Quick question regarding M5 mpg calculations - The Unofficial BMW M5 Messageboard (m5board.com)

DIPLOMAT · 15th December 2004, 13:51

Hello,
I have done many searches but coul dnot find the anmswer to my question.
I have had my beast for a little over a week now and have an mpg question.
I reset the computer and drove the car a few days and got a mear 12mpg. Now I was driving the car quite un-aggresively and was shoked of the low mpg. do you believe my readings are correct from the obc, or does it usually take at least one full tank to gte a good estimate of driving mpg? I am now scared to punch it as my mpg will drop to below 8

I filled up the tank and my Range was only 263 miles which to me seems very low.
comments, suggestions?

cheers
J
ps by teh way car has 27k miles 2000MY

e39m5nut · 15th December 2004, 14:39

Why are you shocked about 12mpg in I assume city driving? The EPA rating is 13 city / 21 hwy so your mileage is accurate.

I get 17mpg in mostly city driving...

DIPLOMAT · 15th December 2004, 16:07

Ok you reassure me, I just had read several posts with people up in the 15-18 city driving and that seemed a lot to me

gsfent · 15th December 2004, 16:26

Quote:

Originally Posted by DIPLOMAT

Ok you reassure me, I just had read several posts with people up in the 15-18 city driving and that seemed a lot to me

A lot depends on your driving. If city, probably not that far off. After 15000 miles, I have about 16.8 with an average speed of 34. That has gone up recently due to a couple of highway trips, but look at mpg as well as average speed.
Regards,
Jerry

marinakorp · 15th December 2004, 16:34

try calculating it manually (fill tank, record mileage, drive, fill again, calculate)

and see if the calculations on the computer are correct. I believe there is an adjustment that can be made for the calculations (on the E39 540 there is , so there should be a way on the ///m5)

the numbers should be fairly close (not exact) but close enough. If they are really far off (like calculated = 15mpg and the computer = 13 mpg) then an adjustment might be needed

Jayson · 15th December 2004, 18:15

I usally get around 265-280 mixed highway and city, getting on it.

Welcome to the down side of 5.0 liters and 8 of those things that make power

SLOMeander · 15th December 2004, 21:42

Quote:

Originally Posted by gsfent

A lot depends on your driving. If city, probably not that far off. After 15000 miles, I have about 16.8 with an average speed of 34. That has gone up recently due to a couple of highway trips, but look at mpg as well as average speed.
Regards,
Jerry

Realize when the computer gives you MPG data or average speed data that (unless the computer has a really big memory) after a certian number of data points it starts dropping off the oldest data (a moving average). So even if you have never reset your average speed, it may only be looking at the last 1000 or 100 miles. Same with MPG. I'd love to know the algorithms, especially the one that calculates expected arrival time.

Rich

Ashok Arora · 15th December 2004, 21:48

If the car has an aftermarket exhaust or faulty Lambda sensors, this can decrease fuel economy. If you feel this is a real problem, ask your dealer to download the fault codes (diagonostics) and check/replace the Lambda sensors.

kcdoyle · 15th December 2004, 22:22

Quote:

Originally Posted by DIPLOMAT

Hello,
I have done many searches but coul dnot find the anmswer to my question.
I have had my beast for a little over a week now and have an mpg question.
I reset the computer and drove the car a few days and got a mear 12mpg. Now I was driving the car quite un-aggresively and was shoked of the low mpg. do you believe my readings are correct from the obc, or does it usually take at least one full tank to gte a good estimate of driving mpg? I am now scared to punch it as my mpg will drop to below 8

I filled up the tank and my Range was only 263 miles which to me seems very low.
comments

I had to chuckle when I read your post. When I first got Ole Red, I was getting around 11 MPG, and at (still) $1.75 a gallon for 93. I thought, Christ, one of the girls is going to have to go to a state college!! My driving has settled down a bit. Just looked and am averaging 13.7 MPG. I did get close to 24 MPG driving across state around 70 MPH with no stopping or passing (and most likely slightly downhill!) I suspect you will see your mileage increase as you get more experience in the car.

greg · 15th December 2004, 23:22

In the last year my commute pattern changed a lot, from almost exclusively around-town (15 mile round trip to ferry kid to/from school = other local errands and appointments) to 3 200 mile freeway round trips per week. Average mileage went from 13 to 17.5.

I once went boating with a buddy - followed his truck and trailer at 55mph for 150 miles. (There's a guaranteed new experience for any M5 driver. 55? Thought I was fall asleep from the boredom.) But I reset the mileage indicator "in flight" and I was getting close to 25 for quite a while.

mfettara · 16th December 2004, 00:27

Hello,

higher octane reduces the consumption, I use 98 oct here in Switzerland and 99 oct in Italy (Shell V Power), my max mpg was 25.6 doing very conservative driving (average 75 mph on a highway with cruuise control) in my usual aggressive driving I do about 15.7 mpg.