<Caveat>: I understand full well that the chances of any S197 being competitive in STX at the national level is a wet dream. With the top competitors in STX being Civic Si's and being light weight at that, even the new Fast Track rules if approved would not make STX any more friendly for the S197's new Street Touring home at the national level. These thoughts are more for local than national level competition. I also understand that Vorshlag is doing this with a 2011 Mustang GT, and I'm not surprised they are having troubles making it perform the way they want. Too much power, not wide enough or grippy enough tires, not having worked on fixing the rear suspension. I hope it turns out to work in their favor and break the mold on S197s skipping the STX class for ESP when they start modding. </caveat>
Warning: LONG POST WITH NO CLIFFS!
Locally the fastest STX driver here that I've seen is an unknown prep Acura Integra Type R. At the last event (not a good event for me) he ran a fastest time of 47.316. I ran a fastest time of 50.093. I think with better tires and better suspension I could make up 3 seconds of time on a 50s average course. For sure it is set up to run well, lowered, front splitter, nice wheels and tires I'm assuming shocks/struts as well. I think it's achievable locally anyway.
Street Touring is is a very interesting class, the STX category allows 9" wide wheels and 265mm wide tires for 2WD vehicles, but allows a TON of suspension modifications for live axle cars that are both interesting and nearly equal to ESP in terms of prep level. I've created a short list of items that are approved suspension wise that are applicable to us steel girder rear suspension guys:
-Strut Tower Bar (2 point)
-BOLT ON Sub Frame Connectors
-265mm width tires, 140+ treadwear, 9” wide rims
-Shocks/Struts and mounts open
-Coilovers (provided the rears use an adjustable spring perch and don't convert to coilovers like the Griggs set up)
-Stainless Steel Brake Lines
-Any brake pads and fluids
-Front and Rear Sway Bars
-Camber plates are allowed
-Torque Arm (can't be attached to Sub Frame Connectors)
-LCA Relocation Brackets
-Cold Air Intake + Tune
-Full Exhaust (must retain high flow Catalytic Converter in close to stock location)
-Short Throw Shifter
-Aftermarket Limited Slip Differential
That is A LOT of modifications to make up some time. I'm confident new tires will be at least a second or more. The problem is going to be Weight, weight and more weight and no way to remove lots of it.
Here are my thoughts on this: I've already determined that next year is another year in F-Stock but on new tires, hopefully shocks/struts and front swaybar. That takes care of what I'd consider some of the larger expenditures for the car. The tires being a recurring cost every year (maybe every 2, we'll see how the star specs wear) but here is ultimately my plan:
Dunlop Direzza Z1 Sport Star Specs, this was obvious. Size for the proper STX build would be 265/35/18s on a 9" wide rim which is pretty easy to accomplish for the S197 but next year will be 245/45/18's on the stock wheels for F-Stock.
Koni Yellows, if I can get them. The fronts are still on national back order...
Strano Performance Parts Sway bars with competition endlinks. I plan on running the front for sure next year in F-Stock, having them both allows me to add the rear when I jump out of F-stock to whatever class.
That pretty much covers the cross-over between Stock and ST, now on to the good parts!
Steeda Competition Springs, should be 225lb/in front and 185 lb/in rear. Drop is only 1" front 1.25" rear. These are supposed to be linear springs which me likey!
Camber Plates/Strut Mounts:
Steeda HD mounts. These should allow me to dial in a more aggressive camber setting. Shooting for the -2º mark, maybe slightly less. Should be easily achievable with the lowering springs adding some and then the rest on the HD mounts.
Fays2, this has been obvious for quite some time that this would be going on my car!
This should take care of the axle stepping out sideways from lowering and should fix the PHB geometry issues.
LCA Relocation Brackets:
The rules are pretty iffy. The rules state that the lower control arms cannot be replaced or relocated but the mounting points are open as well as bushing material?? I take that to mean I can't move them inboard/outboard from the stock locations, but mounting them higher or lower at the axle side is acceptable? If that is the case, Steeda's LCA weld on Relocation brackets sound like a great idea. Many holes to get the level LCA's at the lowered ride height and if I need more anti-squat then I can adjust them lower on the axle side.
This addition was the part that is shocking to me in Street Touring. I can understand "replaced" but it says "A torque arm or traction arms can be added or replaced". The only stipulation on mounting a torque arm states "6. SFCs may not be used to attach other components (including but not limited to torque arm front mounts or driveshaft loops) and may serve no other purpose." Being as Griggs is the only company that produces a quality Torque Arm for the S197, and that Griggs does not use SFCs in the S197 packages, the Griggs T/A does not attach to the SFCs (since there are none in their package) and even if I added SFCs they still wouldn't attach to the SFC. Instead it attaches to the boxed portion of the floor pan just behind the transmission near the H in the exhaust pipes. There are no other stipulations on mounting a Torque Arm, so it can be welded or bolted. I'd plan on welding.
I'm sure some will wonder "why?" on the torque arm, and all I have to say is:
2009 Mustang GT Autocross - Oskaloosa Airport, Oskaloosa Iowa - Run #1 Suspension View - YouTube
The Pinion angle changes, the violence of the up and down motion and the PHB geometry as a whole just frustrates me. I'm sure that the majority of the issues with pinion angle change is in the LCA bushings flexing under hard acceleration, but I'm hesitant to put poly/poly bushings in the stock LCA's let alone use poly bushings at all on either end. I'm not sure replacing one end with poly and leaving the other the stock rubber bushing will help even a little. The Torque arm eliminates the issues with the LCA bushing compliance in the pinion angle change, and should allow them to do their job properly without binding. I'm sure just getting shocks and springs would calm the rear end down significantly too.
That right there should put down a pretty impressive array of suspension components to cut time off of the car. Being as I'll be running the car for 2 years in F-Stock I think it would be a fun build as a step between ESP (where I'd like to be) and F-stock where it will be coming from. You'll notice I have not added power, or touched the brakes yet. Eventually I'd like to take this car to some "fast friday" events at the now open again Mid America Motorplex's road course, which will have me adding the brake cooling ducts (probably fab up my own), stainless steel brake lines, brake pads with their own set of OEM brake rotors. This class seems to be the perfect balance of consumables (Tires) and performance. A CAI is legal with a tune, and it may be an option if I feel the tires can take the added punishment of a few more HP. We'll have to see if the Dunlops will hold the stock power well enough in a corner.
I think the nice thing about the above suspension set up is a set of wide A6's on wide wheels would land me in ESP with a semi competitive set up. I could even get more aggressive with the dampers and springs using a set of Coilovers (KW Variant 3's most likely, with some form of high quality spring in the 400 lb/in front and 200 lb/in rear range).
What do you guys think? Obviously weight is the big issue for competitiveness. Adding a Torque Arm adds unsprung weight to the heaviest suspension in the car but improves the geometry of the rear end SO MUCH I think the improvements would be worth the added weight. The question is down to whether or not the Dunlops can remain sticky without going greasy.
Comments? This is obviously quite a ways out time frame wise, so don't expect build updates. I'm not sure I'll even go this route, more or less playing to see if anyone else thinks it has any merit locally against stiff national level drivers. Am I just a nutter thinking it could be competitive locally? Don't answer that