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Experiencing Bad MPG
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05-14-2013, 12:54 PM | #1 |
BD_e92
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Experiencing Bad MPG
Hello everyone, so I am running the HPF gen 2 exhaust and bms dci right now as my only bolt ons and no tune yet.. I went from averaging about 17-19mpg with the HPF exhaust and now after installing the dci I'm down to about 14.5 mpg.. can anyone shed some light on if the dci could affect my mpg that drastically?
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05-14-2013, 12:58 PM | #4 |
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05-14-2013, 01:01 PM | #5 |
BD_e92
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lol definitely did that in the beginning and figured that was why it decreased significantly, but after my last fill up i reset the mpg in the vehicle info and drove normal for a week with very little hard acceleration and it averaged out to be about the same
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05-14-2013, 01:08 PM | #6 |
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I average 18.9mpg and I drive mostly highway. Your mpg seems normal to me
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05-14-2013, 01:10 PM | #7 |
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heavy foot... bets way to measure MPG is do it yourself. fill the tank and reset the trip counter.
drive around till it's less than half at least (or whenever, but the more the drive the more accurate the measurement would be). Refill and divide the trip counter number by the # number of gallons it took to refill. Also take it easy
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05-14-2013, 03:35 PM | #8 |
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I found your problem...
Your foot is too HEAVY with the new intake and exhaust sounds. My MPG average over the course of 20,000 miles was 21.0. Your drive habits can sway this number largely. I know a few N54 locals that get about 23-24 Average MPG and others who have a heavier foot with more city driving in the 17-18 range. |
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05-14-2013, 04:13 PM | #9 | |
BD_e92
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Quote:
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05-14-2013, 04:33 PM | #10 |
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The n54 doesn't have a MAF sensor so there' really no explanation of why the DCI filters themselves would have any effect on your fuel economy.
Have you checked to make sure you didn't accidentally knock your charge pipe loose? The charge pipe is in the general vacinity of the intake location and if you fought trying to get the DCI to fit, you might have knocked it loose. The MAP sensor is located on the charge pipe and if there's a leak, it could in theory cause a loss in performance/fuel economy (although you'd likely throw a code). Aside from knocking something loose, there's really no other explanation I can think of aside from a change in your driving habits, bad gasoline, or a significant change in weather. |
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05-14-2013, 04:51 PM | #11 | |
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How much highway do you do? I woudn't sweat anything. Most of the spark plugs changes at 25K are for vehicles with a tune. 50,000 would be for a non tuned vehicle. There is really nothing a cat back exhaust or a dual cone intake can do that would tell your ECU just to waste more gas and spit out more fuel. |
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05-14-2013, 04:55 PM | #12 |
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With 90% city driving I get 15mpg or so in my 1er.....so yea :/
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05-14-2013, 05:02 PM | #14 | |
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05-14-2013, 05:31 PM | #16 |
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I am averaging 24.5 mpg and have gotten as high as 32 mpg on road trips.
I have intake,cat-back exhaust, Helix IC, Vishnu Procede and charge pipe. I have 85k miles and this has been consistent through out that mileage. 14-15 mpg would bum me out. |
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05-15-2013, 08:15 AM | #18 | |
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I thought I was getting 17 mpg (according to the car), after calculating myself I found that I'm actually getting 22.5 mpg. |
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05-16-2013, 11:56 AM | #20 |
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I've got a tune on top of what you've got and a moderately heavy foot getting 21.7 avg mpg... something is wrong with your foot or car!
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05-16-2013, 12:24 PM | #21 |
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I drive mostly stop-and-go in suburbs. I've noticed my mileage avg dropping per model of BMW i have owned
325ci - 25 mpg 328xi - 24 mpg 135i - 18 mpg 335i - 19.4 mpg Ok, so I have improved with my 335i over my 135i
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05-16-2013, 02:05 PM | #22 |
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When I was getting MPG like that my plugs/coils were starting to go bad. Replaced em and getting like 21-25 now.
14-15 did really bum me out, especially after a few quick tanks. |
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