Spring Rate advice for ITA Miata

[JohnW8]

Without revealing any personal or team secrets regarding spring rates, is there any particular range of spring rate that works well with the NA Miatas for ITA competition?

I come from a SOLO back ground and what works well for me there may not in ITA. I'm just trying to get a little feedback to make sure I'm not making a big mistake putting on softer springs from the 700/325lb springs that came on the car.

Any advice would greatly be appreciated.

[tnord]

which shocks?

[JohnW8]

I'm using the Spec Miata Bilsteins that came with the car.

[Marcus Miller]

1.6 or 1.8?
what sway bars?
what tires?

[JohnW8]

1.8L with Eibach Spec Miata 27mm front 15mm rear sway bars, I'll be using Kumho V710s 205/50/15

[tnord]

1.8L with Eibach Spec Miata 27mm front 15mm rear sway bars, I'll be using Kumho V710s 205/50/15

i have the SM bars as well, but will be using Koni 8041 Race shocks instead. the SM bilsteins can't effectively dampen the higher spring rates, as they are just OEM street shocks from the R-package cars.

i just bought 850 and 800 to try out for the front, and 400 for the rear. we'll see how it goes.

if i were you i would go down to like a 700lb front spring (from 750 iirc) and use the SM rear (350?).

[Marcus Miller]

Trav, sm is 700 /325.
John, what is the goal of changing springs?
maximize the speed of the car without changing shocks or bars?
Are you willing to revalve the shocks?

if we aren't touching the shocks/bars, I would run 650/350.
If you are willing to play with the shocks, I would look at the ranger Travis is in.

Properly valved, the bilsteins are okay, just not a adjustable as the koni/JRZ world.

[tnord]

i'm with marcus.....with existing shocks i'd go 650/350 given what he posted as correct SM rates. if you're willing to send the bilsteins off for revalving.....then the rates i'm using might work, maybe slightly less.

[JohnW8]

Thanks for the info guys. I believe the Bilsteins are just not up to the job of the 700lb springs. AS a matter of fact I believe one if not 2 shocks have bad seals in them. I just wasn't sure if the Miata drivers were increasing or decreasing the spring rates compared to SM. I will be changing out suspension soon enough, I just want to get through the DD School at Roebling before I dump more money in the car.

Thanks!

[Marcus Miller]

in general, we are going up in rate, but we aren't using the sm shocks :)
like i said, bilstein can revalve them to make them work at higher rates.

for posterity, I'm using the following on my 1.6:
sm 1.6 front bar
stock 1.8 11mm rear bar
koni 8041-race
springs are 800/450

Marcus

[VinnyV81]

Hey John! Good to see that your car is coming along. These guys sound like they know what they are talking about. Best of luck to you at the RR school.

-Vincent.

[Andy Bettencourt]

I crept up on my set-up as well. 850/400 is where I feel I found the best balance and grip without a splitter.

[JohnW8]

What is the advantage to going to higher spring rates?

[Andy Bettencourt]

What is the advantage to going to higher spring rates?

Less body roll? Was that a trick question? :)

Seriously, at some point, there is too much spring for this car. I am just not convinced I have found it yet. I have ceratinly sacrificed wet-weather performance (I can run just as fast in our SM rental cars in the wet) for dry weather grip.

The issue with this car is that it feels great no matter what you do. With our ITS RX-7's, you know immediatly if you did the wrong thing in terms of set-up. Finding the fast set-up for me is done primarily with the Data and the stopwatch.

[IPRESS]

John, Let me recommend speaking with Shaikh at Fatcat Motorsports in CA. He has done a lot with the Bilstiens. He is a very good source for info on what you are looking at.

[Marcus Miller]

Less body roll? Was that a trick question? :)

Seriously, at some point, there is too much spring for this car. I am just not convinced I have found it yet. I have ceratinly sacrificed wet-weather performance (I can run just as fast in our SM rental cars in the wet) for dry weather grip.

The issue with this car is that it feels great no matter what you do. With our ITS RX-7's, you know immediatly if you did the wrong thing in terms of set-up. Finding the fast set-up for me is done primarily with the Data and the stopwatch.

Lower static ride height to gain camber while staying off the bump stops? :)

[JohnW8]

Lower static ride height to gain camber while staying off the bump stops? :)

That's why autocrossers use the higher spring rates. I'm thinking as fat as that SM swaybar is there's plenty of roll control. I'm a total noob when it comes to this Road racing stuff and I never imagined there was so much to think about, worry about, set up, configure, tune, tweak etc etc. Maybe I'm overthinking it. I take advice well and learn from trying so this should be fun getting the license. I'll worry about getting faster as my seat time goes up. Thanks for the info.