Originally Posted by ghoffman

We have a new (last summer) shock dyno and have tested almost every brand of Corvette shock mentioned above. There are indeed huge differences out there and I will keep the specific data private. I can think of no easier way to get into a pissing contest than publish what we found. You would be surprised how bad some of the "name" shocks really are. Some random and general thoughts on our testing so far:
When we were at Penske's facility last year, I asked about QC and incoming inspection. I was told that a 1/2 mil (0.0005 inches) in some piston dimensions can mean 20-30 pounds worth of force. This is on CNC made parts held to the tightest tolerances, produced to aerospace quality standards. This is why each and every Penske is dyno'ed before shipping and if it is not correct, it is torn down and made correct. When you buy Penske's from us, we include the valving data, and dyno data on each shock, including the raw data and software to run it if you wish at no cost. We share all of the information with the customer, and do not play the private game. The sensitivity to tolerances mentioned above kinda makes one wonder what will you get on a assembly line made product. The day were there they were finishing up all of the Talladega NASCAR Sprint Cup shocks that every competitor must use. They were all exactly the same and had anti-tamper seals and special tamper proof N2 fillers.

We have tested many Spec Miata shocks recently, and it is amazing how non-spec they all are. We have not tested 2 Spec Miata shocks that were even close to each other yet. There seems to be a cottage industry for revalved SM shocks and since SCCA has no dyno curve that the competitors have to match, the valving is semi-open at this time. Rumor has it that the only way to tell (without a dyno) is the labels have smudged letters because of the solvent used to clean the body after re-valveing. Some have claimed that there might be SM shocks with Penske type pistons inside, but that is only a rumor!

Another really interesting thing is how much the gas pressure varies with some brands. In some cases you have the same internal pressure but the separator piston seals leak and the N2 has made its way into the oil. This is immediately noticeable because it sounds like a kid sucking at the bottom of a soda. Another thing we have seen, especially with some of the OE shocks we ran as baseline, is the amazing effect of a slight ding in the body of the shock. I saw that with my own personal C6Z left rear stock shock. They did look pretty good though considering 7000 miles and a bunch of NHIS days. I could go on for hours, but I'd hate to be a cure for the sleepless!

In any case in answer to the question above, we can supply the Penskes for your car to meet any rule set for any club. One of the outstanding features of the Penskes we sell, is that the bodies and shafts are available in 1/4 inch increments. We optimise the body length for max bump travel while maintaining adequate fender clearance for any tire combination that you are running, while running as long a shaft as we want (within limits of course) to optimize droop travel. Some classes need stock length bodies and shafts, we can do that too. The point is we are not stuck to one or 2 off the shelf configurations like with mass produced products. And of course, they are available in non adjustable, 2 way adjustable (the new 8300 is awesome!!), 3 way 8760 (what I will be running this year) in your choice of Heim joint mounts or the OE style pin and rubber mount. Our new upper mount is CNC aluminum, has a stainless steel shoulder bolt for no threads in shear and has a zero tolerance fit for no noise.


The prototype shown will have the shaft threaded and will be common to C4, C6, C6, and C6Z and will be anodized black and red.

The new rear clevis has the rebound adjuster integrated into it so a ball driver is all that is needed. It has 8 "clicks" per turn, 5 turns from full hard to full soft.


What do you want to do?
Cheers,
Gary