Alright so I know a few of us have been looking into STX for our Cobalts. STX is a fun class and seems open to a good driver with a good setup every year at nationals. Right now it seems that the IT car to have is the Mazda RX-8 and in 2012 the rule gap will be clsed that allows they 89 civic si to run STX.

This thread is for any STX steup questions that we have and info sharing, if anyone wants to share their setup

SCCA Rules for STX are as of the 2011 Rule book

14. STREET TOURING CATEGORY
The Street Touring category of vehicle modifications is meant to fit between
the current Stock and Street Prepared categories. This category
provides a natural competition outlet for auto enthusiasts using affordable
sports cars and sedans equipped with common suspension, engine,
and appearance modifications which are fully legal and compatible
with street use anywhere in the country
Vehicle eligibility lists are now in Appendix A.
Under the provisions of Section 1.1 of these rules, Regions are free
to allow any other version of the ST concept which meets their local
needs. In particular, some leeway in the area of bodywork allowances
(e.g., wings/spoilers beyond those allowed in 14.2.F) is encouraged at
Regional Solo events.
See Sections 3.8 and 8.3 for documentation requirements.
14.1 AUTHORIZED MODIFICATIONS
All Solo Rules Stock Category allowances, plus all allowances contained
in 14.1 through 14.10.

14.3 TIRES
Tires must meet the eligibility requirements of the Stock category with
the following additional restrictions:
A. Tires must be mass-produced standard production tires designed
for normal highway use on passenger cars. Low volume and/or specialty
tires will be specifically excluded below.
B. Tires may have section widths up to and including the following:
ST, STS, STR (AWD) – 225 mm
STX (AWD), STU (AWD) – 245 mm
STR (2WD) – 255 mm
STX (2WD) – 265 mm
STU (2WD) – 285 mm
C. Tires must have a minimum UTQG treadwear rating of 140 and a
minimum molded tread depth greater than 7/32” as manufactured.
D. Tire models must not appear on the following list, which may be altered
at any time by the SEB upon notification of the membership.
Pirelli P Zero Corsa
14.4 WHEELS
Any wheels are allowed with widths up to the following:
ST, STS, STR (AWD) – 7.5”
STX (AWD) – 8.0”
STX (2WD), STR (2WD) – 9.0”
STU – unlimited
14.5 SHOCK ABSORBERS
A. Shock absorber bump stops may be altered or removed.
B. Any shock absorbers may be used. Shock absorber mounting brackets
which serve no other purpose may be altered, added, or replaced,
provided that the attachment points on the body/ frame/subframe/
chassis/suspension member are not altered. This installation may
incorporate an alternate upper spring perch/seat and/or mounting
block (bearing mount). The system of attachment may be changed.
The number of shock absorbers shall be the same as Stock. No
shock absorber may be capable of adjustment while the car is in motion,
unless fitted as original equipment. MacPherson strut equipped
cars may substitute struts, and/or may use any insert. This does not
allow unauthorized changes in suspension geometry or changes in
attachment points (e.g., affecting the position of the lower ball joint
or spindle). It is intended to allow the strut length changes needed to accommodate permitted modifications which affect ride height and
suspension travel.

14.6 BRAKES
A. Cross drilled and/or slotted brake rotors may be fitted (same size/
type/material as standard) provided all such voids are within the disc
area, and comprise no more than 10% of that area.
B. Brake lines may be substituted with alternate DOT approved flexible
brake lines.
C. Air ducts may be fitted to the brakes, provided that they extend in a
forward direction only, and that no changes are made in the body/
structure for their use. They may serve no other purpose.
D. Original equipment ABS braking systems may be electrically disabled,
but may not be removed or altered in any other way.
E: STX and STU: Non-standard brake rotors may be used provided
they are of equal or larger dimensions (diameter and thickness) and
made of ferrous material (e.g. iron). Thickness includes the individual
plates of a vented rotor, as well as the overall dimension. The diameter
for replacement rotors is measured at the minimum outside dimension.
Aluminum rotor hats are allowed. Cars originally equipped
with solid (non-vented) rotors may utilize vented rotors. Cross-drilled
and/or slotted brake rotors may be fitted provided all such voids are
within the disc area, and comprise no more than 10% of that area.
Brake calipers and mounting brackets may be replaced provided they
bolt to the standard locations and the number of pistons is equal to or
greater than standard. A functioning emergency brake of the same
type, operation, and actuation as OE must be present. Drum brakes
may be replaced with disc brakes of a diameter equal to or greater
than the inside diameter of the standard drum. Such conversions
must be bolted, not welded, to the axle/trailing arm/upright, and must
include an integral, redundant emergency brake. Changes to backing
plates/dust shields/brake lines to accommodate these changes
are permitted but may serve no other purpose.
14.7 ANTI-ROLL (SWAY) BARS
Substitution, addition, or removal of any anti-roll bar(s) is permitted.
Bushing material, method of attachment, and locating points are unrestricted.
This does not authorize the cutting of holes to route the bar(s)
or links. Components such as anti-roll bars and strut housings that
serve dual purposes by also functioning as suspension locators may
not be modified in ways that change the suspension geometry or steering
geometry. Non-standard lateral members which connect between
the brackets for the bar, including allowed strut bars per 14.2.G, are
permitted.
14.8 SUSPENSION
A. Ride height may only be altered by suspension adjustments, the
use of spacing blocks, leaf spring shackles, torsion bar levers, or
change or modification of springs or coil spring perches. This does
not allow the use of spacers that alter suspension geometry, such as
those between the hub carrier and lower suspension arm. Springs
must be of the same type as the original (coil, leaf, torsion bar, etc.)
and except as noted herein, must use the original spring attachment
points. This permits multiple springs, as long as they use the original
mount locations. Coil spring perches originally attached to struts or
shock absorber bodies may be changed or altered, and their position
may be adjustable. Spacers are allowed above or below the spring.
Suspension bump stops may be altered or removed.

Now This is just some of the info, the rest can be here
http://www.scca.com/documents/2011%2...lo%20Rules.pdf

Pleas post links up to part that would work for this calls as you find them, like wheels, coilovers ect ect since our options with the cobalt is small.

 

Great thread idea! I'm running an 09 SS Sedan. I have Pedders,245/40/18 Star Specs on the OE wheels, Hawk HP plus on the front and a 1.25 rear bar. -1.9 with 1/8 to out front. I tried the XXX bar but found the car car to be too tail happy for some of the courses we run in this area. We have two lots to run on, one small and tight and the other is run on the taxi ways of our local military base so it has very fast transitions that can't always be done under full throttle so the 1.25 seems to work best for my driving style. The first event with the smaller bar was in wet conditions and I was able to get FTD overall and PAX by 1.7 seconds over the 2008 SCCA D stock national champion in his type R. I think the XXX(1.5) would be the ticket with wide R comps. My Forgestars have finally arrived and it only took 17 weeks! I'm hoping to get my new tires before the event this weekend, come on UPS!! I'll have 18x8.5's with 255/35/18 star specs. I'll update early next week.

 

wow 245-40s on stock rims? nice!! I have been running 235-40s at street tire events.

 

Great thread

My set-up: 255 Hankook RS3s on Team Dynamics Pro race 1.2 wheels 17x9s with a +30 offset. Occasional rub in the back over really big dips at high speeds but have never rubbed on track. Camber limited due to strut clearance up front to 1.7* Hawk HP+ front HPS rear, Like the rear pads fronts HP+ seem to like they need to much heat for shorter autox and can't handle enough for track days, Pretty good for large autox courses though. Hardcore rear bar and padders springs. Working on a nice STX HP tune, the 7k rpm redline is great.

Currently looking for a good camber plate option for the front. John Powell recommends the VW Ground Control ones, very nice and great quality and value but, you have to hack up your strut towers. Jbody performance has some But, everyone hates that company. No ones been able to tell me about their camber plate quality though. Overkill Engineering Motorsports says they can make me some for $300 but without knowing much about them I'm hesitant to send them money without seeing the product first. If anyone has any thought on that llet me know. I've thought about elongating the hole on the stut tower just a very small amount. Pretty sure just a few mm on the holes should net me about another 1/2 a degree of camber. thoughts?

 

The 245's were a last minute choice as my OE tires were done and the 8.5's hadn't shown up yet. I figured the new wheels would be in a week so no big deal but that wasn't the case as it's been closer to nine or ten weeks. Both the 235 and 245 call for an eight inch wheel min and the 245 would be better on the 8.5 so I went that way. They do rub on the rear over bumps or with weight in the back. I'm still surprised at how well they have performed on such a small wheel. Looking forward to the 8.5's.

 

I don't have any info on a camber plate but there is a TSB that allows some modification to the front suspension that will allow you to get three degrees of negative camber up front. I'm sure your local dealership could give you more information on the process.

 

He can't do that mod because there is no strut clearance as it is. If it were me, I would run a small spacer and do the mod. Shocked how much camber I was able to get with it (although I did the upper and lower holes on my car).

 

coilovers tend to have a smaller shock body so that might help with the clearence issues.

I have started looking up wheels and tire sizes for my build, if it happenes.

If i go with a similar wheel setup as jboogie I would think about going 265 w/coilovers. If i went with a 265-40-17 the tire sidewall .7in taller than stock, and that can hurt overall gearing a bit. Sadly no one makes a 265-35-17 lol.

 

I could run a spacer no problem. I've already got longer arp wheel studs after breaking one at an event a few weeks ago. I am seriously concidering pulling the struts and looking at the bottom of the stut tower and if it seems beefy enough slotting the holes. Just 5mm should get me more than enough to run 2.5*

 

I've been running my all-seasons on the back on the street for the past few days. 255 h-s3s front 225 continental dws rear and I really like it! The beak away isn't as smoothe as the hankooks but I really love the rotation. I think next season I'm gonna try 265 fr 235 rear starspecs. Maybe even try powels xxx rear bar with an eibach front, it should keep more camber through a curve with the upgraded front bar. Just a thought.

 

yeah a staggered tire setup would be nice but at 180 a tire i wana rotate them for the 1st season lol. and depending on car setup i think that would decide what size to go with in the rear. 255, 245, 235.

 

There is plenty of beef, just did "the mod" this past weekend. Camber dramatically increased, clearance a bit tight for my 255/35r18 RE-01r street tires (on 18x8s), plenty of clearance on the stock wheels and 245/35 A6s.

Edit: Talking about the strut mod, not the strut tower mod, misread post.

 

I was thinking the same thing. I talked to multiple tires shops on getting me the star specs and they all said they run wide and didn't recommend anything larger then 225 on the stock rim.

 

i went 235-40-18 and they fit just fine, no issues at all. The tire shop just doesnt want to order a special order tire, install them and then they dont fit lol.

 

Ran through 2 sets of 245/35-18s Kumho XS on stock wheels. Loved'em....when it was hot

 

I have 255/35/18's on 8.5's with a 35mm offset and 1.9- on the front. The tire on the inside is about an 1/8 away from the swaybar mount on the strut. I'm not sure how much more camber it will take. I opened my strut holes up as well and yes there is plenty of meat.

 

Kumhos and Hankooks need heat like most tires but they seem to like a little more and they take it very well.

 

I currently have star specs, and they seem to not like getting very hot. I spray them down after every run, but they were still just pushing through turns like crazy at the last event. I decided I would not light them up at the start line and that helped a lot. Just my 2 cents about those tires.

 

agreed. i am on star specs for my street tires right now and I give them one run to heat up but then they need spray if its to hot out. They like the cold, they do very well in the wet, they just need to be kept warm, not hot lol.

 

Update for anyone interested in the strut mod. I did the mod this past weekend (enlarged holes in the strut), and I just strung the car to align it, so I was only able to set toe.

Finally got the car on the alignment rack today, found I was able to get 2.8* negative camber on both sides with the stock bolts. Didn't want to go much further with the 255/35r18s, they were pretty close to the struts.

 

2.8? Must have gone past the ring then? Cause I went up to the ring and only got about 1.8 and thats safe for Dstock.

 

I did the upper and lower holes to the ring. I realize that only the lower is legal (?), but DS isn't much of a concern to me anymore, stuck in DSP at hillclimbs (SOLO 1, no stock classes).

 

ahh i see. yeah i only have to worry about DS right now thats why I ask.

 

Let me know how the 2.8* works out. I'll probably go 2.5* cause it's still my DD But, I think 2.8-3 would be perfect if you could get the power down.

 

Well right now I have been looking into coilovers. I have emailed Ground Control, KW, Pedders asking about spring rates. Thus far I have only heard from Pedders and they were less than helpful lol. I am trying to setup a possible situation where i can change spring rates if needed. I would like to start with 850lb springs in the rear and maybe less up front, but Im working on that.