Here's an interesting article about increasing efficiency AND reducing emissions by blending gas and diesel in engines.
Technology Focus - November 2009 Issue
Scroll down the page to BLENDING FUELS TO BOOST EFFICIENCY.
They're talking about a prototype that gets 53% thermal efficiency versus 33% for conventional diesels. And they say that gassers could be drastically improved from their current 25% efficiency.
Now THAT would be a good thing. And being able to avoid things like catalysts and particulate filters wouldn't be a bad thing either.
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First truck -- 1929 Model A Ford pickup, restored from ground up. Wish I still had it!
99.5 F250 PSD Supercab LB 4x4, ZF-6 w/SB Con OFE, 3.73LS, Boost & pyro gauges, Swamps S175/146 injectors, DP 80 HP Econo PCM (classic version

), AIS,
coolant filter w/"hokum" bracket, regulated return,
heated mirror mod, lighted cupholder, Marinco heater plug-in.
Hard or no-start? Check Here