"knocking" sound when WOT

[cab2g]

OK, don't make fun of me if this is normal, but I am wondering... I just upgraded my exhaust and now I hear more when accelerating. When I am WOT in high RPMS I can hear what sounds like a rapid knocking or slapping sound if I am passing near a wall. Is this just the sound of the fuel detonation or is it something like piston slap? I don't notice it from inside the cabin, only when passing a barrier that reflects my exhaust sound.

I don't hear any knocking when the car is at idle.

[jrpimp00]

Could.be exhaust leak. Get under the car with it running

[Iwantone2]

^^^possibly this

[ffrcobra_65]

I suspect an exhaust leak too. Did you do full exhaust? If so, get under the car and see if there is soot anywhere around the exhaust ports. If you find soot, there's the source. Exhaust leaks are more noticeable when the engine is cold and small leaks often go away or become almost undetectable at idle after the manifold gaskets have warmed up and expanded. You get to high RPMs though and the exhaust will just blow through the leak and eventually blow out that part of the gasket.

[cab2g]

well, just hopped under the car while it was running from a cold start. I didn't see or hear any exhaust leaks. Maybe my ears are just being overly sensitive. I didn't hear any "knocking" in the garage when the car was stationary and my wife revved the engine.