Custom coilovers: whats my starting point? (dampening and travel)
 

If you are not aware I rally an FC so there is no out of the box solution for my application. Right now I run bilstein HDs but to get the spring rate I desired I went with RS*R for the rear and RB for the front but this makes the car too low which is not good for offroad racing. This can be corrected with some coilovers, the question is. I want to understand a starting point.


Ideally I need a longer spring 10-14" to support max droop but I need to figure out the max travel I can go before I'm just popping balljoints due to bad angles. Mazda competition parts sell coilover kits for the car and then I can add a strut cartridge and get upper camber/caster plates after choosing my desired springs and then it should be all good to go.


I do not see in the FSM anywhere it calls the length of shock travel front or rear or what the dampening is, I've tried searching but nothing comes up - its always about lowering the car or ideal alignments for some application that doesn't suit me.

First where do you want the ride height? I'm assuming stock or slightly higher.

You can only get a shock/strut so long in the car just because of geometry and interference concerns, so that is going to be your max droop. I would figure out what that overall length needs to be first.

Put the car on jack stands with suspension in it without the swaybars and springs on and figure out what the max shock length can be.

From there you need a cartridge that can support that overall length and bump travel, then you'll know what length of springs are needed.

+1 just put the car up and measure. KYB gives dimensions, so you can get some idea of shock travel and such KYB Online Parts Catalog

I would like it to be a few inches above stock height and the car doesn't run swaybars.

If I am understanding you correctly, you are saying that I just need put it in the air without the shock assembly/sway bars to determine the rest max droop? Or just bolt the shocks in without any springs attached?

in the rear you can do no shocks, in the front you need the shock and no spring

To clarify, this is because the front suspension is a strut, while the rear is a semi-trailing arm. With struts, the shock is part of the suspension geometry, whereas the spring is not. With a trailing arm, multi link, or a-arm suspension, etc., you don't need the shocks or springs installed to see how the suspension moves.

exactly.

a strut is a damper that is part of the suspension geometry, while a shock does not. there is also a construction difference in a strut, because it needs to handle the load from the suspension.