started noticing this recently
but when I get the car up to 9000RPM and change gears
there is a little woosh noise
I dont remember this happening when I had the stock cat but I dont drive the car too often so I cant be sure
also, at low rpms giving it a little gas it kind of sounds like a diesel engine with the gurgling and a slight wind noise
that sound normal?

 

Completely normal on gearshift at high RPM. With a catback exhaust you will see huge flames out the back going 2nd to 3rd @ 8500 RPM. In response to your idle, that doesn't sound good. Poor ignition system components would be my suspicion (coils, spark plugs and wires). Have you ever compression tested your engine?

 

thanks for the reply
engine was installed under warranty about a year ago and has about 8,000 miles and coil packs are brand new
car idles perfect, needle does not move
just when I tap the gas cruising at low speeds, I can hear the exhaust flowing
car has been in storage a while so I just can't recall what is normal
but as long as shifting at high rpms I should hear something then we are all good
thanks

 

I noticed in your signature you have an AT rx8. Revving to 9000rpm can be harmful to the torque converter.
As for low rpm diesel noise can just be poor ignition, some people running on one rotor also makes a noise similar to diesel noise.
It can also be a spun bearing. My friend bought a RX8 with a spun bearing that makes a diesel noise at low rpm.

 

I believe AT RX8 has lower redline than the manuals. Something around 7k-ish.

Gotta say I have not heard of any whooshing noise. But it's all subjective definition.