I've spent days reading old posts on this subject, and in conclusion I decided I'd give it a go and try them. purchased two OEM VW/Audi sensors (Bosch 032 ending #'s) and installed them here are my results but first a little background on this car recently acquired 2002 e39 M5 51,000 miles did a thrall inspection and maintenance follows. Changed all fluids/Filters, New OEM spark plugs, AFE filters on stock Airboxes, TMS shark Injector (7000rpm) 91oct. tune, belts and hoses, mafs removed inspected / cleaned and reinstalled. Car runs great idle is good and very responsive throttle. Car has been well maintained and I doubt ever abused (know the prev. owner)....
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After above work was performed I did a L/H test and was 119-126 in 2,3,4th gears these were the original maf's (Bosch 029's) I live at 900ft elev. and ambient temps was 36deg. F<o
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Next I went back to the shop and swapped to the VW/Audi sensors (they did have the extra little hole and I did NOT plug them) went back and retested L/H on same road getting essentially the same reading +/- 2 L/H. <o
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Here's the twist I saw an immediate 3mpg reduction in fuel economy as recorded on the cars computer same course and driving style with the VW/Audi sensors vs. the original 50K mile oem's....? I couldn't believe my eyes I rest the computer three times and kept getting the same Mpg readings.<o
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Went back to shop swapped back to the original used sensors and the lost Mpg came right back... BTW I felt no difference between the two different sensors. Engine seemed to have same power, and idle quality and throttle response was near identical.<o
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Comments or explanations? <o
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After above work was performed I did a L/H test and was 119-126 in 2,3,4th gears these were the original maf's (Bosch 029's) I live at 900ft elev. and ambient temps was 36deg. F<o
<o
Next I went back to the shop and swapped to the VW/Audi sensors (they did have the extra little hole and I did NOT plug them) went back and retested L/H on same road getting essentially the same reading +/- 2 L/H. <o
<o
Here's the twist I saw an immediate 3mpg reduction in fuel economy as recorded on the cars computer same course and driving style with the VW/Audi sensors vs. the original 50K mile oem's....? I couldn't believe my eyes I rest the computer three times and kept getting the same Mpg readings.<o
<o
Went back to shop swapped back to the original used sensors and the lost Mpg came right back... BTW I felt no difference between the two different sensors. Engine seemed to have same power, and idle quality and throttle response was near identical.<o
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Comments or explanations? <o
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