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Old 11-15-2010, 07:40 PM   #24 (permalink)
Big Dave
Master EcoModder
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Join Date: Jan 2008
Location: Steppes of Central Indiana
Posts: 1,313

The Red Baron - '00 Ford F-350 XLT
90 day: 27.99 mpg (US)

Impala Phase Zero - '96 Chevrolet Impala SS
90 day: 21.03 mpg (US)
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OK. Where to start?

I don't think 20 MPG is in the cards unless drive at speeds that would get you shot/arrested on the Grapevine. But you can get improvements.

At 5 MPG I'd bet you are wildly overgeared. Probably a 4.56:1 axle. For that truck maybe you should think 3.73:1.

Check your brakes. Sintered metallic brakes rust on the edges and swell up, causing drag. Easy to check. Jack up the front end and give a wheel a spin. If it spins easily, that isn't your problem. If it stops in less than 2 revolutions remove the brake pads and use a grinder to chamfer off the edges. If one drags, probably all four drag.

The wing thing on the cab is effective. You need to fair in the undercarraige, especially under the cab. A proper boattail might be 590 feet long.

If you don't want to come down long grades like a Dauntless at Midway, a US Gear exhaust brake will help a bunch.
2000 Ford F-350 SC 4x2 6 Speed Manual
4" Slam
3.08:1 gears and Gear Vendor Overdrive
Rubber Conveyor Belt Air Dam
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