djlarroc

my mileage on this tank was already terrible. i was already on pace for about 355 on this tank. i had to fill up today, and ended up w/about 352. the seafoaming should not have deducted 80-100 miles off this tank. 2-3 miles, maybe.

going to see how much i get w/the 91 aki now.

djlarroc

yes, i understand.. i will track mileage over again w/the 91. we only have 85, 87, and 91 in CO (for the usual). So it's either run 87 like my old e39, and w/the altitude here, equaling about 89, or running 91 equaling about 93. Would expect this car to even surpass the e39 mileage on higher octane, but i doubt that will be the case.

crewzer

OK. Just to be clear, 87 AKI is 87 AKI, and 91 AKI is 91 AKI, regardless of elevation or location. The grade label changes (85 AKI at higher elevation vs 87 AKI at lower elevation for "regular", etc.), but it's the lower air density at higher elevations that generally allows lower AKI fuel to be used in normally-aspirated (non-turbo) engines. However, everything else being equal, most modern engines advance their ignition timing as air pressure / density drops, so this can be a fine balancing act.

89 AKI may not be widely available in your region. But, like many (most?) gas stations that "make" mid-grade by mixing regular and premium when it's pumped, you can "make" your own 89 AKI by mixing 1 part 85 AKI to two parts 91 AKI.

Best of luck!
Jim / crewzer

djlarroc

haha.. i never thought of that! good info! and yes, i agree on the grade still being the same.. just used to people saying the elevation here makes it seem more like.. etc.

still, i believe something else is going on w/my car. when i fill up, i get 450ish to empty on the obc.. vs my e39 used to always say 500ish.. and my obc has been reading an average of 25 mpg. my e39 used to read average of 23, so not sure why this car is wasting that much more. it's a CA car.. could it be that all the extra emissions crap is affecting fuel economy?

tomstin

Of course you need to verify the car doesn't have any maintenance issues but a contributing cause may be the winter blend gasoline. Notorious for reduced fuel economy.

sahiljain22

OP - everytime I fill up my car, it says I'll get 500 miles out of it (and I have gotten it on super long drives where I was literally filling up and driving 500 miles). But frankly, I get 300ish without much spirited driving. I will clean up the MAF this weekend but it seems to me that every small thing (cold restarts, idle time, auto weather, electronics, that extra pedal push after the toll booth) drains the fuel economy.

Let others here know what you find.

03grey5

WHAT?! damn when i had that same ratio of mixed driving while I was commuting to UCI, i didn't get anywhere near 400. I thought my e60 was normal...

With 0 high way driving. I'm getting less than 350 full tank. Ridiculous.

John, can you do some open heart surgery on my car and fix this shit? Will supply beer + pizza + chicken. K Thanks!

bpg535i

Just filled up again yesterday with 369 miles on the tank with about 65 mls displayed.

I suppose if I let it run down to fumes it would be getting over 400 miles per tank.

My driving is above 90% highway, 10% city, 80 miles a work day.

Ghostteck

i avg 11 city 15 highway but i still love my car =)

G530

25 mpg featherfooting and rolling down slope on the freeway ---> all giddy. Same fwy home now up slope 18 mpg.

Most accurate way to get mpg is to start with full tank, trip it, drive it until 1/8 or 1/4 and fill up tank. Take miles driven and divide by the # of gallons filled. You can then guage how accurate your car puter is.