I need to put my stock cats on so I can get my car smogged soon and I was just wondering if the split air tube is very important for that? I capped it off as per racing beats instructions and its the only thing that's annoying to get to in reverting to stock. Will I still pass star smog with it capped off?

 

Car is an s5 fc na by the way

 

technically it will fail the visual without the pipe, but since its not being used during the test, it will pass out of the tail pipe.

 

Won't HC be too high because there's not enough air for it to react?

You could probably get away with just a long rubber hose with a check-valve in it for a temporary fix if you lost the original metal one.

 

the car is not using the split air pipe during the test. during an emissions test, the air pump air is going to "port air" which is the exhaust ports directly.

 

So what's the verdict? Can I just leave it capped off and hook my cats back up and pass? It passed perfectly fine last time but that wasn't star and I'm really worried

 

j9fd3s said it will fail on the visual - which I believe I've read that in CA, they wont even test it, but I'm sure it was j9fd3s who recently posted about CA emissions testing - which also varies by what county you live in.

 

How many emission testers are even going to know that pipe exists? Or what it does?

 

Don't they find a visual reference?

 

i have passed smog without the split air pipe, like i say it does nothing. worst case they have this big thick book that lists ALL of the smog equipment on every car ever.

oddly with the Rx7's they usually don't look at the book, but my brothers vw, man they get a comfortable chair, and do some reading. then they refuse to smog the car.

 

What does it do though? That's another question I have

 

Its there for backpressure to open the 5th 6th ports, in all reality, the air pipe is for performance, not emissions. Emissions testers "think" it part of the emissions because they see it hooks up to the exhaust and automatically think that

I had a guy at a muffler place that refused to put on my headers/magnaflow mufflers because of the pipe being emission related....needless to say i put the header on myself

 

some air pump air is sent through that tube, but its mostly on decel/transitions, so it doesn't get used much

 

Ohhhhh it's just one thing after another isn't it? In trying to get my downpipe and presilencer off, I found that the stud and bolt from the exhaust manifold to the downpipe had problems. Long story short, the stud and bolt are now no longer attached and I need new ones. What size is the stud?

 

This one.

 

It's a metric stud, measure it. Use plenty of anti seize when re-assembling (you should be using it on every fastener you remove and replace). You'll thank yourself later.