DG-FNR
20+ Year Contributor
- 229
- 49
- Oct 21, 2002
-
Geary,
NB_Canada
This setup is similar to a design I had mostly worked out in 2004 or so; a way to fit Penskes (or any shock with an integrated 1/2" heim joint) onto a DSM.
So in broad strokes, this is a way to do it.
As always though, when it comes down to implementation, the devil is in the details.
- my lower adapter was to be 4130 steel, and hollow. It screws onto the shaft, then a locknut secures it from the back side (inside the hollow) The upper surface (on the shaft side) was contoured to fit the appropriate socket on an upper hat (Bilstein or Penske, as appropriate)
- My upper mount was based on the aluminum Koni mount, but with the spherical bearing housing replaced with a par of clevis "wings" on the underside of the plate. Coming in from below like that lets you feed the loads from the clevis directly into the support structure of the shock tower so it is nice and stiff.
The major upside from this setup compared to the Koni setup is that it lets you use any standard racing shock, which vastly opens up the pool of decent shocks, given that the direct OEM fitment is so rare. The downside is that the cost is much higher, as there are more parts to machine and the machine setups are more complex. On top of that, the shocks are more expensive than the Konis (although you get a lot more capability)
I had most of the details worked out and was ready to do prototypes, but when the far cheaper Koni setup only sold ONE unit (and I had 10 on the shelf) my boss kiboshed any future DSM products, and made me work on Corvette stuff instead. We sold dozens of $5000 Corvette setups, but only ONE $2200 DSM setup....
For my own car, I already had a set of Bilstein bodies modified to fit the OEM mounting, so I really had no need for them myself, so they stayed on the drawing board.
I dynoed a bunch of QA1 shocks and rebuilt and revalved some as well. Their initial price is pretty low, so they are a favorite brand of cheap-assed circle track racers and kit car guys. They are a better shock than a JIC or Tein, but only just, and they use a lot of tech that was obsolete in the 1970s (gas bags instead of separator pistons fer crissakes) They can be made to work, but they will give up performance to a properly valved Koni or Bilstein.
Like all else, you get what you pay for.
If you are looking for the sweet spot of cost to performance, the Koni setup is the way to go. If money is no object, this kind of setup (with the proper upper mount) offers more shock choices and opens up a whole new world of very, very good shocks. If someone were to hold a gun to my head and make me build another racing DSM, the clevis design would come off the drawing board and Penskes would go on.
DG
So in broad strokes, this is a way to do it.
As always though, when it comes down to implementation, the devil is in the details.
- my lower adapter was to be 4130 steel, and hollow. It screws onto the shaft, then a locknut secures it from the back side (inside the hollow) The upper surface (on the shaft side) was contoured to fit the appropriate socket on an upper hat (Bilstein or Penske, as appropriate)
- My upper mount was based on the aluminum Koni mount, but with the spherical bearing housing replaced with a par of clevis "wings" on the underside of the plate. Coming in from below like that lets you feed the loads from the clevis directly into the support structure of the shock tower so it is nice and stiff.
The major upside from this setup compared to the Koni setup is that it lets you use any standard racing shock, which vastly opens up the pool of decent shocks, given that the direct OEM fitment is so rare. The downside is that the cost is much higher, as there are more parts to machine and the machine setups are more complex. On top of that, the shocks are more expensive than the Konis (although you get a lot more capability)
I had most of the details worked out and was ready to do prototypes, but when the far cheaper Koni setup only sold ONE unit (and I had 10 on the shelf) my boss kiboshed any future DSM products, and made me work on Corvette stuff instead. We sold dozens of $5000 Corvette setups, but only ONE $2200 DSM setup....
For my own car, I already had a set of Bilstein bodies modified to fit the OEM mounting, so I really had no need for them myself, so they stayed on the drawing board.
I dynoed a bunch of QA1 shocks and rebuilt and revalved some as well. Their initial price is pretty low, so they are a favorite brand of cheap-assed circle track racers and kit car guys. They are a better shock than a JIC or Tein, but only just, and they use a lot of tech that was obsolete in the 1970s (gas bags instead of separator pistons fer crissakes) They can be made to work, but they will give up performance to a properly valved Koni or Bilstein.
Like all else, you get what you pay for.
If you are looking for the sweet spot of cost to performance, the Koni setup is the way to go. If money is no object, this kind of setup (with the proper upper mount) offers more shock choices and opens up a whole new world of very, very good shocks. If someone were to hold a gun to my head and make me build another racing DSM, the clevis design would come off the drawing board and Penskes would go on.
DG
