Fluttering sounds at slow throttle release

[SGKDSM]

I'm experiencing some loud fluttering when I ease off the throttle after installing an APEXi FMIC. I'm using the 1G bypass valve with Dejon tool upper piping and I have an Evo III 16G. The flutter only started after the FMIC install, though. It only happens at very low speeds/low boost when I'm backing off the accelerator. The bypass valve appears to be working fine the rest of the time. If I let off the throttle all the way quickly it just purges as usual rather than fluttering. If I'm at higher boost levels everything sounds normal when I let off the throttle. This is on an A/T by the way. Is this something I need to be concerned about?

I've searched in the forums finding many references to BOV flutter and compressor surge, but I'm still not sure what this is exactly and how to fix it. The BOV is running off the stock intake vacuum line location and I'm not venting to atmosphere.

Thanks,
Stephen

'97 TSi AWD
'04 WRX sedan

 

[Larry L]

I had a simular problem but I was using a 1G BOV that was crushed a little too much and not letting the excess boost escape between shifts. So unless your BOV is crushed i'm My brother has an 04 EVO w/ the GReddy BOV and his also flutters at low throttle release. Don't know....I'm just confusing myself....Too many bong hits tonight..