Rear Coilover Install

[aston@ultrasw.c]

I have installed ER rear coilovers (super product BTW)

They are a tight fit, which I kinda' expected. After 2 hours of track time the contact was plain to see.










This is the left side, the right is similar only less severe.

So the question is what to do about it?

I could take a little toe out, which would move the hub to the rear - better centering the spring, but I like the toe where it is.

I could beat on the tower, which I am not afraid to do, but I don't think I will get enough clearance.

My idea is to cut the tower as shown, move the sides apart and away, then weld in a strip to close the gap.

Access will be a PITA and I could end up welding my head etc so before I dived in I thought I would ask questions

The goal is to do it once and forget about it.

[Steve@Rennsport]

Did you use 2.25" or 60mm springs?

[Elombard]

What if you removed the entire "cup" fabbed up a new one on the bench with that as a template- opened up the holes in the cross member and welded it back in. Is there room in the cross member for a bigger 'cup'? You could even drop the ride height a little if you wanted.

[winders]

Looks like a Hypercoil OBD spring. The coils at the ends, probably 2.25", are smaller than the coils in between.

[blue911rsr]

Sell the ones you have and get some upside down coil overs . No cutting or welding required.

[aston@ultrasw.c]

Originally Posted by Steve@Rennsport

Did you use 2.25" or 60mm springs?

From Elephant Racing, "We use 2.25 inch Hypercoil springs."

[aston@ultrasw.c]

Originally Posted by Elombard

What if you removed the entire "cup" fabbed up a new one on the bench with that as a template- opened up the holes in the cross member and welded it back in. Is there room in the cross member for a bigger 'cup'? You could even drop the ride height a little if you wanted.

I could - I was trying to be as non-invasive as possible.

I want to end up with enough room that if I did raise or lower the ride height a tad I wouldn't have the same prob.

[aston@ultrasw.c]

Originally Posted by blue911rsr

Sell the ones you have and get some upside down coil overs . No cutting or welding required.

Chuck, is it too late to send them back

[winders]

If it were me, I would fix the clearance issue and then replace any springs that have been scrapped up in the process. That would be both the main springs and the tender/keeper springs.

[aston@ultrasw.c]

In my experience Elephant Racing supplies a superbly engineered product, that doesn't actually fit my car. Great.

[JohnJL]

Hotbits offsets the top mounting bolt for this reason, and to allow more room for the remote canister hose.

[Steve@Rennsport]

You need a clevis kit so you can mount the shocks upside down, assuming these are safe to do so.

We fit these in the majority of cars with coilovers just for these reasons.

[safe]

Originally Posted by aston@ultrasw.c

In my experience Elephant Racing supplies a superbly engineered product, that doesn't actually fit my car. Great.

They have a version for the pre 72 tubs that has the springs further down, bellow the cup.
Even that was to tight for my -69 so I had to put the BFH to good use.
I think the BFH could fix your issue.

[Sboxin]

Originally Posted by aston@ultrasw.c

In my experience Elephant Racing supplies a superbly engineered product, that doesn't actually fit my car. Great.

We used ER coilovers on our 1978 911SC race car with no fitting difficulty on the rear.

Could you put a spacer on the lower shock connection to the trailing arm to move the lower end inboard? A couple of washers should do it.

Also, sometimes the Porsche bodies are not always an exact fit - a few MM here and and few MM there . . . just sayin' - - We had to lathe down a wheel spacer for our Boxster by 1.5MM to fit some wide track tires on the rear end - - the body was off by that much from left to right side. .

It may be your car and not the parts . . .

We would still like to see you on track here in Phoenix some day,
Regards,

PS: Recently got a tip from Jim Hendricks - put the tender springs on top so they don't rub on the threads of the coilover adjuster.

[safe]

Originally Posted by Sboxin

PS: Recently got a tip from Jim Hendricks - put the tender springs on top so they don't rub on the threads of the coilover adjuster.

+ It would make them sprung weight instead of unsprung...

[Mahler9th]

In my experience, the clearance for these kinds of changes can vary depending on several variables. I just went through this with a major suspension change.

I got some suggestions from a good friend with pro level experience. He suggested I create more clearance with my hammer, and that I space the shocks inward with spacers on the lower shock bolts. I did so (probably about .150 inches per side).

My friend suggested I could space each side in as much as 1/2 inch if I needed, as long as I had a proper lower shock bolt.

No more clearance issue. No need for new springs or perches or upside down shocks. Easy, fast and cheap solution.

[winders]

Originally Posted by safe

+ It would make them sprung weight instead of unsprung...

Except that, if anything, it makes more of the heavier main spring unsprung weight so there is a net loss in sprung weight.....

[Cory M]

Originally Posted by Sboxin

Could you put a spacer on the lower shock connection to the trailing arm to move the lower end inboard? A couple of washers should do it.

Try this before modifying the tub or parts. My Moton set up uses a spacer at the lower bolt to provide clearance and allow the shock to articulate.

[mreid]

I used a 1/2" spacer at the swing arm mount.

[Mahler9th]

One more thing that may be obvious but is prudent to add: interference here could affect handling.

In my case, the interference was the result of a change in spring thickness. I went from 550 to 700 pound springs. Even though the ID was the same, the OD increased slightly with the stiffer springs (larger diameter wire). That increase was enough to cause interference, which I noticed in handling on the track.

After using my hammer to improve the situation, I decided to ask my friend what else I might try, and he suggested spacing the shocks in. I added a washer and moved my tie downs inward which moved the lower shock mounts inward. It worked. I may need to do some fine tuning with a few more washers or spacers once I settle on final alignment and height specs.

With all of this it is important to know what you are using for lower shock bolts and ensure their condition is appropriate.

I should also add:

1. In my experience it is not necessary to toss springs that have paint scraped off.

2. The OD difference between Hypercoil and Eibach springs for the same rate are about the same. We have to remember that the spec is 2.25 ID, and that the OD will be affected slightly by coil thickness which is proportional to rate.