Interesting dialogue between Erik and Sean, both very knowledgeable on the subject. When they get into the highly detailed techno-babble, they both lose the attention of the Viper owner.
I've enjoyed working with each of them and my check book proves the degree of flattery and respect I have for their advice. Here's my take for all you mere mortals who are trying to improve the handling of your Viper. I have nothing to sell you.
Leave your Viper completely stock unless it is a track-dedicated car! If you have a track car, then please read further.
Suspension set-up techniques for a production Viper continue to evolve very quickly within the Viper Racing League. This is where 95% of the research is being done. We have all been serving as guinea pigs and our cars have been science experiments for the many vendors trying to help us go faster. They (and we) are still learning and changing our opinions frequently. Next year we will think we were pretty naive today.
Changing shocks and spring rates from stock equipment will defintely improve lap times, but it requires much experimentation to determine which spring rates and shock settings produce the most significant improvements for any particular driver. For most of the VRL drivers, this is "Black Magic". They couldn't even show you where the shock adjusting screws are, let alone how to adjust them to make the car handle the way they want it to. You will have to spend many thousands of dollars on track testing and suspension consultants before you can even come close to helping yourself.
Penske and Moton shocks seem to be the favorite choice of the VRL racers, greatly outnumbering the Koni, Dynamic or JRZ. This will change in the future, and here's why and how. It will depend on which Viper vendor gets the best financial distributorship arrangement with a shock manufacturer and then spends the most amount of money and effort promoting the product as the next best thing to sliced bread. Moton wasn't in existence a couple years ago and would be unknown to the Viper community were it not for the marketing efforts of Archer Racing. Since Archer supports the VRL and is a distributor for Moton, guess which shock is being sold to the VRL racers in the greatest numbers today? I'm not saying this is a bad thing...it's simply how the world works. Unit cost and production-line consistency have determined which shocks go on our Vipers from the factory. That's why the change from Koni to Dynamic. I suspect Penske was way too expensive, but not for the factory/Oreca racecars! I love my Penskes, have raced them hard for over 5 years, and I've never had a shock failure. They are expensive (about $4,800 for a complete set with hardware and no springs), but not nearly as expensive as the time and effort required to learn how to adjust shocks of any make or brand. Don't let anybody convince you differently.
As far as springs go, the only two choices seem to be Eibach and Hypercoil. Springs are cheap( less than $100 each). Some like really stiff set ups (over 1000 LBS) and others like relatively soft set ups (under 1000 LBS). Both set ups are significantly stiffer than the stock springs. I've run spring rates as low as 300 LB and as high as 1,200 LB. Whether I run the soft or the stiff set up, there are still uncomfortable amounts of body roll and bottoming out of the shock. None of us can find a stiff enough set up or high enough ride height to keep the shocks from bottoming. This is very frustrating because when you do the calculations of load transfer and suspension travel on paper, it shouldn't be happening. The less experienced you are as a driver, the more comfortable you will be with a softer set up.
As far as control arm bushings go, the really fast guys are having success with both Delrin and mono-ball bushings. (It seems the really fast guys are fast, regardless of any equipment choice). Either choice is a vast improvement over the stock rubber bushings. I've had my Delrin bushings for 4+ years, and it's finally time to replace the bushings as they are worn. The "new trick" is to line-bore the control arms before installing the Delrin bushings. The same process is used for Mono-ball bushings. Only time will tell how much better or longer-wearing the mono-balls will be. Mono-balls are about twice as expensive. They are also the bushing of choice on the Competition Coupe.
We have more left to learn than dollars to spend.
