So my Y-Pipe was installed yesterday by my friend and it sounds like a hissing/whistling noise when I'm driving (starting at around 1700rpm). We put it back on the lift and we had my other friend drive and we didn't hear it from under the car but its kinda loud when I'm driving it or when I open my window.. Anyone got any advice?

I took a few pics of the Y-Pipe on my phone so I thought I'd upload them too.

 

is the sound rpm dependant or speed dependant
if its speed dependant - maybe wind?
if its rpm dependant - somethin in ur new y pipe? obstruction, leak?

 

i'm thinking u may have a leak somewhere

 

If there is a hiss, there is leak. After market y-pipes tend to be bit louder w/o the heat shield, the pipe walls are not as thick, and the type flex-pipe.

I know my WarpSpeed y-pipe was really loud around 2K. I went back to stock.

 

who made the y pipe?

 

Deffinatly sounds like a leak try and replace the gaskets with some heavy duty gaskets. When I did my catback I used the gaskets it came with only to have to replace them. I used the double style where it has a ring that kind of fits inside the pipe.

 

My Y-Pipe is from Warpspeed. I'm going to call Warpspeed probably tomorrow or the day after and see what they say.