Help!!! Coilover Install Problem

rjay · 05-06-2005, 12:36 PM

So we were about to finish up the mods on my RS when we discovered the rear coilovers (Ledas) won't fit. I should add that we're using the later aluminum trailing arms. We've heard a rumour that I'm trying to confirm that for earlier cars (this was originally a 1970 T) there is a different size shock body available thats shorter than the ones for 1972+ cars. Anyone have experience with installing coilovers in 1971- cars? Do we have the wrong shocks or are we in for some more fab?

TimT · 05-06-2005, 01:15 PM

You probably have to run the rear shocks upside down, ie the spring on the bottom and the shock body on top.

The crossmember on early cars isnt as coilover friendly as later tubs..

rjay · 05-06-2005, 01:31 PM

Quote:

Originally posted by TimT
You probably have to run the rear shocks upside down, ie the spring on the bottom and the shock body on top.

The crossmember on early cars isnt as coilover friendly as later tubs..

hmmm... Clearly the shocks I was sent arent meant to be installed upside down. The adjustment knob (you can just see it in the picture in the lower left corner) is too large and contacts the rear crossmember.

POKDUB · POKDUB's Garage

From the picture you attached, the coilover at the botom is an inverted coilover, ie spring at the bottom. This end, with the eyelet, would attach to the trailing arm. So it is the right type.

As for its dimensions, it looks a bit on the beefy side. The diameter of the barrel, coupled with the adjusting screw, might be just too big to clear the opening on the cross member. What are the dimensions ?

I am looking to put rear inverted coilovers on my 69' 911E. I have steel trailing arms, and I have been told that one cant fit inverted coilovers to these ??

Will see what develops on this thread.

POKDUB · POKDUB's Garage

Opps !
Duplicate post, removed.

Rufblackbird · 05-09-2005, 10:33 PM

any more pics of the rear coilovers? Seems like they could be mounted both ways. I think for pre-'72 tubs there is not enough room for the coils mounted upright as the shock openings are too small, hence the need for upside down coilovers.

Porschekid962 · Porschekid962's Garage

how much do those leda's run if you dont mind me asking? they look pretty nice, is the front strut their own design or was that fabbed up to fit their damper?

best of luck with your project.

rjay · 05-10-2005, 02:50 AM

The crossmember has gone to the great Porsche scrapyard in the sky. Ever other solution was too much of a compromise. We measured an SC and found that the crossmember is roughly 2 1/4" forward in the later car and an inch or so off side to side as well. There was no way to fit the shock and get full travel even if we found some way to shoehorn everything in. My mechanic, for better or worse, is a perfectionist (check out the welds on my cage via my link below), so out it came (taking a lot of his previous work on the rear towers with it

) I'll post some before and after pix later in the week when we're done. Now that we're fabbing the whole thing, we'll mount them upside down.

As to the Ledas, the price varies upon configuration. I went with single adjustables with blanks to add the remotes for converting to doubles. Ledas, AFAIK, are the only shock to allow for this. They take a while to get, approximately 5 weeks, and require a donor strut for the front. They take the spindle from the donor, chuck the rest away, and will mount it with both height and camber to your specs. We did the standard raised spindles (19mm?) with -1 degree built into to the spindle. I believe the cost was a shade over 2K for the set. To convert to doubles is approximately $400 a corner. So full on they're about the same cost as the JRZs/Penkse setup, but again, you can do it in steps, if you find it necessary, which given my budget seemed like the best option. They are easily rebuildable and at 24 clicks, are supposed to offer a pretty wide range of adjustment.

Elombard · 05-10-2005, 04:41 AM

Pretty!

mmastro · 05-10-2005, 06:19 AM

What kind of springs/spring rates are you running front & rear? What is the weight (or projected weight ) of your 911?
Cheers,

rjay · 05-10-2005, 10:40 AM

Quote:

Originally posted by mmastro
What kind of springs/spring rates are you running front & rear? What is the weight (or projected weight ) of your 911?
Cheers,

If I recall correctly we'll be starting a 450/600 and see how it goes. Springs have been dynoed. Weight is an interesting question. The car started at 2200#, added a full cage and tubing (which we'd estimate at about 90-100# of material, but lost a 22 gal gas tank in favor of a fuel cell, all guages removed in favor of an AIM MXL, was stripped of a lot of rubber, insulation, extraneous wiring + got and ERP front suspension, plexi in the rear quaters and rear screen and of course, we just lost the rear crossmember

. I would suspect that it will weigh the same or (fingers crossed) a little less.

rjay · 05-11-2005, 12:34 PM

Couple of photos. Its a little difficult to see, but the shock with coil will not fit in the tunnel, nor will it fit upside-down due to the adjuster. Everythings out, should hopefully have some of the fab, if not all completed by the weekend. Figured this was such a PITA, that it would be worthwile documenting for future generations.

Here's the crossmember removed:

Starting with a somewhat clean slate:

POKDUB · POKDUB's Garage

The two pictures you posted of the rear coilovers are different. The at the bottom of the first picture are the inverted ones, while the car mounted ones are not inverted ?
Did you reengineer them ?

rjay · 05-12-2005, 03:56 AM

Quote:

Originally posted by POKDUB
The two pictures you posted of the rear coilovers are different. The at the bottom of the first picture are the inverted ones, while the car mounted ones are not inverted ?
Did you reengineer them ?

Nope, they are the same shocks in both photos. Ahhh....now dim bulb goes on about some peoples comments related to upside down mounting. We have monoballs on both the top of the shock as well as the bottom (I believe that was a option specified by my wrench). Perhaps that was confusing some of you. We will in the end invert them. The obvious problem in the second photo is that we couldn't invert them as the adjuster wouldn't fit (and even if it did you couldn't really get in there to adjust it).

Inverting them in the final install will allow us to adjust them through a removable panel in the firewall. If I go to doubles down the road it will be pretty trivial to mount the remotes inside the car. Plus, we get the usual advantage of lowering the unsprung weight.

Rufblackbird · 05-12-2005, 09:19 PM

wow...you guys cut out the crossmember? That's pretty nuts. I can't wait to see more pics!

rjay · 05-13-2005, 06:36 AM

Quote:

Originally posted by Rufblackbird
wow...you guys cut out the crossmember? That's pretty nuts. I can't wait to see more pics!

Yeah...we're kinda crazy like that. Good thing to remember if I'm ever on yer tail in a corner...

rjay · 05-14-2005, 01:06 PM

Heres an update on what we're doing. Obviously had we known that we'd end up here, we'd have taken the tubes straight to the frame rail to begin with. Given that couldn't be done, we've reenforced the frame with plate and boxed in the tube. You can see the marks for where the chrome moly plates will go for the shock mounts. We'll try to wind up putting in a V from each box to the center cross tube. Hopefully you'l see the shock mounts in place in the next day or two. Everything is tacked for a quick engine re-install and mockup before everything is finalized. Have to bow low to Conway Autoworks for their incredible tenacity and skill.

Jim2 · Jim2's Garage

rjay, would you happen to have a scale handy? I would be interested in knowing what the crossmember weighs.

Tks,
Jim

rjay · 05-15-2005, 07:42 AM

Quote:

Originally posted by Jim2
rjay, would you happen to have a scale handy? I would be interested in knowing what the crossmember weighs.

Tks,
Jim

Unfortunately, I think it may already be gone. I'll check to see if we can get a number for you. I did wonder about this myself and although I didn't weigh it, I did pick it up. Actually, I was surprised at how light it was. With the exception of the strut caps, the metal used is very thin. I'd guess that the whole assembly doesn't weigh more the ten pounds at the most. I'd bet that we'll probably at best break even on weight and might wind up adding a pound or three by the time we're done. OTOH, the final result will be far stiffer. Its really pretty amazing how minimal most of the factory welding is around the towers; its not hard to believe that some RSR suspensions have experience stress cracks here. There's got to be a lot of flex in the stock setup.

rjay · 05-16-2005, 03:14 AM

The rework should be done in the next day or two. Here are a couple of photos of the interim work. You can see the shock mount taking shape as well as the crossbracing. The first photo shows the boxing for the frame rail connection (all tigged). The second should give you an idea as to how it will all work in the end. the final one is a detail of the tower and how it will connect to the crossbrace. The adjusters will be accessible from the interior through an access panel.