Suspension gurus please.

**Poggy** · 03-09-2008, 01:31 PM

Hey everyone, i've recently installed coil overs into my ae112 corolla, the car only has around 3cm of suspension travel front and rear, over certain bumps i'm getting really bad knocks, sounds like someones hitting my strut towers/hubs with a sledge hammer, could this be because the wheel isn't traveling enough to take up the bump then when the bump ends the wheel gets slammed up? any help would be greatly appreciated, gone over everything under the car, everything it tight

**oldcorollas** · 03-09-2008, 01:36 PM

yup, sounds about right.

how much bump and droop do you have?
is the 3cm total suspension travel or just bump?

**YLD-16L** · 03-09-2008, 01:44 PM

Not a guru but some thoughts anyway.....

Are you running any form of bottom out bumper/jounce bumper?

What brand are the shock absorbers and are they designed for this car?

I ask because the only things it could be if nothing is obviously colliding is that it's bottoming externally (top of strut/shock to spring hat) or the shock piston is bottoming out internally.

I am assuming from your description that you've got 30mm travel left from a static position and have XXmm of droop in the system?

**Poggy** · 03-09-2008, 02:40 PM

cars not hittign the bump stops, when you measure center hub to guard height it only changes by 3com when car is lifted off ground. maybe get longer springs?

**YLD-16L** · 03-09-2008, 02:43 PM

Ahh it's topping out then.

Longer springs won't help, the droop is limited by the shock extension.

Longer stroke shocks will help so you're not constantly topping them out. Sounds like they don't have any top out bumpers or valving to prevent top-out clunk.

Edit: or lower it another 50mm or so

**Poggy** · 03-09-2008, 03:05 PM

but if i had alonger spring i could winde down the spring seat then the car would have more spring travel when placed on ground?

**Poggy** · 03-09-2008, 03:05 PM

but if i had alonger spring i could winde down the spring seat then the car would have more spring travel when placed on ground?

**YLD-16L** · 03-09-2008, 03:15 PM

Is the car at a ride height that you are happy with now?

If yes then a longer spring won't help.

If no and you can go lower and your only reason for having the setup the way it is now is to keep the spring captive then a longer spring that will let you lower the car and keep the spring captive will help, or get springs retainers/helper springs to keep the current spring captive.

**oldcorollas** · 03-09-2008, 04:08 PM

what is the total travel of the shocks? ho wmuch is bump and how much is droop?
you need to get the shock position sorted, and then think about spring lengths...
if you only have 5-6cm total travel, you could be kocking on both compression and droop... such is the nature of some coil-over setups...