Originally Posted by Joshinparadise
This is an interesting comment, to me and here's why... I used to race cars, and invariably the filter was not in an ideal place to put a hood scoop for ram air... Our's is situated in a perfect spot to do so... Has anyone seen a ram air set up for our trucks? I'm genuinely curious.
Coming from a racing background, I know that i'm not putting out the kind of horsies to justify something like this, however, an argument can always be made for ANY turbo vehicle that bringing in ambient outside air to the filter will always be better than pre-heated air from the engine bay.
There is no advantage for a "ram air" scoop. Generally all those do is allow direct pathway for dirt, water, and debris. But people think they're great because they remember the old carbureted engine days where shoving air into the plenum was good.
These trucks have a cold(er) air source from the inner fender. And it works too. The only question I ever had was doesnt the dust from the front tire get sucked up right there?
Apparently the engineers did a decent job otherwise it would be a problem.
And for those members who keep reiterating that there is NO direct power gain to be had from changing the air filter system. They are absolutely correct because thats not how diesels work... The gain is maintaining cooler intake air to allow for more fueling. Fueling is power but power is heat. Lower the intake charge of more fueling and you help offset the overall EGT's.
That said, back in the early 2000's there was someone who designed and manufactured an enclosed air filter setup which tied into the HVAC cowl air via a 4" hole you had to drill through the firewall. It was called the "Scotty Air System". Did it work?...yes, yes it did as people noted around a 150* reduction in EGT's. The source of air was the best because the cowl is a cool, low pressure, and clean air pocket. The problem is that the turbo noise in the cab became unbearable for most people due to the direct sound pathway of intake noise to HVAC system vents.
So...a BHAF works but need protection from filter damage and also the heat of the neighboring turbo. Yes they will ingest hot engine bay air but its not terrible. Thus a heat shield is very beneficial. I installed a turbo blanket a couple years ago and it was a HUGE improvement in towing EGT's.