PilotSH

To the OP:

so these shocks were built to the same exact spec as the Grimes/revalved A Stock valving that a bunch of people have(except for the DA part)? Do you know where your compression valving weighs in vs the single adj (single adj. valving is in low, high, or middle of your adjustment range?)?

Having had some seat time on those shocks, I'm trying to get a baseline for when I throw on my TC Kline DAs. From your plots and comparing them to Robinson's, it does seem that the TC Klines have more adjustment on the stiffer end, which is what I was hoping for.

Can they revalve the compression on your shocks to go even stiffer, or is that the stiffest valving they have?

Thanks,
James Yom

robinson

FWIW, at the last autox at Lincoln, I used only 3 of 7 clicks of compression f&r, and not much rebound. So, I think anyone with a TCK koni will probably be fine.

sirbunz

No, the TC Klines were built for the Car & Driver T2 S2000 back in the day when the S2000 was classed there. Call TC Kline if you need specifics.

The auto-x valving was as a result of some testing Koni did for a customer with an S2000 that wanted shocks fine tuned for auto-x and tracking. Call Lee Grimes if you need specifics.

I did some further development with the Koni Yellows for my front shocks and had Performance Shock custom built me a pair with stiffer rebound and compression. Call Performance Shock for specifics.

-Marc

Forcednduckshn

James,

Yes, they are the double-adjustable's, but I'm not sure how the compression of the single adjustable's compares to the range offered by my double-adjustable's. I'm sorry, I can't even speculate. I'm also not sure how much farther they can go on the compression, though I have heard it is reaching an upper limit in these units.

After tuning my shocks a bit in 2 events, I can say that having the compression adjustability is a big deal. I've heard some people say that compression is less important than rebound...I completely disagree. The majority of my testing thus far has been by starting lower and increasing compression, particularly in the front. I started at 4 of 12 Front and Rear for the event, and each time I went higher the balance got better and better. I'm at 7/12 right now in the front for a decently grippy, and pretty flat/low amount of bumps lot (Devens, MA.) The car felt better and better by doing this. (Specifically, the car was more stable in transition and kept the inside rear wheel down under tight cornering/larger or more abrupt than ideal steering inputs.) I never got any skating or turn-in understeer issues. I haven't even touched the rebound yet, which I set at 1/2 half turn from full stiff front, 3/4 turn from full stiff rear. I chose the rebound settings purely based on what I thought the car would need, and it feels very good thus far but of course it may be completely different once I get a few more events under my belt and get close to what I feel is an ideal baseline to bring to most events. My sense is that I may go up 1 more click in compression, and maybe back off the rebound a bit more in the rear as I'm still getting subtle inside wheel lift in hairpins/tighter corners.

I won my class at Devens at the NER SCCA Regional (Devens) and took #5 Pax amongst some full prepped cars and drivers. Everyone in stock class was on sticker Hoosiers. I also left time on the table by not downshifting in the 2 tight elements that were offered. I was going more for consistency and verifying the shock settings were doing good things. I would guestimate a few choice heel-toes to 1st would have netted another 3 or 4 tenths raw time. I figure I'll save serious abuse on the car for later in the year.

Pax Pos. Pos. Class # Driver Car Model Total Factor Pax Time Diff. From 1st
1 1 ES 180 Jeff Anderson Toyota/MR2 55.739 *0.829 46.207 0.000 0.000
2 1 CS 63 Bud Collins Pontiac Solstice 55.109 *0.840 46.291 0.084 0.084
3 2 ES 167 Billy Davis Mazda Miata 56.206 *0.829 46.594 0.303 0.387
4 2 CS 89 Mark Daddio Mazda RX-8 55.477 *0.840 46.600 0.006 0.393

5 1 BS 188 Nicholas Barbato Honda S2000 55.028 *0.847 46.608 0.008 0.401
6 1 DSP 188 Nathan Whipple Hype-Arrrggg.... 54.907 *0.849 46.616 0.008 0.409
7 1 BSP 198 Todd Kean Mitsubishi Evo 54.149 *0.865 46.838 0.222 0.631
8 1 DS 39 David Gott BMW 330ci 56.900 *0.825 46.942 0.104 0.735
9 1 SS 57 Grant Reeve Corvette Z06 54.815 *0.860 47.140 0.198 0.933
10 3 ES 22 William Brundige Mazda Miata 56.939 *0.829 47.202 0.062 0.995
11 2 BSP 98 Jeffrey Guerrera Mitsubishi Evolution 54.900 *0.865 47.488 0.286 1.281
12 4 ES 122 Matthew Poynter Mazda/Miata 57.440 *0.829 47.617 0.129 1.410
13 1 HS 24 Chang Ho Kim Honda Civic Si 59.407 *0.803 47.703 0.086 1.496
14 2 SS 142 Russ Siggelkoe Lotus Elise 55.501 *0.860 47.730 0.027

-Nick Barbato

Forcednduckshn

Yeah, I don't expect to be at full stiff in the front for the compression either.

captain_pants

This book is quite interesting. I'm around 2/3rds of the way through it. He definitely promotes higher compression damping given his experiences. I'm going to play a lot more with the compression knob after reading this. I'm 100% guilty of following the old way of thinking of setting compression low and then attempting to tune the car with rebound.

But wow: the spelling and grammar in that book are terrible! I'm stunned it got published with that many glaring errors. I know, the author's first language isn't english (and he writes better in english than many forum posters who only speak english), but proofreading services or even Microsoft Word are pretty cheap. There is also a lot of repetition. It's almost like he forgot that he wrote some sections so he wrote them again. He also mentions multiple times that 'critical damping' is the damping rate at which the suspension will not move at all when a bump is struck. That's flat wrong.

There's a definite component advertising the superiority of the JRZ design, but how could he not as he truly believes that is the best way to build a shock. There's tons of good stuff and real-world experiences buried in there if you wade through it though. It's changed the way I think about shocks.

TheNick

Agreed Corey. I think the publisher looked at the original transcript and went "Hell no!, just print the damn thing - I'm not going to fix this!"


My Penske's are valved similarly to what Jan promotes - took me forever to get Stimola to do it - and you'll note that there are some significant yet subtle "pokes" at Joe and Penske in the book - things you wouldn't catch if you haven't spoken with Joe on the phone.

Mine still have way too much rebound - I can do nothing but leave them at full soft. Exact same rebound valving that you have.

Random1

There is a limit to how soft you can go with the Penske rebound with a given needle valve. Were you able to try out different needles?

Based on all my dyno testing with different shim stack valving for the penskes, the rebound damping has a limit on how soft it will go regardless of the shim stack. This is for a given needle valve. The soft setting is at about -3 turns from full stiff (-3 turns and more gives same result). The shim stack valving controls how firm the forces are that can be achieved.

I'll have to go research Penske needle valves as I have seen more than one.

The rebound softness has a limit and at full firm is varied based on the shim stack. See lower right part of graph where all the curves are similar with softest rebound setting.

TheNick

I haven't tried anything new yet Rob. Just sticking with the valving I have until the offseason.

The needles have different tapers and change the amount of bleed. But I'm pretty sure you knew that already

captain_pants

I'm speaking with James right now, he's able to dramatically soften the shocks from what I originally got. Right now my shocks generate around 700 lbs in rebound at 6 inches/second at 3/4 stiff. The curves I'm considering are closer to 350 lbs at the same speed and adjustment and stay at around 1/2 as stiff all the way up to 12 in/s. For comparison, the OEM shocks generate around 200 lbs at the same 6 in/s speed.

I'm going to finish Jan Z's book before I make a decision on my new valving.