Auto-X Rules: Read This First

[TheWRX]

This is a summary of important SCCA Auto-X (Solo II) rules, with a special emphasis on classes that the 2.5 RS and the WRX can run in, listing which popular mods are allowed in which class. It should answer the most common question, but it does not replace the official rule book, which contains the full details for all the points mentioned here, plus many more rules. There is also a number of links to additional valuable resources at the end of this post.

Last modification: March 24, 2005 (update with 2005 rules)

Classes

Which class you are running in is decided by the car model you drive, plus a category depending on the modifications you make to your car. With increasing levels of modifications, a logical progression is from Stock category (cars with no or minimal modifications) over Street Touring, Street Prepared to Street Modified. There are categories beyond Street Modified (Prepared, Modified) that are not within the scope of this document.

The possible classes for a 2.5 RS are:

• Stock: GS
• Street Touring: STS (STX, STU)
• Street Prepared: DSP
• Street Modified: SM

The possible classes for a WRX are:

• Stock: DS
• Street Touring: STX (STU)
• Street Prepared: ESP
• Street Modified: SM

The possible classes for an STi are:

• Stock: AS
• Street Touring: STU
• Street Prepared: BSP
• Street Modified: SM
• Prepared: FP

The possible classes for a Forester XT are:

• Stock: DS
• Street Touring: STU
• Street Prepared: ESP
• Street Modified: SM

The possible classes for a Legacy 2.5GT are:

• Stock: DS
• Street Touring: STU
• Street Prepared: ESP
• Street Modified: SM

One essential principle is common to all the rules: If a modification is not explicitly authorized by the rules, it is not allowed, no matter how trivial it seems.

Stock Rules (DS, GS)

The following modifications are allowed in stock class:

• Port installed options: rear spoiler, diff protector, armrest extension (specifically allowed in February '03 FasTrack, the general rules allow factory options only).
• Appearance, comfort and convenience options, e. g. gauges, alarms, turbo timers, shift knobs.
• Removal of spare tire, tools and jack.
• Harness (seat belts cannot be removed).
• Any DOT approved tires (see rules for restrictions), including R-compounds, of any size (no modification of fender well).
• Wheels (stock size only, offset within 0.25" of stock).
• Wheel spacers (resulting offset within 0.25" of stock).
• Lug nuts.
• Brake pads, speed bleeders.
• Shocks that maintain stock ride height, can be adjustable. See rule book for details!
• Front sway bar.
• Different alignment using factory adjustments (no camber bolts).
• Spark plugs.
• Air filter element can be removed or replaced.
• Cat-back exhaust.

STS Rules

All modifications from the Stock rules are allowed, except for:

• Tires only up to 225 width, and at least 140 tread wear rating.

In addition, the following modifications are allowed:

• Remove air condition.
• Pedal covers.
• Seat (fully upholstered seating surface, must weight at least 15 lbs).
• Removal of factory emblems (debadging).
• Rolling of inside fender lip.
• Addition of body kits.
• Replace rear wing and bumper covers (wings up to 8 square feet).
• Wheels up to 7.5" width, any diameter.
• Cross drilled and/or slotted brake rotors (standard size).
• Brake lines, e. g. stainless steel.
• Air ducts for brakes.
• Disabled ABS (not removed).
• Shocks (fewer restrictions than stock). No electronic adjustment, like Tein EDFC!
• Springs (can be height adjustable, e. g. coilovers).
• Any suspension bushings, non-metallic.
• Any differential mount bushings, non-metallic.
• Any subframe mount bushings, non-metallic.
• Adjustable camber plates (caster adjustment allowed).
• Camber bolts.
• Adjustable front control arms (only if no front camber plates or camber bolts are used). Must have non-metallic bushings, spherical bearings are not allowed.
• Adjustable rear lateral links (only if no rear camber plates or camber bolts are used). Must have non-metallic bushings, spherical bearings are not allowed.
• Rear sway bar, mounts, end links
• Strut bars (not triangulated).
• Battery, relocation of battery (to trunk).
• Air Intake.
• Headers.
• Reprogrammed ECU or piggyback that controls ignition and fuel by modifying inputs to ECU.
• Short-throw shifter.
• Crankshaft and accessory pulleys.
• Engine mounts (non-metallic).

STX Rules

All modifications from the STS rules are allowed. In addition, the following modifications are allowed:

• Tires up to 245 width.
• Wheels up to 8.0" width.
• Brake rotors (diameter equal or larger than factory, ferrous or aluminum alloy).
• Brake calipers (original attachment point).
• Brake dust shield modifications to accomodate alternate rotors and calipers.
• Uppipe (can be catless).
• Turbo-back exhaust. Must contain at least one (high-flow) cat placed not more than 6" after the original exit of the last factory cat.
• ECU reprogramming. Map must have unaltered factory boost maps.
• Piggyback, see STS. No changes to boost control are permitted. Examples of allowed devices: Vishnu Unichip, Cobb Unichip without Boost Control Unit, Apexi S-AFC. Examples of illegal devices: TurboXS Unichip (controls boost), UTEC (acts as a standalone for timing control).

STU Rules

All modifications from the STX rules are allowed. In addition, the following modifications are allowed:

• Wheels of any width (tire width still limited to 245 for AWD vehicles).

Street Prepared Rules (DSP/ESP)

All modifications from the STU rules are allowed, except for:

• Removal of factory emblems (debadging).
• Body kits (only front and rear spoiler allowed).
• Non-standard brake rotors and calipers.
• Front control arms and rear lateral links.

In addition, the following modifications are allowed:

• Some updating/backdating with parts from different model years, see rule book for details.
• Modification (e. g. rolling, cutting) of fenders for tire clearance. Adding of fender flares.
• Seat (fully upholstered seating surface).
• Remove seatbelt for replacement with harness that meets safety restrictions.
• Any steering wheel.
• Front spoiler.
• Rear spoiler.
• Removal of radio/stereo.
• Any DOT approved tires (see rules for restrictions), including R-compounds, of any size.
• Wheels of any size and offset.
• Cross drilled and/or slotted brake rotors (ferrous, standard size, no two-piece).
• Brake cylinder.
• Fuel injectors and pump.
• Intercooler (including hoses).
• Intake water injection.
• Turbo-back exhaust (no cats required).
• Clutch (metal).
• Flywheel (metal).
• Shifter and shift linkage, e. g. short throw shifter.
• Transmission mounts (non-metallic).
• Differentials.
• Standalone engine management for non-turbo car (?).
• Port matching (see rule book).

Street Modified

Consult the rule book for details of the Street Modified rules. Street Modified inherits all allowances from Street Touring and Street Prepared. The following does not attempt to list all additional modifications that are legal in this class, it just lists a few popular mods that are common in Street Modified, but not allowed in Stock, Street Touring or Street Prepared:

• Certain replaced body parts: e. g. carbon fiber hood, fenders.
• Larger hood scoop, hood scoop splitter.
• Removed rear seats.
• Suspension control arms, lateral and trailing links.
• Metal bushings, subframe bushings.
• Different/updated turbo.
• Blow-off valve.
• Intercooler water spray (?).
• Any kind of boost control (MBC, EBC).
• Any other changes to boost control, like the popular resistor mod.
• Engine management systems that modify boost, e. g. Unichip with boost control unit, as sold by TurboXS and Cobb, UTEC, or reflashed ECU with altered boost maps.
• Standalone engine management.
• Internal engine modifications.
• Engine transplant with different Subaru engine.
• Different/updated transmission.
• Steering rack.

Beyond Street Modified

Consult the rule book for Prepared and Modified categories. The following list is just a reminder of a few popular mods that are not allowed in Stock, Street Touring, Street Prepared or Street Modified, they will put you into Prepared/Modified classes where you will be competing with race cars:

• Replaced body parts not allowed in SM: e. g. trunk lid, STi bumper beams (?).
• Weight reduction not explicitly allowed in SM: e. g. gutted interior, removed heater, wipers, lights.
• Tires that are not DOT approved (racing slicks).
• Anti-Lift Kit (relocates suspension mounting points).
• Braces other than strut tower braces: triangulated braces (V-braces), lower arm braces.

Not Allowed In Any Class

The following are not allowed in any class:

• Nitrous (bottles not allowed on event sites for safety reasons).

Uncertain Mods

No clear rules are currently available for the following popular mods:

• Ground wire mod.

Common Questions

• Can I run 17" wheels in Stock on my WRX? They are a factory option!
  No, the 17" wheels are a dealer installed option, and are not allowed in Stock.
• Why is my XYZ mod illegal? I ran with it all year, and tech never said anything!
  Tech inspection is only responsible for checking if your car is safe. Properly classing your car is your own responsibility. Unless somebody files a protest, nobody will check if you have illegal mods for your class. Even if nobody ever protests, many people think that running with illegal mods is unfair and shows a lack of respect for your fellow competitors.

Additional Resources

Official rule book (available for download)
FasTrack (official SCCA publication containing latest rule changes)
Solo II information on SCCA web site
Rules on moutons.org (partly outdated)
Rules in table form (seems to have a few mistakes)
Rule and car setup information at subrew.com
SCCA Forums (message boards)
Solo2.org (message boards)

[ellisnc]

you sure ALK leaves you in Smod?

I was thinking modified suspension pick up points put you in prepared?

[ChrisW]

Great work...

For reference, I have asked these questions from a member of the SEB, Charlie Davis.

• brake rotors. Currently in SP you cannot change the rotors or calipers unless it is available under the update/backdate rules. there is a proposal to change this for next year to allow the use of cross drilled and slotted rotors of the same diameter as stock.
• I have been told that you cannot change the engine mounts unless available under update/backdate rules.
• NO hardened gear sets or dogbox trannies. If you can't order it from the factory, can't do it. (where is the STI typeRa when you need it?)
• Offset bushings are generally not allowed except when the ratio of metel to bushing material does not change.
• No aluminum lower control arms. Sorry, has to be a factory installed item.
• NO ALK!!! The ALK kit is not even legal for SM. Why? it changes the orientation of the lower control arm to provide more caster. This change in suspension geometry is not allowed in SM or SP.
• replacment seats. In the STS/STX class, you can replace the seats with aftermarket units as long as it reclines. In SP and SM, go for it. you can use any seat you want as long as it's padded.

[TheWRX]

Originally posted by ellisnc
you sure ALK leaves you in Smod?

No, I'm not. That's why the title of that sections says "SM and Beyond". The SM rules look quite different from the S/ST/SP rules, and I must admit that I never even read the rules for Prepared and Modified. The idea of that section was really to list a few common mods that might bump you into an unexpectedly high class. I'm not qualified to explain SM rules, and it wasn't the goal. If somebody wants to build an SM/P/M car, they'd better get very familiar with the rule book before they even start.

Chris: Thanks for the remarks, I might have to check about some of these things another day. Just quickly:

I mentioned the STi engine mounts according to this STX rule: "Alternate motor mounts and/or engine locators (bobble struts) sold by the vehicle's manufacturer or their Motorsports subsidiary or affiliate (Chrysler/Mopar, Toyota/TRD , Honda/Mugen, etc.) are allowed."

STX has more generous rules for seats that STS: "Alternate driver and front passenger seats are allowed, but they cannot be constructed of a solid outer shell and must have a suspended bottom cushion and be fully upholstered." Note that they don't have to be reclining.

[trhoppe]

One thing IMHO about modding past DS and STS. If you do those, you might as well throw yourself in SM and have fun. In CP and whatnot you usually have few competitors and if someone has a REAL CP car you will get your arse kicked.

GREAT Job on the rules though!

[OldRacer]

Excellent job, sir; appreciate the time and effort. This ought to help a lot of people.
Len

[shifterkartracer]

Great job. Very clear and well organized reference for anyone who is unsure where they fit or contemplating additional mods. Thanks for your work.

[shifterkartracer]

After reading another thread, I have a question. Are data acquisition systems legal for auto-x? I don't recall seeing any mention in the rule book and I'm not sure this is really considered a mod. I'm not sure how useful it would be on an autocross course but it would be very nice for track days. I suppose you could just remove it for autocross . . .

[KC]

TheWRX... I think Chris' list is referring to SP rules where things in STX cannot be carried over to SP (Additional items to add to your exclusion list... and they are all correct, none of the things Chris listed are legal in SP).

Also, I think there should be a note for STX that the rear differential mount is NOT considered a 'tranny' mount. (Reference April FasTrack for SP)

One thing IMHO about modding past DS and STS. If you do those, you might as well throw yourself in SM and have fun. In CP and whatnot you usually have few competitors and if someone has a REAL CP car you will get your arse kicked.

Or STX on your way to SM as you can do Engine & Tranny Mounts and have unlimited brakes, yet don't have the cost of sticky race tires.

After reading another thread, I have a question. Are data acquisition systems legal for auto-x?

Yes. As long as they are secured when running and when going through tech, make sure they know about it and they can see it secured. Things like GEEZ! paved the way for those types of systems.

Great job on the listing.

--kC

[ChrisW]

Can we make this a sticky?

oh yeah, bump...

[TheWRX]

Edited with minor updates for:

• add "no rear differential mounts" in STX
• add brake calipers in STX
• tried to clarify seat regulations in STX and SP
• no engine and transmission mounts in SP
• mention transmission upgrade in "SM and Beyond"

Thanks to everybody for the positive response! Yes, I was hoping that this could be made STICKY.

[OldRacer]

Bump.
Yes.
Sticky....

[bemani]

Originally posted by TheWRX
Street Modified and Beyond[*]Larger hood scoop.

I've been running in the wrong group all along ...

[trhoppe]

Yup, don't try a larger scoop in stock or STS(X). Thats a illegal flow mod. You might be able to get away with it in STX but you will get yelled at for running something like that in stock class.

[K-WRX]

How about making this thread STICKY ? Great job of clarifying the rules that someone posts a question about, every other day or so.

[DDMan]

DAMN, I'm gettin the ALK for my car.... so I gotta run in the modifieds....oh HELL NO!

Maybe I can make it look STOCK and no one will complain

I KNOW its not polite to be in the wrong category...but HELL, I'm a newbie and want to at least have a little experience before I jump into a higher category....plus I never compete for points and if I ever did, then I would run in the right category.

[KC]

Originally posted by DDMan
DAMN, I'm gettin the ALK for my car.... so I gotta run in the modifieds....oh HELL NO!

Maybe I can make it look STOCK and no one will complain

I KNOW its not polite to be in the wrong category...but HELL, I'm a newbie and want to at least have a little experience before I jump into a higher category....plus I never compete for points and if I ever did, then I would run in the right category.

That's just the wrong attitude. You know the rules and you wish not to abisde by them. Very nice.

If you're not going for points and just against yourself, then it doesn't matter what class you're in.

The thing to think about is... you have someone who's worked really hard to prep his car for the class, and is going for class points. Then you show up in your wrong classed car. If you finish AHEAD of them, you have now robbed them of their rightful points, because if you were classed right, then you shouldn't have been there in the 1st place. And if that one time you run you take enough points away from them to trophy at the end of the year? NOT a good idea.

Run in the class you belong in. Then you can compare your times to that in the class you WANTED to run in to figure how competitive you are.

You said yourself, you're not going for points... but what about the other people that are? Run in the proper class and you don't have to worry about taking points away from people.

--KC

[BruceC]

Maybe I missed it, but it's worth noting that removing the intake silencer on the WRX is enough to put you into STS(X) as well.

Even though my car is bone stock otherwise, including the super-sticky RE92's , my Kartboy shifter and "snorkellectomy" put me into STX. Doesn't seem fair, somehow! But "rules is rules"...

Excellent post. I also vote to make it a sticky.

[TheWRX]

Originally posted by BruceC
Maybe I missed it, but it's worth noting that removing the intake silencer on the WRX is enough to put you into STS(X) as well.

It's part of the general principle that probably can't be emphasized enough: If it's not listed as permitted, it's not allowed. And it doesn't say anywhere in the stock rules that you can remove 10(?) pounds of plactic from your air intake system.

The STX index is only very slightly higher than the one of DS, so unless you want to run race tires, it's a great class to run in if you like to make a few small mods to your car. It will probably require more $$$ to get your car really competitive on a high level in STX, but as long as your driving skills still need work, I wouldn't worry about that.

"snorkellectomy" definitely wins the prize for word of the day!


I couldn't agree more with KC about bending the rules. Sure, if you're running in local events, and you're at the bottom of the rankings, most people won't care if you have an ALK on your car. But where do you draw the line? The next guy might be a little faster than you, and have more significant mods, is that still ok? There is a simple way to avoid these kinds of questions, which is by following the clear line that is given by the rule book.

[trhoppe]

Rule 13.10 A says "The engine air filter element may be removed or replaced. A replacement element which is taller than standard may not be used to hold the air cleaner cover open. No other components of the air induction system may be removed, replaced or modified"

With this rule, it means that you cannot modify the "snorkle". It might not be fair if you have a stock WRX with RE92s and a modified "snorkle". Then again you don't have a stock WRX anymore though

Anyways, think about it this way. I have a DS WRX with any and ALL allowable mods on it. Lets say that you would put the same mods on yours but also modify the "snorkle" and then beat my by 0.01 of a second. (I've seen margins like that and smaller all the time). Would it be "fair" then though? I think the "snorkle" is good enough for a few hundreths around a 60 seconds autox course. With margins of victory in the tenths and sometimes thousands every little rule should be followed.

I understand if you are new at autoxing and have something like a modified silencer and a short shifter, ask your competitors in your local class if they mind. Most of the time they won't unless you beat them. If you finish DFL then no big deal, but if you beat someone who has a totally stock car it becomes unfair.

-Tom
thats how I REALLY feel

[Midwayman]

Might want to clarify that body kits in STS means bumper covers, lips, spats,spoilers, etc. Light weight hoods and trunk lids have specificially been disallowed in fasttrack updates.

Also if your body kit is completely CF (as in a obvisious weight reduction attempt) you can be protested.

[ellisnc]

Originally posted by DDMan
DAMN, I'm gettin the ALK for my car.... so I gotta run in the modifieds....oh HELL NO!

Maybe I can make it look STOCK and no one will complain

I KNOW its not polite to be in the wrong category...but HELL, I'm a newbie and want to at least have a little experience before I jump into a higher category....plus I never compete for points and if I ever did, then I would run in the right category.

You're a jerk if you do that... If you don't care about points then what difference does it make what class you run in and where you finish in it? It probably doesn't make that much of a difference because you're probably such a slow driver that you'll always finish out of the points in D-stock anyway where Type R's will kick your ass.

actually sometimes it's more fun to run in a different class than all your Suby buddies because then you can watch them all drive later.

[DDMan]

First off, I ran in GS...I have a 2.5.

And I KNOW its not polite, and next auto-x I WONT run in GS. At my first auto-x I had:

CAI (PDM intake)
Kartboy shifter and bushings
cat-back Magnaflow exhaust
20mm WRX rear swaybar

I was quite a bit out of the rules, but I think I learned alot. Next auto-x I will have the ALK and Lightweight pulleys. I will probly run in either STS or DSP (dunno which as of now)

The cool thing is that everyone I know should also be running in that class (who WAS running in stock categories last time).

Ill start being more fair, and sorry if I pissed anyone off

[ChrisW]

DDman,

the ALK kit puts you out of STS and DSP. Run if you want but be prepared to be protested.

I just found out that a friend of mine (PaulC) lost 2nd place because of a 240zx running a SR20T motor just 'cause he wanted to run with his friends. Now this guy was warned before he gridded, but still he managed to piss off more than his share of STS competitors running for points.

[ellisnc]

the only mod that puts you out of ESP which is what the WRX is classified in as far as I know is the ALK

but with your mods you'll probably get ripped up there anyway so feel free...

what's the big deal with the ALK anyway, you can tune most of the understeer out of the car with roll bars and coilovers. And brake dive increases with it installed. I've heard it's a good mod but it's going to cause you a lot of headaches if you autocross your car that often.

I can almost promise you more than one person saw this thread here that will be at your next event and will protest you and they'll throw you right into Modifieds.

rules are rules, yeah you can't run with your friends... then don't do that mod, or take it off for every event.