Originally posted by stingray454:
Originally posted by Fmr12B:
Roger,
In the rules under STS and Engine it states: Headers, emissions-legal
It does not go into detail about emissions on the page you linked. I would think because I have a CAT that is 50-state legal in my S-Shop Y that I would be OK, because it is emissions legal.
Let me know where I'm wrong..... I'm sure I am.
Thanks for the link to the SCCA rules Roger. The Y-pipe issue is very interesting. I guess what kills it is:
"Engine and transmission must remain unmodified, including emissions equipment, except as noted below: "
Since the Y-pipe has a high-flow cat and is an emissions part, that would be considered a modification to the emissions equipment. What is puzzling though, is that headers are allowed, yet many headers directly affect the emissions equipment, in particular the elimination of the pre-cats, and the OBDII functionality of monitoring precat performance with upstream and downstream O2 sensors.
The rule is ambiguous in the sense that although the Y-pipe has a higher flowing cat, it's still 50 state emissions legal, and even exceeds this STS requirement:
"All STS vehicles must comply with the Federal 49-state safety and tailpipe emissions test requirements as a minimum. "
So, I think the Y-pipe falls into a grey area on the STS rules.
Nobody ever said life was fair. The 49-state legality clause is a minimum. The "unmodified" clause restricts you further. Little 4-banger Hondas with no pre-cats can run 49-state legal headers all day. We can't, because it would require us to break the "unmodified" rule.
The only "grey" area I see is the pipe between the pre-cats and the main cat. That's why the "optimized Y" is OK.
