Suspension Theory/Chat Thread

[Highrev1]

Originally Posted by Moose

Hi Rev is soooo Correct here .... the difference in the "quality" and consitency after corner-weighted is amazing ..I regret not doing it sooner on the race car when I had it. Moose

I wish I wrote that but that was from the Grassroots article But I have had many of my cars corner Weighted if that counts

[Sirbelch]

I'll have to find someone round here. I just wanted to give it a go myself. Melter Racing has one employee and that employee likes to do it himself that way he can't get mad at other people.

From what I know, (which is much) it seems like a lot of raceshops are down south. But with 2 quality race tracks near my house (Sears point is 40 minutes from my door and Laguna Seca is 3 hours), there has got to be someone around here that can.

[Moose]

Originally Posted by Sirbelch

I'll have to find someone round here. I just wanted to give it a go myself. Melter Racing has one employee and that employee likes to do it himself that way he can't get mad at other people.

From what I know, (which is much) it seems like a lot of raceshops are down south. But with 2 quality race tracks near my house (Sears point is 40 minutes from my door and Laguna Seca is 3 hours), there has got to be someone around here that can.

Try asking on your local SCCA / NASA /AUTOX MSG forum ... that is where the info is moslt likely to be hidden as to who has rental scales

Moose

[Sirbelch]

Originally Posted by Moose

Try asking on your local SCCA / NASA /AUTOX MSG forum ... that is where the info is moslt likely to be hidden as to who has rental scales

Moose

[hmodel88]

ok i have an LX and i just want to know which is better...

having the font and rear Si sway bars or just the rear???
everyone is posting different things and im just wondering what the definite answer?
thanks

[Sirbelch]

Just the rear will get you more rotation than the front and the rear. I do believe that the LX front sway is 25 mm which is only 4 mm smaller than the Si.

[hmodel88]

Originally Posted by Sirbelch

Just the rear will get you more rotation than the front and the rear. I do believe that the LX front sway is 25 mm which is only 4 mm smaller than the Si.

alright thanks for the info...
now what parts will i need to put it on my car?
just the bar and use the old bolts...??

[Moose]

Originally Posted by hmodel88

alright thanks for the info...
now what parts will i need to put it on my car?
just the bar and use the old bolts...??

New:
-Swaybar (10)
-Swaybar Bushings (11) and D-brackets (12)

Re-Use
-D-Bracket bolts (39)
-Endlinks (15/16)
Endlink bolts (32)



Moose

[Cookstar]

I don't understand how one chooses spring rates for a car. Is there some science behind it? Are there formulas that you use? Or is it some kind of black art? I wanna know.

[Cookstar]

I saw the previous post about the corner weights. I'll start study that section.

[Highrev1]

You really want to find out wheel rates in order to better help determine what spring rates to run.

[Borbor]

Originally Posted by Highrev1

You really want to find out wheel rates in order to better help determine what spring rates to run.

But you can't do that without knowing the motion ratio. On a street car, it's even more complicated, because you have to take into account the ride quality, which means you have to take into account your sprung and unsprung mass. Those 4 values would determine your ride frequency and your hop frequency. Besides, the tires that you run determines the wheel rates for the majority of the time anyway :P

I know that you know, but I'm fairly certain the guy asking the question didn't.

The math isn't that hard. No calculus involved anyway, so it ain't that bad. Just write down all the numbers that you know in their proper units, apply the formula and voila. That's how I roughed in my spring rates, and so far they seem to work well on the track w/o being too harsh on the track.

Now I'm trying to predetermine a damper dyno graph BEFORE I send it out for a revalve

[Sirbelch]

Borbor, what are you running?

[Borbor]

Originally Posted by Sirbelch

Borbor, what are you running?

Koni Yellow with GC sleeves

550 front

475 rear. IIRC. (it's either 475 or 430 rear. Have to chk in the spring if you want. Car's stored at the moment)

If my calculations are corrent, the ride frequency is JUST under 2Hz. It's 1.9 front, 1.7 rear IIRC.

[Sirbelch]

For an FG? Also, wouldn't you want a higher frequency rate in the rear to better promote rotation on corner entry? Don't worry about checking the rates.

[Borbor]

For AP1

[Sirbelch]

Well, then, just forget about the whole more frequency in the back thing.

[Borbor]

I'll see if I can dig up my notes at home. There's a whole reasoning why I picked those rates compared to stock as well as the wheel choice I'm runningn currently.

If I find it, I'll share it with you guys and then you guys can see what to do (or what not to :lol: )

edit: here it is, in its entirety that I've posted elsewhere. This was back in June when my car was still running stock AP1 wheels and S02 tires.

Disclaimer: This post is about how I came about to modifying the suspension on the S2000. Feedback and comments welcome.

First of all, I can hear it already: Honda did a great job in designing this car, how dare you modify something that good already?

Yes, yes, how dare me indeed. Personally, I felt a bone stock S2k would be quite quick on the track with upgraded pads and brake lines. It is THAT nicely sorted out from the factory. The rear bumpsteer issue isn't really that big of a deal IMO, since other than one time where I had to really be on the ball to save the car in pouring rain on the track, I've yet to have any huge oh shit moments.

Having said that, I wasn't too happy with the ride height of the car, nor was I happy with how the car felt over bumps during my drives on the streets of Toronto; so I went out and did about a month of research and calculations of my own before deciding to finally purchase a set of aftermarket suspension.

My first complaint about the S2K on the street is that its highspeed compression is way too stiff. I couldn't quite understand how a car from the factory felt so stiff, yes it handles like it's got velcro between the tires and the asphalt, but man it could get bumpy. I ruled out the Japanese dampers from the very beginning since various dyno plots I've seen show very little changes despite offering you 16 to 32 levels of adjustment. I didn't want to blow a HUGE amount of cash at the moment for suspension as I wasn't sure if a weekend car and an occasional track car warranted Koni race shocks at 950 per corner. So in the end, I decided on Koni yellows with GC coilovers.

AFter making that decision, it was onto spring rate calculations. The biggest mistake I see most people make when they pick out a suspension setup is to read what other people are using, ask them how they "feel" about their chosen spring rates, and then go from there. That doesn't cut it for me. I'm sure there are others out there who are running my rates, but I didn't care about it one bit. After talking over with some credible sources, he suggested 2Hz would be the absolute max I'd want to go for my application. From the various sources I've read (Milliken and Dixon); this seems to be a good starting point for now. So with that settled, it was time to hunt down some magic numbers on the internet.

You can't determine ride frequencies (the higher the frequency, the harsher the ride basically) without finding out the motion ratio of your suspension. If there is one number that needs to be hunted down, it is this one. It determines not only the RF, but also the wheel rate (which is the only "spring rate" that's worth a damn at the end of the day) I'm not entirely sure how accurate the numbers I found on s2ki is, but for now I'll use them before I go and strip my body panels off and measure them physically msyelf. (which I'll probably do sometime in the winter)

So after doing a bunch of calculations and rechecking my units and what not, I finally decided on my spring rates. Ordered my suspension and waited for a month before they came in. Installed it this weekend, and drove it today. The car rides WAY better than stock on the street. (which, as it sounds, is hard to believe). It confirms what a lot of people've been saying how the OTS Koni yellows feel softer than stock; i'm fairly certain the high-speed compression is way softer. 550lb front and 430 rear translates to about 270 wheel rate front and 193 wheel rate for the rear if the motion ratio numbers I found is to be believed.

The ride isn't overly harsh, as a matter of fact it isn't harsh at all. As my mechanic puts it before I left, "even a pregnant woman would have no complaint riding in it"

Cornering wise, I'll have to update later this month when I take it out to the track, but my alignment settings are as follows:


it's a variant of the UK based settings. The ONLY change I made to the UK OEM was the front toe, which I chose to have 0.05 of a degree out. Overall my mechanic did an alright job, the front right camber was off by 0.04 of a deg and the front right caster was off by 0.04 of a deg, something which I won't feel behind the wheel.

Car's dropped 3/4" all around. I can already see I should've done 0.5 front and 0.75 rear; for now the car looks dropped in the front, but not in the rear :P

Rear rebound is half a turn from full soft; just so I don't get too soft a rear rebound to load up the front too quick and have the rear end come out on me too much. The front is already lower than the rear, even at the same reduction in ride height, which means as it is, it'll promote turn in. Ride height turn in promotion + front toe out (another factor that promotes turn in) and you get a really pointy car; gotta counter that with a slightly stiffer rear rebound relative to the front to offset those effects.

[Zeuceone]

translation..?

[Sirbelch]

It takes a lot of work to pick a good suspension. Its more than just slaping on some coilovers and calling it a day.