I put on a BHAF a month ago but used the old intake hose. Now the other day I picked up some 4" aluminum pipe ,2- 45 degree elbows and an air restriction gauge and changed out the old pipe. It seems to be louder now but I can hear a fluttering sound when I stomp on it. Do you think it is air turbulance and maybe needs a 6" pipe?????

 

Is the truck a manual? If so, it's likely compressor surge, caused by too high a pressure ratio across the compressor and too little flow. If that's the case, it should do it at low RPM's, but not at higher RPM's. It is hard on the turbo, and can cause the shaft to snap if done repeatedly. It does sound cool though.

A fix for it would be an HX35 or the compressor side of a WH1C or H1E, as they have a map width enhancement slot to prevent surge. If you don't want to spend any money, then I'd just say try to avoid getting on it hard at low RPM's.

 

what is an air restriction gauge?

 

It's definitely surge. It's always been doing it, (since the Banks turbine housing anyway) you just couldn't hear it through the stock intake.

Peter, he's talking about a filter minder.

http://www.filterminder.com/