Originally posted by CumminFast
I think Pscotty and the mega cannon kits are too much money for what they are really worth. My pscotty is just thin plastic that they charge $150 for. That is a huge ripoff.
Sorry Rick, I gotta pick on ya here
And the disclaimer: We do sell the Scotty Air II here, so you may want to take my comments with a grain of salt. And I also have to come clean: When I opened up the box of the first Scotty I ever purchased, the first words out of my mouth were 'What a piece of junk'
And now onto the point. Through extensive tests, both by ourselves and by independents (many of whom are TDR members, and have posted their results here) we can say, with confidence, that any sort of air intake, be it the MegaCannon, Scotty, or Volant will work better than a simple filter laid under the hood of your diesel.
Results vary based on truck, configuration, and outside air temps but the typical EGT reduction from a BHAF or aFe filter laid under the hood will be in that 75F - 125F range at WOT compared to a stock airbox. A simple heat shield will often result in another 25F reduction in EGTs. A heat shield that seals to the hood of the truck is good for an additional 25 -50F reduction in EGTs compared to running an open element. A sealed unit that draws only outside air from the fender area is good for about 150 - 200F reductions below stock air boxes, and units which draw from a cowl location and fender inlets appear to be good for 200 - 350F max EGT reductions (below stock airbox numbers).
Are they worth it? If it were me, and I wasn't a vendor, I would say most definitely (this is where you may want to exercise the grain of salt). The average air system sells for about $200 US, and will deliver approximately 150F - 350F reductions in exhaust gas temperatures. This means you're spending anywhere between 57 cents/degree and a $1. 33/degree of reduction. A typical 4" exhaust system will reduce EGTs by about 75 - 100F, at a recent cost of $299 or $2. 99 - $3. 99/degree of reduction.
An open air element with no protection, and I'll use the aFe as an example as its the one that I'm most familiar with, with run you about $60 US for about 100F of reduction. About 60 cents/degree.
Anyway, I'll quit with the infomercial and return you to your regularly scheduled programming now
Rod
Attention: TDR Forum Junkies 
(I tried that route!)
