I noticed that I have rasp at high rpms on this setup doing further research I found out that the JIC Y-Pipe has Inlet Diameter: 60mm (2.36") and a Exit Diameter: 80mm (3.15") My fujitsubo exhaust has a 3.0 diameter. I thinking the y-pipe is causing the rasp and turbulence. Am I right? What is the diameter of the stock cat outlet? Would the rasp go away if I get a fuji y-pipe or megan. I searched for a solution didn't find anyone with the same problem. BTW Tanabe is not the best Y-pipe stated in that sticky up there. Its only a Inlet Diameter: 60mm (2.36") and Exit Diameter: 70mm (2.75") That would rasp holy hell.

 

do you run test pipes??

 

Test pipes and RT cats will rasp with that setup. I switched to Crawford cats and rasp is gone.

 

a friend of mine has fuji exhaust w/ jic ypipe and fast intentions RTP on his g35, and theres no rasp. sounds pretty nice imo

 

I don't have test pipes, I have stock cats, and stock headers. For the exhaust sorry I wasn't specific I have the Fujitsubo legalis R

 

perhaps you have an exhaust leak

 

I thought that too, I checked all my bolts and gaskets and everything looks tight. Sounds like a Rattly RASP at high RPM.

 

put it up on a lift and check it out...could have a crack somewhere too

 

I will check it out this weekend. So the difference in size in the y-pipe outlet and the exhaust inlet won't cause rasp?

 

It depends on how much of a difference in diameter there is.

A contraction of 3.15" to 3" isn't the cause. That's much too small of a difference.

 

Rasp is overrated. Learn to love it. Its your friend.