8300. They are still on the car, but are in need of a revalve for significantly less terminal rebound if I start to take this STR thing more seriously.

 

Were you able to get those to adjust primarily in the slow piston speed regime (like, 2 inch/second and below)? Mine currently adjust only above 2"/sec.

If so, what piston type do you have?

 

No the adjustment is pretty even across the range but I am using a linear piston on the compression side with a good amount of preload in the stack so it has a mild knee at 0.5 in/sec. I'll likely go D/D on the next rebuild as well as taking out the rebound mentioned above.

You can see the original dynos here: http://www.alvanderp.com/pics/penske%20dynos.pdf

The fronts have since been rebuilt for more compression, as I was maxing out the adjustment range on concrete.

 

[QUOTE=alvanderp,Jul 10 2010, 05:29 PM]No the adjustment is pretty even across the range but I am using a linear piston on the compression side with a good amount of preload in the stack so it has a mild knee at 0.5 in/sec.

 

Drew's rebound side looks digressive, too. SRP seems to know some tricks, so I believe that they could have made a digressive/linear piston behave as shown on Drew's plots.

Drew, that looks like a wonderful amount of low-speed compression adjustment. My max and min curves lie on top of one another up to about 2"/sec before they gradually diverge. It's actually very sad to look at, and I hope SRP can do a lot better for me.

 

[QUOTE=Orthonormal,Jul 10 2010, 10:35 PM] Drew's rebound side looks digressive, too.

 

My VDP/linear pistons had their knee that high on the VDP side. And my double digressive pistons are set up with the knee around there too.

 

I am not saying it cannot be done. I would just ask why you would want to? What's the reason why you would want a digressive curve with a knee at such a high force?

A digressive curve typically works to eliminate high forces at higher rates (i.e. greater than the low rates where good handling is desired)? The goal would be to absorb high speed inputs and keep the tire on the ground.

 

That's exactly my thought, low speed is the handling, high speed it the road defect. If anything I want the blowoff not ramp up to be able to use the berms, not send me into low-earth orbit.

 

I'll try and dig up the invoice, but I'm 99% sure its an L/VDP piston.

Are you trying to say that in your experience Penske linear rebound pistons flatten out like that at x force(defined by the shim stack) regardless of the position of the adjuster?
My rebound curves look exactly like a friend of mine's 8300's with a dual VDP setup, that's why I ask.