catalytic converter removal (plus class question)

[AndyYankee17]

right now I got a daily driver, completely stock: I'm guessing it's in the "stock" class? not sure about the lettering, still looking.

car's registered in MA and is '94, it doesn't get emissions tested. I'm wondering if I should cut out the cat (supposedly better fuel economy and power).

I believe this would leave me in stock for rallyX (page 20 of the rules):

11. Exhaust systems from the catalytic converter back may be removed or replaced with the
following requirements:
a. The exhaust must exit to the rear of the driver.
b. The exhaust must comply with local noise restrictions

but in solo that would be a bump out of stock, correct?

Modifi cations of any type, including additions to or removal of, the
catalytic converters .... are not allowed

anybody know how far out it would be? enough to make it not worthwhile?

I believe I would register the car as HS, '94 buick century, it's a 2.2L I4 FWD 3 speed auto. nearest thing I could find is a chevy cobalt, not sure how interpret the rules....


also, I'm a novice, haven't solo'd yet, maybe it won't make a difference for a year until I'm forced out?

[pzahornasky]

I believe that cat removal puts you into F Street Prepared.

[AndyYankee17]

either way it's class F? F Stock/ F street prepared?

these classes are a little bit confusing, I guess I gotta spend more time in the paddock

[neilschelly]

either way it's class F? F Stock/ F street prepared?

these classes are a little bit confusing, I guess I gotta spend more time in the paddock

The letter doesn't mean anything between classes.  That should be an HStock car in Stock classes, yes.  I imagine the car would also qualify for ST if you want to run in Street Touring.  FSP if it's prepared for Street Prepared.  I won't guess at the rest of the prep levels, but they don't really matter here.

Essentially, the stock preparation level (stock wheels, stock exhaust up to the cat, stock intake, stock suspension, etc) is the same for all cars, but all cars are not equal, so they fall into different letters of stock.  The same goes for SP, where all SP cars have the same preparation level and allowed modifications, but a Porsche 911 with those modifications will be in a higher SP class than a Suzuki Swift, so they are in different letters.

Your car is probably stock if you don't remove the cat and SP if you do.  I wouldn't worry about modifying the car at all right now.  Come out and race and see how you like it.  The presence or lack thereof of your cat will not make a difference on your first day.
-N

[tkvtec]

Also, removing your cat will put you into prepared category for RallyX.  The rule states anything beyond the cat can be removed... not the cat itself

[AndyYankee17]

Also, removing your cat will put you into prepared category for RallyX.  The rule states anything beyond the cat can be removed... not the cat itself

I read, in the stock rules, "Exhaust systems from the catalytic converter back may be removed or replaced...."

not an english major but that sounds like it's allowed.


like I said, I'm not removing the cat for performance, just to get a little bit more gas mileage out of it. plus it doesn't work anyway (failed emissions back when MA did them for '96 and older)

[ChrisFranson]

I read, in the stock rules, "Exhaust systems from the catalytic converter back may be removed or replaced...."

not an english major but that sounds like it's allowed.

"...from the catalytic converter back" means exactly that. The emphasis being on from. You cannot remove the converter in stock.

[dhcernese]

"...from the catalytic converter back" means exactly that. The emphasis being on from. You cannot remove the converter in stock.

He's right, it's written ambiguously.  It means beyond/behind the cat can be removed.  As Chris says, you can't remove the cat.  Even in Massachusetts (where you and I are no longer subject to emissions testing), it will fail the annual safety inspection if anyone looks (because they're bored because they no longer have to do an emissions test).  Ask me how I know this.

[AndyYankee17]

do you do inspections? a guy at my work used to, that's how I know it's not needed.

I decided not to do it, wouldn't be worth it. I read an online magazine that said their test car went from like 150 to 151 HP without a cat, and to like 153 without a muffler.


I have heard about ramming a pipe through the cat though

[GrantR]

I have heard about ramming a pipe through the cat though

Don't let the SPCA hear about that

[demelok]

hollow out the cat. drop the exhaust cut open the top half. take out the guts and weld the cap back on. mines completely hollowed out but mass hasnt had the sniffer for almost 2 years now. its only "visual safety" and then go to the scrap yard and get some money for the guts!

[ChrisFranson]

Gutting the cat is still not stock legal in either rallycross or autocross/solo.

[AndyYankee17]

MA inspectors are generally lazy, I just got through with a massive bright safety orange on solid black background ABS light on

[Gus Heck]

hollow out the cat. drop the exhaust cut open the top half. take out the guts and weld the cap back on. mines completely hollowed out but mass hasnt had the sniffer for almost 2 years now. its only "visual safety" and then go to the scrap yard and get some money for the guts!

In general any modification to a stock part that provides any performance enhancement is equivalent to using an aftermarket part. Stock generally means "as delivered from dealer" (with the exceptions listed in the rule book). If you want to be creative that's awesome, but stock is not the right class for that stuff. Stock class is meant to keep the car somewhere near saleable condition, road legal (in general), and limit the cost of participation. Stock is where you play when you don't want to compete with someone who can afford to try transplant alternate motors or upgrade their hubs to run super sized tire or whatever...

The gullibility of state inspectors is irrelevant to the rules for racing. None of our classes require the car to be registered for use on the street, so the ability to pass inspection is irrelevant to the ability to legally race in a given class.

[cmt52663]

Don't let the SPCA hear about that

ROTFLMAO

You are a troubled, troubled man....