Vaughn,
What Yogi - PIA - Bear

Is talking about is during my Testing with the B-1 I found the Stock Air box with a K&N would not flow enough CFM. I was sucking the Filter minder down to 100%.
I did not have time to install a Scotty Air System So I installed a BHAF style air filter. Air Flow CFM was then fine. But when I was Loaded Heavy with a Trailer for EGT tests I found that the air entering the Air filter / Turbo Inlet was over 100 Deg's hotter then the Outside air temp. EVEN at 75 Mph and 34 deg's outside the Air filter intake temp would climb over 140 deg or more.
For the first time in two months and alot of testing even at 70 deg outside air temps the intake charge air (Turbo Compressor outlet) was over 340 deg's. It would climb over 440 deg if I remember right. This means much higher Egt's. Just from the heated air entering the airfilter.
The BHAF is a great filter for high CFM but any filter not ducted to the outside air will raise EGT's, combustion pressures and Lower HP and Mileage.
I then installed a "HIGH CFM ScottyAir II" (Avail Soon) And my Air Intake temps dropped to within 10-20 deg's of outside air temps. The Charge air from the B-1 stopped going over 340 deg and my EGT's Dropped 150 - 200 deg's further.
If you heat the air before it gets to the turbo even a Very high efficency turbo within it's map area will heat the air many times over during compresson and you end up with less Overall performance gains.
This was again confirmed on Yogi's six wheeled Office Chair.
He had a Bhaf and with the B-1 installed the EGt's were lower than his KS14CM2 Turbo But when he returned after towing half way across the US I found signs of excess heat in the Charge air. We reinstalled his Bombed OEM box with a AmsOil filter and his EGT's Dropped even More.
Sorry for the long post... What I have learned from all of this is if 100% of the OEM Truck and Car manufacturers Duct the Air intake to the outside of the engine compartment Maybe they did do something right.
