I was wondering, with an atmos dump valve the dumped air has been already measured by the sensor, and then its dumped, so this mean the Air/Fuel mixture will get all fccuked, right?...Is this a problem or can the engine survive this on the long run without any problems?

It makes no difference.

Only you get a slightly richer mixture for about half a second and gives flames on the over run

I have also noticed a strange noise coming like an echo from inside the intake pipe every time I change gears after pulling hard after installing the DV.

The sound is like a tire touching the plastic cover just that it comes from inside engine bay or inside pipeline...
I'll try to tape it so you can give opinions.

Quote:

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and gives flames on the over run

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So why does an atmos DV give flames and a recirc not?

AFM expects the air to be recylced back into the inlet, since its not and air is missing, there is more fuel than air going in, hence giving flames on the over run