No smoke, even under max fuel is nice but I'm really doing it because some old dieselhead from Canada is claiming 60-80mpg by just by leaning out his TD (i.e. turning off the LDA) and fiddling with his fuel system. Maybe, maybe not...
but to do this he has supposedly messed with injector breaking pressure, shims, injection pump, etc... So, it could be possible. Especially considering diesels are designed to minimize NOx, while maximizing power and fuel economy.
A 30-40% increase in efficiency isn't unheard of when that's all you're optimizing. Hell, you can do that at highway speeds just with aerodynamic mods (I kinda wish manufacturers would do that, but I guess they don't want something that looks too "weird". Getting 50+mpg highway in a Z06 would be pimp), which are probably coming sometime in the future anyway.
When you start stacking 1%, 5%, 20%, 3%, etc... gains on a car that already gets > 50mpg, then you can get some nice numbers pretty quickly. Synthetic tranny/engine oil should yield a 1-4mpg increase, low RR tires another 1-4... right off the bat I'm close to or over 60mpg. If fiddling with the fuel system and tc'ing it out can provide a 20% increase in efficiency, then I'm at 70+ right there. And I haven't even touched aerodynamics yet... cutting the .43 CoD in half could yield well over 100mpg highway.
Something else that might be fun is messing with the LDA, max fuel screw, governer, maybe I can have something that puts out ~60hp/80tq at 70-120mpg, or 100hp/125tq at 50-60mpg with the flick of a switch.
Ultimately, the best part is dicking around with my car...
