Chris wrote:The OM606 swapped F250 likely has 3.55:1 axle ratio, coupled with 33" tires, and overdrive 722.6 auto, the engine is barely above idle when cruising on English B roads.
In a 460 G with basically 5:1 axle ratio, even with overdrive transmission you'd have to run 47" tall tires to equal the ford's super economic cruise RPM.
The super low gearing found in nearly all 460s makes for some pretty terrible economy numbers.
The Gs squared off edges and heavy weight amplify this affect.
In college I studied transportation design at The Art Center in Pasadena, my aerodynamics teacher demonstrated how a vehicle sized 'brick' with sharp 90' edges in a wind tunnel behaves (not very aero), then he put the same brick in the tunnel but with 4 inch radius (think uhaul trailer) on all the edges, this yielded 40% decrease in drag at the same speed.
vadimivanovich wrote:FWIW the W210 uses the overdrive 5-speed 722.6
G Nome wrote:Drew,
Our G ways in at about 5000 pounds. SWB 463. Square box vs pretty slinky W210 or w124. Meaty tires vs street tires Etc. 20 MPG would be nice.
Kent
AlanMcR wrote:Well, the factory OM606 setup, with the 722.6 overdrive transmission and the overdrive transfer case, averages 20mpg if driven reasonably. Maybe 22mpg if driven gently in good weather. 2600rpm at 65mph.
Chris wrote:The OM606 swapped F250 likely has 3.55:1 axle ratio, coupled with 33" tires, and overdrive 722.6 auto, the engine is barely above idle when cruising on English B roads.
In a 460 G with basically 5:1 axle ratio, even with overdrive transmission you'd have to run 47" tall tires to equal the ford's super economic cruise RPM.
The super low gearing found in nearly all 460s makes for some pretty terrible economy numbers.
The Gs squared off edges and heavy weight amplify this affect.
In college I studied transportation design at The Art Center in Pasadena, my aerodynamics teacher demonstrated how a vehicle sized 'brick' with sharp 90' edges in a wind tunnel behaves (not very aero), then he put the same brick in the tunnel but with 4 inch radius (think uhaul trailer) on all the edges, this yielded 40% decrease in drag at the same speed.
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