Ecoboost engine question
With the Eco doing so well and loved by many and bragged about by Ford. Why is it not offered in the F250 ? I love mine but I'm curious.
Forum Discussion
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The reason Ford doesn't offer the 3.5 EB in a 250 is that the heavier rear axle in these trucks irrevocably drags the mileage down. A 3/4 ton with a 1/2 ton axle would get similar fuel economy as the 1/2 ton itself, or visa-versa, the 3/4 ton axle in a 1/2 ton would suffer the same poor fuel economy as the average stock 3/4 ton.
So the expensive variable displacement, aka turbo, in the EB would seldom run at the economy of only 3.5L normally aspirated, and not achieve the EPA target that the 1/2 ton does. It would always have to run at slight boost.
In other words, 20 hp might move a easy rolling 1/2 ton at 65 mph, but the 3/4 ton would require 30 hp to roll the same conditions. It is just as well to use a cheaper larger displacement engine at low throttle than a small engine always at slight boost.
On the other hand, I believe that a turboed engine is slightly more efficient than a NA (normally aspirated) motor for the same hp and/or equivalent displacement. The reasoning is that the end exhaust is slightly cooler on the turbo, meaning it derives more power (more is used to do work) out of the same fuel that must be equally burned to provide identical propulsion of a pair of trucks. One of the pair is assumed to be turboed, the other NA in this imaginary test.
So for that "efficiency" reason I would like to run a 3.5L EB in my Excursion, instead of the V-10, just to see.
Wes
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The reason Ford doesn't offer the 3.5 EB in a 250 is that the heavier rear axle in these trucks irrevocably drags the mileage down. A 3/4 ton with a 1/2 ton axle would get similar fuel economy as the 1/2 ton itself, or visa-versa, the 3/4 ton axle in a 1/2 ton would suffer the same poor fuel economy as the average stock 3/4 ton.
So the expensive variable displacement, aka turbo, in the EB would seldom run at the economy of only 3.5L normally aspirated, and not achieve the EPA target that the 1/2 ton does. It would always have to run at slight boost.
In other words, 20 hp might move a easy rolling 1/2 ton at 65 mph, but the 3/4 ton would require 30 hp to roll the same conditions. It is just as well to use a cheaper larger displacement engine at low throttle than a small engine always at slight boost.
On the other hand, I believe that a turboed engine is slightly more efficient than a NA (normally aspirated) motor for the same hp and/or equivalent displacement. The reasoning is that the end exhaust is slightly cooler on the turbo, meaning it derives more power (more is used to do work) out of the same fuel that must be equally burned to provide identical propulsion of a pair of trucks. One of the pair is assumed to be turboed, the other NA in this imaginary test.
So for that "efficiency" reason I would like to run a 3.5L EB in my Excursion, instead of the V-10, just to see.
Wes
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