Join Date: Oct 2012
Location: Batten Roodje
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Your factory airbox flows well enough to support documented 500-550 rwhp, but crucially it also filters small enough particles at that flow. That’s the main problem with a lot of aftermarket air intakes: they outflow the bejeezus out of the stock box, but they don’t filter finely enough to preserve the turbo’s compressor blade leading edges (pitting them will affect airflow and thus power). Exception based on filtration-at-flow data I’ve seen is the S&B dry filter - it flows more than the factory box and filters near as much as identical to the factory Fleetguard. But replacement filters are a lot more expensive and the change interval is the same. It might drop intake air temp a bit, but for two factors: first, the turbo is going to negate that when it pressurizes the air anyway; and second, the engine likes a little bit of heat to operate at max capable efficiency (around 135-150* manifold air temp).
If you’ve got money to spend and you just like the look of the “cold” air intake, a good filter isn’t going to hurt anything. Just be cognizant that it isn’t really going to help anything in front of a stock turbo either.
The factory exhaust on the 6.7 trucks is about as free flowing as it can be given emissions standards. All your restriction (and muffling) is going to be, as said above, from the filters. A DPF-back system (marketing hype; its basically a fancy way of saying “tailpipe”) may change the tone a bit but it’s not going to increase the volume or help power / efficiency. It’s sorta like screwing a 2” garden hose onto a 1” spigot: it’s still only gonna flow so much. Your exhaust filters are effectively the spigot here. The factory muffler-looking thing is just a straight-thru resonator. The inside looks like an old Borla or Flowmaster glasspack but without any of the packing.
Same as the intake, if the look tickles your fancy, it’s not gonna hurt anything. A 5” DPF-back will give you a slightly deeper tone but not much more volume. Major caution I’d offer is material. It’s really hard to beat the OEM stainless steel unless you wanna spend the coin on the high-end aftermarket stuff. That said, I’ve got a 5” aluminized exhaust on my truck for almost 80k now and it’s perfectly fine yet, but I’m in the Dirty-Dirty where “winter” is a 4-letter word and “road salt” is a completely alien concept.
For gauges I think you’d be really hard pressed to beat the CTS for the price. The one thing I like about the Banks better is the expandability to control stuff like water-meth injection or their “Banks Brake” software but i think the gauge layout (and number of PIDs you can effectively display) is still better on the CTS. I haven’t looked at the MM3 so no idea how it’d compare.
Hope this helps. Congrats on the truck!
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08 Resistol. Anarchy EFI, 5" TBE, grid delete, fleabay elbow, Sinister coolant filter, Carbonite DP sensor, CSS -4" springs, reverse level, CalTracs, Amsoil bypass filter, Revmax VB/TCM, Mishimoto stock replacement radiator.