Hi, anybody with coilover shocks know if these will fit?

Craig

Shock.jpg

 

Uncompressed length is 3" short, but you'd take care of that in your fabrication of the top mount. With that the eyelet mount it would be the same effective length as where the stock shock shaft shoulder hits the top mounting plate above which there is a BIG rubber donut that acts as an undamped helper spring (Jim Morton measured it as having a modest spring rate). You would eliminate that, although you might provide a bit of isolation in a bushing. Have fun designing the top mounting.

 

Is it the same front and rear? I want to buy these shocks but my car is not avaliable to measure.

Craig

 

Craig it appears there is so much that you do not know that I am a loss to try to explain all that you need to know before you buy a shock and or springs which is not made to work with your car. Bill's comment "Have fun designing the top mounting. " was not a positive one at all but indicated that it takes a lot of work , design skills , machining and usually welding. And frankly 5 inches of travel seems a bit short but I have not spent much time measuring although that is really what you need to do...Your current rear shocks are about 22 inches long ....

 

Jim, are you able to suggest the lengths I should be looking at. My car is burried under a ton of snow
so a little difficult to get at. As far as fabricating top mounts, I have no problem with that.

 

Uh, danglerb?

 

Apart from looking really Kool! , costing a bunch in experiments and taking lots of time and $, what will these do for your car that a set Eibach/Bilsteins or similar wont do? Have you compared the spring rates with 928s figures from stock to racing, or any of that stuff? I cant see a snub rubber there anywhere to handle bottoming situations. The Eibach/b set up can be hard to beat for street use, or just go to factory M474 springs and Bilsteins - I like mine with new/reco shocks, while some find it a bit harsh.
jp 83 Euro S AT 51k M474

 

This is obviously not a drop-in replacement. The length is close enough, and that is all I was indicating. The 5-inch travel is actually about right, although it sounds small (see illustrations below). The fabrication of an upper mount would be a healthy exercise in engineering, but it is doable if you have the engineering skills and a machine shop, This would be personally way out of my league.

Anyway, as to the length/fitment...Here is the anatomy of a front coilover. The rear is close to the same.



Although the total length of the shock is 23", a lot of it is the threaded end which is above the actual mount point under all that rubber donut hardware.


The unthreaded part of the shaft represents the absolute maximum compression range, but this is before all the parts are installed. It measures about 6" (parallax error makes this look slightly longer than 6" below). The stock hardware takes up a small amount of this by a metal ring that mounts on the top of the shock body, a plastic washer/spacer. Of course, the bump stop takes up a couple of inches, although it shouldn't be counted. The compression range of the stock shock is further reduced when it is mounted. It must be compressed about 3/8" to mate with the lower shock mount hole with the suspension hanging free during installation. So, 5" is close, compared to stock.


The total working length (from the bottom of the shaft threads to the center of the lower mount) of the shock is 19", compared to the 18" for the shock in question. It would be better if you could get 19" with 6" travel, but I don't see an insurmountable problem with fitting these shocks. I don't know if these shocks are worth all the effort that would be required. The rears would need even more interesting work to deal with the lower mount - you would need to fabricate a new lower mount location. Stock is 22mm and angled about 4 to 5 degrees. Again, this can be done and has been done.

 

Thanks Bill, I appreciate you posting those pics, they help alot. I don't have an engineering degree
but am able to fabricate the parts needed to do the install.

Thanks again
Craig

 

Craig:

If you go this route, your mount fabrication would make a hugely interesting topic.

 

I'm thinking the rear may be a little short and my consider a longer shock there, the front seems
to be close enough. I'll keep you posted

 

Other than the lack of travel, the big problem in the rear will be the 22mm pin for the lower mount.

What shocks are those? It looks like some sort of craptacular ricer shock.

 

I would like more travel, even if 5" is close to stock. The rubber donuts in the stock top mounts also provide some extra travel not accounted for. Please look over the stock mounting system much more closely before you jump. My review here is pretty cursory. You should get a spare stock assembly for more careful measurements.

Also, in the rear, you would probably end up with a lower mount bracket on the top of the lower A-arm. This will mean a shorter than stock shock. Take a look at this modified rear suspension.

 

No, they are not craptacular ricer shocks, they're Dynamic Suspensions coil overs. Thanks again Bill
perhaps I'll drag my car out from under the snow and remove the shocks. I like the setup in the pic,,,
is that your car?

 

That's Mark Anderson's racer. Note that he has another set of brackets on the A-arm much further to the outside, so his suspension went through several revisions and probably has gone through a few more since I took that picture several years ago.