I guess I can't grasp the concept of recirculating discharged air from a wastegate. I'm not sure it would lower the boost pressure in the same way as venting to atmoshere.
Wouldn't the air be reheated as it passed through the s/c making higher IATs? At 130*? iats the pcm will start to pull timing, which will hurt performance.

Here's a wiki clip on why a blow thru maf may be better:

"Laminar flow, sometimes known as streamline flow, occurs when a fluid flows in parallel layers, with no disruption between the layers....... It is the opposite of turbulent flow. In nonscientific terms laminar flow is "smooth," while turbulent flow is "rough."".

imho, once the air has gone through the intercooler, it is should be the most stable. Also the distance from the throttle body is much less, so better response.

 

I'm not sure either as nobody seems to do it, and probably for a good reason, my line of thinking is that the vented boost say 200-400 cfm at the highest rpm before shifting would displace 200-400cfm worth of fresh air. Let's say at 10 psi of boost your engines getting handed 1200 cfm at max boost/rpm, but your blowers pumping 1600cfm, the 400 cfm is being dumped between the air filter and blower and yes, as you dump more boost as the rpm's increase and the amount of "heated" air increases, but your still injesting approx 1200cfm worth of fresh air, although venting to atmosphere wouldn't heat the intake air at all, but if your only dumping a couple #'s, I'm sure it isn't enough to cause problems. However; if you were pullied aggressive enough to create 20#'s and only using 8-10lbs; you'd be injesting a "lot" of heated air and maybe causing problems, I don't know. Right now I'm pullied for about 9-10psi at my current elevation of 6500', and I'm thinking at sea level I could maybe generate up to 13-14psi at the current drive ratio I'm using, at that rate, I imagine I'd only start dumping boost at around 4-4.5K rpm before hitting 10psi, and shifting at 5K, so I don't think I'd constantly be dumping compressed air, only at the top of the rev range. Hell, I'm confusing myself now.

 

Maybe this will help you. At sea level the air pressure is 14.7 psi. At 6500 ft it is 11.56 psi. you have a 9 psi set up. The absolute pressure at 6500 ft is 9 psi + 11.56 psi for a total of 20.56 psi. At sea level you will have 23.7 psi of absolute pressure coming out of the blower. That is roughly a 15% increase. I have a 12 psi pulley at 600 ft. So my absolute pressure is 26.43 psi absolute pressure. About 15% more than what you will see.

Regards

Jean Marc Chartier