Close lips and do a low hum entirely through your nose. Or, like carburetor with the air filter off. That is what this noise sounds like from the engine (turbos?), from approx. 2 to 4,000 RPM. It's more pronounced under acceleration. Under hard acceleration noise noticeably stops at 4,000 RPM as if some valve or flap suddenly closes. Please tell me what it is and how to fix it.
Thanks
CRQ

 

Do you have any mods? You could be cursed with the fd moo!!!! Does is sould like a cow mooing under your hood? If so, CONGRATS you have experienced the great rx7 air pump cow moo.

-josh

 

Yes, it could be that cow and I do have modifications (Pettit Racing Turbo upgrade), but this is a new sound. The mod was done last year. If it's the air pump how do I fix it?
Semper fi,
Bob

 

man oh man... the mooo?
come on guys, this is the charge releif valve!

there is a valve that vents the prespool charge of the secondary turbo before it comes online... this is dumping into your engine bay making that valve - at 4,500rpm an actuator closes this and away you go on secondary.

 

Thank you. Now that I know that it's the "charge relief valve" how do I fix it so it no longer makes that noise? Is performance suffering in its present state?
crq@comcast.net