bottoming out??!, what do you guys think of this? Options

[jcengland]

basically my car has been lowered, apparently its 40 but looks more like 60mm, anyway if i go over a fairly big bump or dip at 25mph+ it will give a nasty knock and feels like it has totally bottomed out, either the sump brace hits the floor or the springs have completely compressed.

Now the question is do you think my car needs new springs (which i think is the case as it is not a bouncy ride) or do you think i need new shocks?

Personally i think i need a new set of "correct springs" i susspect the wrong springs have been fitted, i.e the front has not the correct spring rate or they are old and fategued.

any comments appricaited cheers joe

[SwissFerdi]

Blown shocks, potentially?

[jcengland]

surely shocks/dampers only control the rate at which the displacment takes place, i.e the rate of displacement with respect to time(force x velocity). But springs control displacemt which is not relative to time, just a displacemtnt, i.e the force requuierd to displace the spring by say (x) will always be the same, i.e 200kg per mm.

now my car is not bouncy whcih suggests the shocks are not blown. If the springs did their job even without dampers the car should not bottom out as the maximum load should not exceed the maximium spring rate, it would simply be bouncy.

[95CelicaST]

Are your bump stops still there?

Any pictures of the setup? I don't know any spring that lowers 60mm...

If you go to the rear of the car and push down a few times on the trunk lid/hatch lid, does the car oscillate a couple times before stopping? If so, new shocks it is.

[trdproven]

it can be blown shocks but it could also be your car is too low. IDK what your drop height is, but maybe your bump stops "Spring Bumpers" are worn out, or they are gone. Replace them and your car won't bottom out.

[yellowchinaman]

knackered springs. Not shocks. Cheap springs do loose their memory flex over time especially if they're not mae to weight specific, it'll flatten in time.
Also do you have 18" rims?
Bump stops do help but if it's bottling out it'll still bang. I'd say change the springs.

[trdproven]

actually the bump stops will prevent the bang.

[yellowchinaman]

actually the bump stops will prevent the bang.

Only silences it but its still hitting. Just metal on rubber not metal on metal. If your springs where good it shouldnt even hit in the first place.

[trdproven]

^ With a low drop you are shortening the travel distance on the shock anyways. The bump stops truely only work on a lowered car. You are talking about stock height, but even with what you are saying means you don't have a low enough drop to even worry about bump stops. There is no way to get around a good lowered car without bump stops even with good shocks and a good bump, you'll still bottom out, trust me. I've ran between 1 - 3.5" drops and only the TRD springs never bottomed out because it didn't really do anything. I've tried 3 suspension setups so have a pretty good opinion on it. Plus what do you think bump stops are for, when you hit a good bump, it'll prevent the metal to metal contact and decrease the wear of the shock from fully being compressed. Honestly if your car is not dropped low enough or stock, bump stops are not something to worry about ive tried that too.

This post has been edited by trdproven: Oct 22, 2009 - 7:11 PM