I Have a 2004 Nissan 350z with a Cat back exhaust.

When I down shift, I get this gargling noise.... like air pockets in my exhaust. I know I sound like a newb asking this. Its just been recently happening to me. I can get a video of it if needed. Little help in pin pointing the problem if any?

 

either its normal (you get it a lot with open exhausts) or you have an exhaust leak.

Are you in Vegas now ? www.350zen.org is one of 2 local Z groups.

 

umm when did you install the exhaust and when did the "gargling" start?

 

Got the exhaust.. march this year ... I didnt notice it until.... last month.

 

Some exhausts have a break-in period but it usually doesn't make a completely new type of sound.

What exhaust do you have?

 

Top speed pro 1 . Im sorry guys i should of include dthis in my original post.

 

Check for blown out gaskets.

 

It's 100% normal and the sound is there to stay. I like it, a nice throaty gargle from an angry beast. The gargle is the reason my neighbours grab their kids and hold them close when I come around the corner at an all mighty 20km/h in 2nd gear...

Anywho it is typical of a cat-back system with no real muffler, (straight through like topspeeds), I think it just had to do with the engine vacuum/exhaust speed changing. (Imagine turning turning a 2L pop bottle upside down, the pressure differential from the atmosphere to the air (vacuum) in the bottle draws air back up into the bottle causing it to gargle. I'm no exhaust expert but same principal I believe.

 

dbl post