1sikbenz

Just got 38.3 M.P.G. on the way to work tonight, slow lane, cruise control set at 61 M.P.H., no A/C, windows & sunroof closed, it actually peaked at 38.3 for a minute or so, but was staying primarily at around 37.5ish, I wonder if I could get any more if I had a K&N filter, & Kleeman / Supersprint Header & free flowing exhaust? - Thoughts?

ctC230K

damn! nice... most i've gotten so far is around 34.5. i like to drive fast.

patrick_y

I hate to break it to you, but if you are using the Trip Computer MPG calculator, it's not very accurate, it tends to overestimate your efficiency and underestimate your fuel consumption. Meaning that if it says you're getting 38 MPG, you are likely getting less.

Try using the one you have to manually reset at every gas station pump. Then calculate between how much gas you put in and how far you went on that tank. You'll find a discrepency. A big one.

drho2004

hmm the most i ever gotten is 30.2pmg driving from long beach, ca to redondo beach,ca in semi good driving, at about 65mph-70mph. i think the trip computer is pretty accurate actually, i didnt trust it at first so i did the same test that patrick y said. when i filled up i checked how many miles the trip computer tells me im going to get with the full tank. it tells me about 458-486 miles for the tank. ok, i do 42 miles round trip everyday for work, thats 210 miles per week, or about 420 miles for 2 weeks, i dont really drive too much on my days off. i fill up about every 2 weeks, so give or take, its accurate enough i think.
ill post pics when i get home

barrykaye

I agree. I have seen the trip computer show readings in the mid 30's but doing the manual calculations between fill-ups generally shows something less. I haven't found it to be a huge discrepency but a couple of MPG is not unusual for me. It seems to depend on the type of driving I do. I have found the computer to be accurate if I've burned an entire tank of only highway miles but mix any city driving in there and the "real" numbers go down.

MercedesFTW

Hmmm...highest I've gotton was 19.0mpg cruising at 60.

Average? 14.5mpg.

advans

I just got back today from Mt.Pocono, PA to NYC. 2 1/2 hr drive mostly highway with no traffic. Trip Computer gave me 23.2, actual 21.8 mpg. not that bad.

Tangerine

lol, wanna trade cars? my car has better fuel efficientcy but it might be a tad slower

drho2004

interesting, i wonder whats the best the m271 can get? BTW im on auto tranny, anyone know whats the diff. between manual and auto? all things fair i mean, i.e: hwy miles vs hwy miles?
it is true, once u throw in city driving things get changed around. the best ive ever gotten in city is 27mpg, and that was comming off the 30.2mpg hwy run. usualy its between 21-25 in the city, but when u punch them, the mpg dip to the 18's. i gotta say im quite impressed that these cars go into the mid 30's, even on hwy runs, thats like econobox territory. how about the new 2.5 v6's? whats the best someone gotten on them?

1sikbenz

Well, I'd agree with you, the only thing is, I believe calculating it manually (re-set trip computer each fill up) would reflect total M.P.G. for ALL miles driven between fill ups which would give me a better OVERALL M.P.G. reading, what I'm saying is that on my nightly COMMUTE (ONLY) to work I have achieved the 38.3 M.P.G. which in and of itself is also a estimated number, I'm sure the M.P.G. calculater is reasonable but not 100% accurate, in my commuting rate I usually fall between 35-37 M.P.G. nightly. - Engine & driveline are all bone stock.

patrick_y

Yes, if you calculate it at the pump using the total gallons inserted and the total miles travelled, you'll get the actual MPG for that tank.

I understand your thoughts that the trip computer will tell you your stats for that trip only on the "After Start" trip computer page.

However, I always reset my "After Reset" trip computer during my fill up and I log down the discrepencies.

Here are a few examples...

8/07/06: Computer 26.9 MPG; Actual 25.49 MPG
7/16/06: comp 28.0; act 25.7
7/02/06: 27.7/26.61
6/14/06: 29.5/27.74

That was just this year's. Last year's was worst. For a moment, I thought our cars were programmed with Imperial Gallons (UK and Australia) instead of US Gallons (that'd actually make it more accurate).

EV0LVE

I was inspired by this post, so i thought I'd check it out. I got 38.2 mpg today!!! That was driving at speed limit. I drove for 38 miles on the freeway heading home, traffic was light (yeah in West LA) and by the time I got off the freeway I read 38.2, wow!!!

FrankW

18.5 mpg today...ran about 150miles around towns/freeways and all out getting beat by a insanely fast B5 S4 wagon.