Thread: 3/4-ton Diesel
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Old 05-26-2011, 05:36 PM   #3 (permalink)
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Location: Indiana
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White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
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Ok, well let me give you some examples of how things change.

1) My pickup has much, much more mass, therefore much more momentum, therefore I can coast a considerably longer distance.

2) I can't do engine-off-coasting because there's no way to steer that thing without power steering. That being said, idling is comparatively more efficient with a diesel (no throttling).

3) While a grill block-off would help aero and help the engine warm up faster (decreasing heat losses), BUT it would also have the effect of decreasing the effectiveness of the intercooler, therefore, intake temps come up, decreasing engine efficiency.

4) Insulating the exhaust manifold helps a turbo diesel by sending more energy for the turbo--it wouldn't have much effect on a naturally aspirated engine (other than reducing under-hood temps.

5) I played around some with pulse-and-glide without noticing any benefit. Maybe I'm not doing it right, but 2 things that are different from a gas compact car are A) The larger, more massive engine takes more energy to re-accelerate, and B) There is tubo lag, so the engine may be much less efficient in a "pulse" than it would be staying steady.

Right now, I think the aero-cap is going to be the biggest improvement I can make. Anyways, just some of my ideas about things that are different. I'm interested to hear others' opinions & ideas.
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