Suspension & X-member modifications

Suspension related stuff goes in here.
Post Reply
Mark_vaughn

Suspension & X-member modifications

Post by Mark_vaughn »

Hello Everyone.

I am trying to finnish up my car and I have a question for the collective knowledge.

The main question is "How will this modification affect my car/handling/steering/safety?"

Probably not anyone who did the exact same thing, but I like to hear all thoughts on the subject.

In short I had x-member and frame problems. So I cut/welded and strengthened my frame/x-member. Pictures are worth 1000s words:

My Problem:
Image

Another Problem:
Image

My Solution:
Image

After it is done:
Image

New bolts for sway bar too as one had broken:
Image

All this made the whole front section much stronger, but it lowered the x-member and thus the lower A-arm mounts about 3/8". The modification is exactly the same on both sides, so my hope is that other than maybe throwing the allignment out a little everything will be OK.

I fabed up a oil pan guard, so that isn't so much of a concern at the moment.

The first problem came up when I tried to re-fit the shocks, they are about 3/8" too short!! I can't attach the top bolt with the car off the ground. I hope that with the weight on the suspension it will compress enough to let me catch a thread. But if it does, then will it hurt the shock if after I hit a bump the suspension tries to extend and bottoms out the shock? Are shocks designed to take that? Should I get longer shocks?

As you see, several questions that I am working through and would like any feedback anyone would like to give.

Great forum guys, we just need to make it as popular as that other one...
So Cal Mark

Post by So Cal Mark »

the later 2L x members have a plate added to lower the unit for engine clearance, so it shouldn't upset the handling too much. Having the shock as the limiting factor for suspension travel may be a problem though. The shock will break if it's yanked hard enough. I'd avoid getting airborne!
BluEyes

Re: Suspension & X-member modifications

Post by BluEyes »

I don't see a droop stop on the suspension of my Spider, so I am assuming that the factory used the shocks to limit downward travel anyways. It is a pretty common practice, especially on rear axles and McPherson struts as well.

Of course, I will second not getting airborne! This is always a condition to avoid!

As far as the suspension goes, I can't be so positive. I doubt it will hurt your alignment or driveability, but it will negatively affect the geometry performance-wise. Spacing the inner ends of the a-arms farther apart does two things. Firstly, it lowers the roll center, which will cause an increase in body roll. Secondly this will reduce the negative camber gain of the suspension during cornering. If this is a street driven car, I wouldn't sweat it though. You will likely never feel the difference. If you intend to autocross the car though, I would go back and see if you can redo it so the lower a-arms are at stock height, or even slightly closer to the upper arms.
Post Reply