Axle tramp/wheel hop

Discussion in 'Suspension, Brakes, Wheels & Tyres section' started by Agreen, Mar 10, 2020.

  1. I was suffering from a bit of this on two long left handers on Anglesey track recently.

    I'm thinking maybe adding some preload to the coilovers will help with this as it'll help to push the inside wheel down when cornering?

    I'm also going to have a play with the adjustable drop links as it's all just been thrown together and not set up properly yet!

    Anyone else ever had this issue? It's a 225.
     
  2. -Jamie-

    -Jamie- RSM Moderator

    How are your engine mounts etc?


    Adjustable damping? I'd be wary of adding anything more than the minimal required preload


    Adjusting droplinks won't make a difference either, they are pretty much just there to take any preload off the arb when it's sat in its natural position
     
  3. One of the things I noticed during mapping was the condition of the engine mounts! Visibly, they looked fine, but on acceleration there was a surprising amount of movement! I was changing the top anyway, may be a good idea to go for the gearbox mount as well (lower mount already replaced).

    I didn't have this problem before the diff, coilovers etc etc so was thinking it was more suspension related. May reduce the damper stiffness, see if that helps.

    I do have some minor play in the bottom arms, was thinking polybushes may reduce this flex which may help, or even exacerbate the problems.
     
  4. -Jamie-

    -Jamie- RSM Moderator

    I'd do mounts first and see if that helps


    What suspension is it? Tend to find the cheaper dampers do get a bit bouncy with simialr symptoms, Mine was terrible for it on B14s at the Ring even though all my mounts were fresh or uprated
     
  5. Bc rm series coilovers.

    I'll start with the mounts and work from there.

    Probably completely unrelated, but I'll look at the drop links because I gave 0 attention to their length in comparison to the oem.
     
  6. -Jamie-

    -Jamie- RSM Moderator

    Did you try playing with the damping settings?
     
  7. Tbh, no.

    These bc's are inverted, so the adjustments are done from underneath which is a pain!

    The first outing this year was more of a test run for everything and an opportunity to think of ways to improve on what we've done so far.
     
  8. ianplymouth

    ianplymouth RSM Club Member

    could be your diff locking up causing the jumping, if both wheels are turning at the same speed around a corner one has to slip or something will break.

    Had it a couple of times with my 225 with a quaif fitted
     
  9. Possibly, only seemed to do it around the left handers though, nothing on the rights at similar speeds/angles. Speeds were around the 50-70 range.

    I definitely need to stiffen the rear, had some understeer which I'm hopeful can be alleviated by stiffening the rear!
     
  10. ianplymouth

    ianplymouth RSM Club Member

    There will be more weight on the right handers, unless yours is left hand drive :openmouth::laughing::laughing:

    How many times have you been on track ??? with these cars its a bit slower in and boot it out, once the diff is locked in full power by the apex :sunglasses::sunglasses:
    Or you could try the lift off oversteer approach too corners.
     
  11. I was with a passenger so weight difference would be negligible tbh!

    The understeer was a pain, I couldn't live with an old civic type R around the long right before the fast straight! The rear seems too soft, even lift off oversteer wasn't too forthcoming!

    Thinking new bushes and adding the arb.

    Need to have a think about intake temps too, was hitting nearly 30c with ambient around 6c!
     
  12. ianplymouth

    ianplymouth RSM Club Member

    Just read back through some of your posts to see where you were, long left handers at Anglesey ?????
    Been there a few times and can't remember where the long left handers are.

    I had purple bushes in my suspension but i didn't bother with an anti roll bar on the rear.

    Are your BC's adjustable, mine are and front and rear are 30 position, what was the weather like and how many clicks did you have front and rear.
    Did you put camber on the front ???? I had 2 degrees
     
  13. You've got turn 1 where the pit exit is at the end and the turn just before the straight with the hairpin. The slower cornerslike the tight hammer head and last corner didn't seem to give me issues, but the diff was most effective at those.

    I didn't play with the adjustments but they're set 8 clicks from stiff.

    Really need to get it corner weighted and the camber set up, but thinking of a half cage so would want to fit that first really.

    Don't get me wrong, she was quick out there and smashed a meglio, but there's definitely room for more with little expenditure now, confident these issues can be dialled out with minor set up changes!

    It's the intake temps that were a little concerning, may set up a cold intake as my foam filter is stuffed just above the box so will undoubtedly be dragging in hot air! May toy with some washer jets onto the intercooler to try and cool the rads too! Oil temps remained steady which is probably the most important thing.
     
  14. ianplymouth

    ianplymouth RSM Club Member

    When you said long left handers i was thinking about the one after the banking and the long slight right they class as a straight, had it there in a R26r i was a passenger in.

    I never set mine up, always meant to but never bothered, do you have the softer springs on the rear, i had 8kg front and rear, someone else said they had this sort of problem and said to me to go harder on the rear.
    If its dry i run 25 ish clicks front and rear, in the wet 5 clicks, use the same sort of settings on the mk3.

    2 degrees front camber makes a lot of difference, there's nothing you can do with the rear which is a shame.

    What intercooler are you running
     
  15. They're either 7kg -7kg or 8kg -7kg.

    Yeah, camber will no doubt remove a chunk of that understeer!

    Currently running a forge intercooler which by all accounts, aren't the best! Nearly 25c above ambient was surprising, thinking of an enclosed filter with the inlet cut into the bumper and water jets on the intercooler to help with heat soak. Shouldn't cost more than £40 so worth doing some tests.
     
  16. ianplymouth

    ianplymouth RSM Club Member

    I had a charge cooler fitted to mine, worked quite well, just needed to modify it to get it 100% it fitted where the battery used to be and a small rad for the cooling, no room in the mk3 really so went for an Airtec, on standard tune the readings on the monitor were saying less than 20degrees with an ambient of 15 degrees, thats on track giving it some :sunglasses:
     
  17. 5c above ambient is incredible, I've heard the airtech is a good choice, the pro alloy too apparently. Mine had a forge already fitted and I cant justify the additional cost of a new one for minimal difference.

    Stripped the brakes this afternoon and measured the drop links, they were 300mm in length compared to 280mm standard lol. I've dropped them to 260mm to see if there is any noticeable difference.
     
  18. ianplymouth

    ianplymouth RSM Club Member

    I didn't even bother with adjustable drop links on my 225, just set the springs to the same height and fitted them, then measured the wheel arch to ground measurement and adjusted both sides by the same amount of turns, worked well for me.

    The MK3 is different, i had my BC's supplied, fitted and setup by CGR, probably needs readjusting again now
     
  19. I just got carried away with the shopping basket ordering all the parts tbh :laughing:
     

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