Quote:
Originally Posted by Spartarus
I've always thought the "bad fuel" or "poor lubricity" argument was, at best, a lip-service band-aid for very poor manufacturing tolerances, and very poor material quality control.
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I agree that it's tolerance & material based, combine with the fact that a DI pump is pushing several thousand PSI of fluid (even at small volume) it's a hard nut to crack. There are SAE papers about trying to solve a noisy HPFP because adding weight for sound deadening is counterproductive. I bet Bosch, Delphi, and Hitachi have spent hundreds of thousands, if not millions of dollars each trying to make a quiet HPFP.
http://papers.sae.org/2013-01-0253/
http://papers.sae.org/2011-01-0930/
I haven't heard crickets in 3 years and 40,000 miles, 99% of my driving is within a small region. I think that for a powertrain designed for a <$25k price point suffers from looser QC and as such the pump is designed to 'wear in', I'm not the only one who's had their pump go quiet after 'breaking in' and a few got lucky having one in spec off the shelf.