OK, so one more thing....

The Stillen and aftermarket pipes might lead to a tad more HP since there are no resonators in the aftermarket one, which I suspect would make it much louder than a 350z or G 2007+.

Also, I am in CA and I am all bout staying legal and passing smog including visual.

If I change to an aftermarket Y pipe, is that considered illegal.? It should be as I am not altering the cats.

 

bump on last post

 

cat-back exhaust should be legal as long as its not too loud

 

You're fine jaswrx

 

not talking about catback!

Talking about Stillen Y-pipe as opened to OEM HR Y-Pipe...the Stillen does not have resonators, etc.

 

Maybe if you used better grammar you'd be easier to understand. But we'll answer your question again. Modifying anything from the CAT BACK is legal. And the OEM y-pipe doesn't have resonators. I wouldn't add another y-pipe unless you have a full exhaust

 

....then what is the difference in the Stillen and OEM HR Y-pipe?

From the pics posted, the OEM looks like it has resonators.


Why do you not suggest I use the Stillen unless I have a "full exhaust"?

I will be putting the coupe midpipe on... as discussed.

 

Maybe what you're seeing are flex pipes? I've heard the stillen is the best of all aftermarket Y-pipes and has the best flow... but to be honest It would be the last thing Id do. Your cats are the most restrictive part of the exhaust... the Y-pipe really isn't restrictive... Your aftermarket Y will just change the piping diameter and improve flow minimally... and the muffler has a lot to do with restriction and flow and sound. Basically what I'm getting at.. is that it doesn't affect your performance as much as any other part of the exhaust does.

 

Then you are saying, the cats are restrictive and high flo cats make that much difference. Why is that? Is it becasue the materials are different and I have seen the inside of high flow ones and OEM and they appear to be the exact same.

 

http://www.350z-tech.com/zwiki/High_...tic_Converters

This will give you a basic run-down of what Cats are and such... Basically, The stock cats have honeycomb in them that are VERY close together and small itty bitty holes that allow air to flow through... while filtering it for the environment. Obviously... this slows down air flow... kinda like getting something stuck in a straw. High flow cats have larger honeycomb holes to allow air to flow more freely.. while still effectively filtering the exhaust gases. Obviously, test pipes (or test pipes, race pipes,down pipes...whatever you wanna call them) have zero restriction and allow the best possible air flow.

 

our stock cats have filters inside, one on top, one in the middle, and one through the exit.

aftermarket cats that i had before, didnt have any filters, beside those punctured holes with steel wools behind it, that blew on me. FML

if i were you, buy like 2-3 U-J-Bends, some flanges and build your own y-pipe, or not, build your own exhaust system. it's always better to sound different from the crowds.

i should have pictures somewhere in the exhaust compilation page with my custom y-pipe in there. my y-pipe probably looks different to alot of g35 sedan, because i built it for the awd.

-liz

 

changing out the Y-pipe, midpipe, and muffler OR ANY COMBINATION of these is not going to make you illegal (assuming you aren't too loud - noise ordinances)