Pat-SoCal

The Koni motorsports on Ming's S4 handle transitions from compression to rebound very quickly and fluently. By far the best displacement shock I've ridden on. I couldn't really quantify for him the need to switch to a nitrogen charged race shock after going for a ride in his car. Although I do think his koni's need a little tweaking on the compression side.

ryans4

...but I'd say most all that I saw (dyno wise) had a huge range of compression adjustment out of the compression adjuster. Just can't get the knee down low like you can in the OHLINS/PENKSE's, and the 82xx is more prone to creeping as it heats up. Not full on cavitation, but defintitely changes.

But still, very much a low speed compression adjustment, and a very good range to play with.

O.W. Kenobi

Would you guys mind speaking in layman's terms for those of us who haven't been reading the latest issues, just in case we may have missed some of the handy buzzwords? :-)

ryans4

...

mono-tube = one tube

twin-tube =two tubes, one inside the other with a cavity between them.

twin-tube foot valve = the valve that the oil passes through to get from one tube to the other (inner to outer).

nitrogen = the gas used to fill a damper

nitrogen or gas charged = a damper whose space not occupied by oil is filled with nitrogen or compressed air.

ambient or non charged = a damper whose space not occupied by oil is filled with air at ambient pressure.

displacement (based) = a damper that relies on displaced oil to generate force. Fluid is displaced as the shaft enters the damper and takes up space that was previously occupied by oil, the oil must now move (in a twin-tube, it moves through the foot valve to the outer tube, in a mono-tube, it compresses the nitrogen).

piston = the "thing" on teh end of the shaft with cool holes cut in it to generate a specific force curve in compression and rebound strokes.

velocity (m/sec or inch/sec) = the speed at which the shaft is traveling.

bypass = holes drilled into the shaft to allow for low velocity "bypass" around the shim stack (see below).

shim-stack = a preloaded or not preloaded stack of differing size shims that are on both the compression and rebound side of a piston. As velocity increases, the shim stack "deflects" to allow more fluid to pass through the piston altering the curve of the force the damper makes at varying velocities.

Tomasz@Startup

Also, better is the enemy of good. Maybe you should not try anything that "may" be better.

Pat-SoCal

REPOST :P

Tomasz@Startup

<center><img src="http://pictureposter.audiworld.com/683/bilstein_01.jpg"></center><p><ul><li><a href="http://www.startupracing.com/Docs/Bilstein.pdf">PDF</a></li></ul>

Tomasz@Startup

Re: on a side note, the difference between your 82XX series twin-tube and an OHLINS/PENSKE is huge..

Pat-SoCal

Bypass is usually referred to as "bleed" with the Penske's. You can normally have up to 8 (I believe) bypass/bleed holes in the shims or pistons.

Shim stacks are built outside to inside with the outside usually being of larger diameter and affecting lower speed shaft movements. VDP's are an exception and are a complicated one at that

Velocity/Shaft speed is important because it makes the x axis of the dyno plot... the y axis is of course force, usually in lbs. per inch.

The Penske and Ohlins dampers are filled with oil then charged with nitrogen via a diaphram either in the shock body (Penske 7500/Ohlins ????) or in the reservoir (Penske 8100/Ohlins ????)