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Discussion Starter #1
what is the causes the high pitch rev noise when i hit 3000 rpms by the stock intake when i have custom exhaust(4 inch) how come its not a deep tone? what about the stock intake that makes it do that?
 

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Is the noise when you have your foot on the gas or not. It could be a bad seal in the air box. Also what do you mean by a 4 inch exhaust? Is the piping itself 4 inches or just the outlet?
 

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Tuner/Mechanic
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if your piping is 4 inches, then there is only one way to fix it...have a 2 inch exhaust made. or order a cat-back, but thats way more expensive. if your piping is 4 inches, that high pitch rev noise is your intake gasping. it can't keep up with the volume that the exhaust can handle, creating almost no backpressure. this throws off engine harmonics, the ga16de has to have SOME backpressure to function properly. hope this helps, let us know about your pipe diameter.
 

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Yeah I was going to mention that about the lack of back pressure. I t really hurts low end torque. That is why unless you have a full out race car it doesn't make sense to gut your cat. High flo exhausts for large displacement V8's don't use any thing more than 3inch.
 

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Discussion Starter #5
help

no no no...its like a 1.25 piping with a 4 inch tip and like 2inch inlet and when i punch the gas and go up to 3100 rpms it goes to a high pitch rev noise than 3000rpms and below it makes the deep exhaust tone
 

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Fearsome Fabricator
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My Sentra does the same sort of thing, I guess.

Above 3500rpms or so, I can hear a faint high-pitched whine sound from the engine compartment, kind of like a wee turbo spooling, or an electric motor.

I just ignore it, figuring that if it's bad, it'll break, and then I'll know what it was.

With my new Hot Shot Clone CAI, I don't hear it anymore (too dang loud).

Greg
 

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1.6 Turbo Power
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most likely cause of the crush bends. the bends in the exhaust cause the air to flow smaller when it hits the bends and the velocity its being pushed out causes the whistle. just my .02.
 

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thats normal!.. reving your engine high above 3500 - 3000 your engine is always going to sound high pitched.. not like a turbo spooling thogh.. it should sound powerfull.
 
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