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Discussion Starter · #1 ·
I have an 06 megacab. IIRC it has a 4 inch exhaust from the factory. Will I see any mileage gain from a cat back 5 inch exhaust or is my exhaust free enough that it shouldnt matter? What about a turbo back setup? basically if you were doing mods for a strictly mileage standpoint would exhaust be one of them?
 

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I have an 06 mega cab. IIRC it has a 4 inch exhaust from the factory. Will I see any mileage gain from a cat back 5 inch exhaust or is my exhaust free enough that it shouldnt matter? What about a turbo back setup? basically if you were doing mods for a strictly mileage standpoint would exhaust be one of them?
I'd leave the cat and do a search for free-flowing aftermarket mufflers which will splice into your existing system. There are quiet, efficient alternatives to the restrictive stock mufflers. With your qc drone is a concern with some of the offerings out there. I'm running a Shuttleworth diesel muffler with the stock system and can't detect any measurable gains. A Smarty set on a lower setting should net you a modest gain. That may be the first thing you do.
 

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Discussion Starter · #3 ·
Theres an article in one of the new diesel mags where they got almost 6mpg out of an intake, exhaust, programmer, and switching to synthetics. im hoping to duplicate there results. I was thinking a smarty jr
 

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Six mpg? yeah right.. Looks like advertising hype to me. You're wasting your time looking for mpg's from intake and exhaust upgrades. I saw none on my truck but I didn't really upgrade the exhaust or intake with mpg's in mind, mostly it was just performance and bling thing. It spools better with the intake and sounds better with both that and the exhaust upgraded. Your factory 4" exhaust is plenty good performancewise but you'll probably want to ditch the restrictive factory muffler which helps lower egt's. Then either put a straight pipe in its place or a high flow perf muff if you don't want it so loud. Jr picked me up maybe a half mpg overall always on the 100hp #3 software. I do have a heavy foot though so results there will vary.
 
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