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Old 11-16-2008, 03:09 PM   #3 (permalink)
EcoModding Lurker
Join Date: Nov 2008
Location: Canada
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Three issues; driving habits, motor & drivetrain efficiency and aerodynamics.

Driving habits: These have already changed drastically. Being able to see exactly how driving style influences fuel consumption on the dash makes things very clear. It's a personal challenge now to drive somewhere and keep getting another tenth or half MPG. I drive more proactively, looking further in the distance to anticipate traffic and road conditions which allow better driving techniques. Also, due to the lower gearing of this truck, 4.10 vs. 3.73 on the old one, road speeds tend to be lower all the time. On the highway I drive 95-100 kph rather than 105-110. The peak torque RPM is something I've not found yet, but it seems to like 2000 to 2300. Of course when a road allows I'll drive at 80 kph closer to 1500 RPM. It's not lugging at all and the mileage certainly gets better.

If I understand you correctly, the motor works more efficiently the harder it's working, right? The easiest (and expensive) way to make the motor work harder would be taller differential gears. Going to 3.73 like I had before would make a difference and may be acceptable for power required towing/hauling. Much further and I fear utility would be lost. You mentioned Big Dave's truck. He has 3.08's but also much more power with the powerstroke 7.3 diesel. Many people I've met with diesels easily get mid 20 MPG figures around here. Quite often it's the people with lifts, mud tires and 5" exhausts. In spite of all the things they have done to ruin the vehicles' rolling resistance and drag, it is gained back with interest due to effective power tuning of the diesel. There is simply more to be gained from a modern truck diesel than a similar gas engine without having to make internal mechanical modifications.

As far as aerodynamics go, this truck will not be getting anything terribly out of the ordinary. No boat-tail, no wheel covers, etc. I like the idea of lowering and valences to improve Cd. As mentioned in the original post, I'm actively looking for canopy and tonneau cover solutions which should help. As an aside, the last truck got a very large canopy. It was the largest one I could find. That seems to fly in the face of reason when you are talking about MPG, but in this case not so. Hauling things around is part of my job. Rarely do I go a full day without hauling something and lots would not fit inside a car or SUV. By adding the topper I not only made life easier by eliminating the need for tarps etc, but also get away from pulling an enclosed trailer. Let me tell you that an enclosed trailer has massive drag. A bonus was that when I DID have to use the trailer, there was less drag with the large topper on than without! Now I had more space to haul which translated into fewer trips which nets a total savings in time and fuel.

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