Quote:
Originally Posted by teagueAMX
OK - here we go.
First - part of the rumor is that fewer HPFP fail in Europe but if you do a poll on any given day, and there have been a couple informal ones, member of the forum are aware of HPFP failures in Europe, too.
Second - except for racing fuel, fuel quality differences are a myth. Individual brands' fuel is produced the same and even stored in the same containers but the individual brands' additives are put into the fuel just before delivery. US has ethinol, but if that was the problem then it would be affecting other fuel pumps as well - see points Three and Four.
Third - A low pressure fuel pump, high pressure fuel pump, mechanical fuel pump, electric fuel pumps, etc. are all made with the same metal, the same seal materials, etc. If the fuel is the problem then why isn't it destroying all the fuel pumps? Additionally, the Volkswagen's big marques (including Porsche), and BMW and few others Euro manufactures get their pumps from the same companies. Why aren't they all failing here in the US?
Fourth - Although a number of manufactures are having issues with HPFP in lower numbers, why aren't BMWs other HPFPs having the same issues in the same numbers. Example - BMW makes a nice tt v8 first installed in the X6 50i with a HPFP - go over there and monitor their threads to find out if their HPFP are failing at the same rate. I can tell you they've had some failures but not a high rate.
Fifth - the new n55 has a HPFP. Are they failing at the same rate? Time will tell. It appears IMHO the n54 HPFP has a design defect that apparently cannot be easily corrected.
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First, it is indeed an assumption I made based on feedback on this very forum that in europe much fewer failures are being reported. Come to think about it, it is also very possible that there are fewer 35i in Europe given that buyers are more cost sensitive there but I assumed it to be true.
Second... I used to work in oil as a process engineer and have actually worked in a refinery! Not all gas is being created equal and although aftermarket additives different companies add to the gasoline is a major factor, it is not everything. Even the same brand of gas will have different level of minerals (inorganic) and other components are not being filtered the same way through the hydrodesulfuration and distillation process. There will be batch to batch variations depending on the origin of the oil. How much it will affect the pump, I do not know. One would argue that in reality a lot of the refinery in europe are actually shipping their gasoline to ... the US because europe has gone mostly diesel. I know this for fact from former colleagues. It is however perfectly reasonable to think that given the price of gas in Europe, companies there are more inclined to put different (read useful) additives than in the US. The same is true for Engine oil. There is a reason why BMW imports their synthetic oil from Europe and that you cannot buy the exact same oil in the US. This is a fact, not a rumor.
Your reasoning on the HPFP design flaw makes sense except... If they outsourced the pump and it would be an off the shelf part from an OEM, other cars would use the same pump and would also have increased failure rates. This leads to think that the pump on the N54 might be specific and would have a design flaw making it incompatible or more sensitive to the gas over here. Being it flow, pressure, material degradation or whatever it is I don't know.