bronxbomber252

well I read this and looked back at my dyno plots... I noticed 2 things. One is the near full stiff settings I am using now has too much rebound by you definition. and second that there is some crosstalk between my rebound adjustment and the low speed compression. At softer rebound settings it appears I have more low speed compression damping... would you recommend trying backing off my rebound settings a little and seeing if it's better? (single adjustable custom valved koni yellows)

TheNick

Yeah on my SA Koni's I ran near full soft with 800lb springs. It was way too stiff otherwise.

bronxbomber252

sweet I well try that out. Thanks!

PilotSH

Ok, I REALLY hate to be a pot stirrer, but there is so much FAIL going on in this thread with the amount of misinformation, and I think it's confusing a lot of ppl into going the WRONG direction with their shocks.

First off, Koni twin-tubes do NOT need gas pressure to have compression! Sorry Nick, but I'm gonna trust the engineers (not just Lee) at Koni over your thoughts on this. Koni OFFERS their rebuilt shocks without gas pressure to autoxers. On a Koni twin-tube, the displacement of fluid from the inner tube to the outer tube (caused by the shock shaft entering the shock body) thru the compression (foot) valve is what gives/controls compression. Even with the shocks degassed, there's still air in the outer tube (at atmospheric pressure). Whether that air is lightly pressurized or not, there's no way that it's greater than the hydraulic pressure building inside the inner tube during the compression stroke, so the pressure of the gas is negligible in regards to how much the compression force of the shock.

The degassed Koni twintubes had the advantage of slightly lowering ride height for stock class cars and that's why they were offered. As for proof that it doesn't screw up the compression, I had the rear shocks of the S2000 I was driving rebuilt in the Koni trailer at 2008 Nats. Lee did not have a nitrogen tank in the trailer to regas the shocks, but he told me it wasn't neccessary. I put the shocks back on, and the car went on to have the fastest scratch times on the east course, so I don't think there was an issue with no compression due to them being degassed.

For more info direct from Lee himself, look at this thread:
degassed Konis

I'll start another post on the other big problem i have in this post.

James Yom

bronxbomber252

Just backed them off to a little less than 1/2 stiff... went for a test drive... the car may have leaned a little more but was much more glued to the road, much more stable, and FAR more forgiving. Thanks!

glagola1

Yep, that's the trade off. You get better grip but more body roll on entry... to beat a dead horse, that's why you need lowspeed comp!

PilotSH

Sorry Matt, but I'm gonna have to totally disagree with you. Rebound, and low speed rebound to be exact, is really important and is what gives us the ability to tune the car most effectively. If it wasn't important, then why do most higher end single adjustable shocks (JRZs, Penskes, ASTs, etc) all control rebound and not compression? Tuning weight transfer is the name of the game, and low speed rebound is how it's done. Compression does help to a point, as it increases the responsiveness and turn-in of the car due to faster loading of the outside tires. but too much and the high compression makes the outside suspension too stiff for the car to soak up bumps, skipping all over the place. Using rebound allows the car to transfer weight quickly but doesnt require the outside suspension to be so stiff that it's skipping over rough surfaces. Now, too much rebound will cause jacking down of the suspension, and that's not what we want.

In terms of having so much low-speed that at turn-in the inside wheels lose touch with the surface, I seriously doubt that. Really big sway bars might do that, but not shocks with tons of lowspeed rebound. When you're talking about hitting a bump in the road, yes the tire may lose touch with the surface for an instant, but not at turn-in on a decent paved lot.

I find your shock dynos to be really interesting in that they are the only ones I've ever seen with a progressive curve for autox. Is this the standard Moton valving or is this the autox valving that Saini put together for Moton? I've driven Saini's winning car with Motons before, and I don't think those dyno plots woulda made the car handle the way it did....

Now, this is based on the OP's setup of a stock car running shocks. I know you're doing the tuning on your STR car with very stiff springs, and that changes the game of tuming completely. I'm still researching the relationship with stiff springs myself, but one thing I do agree with you is, you have to go out there and just turn knobs and find what you're comfortable with. If running your settings works, that's great, but making blanket statements that low-speed rebound is the devil will just cause a lot of confusion.

my 2 cents.

James Yom

glagola1

Yeah, well, you know, that's just, like, your opinion, man...

No, but seriously, that's old school thought and the convention. It's wrong in my experience. I've been bucking tradition since 2004 which is also the time that I got my first set of Motons. My curves above are of revalved Motons. The off the shelf Motons for the S2000 are the curves that Saini helped develop. Here are the OTS Motons:



I'm not going to try to convince you here more than I already have. Just give some a try before you completely believe what you think.

PilotSH

If there's one thing that people will never agree on, it's shock valving in autox. I feel like it's more an art than a science. In the 7 years that I've been involved in S2000s in AS/BS, I've seen several different shocks win, with very different opinions that people had on each set of shocks. I've seen ppl win on Ankeny's Penskes, but I've seen ppl poo poo those shocks saying the Motons are better. I've seen ppl poo poo the Motons, saying a different set of Penskes are better (Stimolas). But like I said, all of these shocks have won a National Championship. Now, knowing the background on all of these shocks, I know which one I would go with...

I just wanted to make my point that your opinion is bucking the trend. Whether that's the right way or wrong way, that's up to everyone to decide, but what I didn't want is for ppl to think that that's the traditional way ppl thought of shock tuning. In light of your recent success, I didn't want ppl to think that your way was the norm, only to find out it doesn't work for them. Of course, comparing STR's 900lb springs to the stock 200-300lb springs is like comparing apples and oranges, so ppl need to also be aware of the context of the poster's experience. Who knows, mebbe less low-speed rebound is the way to go for STR...

Hopefully we can find out whose setup is correct one of these days when we get to run against each other.

James Yom

macr88

Anything on this ^

Edit: this is rebound I'm talking about.