446
    Thanked 309 Times in 204 Posts
    Quote Originally Posted by mkawa View Post
    the corse beam is extremely interesting. while we have a traditional torsion beam with a reinforcement tuning bar underneath, the corse axle has a three-sided open torsion pillar with the reinforcement bar through the center. in other documents they call this an "interlocking arm" design rather than a torsion beam.

    also this is completely the wrong place to put this, but i can't stop looking at the front subframe of the corse. it's truly a beautiful piece of metal.

    https://docs.google.com/viewer?url=h...parts-list.pdf

    general question re: non-IRS rear suspensions. what is the rationale for separating the perches for the damper and spring anyway? a coilover spring over damper has the advantage of the damper applying compression and rebound directly to the action of the spring. in all these torsion rears i've seen, you lose damping response, both phase and force, to the flex of the axle assembly. this just seems dumb. is there a rationale to this other than a cost-cutting measure during assembly?
    Been Looking for this Catalog for a very long time TY TY TY!!!!

Page 1 of 6 1 2 3 ... LastLast

Similar Threads

  1. For Sale: Megan Axle Back Exhaust
    By scorpion_king in forum Parts For Sale
    Replies: 7
    Last Post: 04-22-2013, 09:54 PM
  2. Coilover grievences
    By ivmill in forum Fiat 500 Abarth Suspension and Chassis
    Replies: 13
    Last Post: 04-16-2013, 12:51 AM
  3. Coilover Question...
    By tcarretti in forum Fiat 500 Abarth Suspension and Chassis
    Replies: 36
    Last Post: 03-23-2013, 12:05 PM
  4. Replies: 7
    Last Post: 03-17-2013, 11:27 AM
  5. Abarth Seats - USA version vs Euro Competizione version
    By fredfrey in forum Fiat 500 ABARTH General Discussion
    Replies: 39
    Last Post: 04-01-2012, 12:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •