Piping to 300zx exhaust

[Rcg68]

Ok, this may sound like a rookie question, but what is the piping running from the exhaust into the inner fenders on each side? What does it do and what are the consequences of removing it or not putting it back into a new exhaust?
Thank you
Vehicle is a 1990 300ZX N/A

[t.mcginley.jr]

That would be the AIV system, it lets fresh air into the pipes before the main cats to help them run cooler (more efficient). Most people delete them, especially if you don't have emissions testing where you live.

Read this, it will tell you everything about the AIV's:

http://s95014253.onlinehome.us/63104/137858.html

[Rcg68]

Thank you for that write up. I am putting test pipes on my 1990. It is not mandatory that I remove it, correct?

[t.mcginley.jr]

Nope not mandatory, most people just delete it because aftermarket exhausts don't come with the AIV ports welded in