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Old 12-04-2008, 06:00 PM   #83 (permalink)
Master EcoModder
Join Date: Apr 2008
Location: Michigan
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Bio Deezler (sold) - '03 Volkswagen Jetta GLS TDI
90 day: 50.78 mpg (US)

The Beast. - '03 GMC Sierra 2500HD SLT
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Sorry, should be specific. The emissions rules are hurting new heavy duty truck engines the most, from what I've seen. I heard firsthand from an Ford engineer that the new "powerstroke" engine was initially testing at 11-12 mpg (compared to actual driver's results of 15-22 mpgs for the former engine). I've measured personally the BSFC and engine friction on a new 2011MY 5.0L turbodiesel V8 saddled with emissions equipment to be much lower than any other diesel I've run... I was also told that the DPF regeneration event on a particular new HD truck engine takes as much as a whole gallon of fuel! Just to burn off the DPF, turning what could be a small amount of airborne soot that was trapped into (more) pure CO, CO2 and heat.

Auto makers like VW, BMW, and Merc. are engineering new diesel engines marvelously. The technology needed for emissions controls makes maintenance and future repairs a bit scary though... but let's hope they've done things right. Things like in cylinder pressure sensors, DPFs, NOx traps, urea injection, multiple catalysts, hot AND cold EGR, advanced ECM calibration, higher pressure fuel rails and the associated electronics and hardware that must be more durable (heavier) to cope with these things are all EXPENSIVE. VW is cutting their profit margins on the new common rail engines in order to better promote them. The fact is that these new diesel engines could be made cheaper and more efficient if these emissions rules weren't being implemented. Somebody made a comment earlier about these engineers needing a challenge in order to get creative, and this is absolutely true. But these same challenges have discouraged the north american automakers to stay away from diesels, forcing me to buy a German car. I'd much rather drive an American vehicle, they just don't make what I want.

Anyway Treb quit reading this thread and run some CFD already!
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