BigChuck74

After reading the SCCA rule book, it appears that aftermarket LCA's aren't allowed in STU or ESP. For STU, it also says that they can't be relocated, but it doesn't specifically say that for ESP. So are relocation brackets allowed in ESP?

Also, if I install relocation brackets, I suppose that will throw off my pinion angle and I'll need a adjustable upper control arm? Will the relocation brackets be as effective with stock LCA's?

Norm Peterson

I suggest emailing the SCCA at http://crbscca.com/ for clarification.


Typically, if the rules in a section (such as "Street Prepared") do not specifically allow a particular modification then it is not permitted in that category.


However, it is legal in *SP to utilize offset bushings which can perhaps accomplish what you're trying to do in a class-legal manner (if to a somewhat limited extent).




Norm

Sam Strano

LCA brackets are not legal for ESP or STU.

If you install them you are going to be in Street Mod. And no, it does not change the pinion angle (unless they are installed wrong). LCA brackets change geometry, you don't need different LCA's to make them do what they do. But that said, I doubt you need to do what they do.

UCA changes are legal, and I start there on the cars I setup. Between lowering and fixing the bushing issues up there (which is more responsible for axle wind up than lowers anyway), we generally have no need to worry about lowers after that.

BigChuck74

Thanks for the replys. Definitely don't want to go to Street Mod. Are the brackets and LCA's more for high horsepower applications?

Would upper control arms with good polyurethane bushings be a good upgrade for an STU car. The car is an 05 GT with Eibach pro-kit springs, shocks, struts, sway bars, and camber plates.

UPRSharad

The benefit to the control arms is more relative to load than horsepower, if that makes sense. A 300hp stick car on Hoosier A6s can make more load at the control arms than a 1000hp automatic on regular street tires.

Autocrossing can be quite violent on the suspension, tossing the car around those cones. Personally, I can absolutely feel the improvement in stability from upgraded control arms. But keep in mind, I'm not an FS racer, so I'm not limited to the factory garbage.

With regard to poly vs spherical bushings, the sphericals work better, but they make more NVH, so it's up to you to determine what you're willing to deal with. If it was a racecar, the sphericals would be the automatic choice.

Norm Peterson

Brackets can also correct for lowering that's far enough to adversely affect the understeer/oversteer balance particularly during slalom maneuvers.


There would probably be a little conflict of interest going on unless you do some sort of DIY bushing mod. The bushing stiffness that helps prevent wheel hop adds an uncertain amount of rear roll stiffness. Spherical would clearly be better, but per 14.8.B not legal for ST* and per 15.8.C not legal for *SP (think Prepared, Modified, and maybe Street Mod).


Norm

Sam Strano

It doesn't much matter in your case what might happen, because if you want to stay in ESP or STU, the arms cannot be changed or the brackets added.

As for the upper arm. I do uppers all the time. I have a preferred setup which replaces everything from the bracket, through the arm, to the bushing that is in the diff housing (that gets replaces with a spherical bearing). Not only is it all legal, but it's IMHO better for dealing with bumps than stiff LCA's and I find much better for wheelhop as it's the upper arm that is responsible for controlling the rotation of the axle. Not saying lowers do nothing at all in that way, but again they aren't legal and it's kind of moot here for that reason.

One thing I work really hard at it staying on point with the mods. Not only mods what will make the car better, but also what is ok for those of us who do autocross with SCCA to stay legal.