I have definately dropped from 12mpg to around 10mpg since I have gotten my exhaust put on a few weeks ago. Is this just due to me more than likely being heavier on the gas pedal in order to listen to my truck roar? Or is there actually a proven fact that you get worse gas mileage with duals? By the way I have Flowmaster SIDO with 4" tips with the muffler on. Thanks guys.

 

Dang, only 10mpg? Have you done anything else to your truck? I got true duals put on several months ago and I may have lost 0.5-1.0mpg but I attribute that to my new lead shoe I got around the same time

Right now with the AF1 and XCal2 93 octane tune I'm getting about 15mpg drive 60%/40% city/highway, but I've been staying out of WOT until I get my A/F tuned in right (running rich right now).

 

Nope completely stock plus duals thats it

 

I got a solid 1 MPG better with my duals, and that was with a little hot rodding too. Just keep your foot out of it.

 

Even getting 12mpg seems pretty low to me. I've got a SCab though, maybe someone else who has a SCrew can chime in about that...

 

After the long tubes I just put on I drove about 50 miles and I'm getting 21.8 but Thats down here in NC where its flat.

 

I get 10mpg in-town with my Expy (6,000 lbs) with a supercharger and I'm pretty hard on the throttle. I think you should getting better MPG...?

 

whats the report on the new exhaust matt?

 

I love the new headers and the custom exhaust my dad fabed up it took about 3 hours to bend fit and squeze the pipes to fit but we got her done and I must say it sounds bad ***! anyone going to the next troyer dyno day will get to hear it

 

I get 15 mpg when I'm steppin on the gas a lot. I usually get 15/16 city and 18/19 hwy. I have dual magnaflow and airaid intake system, so she can breath, on a Screw 05' Lariat 4x2. Before the duals I got 14/15mpg city and 16mpg hwy. I noticed a big difference (better) on Hwy miles.