STX Rules on Catless Headers?

[NickZHP]

I want to install catless headers into my car but I saw that some sort of catalytic converter is required to stay in the STX class. If I buy these hi-flo Magnaflow Cats will it make the car legal in STX? http://www.jegs.com/p/Magnaflow/Magn...50982/10002/-1 Where would they have to be welded?

[az3579]

Here are the rules from the 2015 National Solo guidebook, for Street Touring category. Sorry, it doesn't copy and paste well and I'm too lazy to fix it.

Catalytic converters: Any catalytic converters are allowed, but must attachwithin 6” (152.4 mm) of the original unit. Multiple catalytic convertersmay be replaced by a single unit. The inlet of the single replacementconverter may be located no further downstream than 6” (152.4mm) along the piping flow path from the original exit of the final OEconverter. The extents of an OE converter are defined by the expansionchamber in which the catalyst is contained, regardless of placementwithin larger exhaust sections. Replacement converters must have aminimum catalyst density of 100 cells per inch and minimum substratelength of 3” (76.2 mm).

[M0nk3y]

Yup, rules are above.

Basically, if you have one set of cats (like just in headers) you must retain OE location within 6"

If you have 2 sets of cats, like primary secondary, you can consolidate the cats to one location (like secondary) and must still obey the 6" location

[NickZHP]

Yup, rules are above.

Basically, if you have one set of cats (like just in headers) you must retain OE location within 6"

If you have 2 sets of cats, like primary secondary, you can consolidate the cats to one location (like secondary) and must still obey the 6" location

Are the only cats in stock ZHP's in the headers? If so, according to the 6 inch rule does this basically mean the cats would have to be in the aftermarket headers...?

[M0nk3y]

Are the only cats in stock ZHP's in the headers? If so, according to the 6 inch rule does this basically mean the cats would have to be in the aftermarket headers...?

I think they are only in the headers, I don't believe you have secondary cats.

Correct on the second statement. That, or you'll have to custom fabricate them in yourself

[az3579]

Our cats are only in the headers.

[M0nk3y]

Our cats are only in the headers.

Thank you for clarifying.

And that's why you don't see much STX E46s out there. They aren't as easy to prep as an E36


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[GoGators]

All correct. I questioned the SCCA a couple months ago on the 6" specification, requesting to delete the 6" rule. they replied in the june fasttrack edition. rejected it of course. see #16696.

it really sucks... nearly every other STX car run a header. we cant.

only reason for the 6" rule I can figure is to ensure weight cannot be moved to much. still a stupid reason.