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Allowable Mods by Class (Autocross)

26K views 32 replies 25 participants last post by  ecugrad 
#1 ·
I've seen a number of posts asking what effect various mods to a car will have on determining the autocross class or classes a car is allowed to compete in. While there is no substitute for the rule book, here is a link to a quick reference guide that breaks down allowable mods by class. Not every class is covered, but the popular ones are there.

http://www.sff.net/people/dburkhead/prepcompare.htm

And here's a link to the 2006 SCCA Rule Book

http://scca.com/_filelibrary/File/2006_solo_rules.pdf
 
#5 ·
From the rules:
14.11 STX
A.The STX class expands the vehicle eligibility limits beyond those specified for STS,
and adds a limited number of allowed modifi-cations.
The allowances are as follows:
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-
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6.High flow catalytic converters are allowed, but must attachwithin six inches of the original unit.
Multiple catalytic con-verters may be replaced by a single unit.
The inlet of thesingle replacement converter may be located no furtherdownstream than 6" along the piping flow path from theoriginal exit of the final OE converter
IOW, a CAT delete is not allowed in STX.
But, you do bring up a good point, in relation to your local emission laws.
However, SCCA couldn't care less:
14.10 ENGINE
Engine and transmission must remain unmodified, including emissions equipment, except as noted below:
 
#6 ·
I don't see any WAY I can attach a hi flow cat within 6" of the original position,seeing as I am running a 4-1 race header. The group I have been attending just puts cars in specific classes by vehicle design,like Mustang or Focus etc and then have sub classes based on street or track tires and off road only eqipment.Seems to work out pretty well.
 
#7 ·
I think I'm going to set up my car for either STS or STX....sucks changing to a high-flow cat put you out of STS....
 
#8 ·
If you already have a 4 into 1 race header, ditch the cat. SCCA already considers you modified at that point.
 
#10 ·
My question is for stock what can I do? I have a zx3(mostly stock, runs in H-stock) and well I have recieved a couple different answers and the rule book is very open ended.
"Option package conversionsmay be performed between specific vehicles of a particular make and model"
So is an svt the same make and model, can I put svt springs, swaybars, snorkel, etc. on my car and still run h-stock class?

Also does anyone know what the Factory service manual say we can adjust, what different parts we may use, and so on.

I know that most gm cars in there service manual it says they may put on a camber kit for alignment so they can do that and still stay in stock class. So does ford have any loop holes like that?
 
#11 ·
^^^The way I would see it, no, you can't put any SVT parts on your car. Reason being, it wasn't a factory option. Even if it was a factory option the car has to be built in those years. So if you could get an SVT suspension on a non SVT from the factory in say 2002 - 2004, your non SVT would have had to been built between those years to qualify to add the parts after the fact. See where I'm going with this.

You CAN get a set of DOT R-compounds on your stock wheels diameter and width, you can run a K&N or other higher flowing drop in air filter as long as you use the stock air box, and I think you can change your bushings in the front say bar, or change the front sway but not the rear. The rear must remain untouched.

I've seen people get kicked out of HS for less though. One guy had a Mazda 3 and he put a stock Mazda 3 spoiler on his car (sedan) but the spoiler wasn't a factory option for his year or something. Had to remove to stay in HS
 
#13 ·
the "option package conversion" has to be for the same model year and it must be COMPLETE. So SVT parts can only be put on the same year, either 02,03, or 04, and you have to put EVERY SVT part on to stay stock. Basically, it's not worth it. Either go up to STS or just stay stock and enjoy the drive. The class you are in is not so important as learning about yourself and your car and HAVING FUN. Also, whether it's nationals or a small event, any SCCA event follows the same rules
 
#14 ·
^^^ding ding ding

Basically you would have to upgrade the entire car to an SVT. Might as well buy one then, ya know.

Just have fun in your stock class and learn to drive better. [thumb] Or if you want to upgrade the car and run a different class.

The one nice thing about stock classes is you can run DOT R-compound tires. You can't run those in any of the street touring classes.
 
#15 ·
if you wish to remain in stock class there are but a few things you can do to the car. Obviously I would recommend upgrading the driver first, but if you want a more mechanical answer here ya go. Any shocks using oem mounting position, stock wheel width/size, but not weight (hint: enkei light weight wheels). Dot-r tires (prefer V-710's), agressive alignment without camber kits. K&N air filter, front sway bar and bushings. Thats pretty much it.
 
#16 ·
also was wondering what the service manual gave as specs for wheel alignment, etc. cause I know that some gm cars can put a camber kit on there car and still run stock class because there service manual says you can do that. Thanks for all of your help
 
#17 ·
The rules are so broad in many respects that you could drive a truck through them.

Things become very sticky and political at the National level, but a lot of the regions tend to be more relaxed.

For example, if an older car is damaged and needs body work (Corvettes, Opels and BMW 2002's come to mind) often OEM replacement parts are difficult to find. As a result, they often resort to fiberglass replacements. Depending on the manufacturer, the fiberglass is marginally lighter than the OEM.

Usually, a discussion amongst the drivers in that class takes place prior to the event or runs. If all the drivers agree to allow the car to remain in the same class, then the officials usually don't take issue with it.

With respect to upgrading with parts from an SVT - and I am not encouraging cheating, there are very few people out there that would recognize a difference. Of course, brakes would be pretty obvious, but if you took the suspension or the stock air box from an SVT and installed them on your car you will notice a difference, but I doubt anyone else would. Especially with a Ford part number stamped on them.

In H Stock, you would see some gain, but not enough to really set you apart.
 
#19 ·
First off you can't run Nitrous at autocrosses, so you'll have to leave the bottle at home, or take it out at the event. That being said, are the tires R compound tires, or do you mean the Speed Rating is R? There is a huge difference.

But for the most part, I'm pretty sure you would be looking at FSP (F Street Prepared)
 
#21 ·
I can't figure out what class I would be in. I have the mods listed below also my back seats and spare tire are gone.
 
#22 ·
Back seat removal automatically kicks you into SM (SCCA 2008 rules). With the back seats back in, you could run in STS, if your wheels are max 7.5 in wide, and your tire 225 max width.
 
#24 ·
I'm super confused here, so decided to ressurect this thread. I've been doing some research on what kind of things could be done to my car but still keep it in the H-stock class.. Currently it is bone stock.

The stock tires are 195/60-15 do I have to get the exact same size replacements? Or could I go 205/40-15? Its kind of hard to find good tires with these same dimensions haha.

Also I'm still confused on what the rules are if I were to want to swap in SVT shocks/struts/springs. From above posters, this would be an illegal move, correct?

My car came with no rear swaybar, so I'm out of luck on putting one of those on as well even though other year Focus' might have one?
 
#25 ·
To stay in H-stock...

You can use ANY size tire... You must, however, use stock size/width wheels, and the offset must be within 1/4" of stock. 205/50/15's are a very popular tire size. [:)] Yes, people HAVE squeezed 225's on stock 6" rims, but the benefit is open to debate as they are pinched...

The SVT shocks/struts are legal, and a common low-cost upgrade (I use them). However, you CANNOT change springs in H-stock, so that's a no-no. [slap] [read]
 
#26 ·
Good news there, I'll probably go with some 205/50-15 Falken Azenis then. I'm going to use my stocker rims. I guess I will pick up some SVT shocks/struts but not springs!

Do you run a front swaybar? Personally I don't think I will run one because it will just increase my understeer..
 
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