So we have been getting a shock dyno at each event in the southeast this season. I had some Koni rears sitting in my trailer that came off my car when I put new shocks on last summer. I have no idea just how old these are, but my guess is that they were likely put on the car sometime in about 2008-2009 which means they have 5+ seasons of racing. I raced on them for about 3 seasons alone. Below is the quote from the Wes who ran the dyno.
The adjuster on the RR appears to be broken, but the curves look decent. the adjuster worked on the LR, but the curves are very ugly and nothing similar to the RR. The LR felt and sounded like it has lost a fair amount of fluid. I've repeatedly seen this with KONI and it IS the biggest problem with them. They just are not consistent and seem to break very easily. You may need to have your KONI shocks dynoed every week. at the very least they have to be checked before you bolt them on your car (new) and hope that they will trade out a bad one.
Wes Burton Performance is the shop with the mobile dyno and deals solely with shocks. Their observation is that the Bilstein that is legal for use in our class is a better built shock, will last much longer, but isnt valved anywhere close to where it should be for racing. The Koni is valved better for racing, but is less consistent from the factory and is prone to much earlier fatigue. Both things to consider when building a new car or replacing your worn out shocks on your current race car. I think I am going to try out the Bilsteins on the car I am currently building.
Wes Burton Performance
burtonshocks.com/