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I'd only go low rpm's with a manual, I want one anyway to experiment with pulse and glide. But elsewhere i'd read there were problems either "lugging" (everyone uses the word, not everyone defines it - a torsional vibration is obvious but i'd think that's obvious and am not sure if its lugging or damaging without that vibration) or talk of the accessory drives possibly not spinning fast enough. (like oil pan just clarified it for me but is that the only issue?)
Whats the rated minimum rpm of the cummins for oil pressure reasons? Is there some not too difficult way to supplement the oil pressure at lower rpm maybe some kind of auxillary pump? (I wanted to have some kind of engine prelubrication before start anyways since starting causes most wear, maybe it could be just left on at low rpm) I'm not sure whether ultra-downspeeding is the only way to go though - enough other specific fuel consumption charts. If SFC is the same at 1600rpm as at 1100rpm it just plain makes more sense to turn 1600rpm due to gear loads and everything. Is there a way to measure SFC after mods in the vehicle or is that really expensive? (for mechanical injection)
Running compound turbos is possible to shift the torque peak even a little lower - i'm not looking to go crazy with power so downsizing the little turbo then putting on a big normal turbo would keep EGT's way down and improve torque further to hold the load. None of that solves whether the rod bearings would be getting enough oil. Would rifle drilling make that big of difference?
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PS i'm familiar with diesel dave though he makes his mpg pulse and glide not steady state. If wishes were fishes i'd love to see steady state mpg figures at say 35mph thru 70mph every 5mph or so for different axle ratios, probably in both 4th and 5th since 5th wont go down that low I don't think. I could then calculate "with X aero improvement it should be like Y". But I don't know if anyone has done that. :P
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