My car makes a lot of noise after 3500 rpm

[FouRG63]

What is that noise coming from. It will be perfectly quiet then right at 3500 the engine gets really loud. Kind of like a vibration or buzzing, ehh I can't describe it that well. Anybody know what it could be? The car is a 1990 GSX.

 

[GSGoinFast]

just a guess but maybe the turbo spooling up?

 

[doodie]

I'm thinking of an exhaust leak. Do you hear a leaking sound outside the car when its idling? Throw a piece of tissue paper or somewhere under the engine when the fan is off and see if it waves around.

 

[FouRG63]

It had a leak when I bought it but I fixed it... It still makes the same noise. It's almost like on a honda/acura when it hits vtec in the upper rpm the whole note of the engine changes and it gets quite a bit louder. Any other ideas??? I'll try to get a video up but it may not be for a while.

 

[96TSi_Chris]

Mine gets louder b/c of the turbo and exhaust, but my best guess would be a exhaust leak right near the exhaust mani.