I know the fourth gen rear suspension components are interchangable, but can anyone confirm if the fourth gen upper rear shock mounts are the same as third gen.

Thrid gen has lower eye-bolt mount and upper stud mount.

I'm wondering if Fourth gen are eye-bolt to eye-bolt design with no top stud mount?

 

The rear shock mounts are exactly the same. Stud through the sheetmetal behind the seat and the eye-bolt at the axle.

 

Interesting! The reason I'm asking is I have seen several ads for coilover conversions for the fourth gens and assume they are basically the same as our cars. I don't trust the stud mount location to hold the weight of the car- I will have to check further into the 4th gens to see if they have more suspport in this area then we have.

I have already plasma cut some brackets to install/weld extra support in this area- and will contact on of the 4thgen coilover suppliers to see if they will seperate their conversion kit (I of course only need the rear) to see if this route will be cheaper. I have contacted Koni on this and they will custom make a rear coilover double adjustable shock to fit my application stating at about $575 each shock (aluminum bodied w/ spherical bearings).

 

i am sure you would need to reinforce the area of the upper mount.

qutoe from ground controls website about their 3rdgen coil over kit for the rear

"We can supply you with all parts needed to make a rear coil-over setup. Extensive and somewhat skillful fabrication is needed. These kits are only legal for SCCA G.T., Production and Modified classes. Despite many requests, we have never figured out a good A/S legal way to do this "

so i am sure it is just a matter of weldeing the supports in so the weight of the car at the point where the shock mounts is somehow connected to to the framerails (i use the term loosly )

if you get it going be sure to post pics!!!! i have yet to see a rear coil over design, and have though about going that route myself before.

 

Here's a sketch of the brackets I have made. I did a cardboard template last time I had the shocks & springs out and then plasma cut a bracket out of 1/4" stock- I have not test fit it yet. The basic principle is the can area 2" away from the shock mount presently holds the weight of the car, so this bracket bolted or welded underneath would re-distribute the stud mount coilover load back to the can area.

My thoughts to just bolting it into place instead of welding is:
it could be removed for replacement of the conventional spring setup for any class racing resrictions that don't allow for coilovers. Bolting it in would not be so perminant and by the underneath placement would give adequate support. carraige bolts could be used on the top side as not to mess up any carpet wear.

 

that is along the lines i was thinking. since i am not an engineer, nor do i know much about fabrication i don't know what sort of materials you would need for that, but for someone with some fabrication and design ability should be able to handle it. you would also probbaly need to reinforce the lower mount in some fashion because i doubt it is designed to handle the load either.

 

Already done thanks to BMR bolt-in Relocators also welded. Note that the extra support bracket (basically designed for alignment and support for bolt-on purposes) is welded to the shock mount and beefs things up tremendously. I planned ahead for this possibility.

 

sweet deal, it looks like it shouldn't be too hard for you to get it going then!

 

I copied a picture of LG Motorsport's rear conversion kit. They use Bilstein 9100 series race shocks with spherical upper and bottom mount bearings & an adapter for the top stud mount. Also they show no extra support-scary- that shock can bust through the top sheet metal over time. I added my upgrade suggestions below.

 

hmmm, interesting. i think you way looks alot better. will have to get under mine when i get home and look, at the spring pearch and the space, but i don't thik it would be very hard for someone who can weld (like you )