Engine Noise in the Speakers

I have a 2002 Z28, and recently when accelerating I hear the engine noise in the speakers. This happens even when the stereo is off. The stereo is stock, and the only real engine mods are N20 and forced air induction.I posted this in the Ls1 tech forum, but they suggested trying the audio section. Any ideas?

Sounds like a bad ground somewhere...might have something to do with the N2O wiring?

That is usually the sign of a bad ground.

I don't see how it could possibly be a grounding issue. Not when the noise is happening even with the stereo turned off.

Did this noise start after you added the N2O? If you disconnect the N2O system does the noise go away?

The noise started after the N20, but about 1.5 years later.

check your ground ive had it happen on mine and my wifes car and they were both a bad ground.

same, had a bad ground. regrounded the amp to the antenna mount (piece that the spare tire mounts to which is no longer there) and problem fixed!