STX Rules and Setup Questions

[autoXracer]

Originally Posted by oinojo

For around $2k or less can get you revalved (my valving) AST 4100s similar to what I ran at Nationals. I would contact MANN Engineering and speak to Jan.

I just recently did a set for an SFR SCCA member and was very happy with the ride and performance.

Would love to hear your thoughts on the 5/9kg setup over a more traditional 7/9kg spring setup?

[M0nk3y]

Originally Posted by autoXracer

Would love to hear your thoughts on the 5/9kg setup over a more traditional 7/9kg spring setup?

7/9k is traditional?

That’s new to me


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[G_Ride]

Originally Posted by autoXracer

Would love to hear your thoughts on the 5/9kg setup over a more traditional 7/9kg spring setup?

Try it out and see if it works for you.

[autoXracer]

Originally Posted by M0nk3y

7/9k is traditional?

That’s new to me


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I wasn’t very clear. What I meant was spring rates in the range of 7 to 9k. Example a square setup or somewhere in the range of 7/8k to 7/9k front/rear. I know everyone has their preference in spring rates, and sway bars have a big impact. I thought of trying out RCE T2’s 7/9k setup with 22m front and 16mm rear.

[oinojo]

Originally Posted by autoXracer

Would love to hear your thoughts on the 5/9kg setup over a more traditional 7/9kg spring setup?

Swaybars are a speed sensitive device in terms of rate, springs are not - they are linear. Often times if you run more front spring than is needed (ride), you end up on the softer end of swaybar settings. This is good for lower speeds, but often ends up hard to drive and less confidence inspiring at higher autox speeds. You also end up with a setup that is site sensitive when too extreme (extreme high rate/small bar).

Swaybars work exponentially. The more the bar twists, the more rate it will provide to a point. The front bar does a fair job of keeping stability as speed increases. However, the swaybar won't work as well if you limit its movement with stiff springs.

How do you find out what is too much spring? Simple. Figure out the ride frequency. There is enough aftermarket support for this platform that you should be able to tune over/understeer with the swaybars and shocks rather than springs. The springs should just be firm enough to give better response but not compromise ride quality. (2.1-2.2 front / 2.4-2.5 rear)

[justinco]

Originally Posted by Simmons

What seat bracket are people using?

Simmons

You want the Buddy Club mounts. 9lbs each.

Buddy Club Racing seat rail, left/driver side
Buddy Club Racing seat rail, right/passenger side

[justinco]

I have 2 events on the 5k/9k setup so far. It is a little different, but I do not feel it was a drastic change from my 7k/7k square setup I ran at Nats. Or, even the 8k/8k springs I ran the year before. The biggest thing I noticed was the car was much better/faster in fast slaloms.

One thing I have learned is that there seems to be lots of different spring setups that can work. I've gotten feedback from a number of notable people/vendors with drastically different suggestions lol as I try to learn more about how springs affect the drive. Everything from 11k/13k, the 5k/9k, everything in between, and even stiffer front springs ie: 11k/9k.

I will be testing 9k/11k here soon, mostly because I don't know much about spring tuning and want to see how it feels for myself. I have some other combinations to try as well, but Fontana will be here before I know it and I need something that works good soon

[oinojo]

Fontana you need something compliant.

[autoXracer]

Thanks for the feedback! Some good info to think about. I agree there’s various setups that work, and everyone has their own preference. Another reason I love STX, having the ability setup and see what works best for you. I was on a softer 5/4k setup first, then 7/6k. Planning my next move lol, as I have 9k springs sitting in my garage.

[cjd]

What swaybars go with the softer front rate? So many things to try!

[Simmons]

I am 400/350 right now

[strat61caster]

Originally Posted by cjd

What swaybars go with the softer front rate? So many things to try!

I have a 20mm Whiteline front and OE rear and I couldn't get it to work (325/500), but I also didn't nail alignment (the consequences of jumping in over my head) and needed to work on my driving talent. Going to try and make it work this year after trying a 425# spring in various configurations with the other two, like Justin mentioned it's kind of incredible that the car feels relatively the same even with radically different spring setups.

@oinojo mentioned using a 22mm solid Perrin front and the 13mm Mann rear in another thread. For whatever reason stiffening the front/rear in ride relatively equally seems to need a big change in sways to keep the roll balance, the front feels soft and compliant but the rear feels super stiff in comparison (at least on my setup, dampers might be playing a factor), I meant to see if I could figure it out with maths but guess I'm just ambitious without follow through like on those SPC bushings I have measurements for

[justinco]

Originally Posted by cjd

What swaybars go with the softer front rate? So many things to try!

For me, I switched to the Perrin 22m front early 2017 (from the Whiteline 20mm). Ran the 14mm OEM rear all year but now on the Mann eng bar stiff setting.

[oinojo]

yes. swaybar is important and thankfully the aftermarket has a vast amount of bars available to meet the needs. I used a Perrin 22mm on full soft and MANN Rear bar on Stiff. Put power down like a champ... oh yah and a STX tuned OS Giken LSD

Springs were 280/504.