Legality of changing LCA's in SCCA ST-Class

[RainierHooker]

Well, I'm trying to accumulate a pile o' parts for my suspension refresh on my 1990 M3 which should occur as soon as I get back to the States this, or next, month. I'm trying to keep the car as sedate as possable but I also plan on semi-regular Auto-X attendance. To that end I'll be running in SCCA STX class.

The various forums are filled with debates regarding Aluminum vs. Steel control arms. The simple fact of the matter is I'm not so confident in my driving to the point where I think I'll 'need' the expense of Aluminum ones. The car's eventual suspension set-up, with most of the components already in the pile will be:

H&R Race Springs
Bilstien Sport Struts/Shocks
ST Adjustable Sways
AKG Eccentric LCA Bushings
AKG 80A Poly Bushings where applicable
Ground Control Touring Camber Plates

Now, the 2011 SCCA Solo Rulebook states that I may add camber plates (Para 14.8C) and that I may change or modify my lower arms for geometry adjustments (14.8I-2) but not both (also in Para 14.8I-2). My car has a build date of 12/89 and so came from the factory with aluminum LCA's, so you would think that I'd have to use the Alloy replacements. However the steel ones don't change any geometry and are a factory replacement part, and they are, in theory at least, a hinderence compared to the Aluminum ones.

Any scrutineers on here?

[RainierHooker]

OK, I've combed the rulebook over and over. Here are the paragraphs in question:

12.4 STANDARD PART
An item of standard or optional equipment that could have been ordered with the car, installed on the factory production line, and delivered through a dealer in the United States. Port-installed options provided by the factory are considered to be the same as those installed on the factory production line. Dealer-installed options or deletions (except as required by factory directives), no matter how common or what their origin, are not included in this definition. This definition does not allow the updating or backdating of parts...

13.0 STOCK CATEGORY
...Alternate parts listed in a factory parts manual are not authorized unless their use is specifically referenced in the factory service manual or in a service bulletin for the specific model...

...Alternate components which are normally expendable and considered replacement parts (e.g., engine and wheel bearings, seals, gaskets, filters, belts, bolts, bulbs, batteries, brake rotors, clutch discs, pressure plates, suspension bushings, drivetrain mounts, fenders, trim pieces, etc.) may be used provided they are essentially identical to the standard parts (e.g. have the same type, size, hardness, weight, material etc.), are used in the same location, and provide no performance benefit. The allowance for use of such replacements does not include camshafts, differential covers, or ring-and-pinion sets, nor does it authorize the use of piston rings having different configurations (e.g. “Total Seal”) from those of the original...

13.8 SUSPENSION (Stock Class)
D. Replacement control arms for vehicles having integral bushing/arm assemblies must be standard factory parts as per Sections 12.4 and 13.0.

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...

14.1 AUTHORIZED MODIFICATIONS
All Solo Rules Stock Category allowances, plus all allowances contained in 14.1 through 14.10.

14.8 SUSPENSION
C. The following allowances apply to strut-type suspensions: Adjustable camber plates may be installed at the top of the strut and the original upper mounting holes may be slotted. The drilling of holes in order to perform the installation is permitted. The center clearance hole may not be modified. Any type of bearing or bushing may be used in the adjustable camber plate attachment to the strut. The installation may incorporate an alternate upper spring perch/seat and/or mounting block (bearing mount). Any ride height change resulting from installation of camber plates is allowed. Caster changes resulting from the use of camber plates are permitted.

I. Camber kits, also known as camber compensators, may be installed. These kits consist of either adjustable length arms or arm mounts (including ball joints) that provide a lateral adjustment to the effective length of a control arm. Alignment outside the factory specifications is allowed. The following restrictions apply:

2. On arm-and-strut (MacPherson/Chapman) suspensions, the lower arms may be modified/replaced OR other methods of camber adjustment as allowed by paragraphs 14.8.B, C, or G may be used, but not both.

[RainierHooker]

So after that novel I just posted I come to the conclusion that I must use the Aluminum control arms if I want to use the camber plates. However, according to the first section I posted in the Stock Category if BMW has said in a TB or other directive that steel LCA's may be substituted then I can.



Anyone have a BMW TB to that effect?

[AlarmedBread]

The control arms are not adjustable so there is no conflict there.

[nrubenstein]

The answer is just use the steel arms. no one will ever protest you for it. It won't be 100% legal.

Also, 14.8 is 100% irrelevant to this discussion, unless you start looking at arms with a different geometry.

[jpreston]

If you're just competing locally, run the steel arms. If you go to nationals, I'd stick with the aluminum arms both for the performance advantage and for the lesser chance of getting protested.

[RainierHooker]

Thanks guys, I wound up ordering Steels for the car. I don't plan on running in anything but local events. Maybe down the road I'll spring for Aluminums, but for now I just want to enjoy the car...

[gobuffs]

Why would either be not legal? E30 M3s came with both during the production run.

[RainierHooker]

Well, its a matter of how you interpret the regs. Since my car is a 1990 model, and because BMW's part system only shows Aluminum LCA's as acceptable for post 09/1988-production cars the 'standard' part would be those. However the gray area (in my mind) comes from the fact that the geometry is unchanged and they are 'similar' in construction.
The more I think about it though, the less of an issue I see...

[jpreston]

The only issue with it is that there are tons of douchebags out there who will protest over ANYTHING that could possibly disqualify you and move them higher up in the rankings.

[race2win]

The only issue with it is that there are tons of douchebags out there who will protest over ANYTHING that could possibly disqualify you and move them higher up in the rankings.

Although this may be true with some people, it's not true for most. If the OP showed up at one of my events with those arms, he would never here a word about it from me or anyone I know since they provide no performance advantage. We would however inform him nicely that they are not legal, & if he ever plans to attend a National event he may want to change them.

Replacing the arms with steel ones may seem harmless...they potentially weigh more, don't alter the geometry/alignment, etc. However, what if a National Champion with an unlimited budget built a custom set of control arms made of un-obtainium that somehow created a performance advantage, yet otherwise looked like the same steel ones? If the OP is allowed to bend the rules with the steel ones, then the everybody else could too, & you would have zero rule stability across the category.

When looking at a rule, don't think of it as something a nit-picking protester would look for, but rather how bending that rule could be exploited. In the SCCA rule-book, if it does not say you CAN, then you simpy can NOT.

[e30s50dan]

Just buy the steel ones and paint them silver! HA!

[AlarmedBread]

Just don't win and no one will care. Or bump into a higher class like street prepared where you should not be competitive. Or do not buy an SCCA membership so you will not accumulate points for regional / national championships.

Or do all of these and still have people complain that you do not have a NLA trim piece installed on your car and just do track days instead. :rofl: