But I had assumed that's what the adjustments adjust. So I'm still unclear why one would need both.

 

Yes, but the adjustments only work within a certain range. If you reach the end of that range while trying to compensate for spring rates at either end of the scale, you lose the ability to fine tune the suspension.

 

Ah, so it's a gross adjustment v. fine adjustment distinction? OK, that makes sense to me.

 

There's more to it than that, but that's the basic idea. Reality is that you should choose your spring rates first, then spec the shocks around that. Of course some times you change springs, or need fine-tune the behavior of the car depending on track conditions etc. and that's where the adjustability comes into play.

 

I guess you are assuming that the mass of the car is a constant in this equation? Because mass, spring rate, and damping all interact.

 

Wow... I turn my back and you work it out! Cool! Yeah... the custom valving is to get the car so you can adjust for conditions and have room to overshoot the setup on either end. Last year I could make my car handle well with the shock build, but I was at one extreme end of the adjustment range. Now with the work over the winter, I'm pretty close to the middle. The last revalving took 30 minutes per shock and I had someone in Portland do it for me. Very quick and easy.

You can daily drive on the high end shocks, but when they're properly valved, it won't be smooth. You can soften them to the extreme end of their adjustment and its OK. It won't be super comfortable though. That said, you'll only need a rebuild once a year or maybe every other year.

In the Penske line, I'd prefer to have the 8760 units over the 8100's that I have. But I just can't justify the $2000 upgrade.

Top 10 at Nationals in 2004 (B Stock)
1. Moton
2. Penske 8100
3. Penske 8100
4. Moton
5. Penske 8100
6. Koni 2812 (custom valved)
7. Bilstein
8. *** Stock ***
9. JRZ Singles
10. Penske 8100

My point is that the stock shocks are pretty darn good. You have to spend a lot of money to know you're getting an upgrade in shock performance in stock class. You've got to really be dedicated to make the jump.

Andy H.

 

How stiff spring rates can stock shocks take?

 

may I ask a "ricer" question?
although this thread is in refference to shocks,
would somebody have a better handling ride (less sway/lean) if they stuck pieces of rubber (some stiff compound) inside the springs ?
it seems that competition springs have a gigantic spring rate, which is why I ask this question out of curiousity.

 

No. This is how the car is shipped with "spring spacers" and the car drives horribly until they are removed.

Springs are not rubber. Rubber absorbs energy. Springs store energy and then give it back.

 

One thing that I don't see mentioned in this thread is that the initial observation about body roll isn't going to be answered by shocks for anything other than transitions. Springs and swaybars will affect the total amount of roll while the shocks "simply" change the rate until a steady state is achieved, making them useful in transitions but much less so for many corners...