System 1st Gear November 1, 2008 Share November 1, 2008 Hi.... I have changed to a set of coilovers.....it is lowered to 1 finger front & 2 fingers back.... but i have the problem of having a loud "thump" sound from the back of the car when i have passenger at the back & going over hump or when the road has a depression....even when i have only 1 passenger at the back.... It sounds like the wheel hitting against the wheel arch fenders..... When i am driving alone then there is no problem.... is the wheel hitting the wheel arch normal when changed to lowered coilovers? i have searched online but it seems that i can't find anyone who has this problem.... if it is not normal then i suspect that it is the compression stroke of the damper has problem..... Anyone can advise me? ↡ Advertisement Link to post Share on other sites More sharing options...
Zoner Clutched November 1, 2008 Share November 1, 2008 I have changed to a set of coilovers How long the c/o is on your car? Link to post Share on other sites More sharing options...
Sucker Clutched November 1, 2008 Share November 1, 2008 It is not normal. Link to post Share on other sites More sharing options...
Supra Neutral Newbie November 1, 2008 Share November 1, 2008 When there is a high hum or deep hump, don't speed over it. If u speed over it, this will happen. There is a loud noise hitting the rear fender. Solution to it is, raise up the height of rear suspension by may a few mm higher. Or re-worked the rear fender so that the fender is facing outwards by a few mm. Hope this helps, cheers. Link to post Share on other sites More sharing options...
Hilander4650 Neutral Newbie November 1, 2008 Share November 1, 2008 1 finger front & 2 finger back should not be the cause..adjust the rear to harder damping may help.. Link to post Share on other sites More sharing options...
Roh96 6th Gear November 1, 2008 Share November 1, 2008 Check the offset of your rims. It should not hit the fender if the wheels are of the right offset. Link to post Share on other sites More sharing options...
Shull Turbocharged November 1, 2008 Share November 1, 2008 possible to be your undercarriage hitting the hump? Link to post Share on other sites More sharing options...
Pandaeyes Neutral Newbie November 1, 2008 Share November 1, 2008 (edited) Just wondering, does anyone adjust his rear damper behind harder than the front? Mine is 2 fingers front and back. I find mine at front ok but when pple sit in my car, passengers complained that rear is bouncy with thud sound when going bumps on roads. Like no damping effect. When I'm alone driving, rear not bouncy. It was ok. So abit confused over the damping settings. Can enlighten? Edited November 1, 2008 by Pandaeyes Link to post Share on other sites More sharing options...
System 1st Gear November 1, 2008 Author Share November 1, 2008 Problem solved.... went to workshop to check it out.... it is the spring too soft...the sound is the sound of the spring coil hitting each other after been fully compressed.... The workshop said that my rear spring is only 4kg type....normal for coilovers should be 6kg type.... so changed the spring to 6kg type & all problem solved....carry 2 ppl at the back & ram over hump also no sound liao... blame myself for changing to cheap type coilover... Link to post Share on other sites More sharing options...
Pandaeyes Neutral Newbie November 1, 2008 Share November 1, 2008 Hi is yours BC? I think mine is same prob as yours. Got thud sound when going over humps. Then I set mine quite soft recently. So pple behind complain going over humps like no damping effect. Link to post Share on other sites More sharing options...
System 1st Gear November 1, 2008 Author Share November 1, 2008 Its H*tb*ts..... i cannot understand how can anyone design a coilover that cannot carry passenger....when i driving alone no problem.... i think u can go fong kim & see wat they can do..... i changed the 2 rear springs for $120 only.... Link to post Share on other sites More sharing options...
Pandaeyes Neutral Newbie November 2, 2008 Share November 2, 2008 Then same issue lor...driving alone no prob but when pple sit in there, that's when prob starts. Guess coilovers is meant for tracking for 2 front pple only. So now yours is more steady with pple inside? Doesn't sink so much? Link to post Share on other sites More sharing options...
System 1st Gear November 2, 2008 Author Share November 2, 2008 yeah! much much better..... i asked the workshop guy....who is quite big size....abt 90kg he says..... He drive my car & i myself....abt 120kg....sit behind him & we went to chiong hump....no sound liao....everything good....... Link to post Share on other sites More sharing options...
Phelan 1st Gear November 2, 2008 Share November 2, 2008 (edited) Hmmm, i'm running on fully adjustable coilovers for my GT. 7kg springs in front and 3.5kg springs at the back. Springs are single rated. Are you using progressive springs? Did the original workshop calulated the static sag of the springs when they installed the coilovers? If they did, your coilvers should not be bottoming out. Another option is to play around with the preload and compression, if your coilovers are adjustable but i wouldn't recommended this if you are a beginner. Edited November 2, 2008 by Phelan Link to post Share on other sites More sharing options...
Pandaeyes Neutral Newbie November 2, 2008 Share November 2, 2008 Some how I feel like what you describe... bottoming out. Like the travel seems soft and already hitting to max but yet, still bounce prob 2 times before it settles down. What shall I do? Link to post Share on other sites More sharing options...
Diamondback Neutral Newbie November 2, 2008 Share November 2, 2008 what's static sag of springs? what's play around with the preload and compression? Link to post Share on other sites More sharing options...
Yuan 6th Gear November 2, 2008 Share November 2, 2008 Quote Hi.... I have changed to a set of coilovers.....it is lowered to 1 finger front & 2 fingers back.... but i have the problem of having a loud "thump" sound from the back of the car when i have passenger at the back & going over hump or when the road has a depression....even when i have only 1 passenger at the back.... It sounds like the wheel hitting against the wheel arch fenders..... When i am driving alone then there is no problem.... is the wheel hitting the wheel arch normal when changed to lowered coilovers? i have searched online but it seems that i can't find anyone who has this problem.... if it is not normal then i suspect that it is the compression stroke of the damper has problem..... Anyone can advise me? Do all coilovers have this problem? This does not seemed to be the first time I heard about such problems with coilovers. Link to post Share on other sites More sharing options...
Phelan 1st Gear November 2, 2008 Share November 2, 2008 Hi pandaeyes, From your decription, your dampers are gone liow. Without knowing what kind of suspension you are using, i can't advise you further. ↡ Advertisement Link to post Share on other sites More sharing options...
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