I would like to open this topic concerning several issues/questions around M3 Gas Mileage.

1 - What are typical gas mileages experienced by other M3 owners.

2 - Can someone explain the Gas Guzzler tax and why we pay the extra $1000 bucks?

3 - How does the computer calculate its Average Gas Milage. My computer seems to be miss-calculating.

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1 - I currently have approximately 6400 miles on my M3. During the entire time, I have kept a detailed record of every fill up and the mileage for each tank of gas. Here are my results:
For the life of the car i have averaged 20.78MPG. The worst tank was 18.0 (where I spent a full day auto-crossing). And the best recorded was 28.0MPG (a trip from DC to Charlotte, NC). It seems unusual to me that I can get as high as 28MPG however the sticker shows an expected 16 in the CITY and 24 on the HIGHWAY.
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2 - My previous car was a 1998 Ford Mustang Cobra. The average over 27K miles was: 18.92MPG. Max: 22.3MPG. Min: 15.8MPG. Why didn't I have to pay Guzzler tax on this one?
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3 - I've been keeping track of the value that BMW's on board computer calculates for each tank of gas. It reads consistantly 1MPG better than I actually am getting by taking the number of miles on the trip odometer divided by the gallons of gas that I pump. Is anyone else seeing this?
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--Tripp
2001 Laguna Seca Blue www.trippcat.com/m3 (http://www.trippcat.com/m3)

I have never gotten over 20 mpg on the E46 M3. I was really actually very surprised at the demise gas mileage.

My C5 vette consistently got over 20 mpg!

The mileage seems to get better with miles from my experience.

The guz tax I THINK is based on the federally mandated min mileage for passenger vehicles...I think. And since its a fed stand..fed tax..it gets added to the sticker? I dont know..just a guess. http://m3forum.com/ubb/smile.gif I did read that the tax is 1300 on the M5.

Gas Guzzler tax is applied to cars (not light trucks/SUV) that have a combined EPA city/highway average of 22.5 or less. M3 being 16/24 has avg. of 20 so you get taxed. I DON'T KNOW when this tax was implemented but I'm assuming that you bought your Mustang Cobra in 97 before it was implemented. Or maybe you just overlooked the tax...I'm not sure.

The gas guzzler criteria generally changes every year. The intent of the law was to encourage manufacturers to continuously improve their MPG. That is why the M3 is classified as a guzzler today, but would have been ok 5 years ago.

I only recently purchased my M3 cab and have yet to purchase gas, but with 200 miles on the odo, the computer shows 19.2 MPG. I have seen the reading go as high as 22 MPG when I really baby it, but as soon as I do any city driving it drops to around 19. So it seems to be consistent with others on this forum.

The question that I have is whether the MPGs would improve as the car breaks in. I have read many articles that BMWs performance and MPG continues to improve until 30K miles. Has anyone seen that?

I expect the computer to be be off by 5-10%, just by design: 1. The sampling methodology , and 2. the tolerance of the flowmeter. I have seen about a 2 MPG difference on another vehicle I own. Your manual calculation is the more accurate one.

I also got 28mpg recently on a 300 mile drive from Washington DC to New Jersey. My cruising speed was about 90mph most of the drive. I do recall that my 99 540 speedo was 8mph faster at the that speed and wonder if the m3 also has that problem. I also wonder what your cuising speed was when you got 28? Could it be that by driving near the peak torque rpm the m3 gets great mpg? Any thoughts? Btw, this is a 2001 Laguna seca blue coupe and I adore it.

Yes... cruising speed was nearly the same. A little slower in VA (no radar detectors allowed) but 80-90 most of the way. I'm still seeing improvements in mileage over the life of the car. My overall MPG average is now 21.68 (now at just over 11K miles). LSB here in Charlotte... thanks for the replys!

Gas prices are roughly 3x what they were when this thread was being discussed, amazing!!

to the OP...there was a posting within the last month on this topic and speed to MPG was calculated and printed...do a quick search to check it out...:thumbsup2:

http://www.m3forum.net/m3forum/showthread.php?t=216328&highlight=gas+milage

here it is

to the OP...there was a posting within the last month on this topic and speed to MPG was calculated and printed...do a quick search to check it out...:thumbsup2:

Looks like the OP posted this 7 years ago.

yea alot are comin back from the dead..

I average about 19.6 MPG on my trip computer ( I haven't recalculated it in about 4-5 months) I drive 50%city 50% highway. It is a 2001/7 laguna seca blue .. 6 speed.. 37K miles as of today.

I drive 25 miles to and from work. Average 70-80mph on the highways. Highest I have gotten was 22.8 MPG and 42 MPH.

At 70-80 mph, in that range, on the basically level to rolling freeways around Richmond, VA, I get 24-25 easy. It surprises the helll out of me, but it's consistent. If I drive back roads, where the avg speed is more like 60-70mph, it pushes 27-28 sometimes. No kidding. This is, of course, per the on board 'puter, so maybe the car is lying to me. Having had the car only since last November, I have not yet checked mileage against the onboard 'puter.

I will say this - I am a bit skeptical about the on board computer for one reason. We have take it on one road trip so far (a damned shame, I'll be the first to say) but anyway, on one leg of the trip we were on roads where we were getting excellent mileage and were easily on track to get well over 400 miles on one tank full. So you know, the car will tell you how many miles you have left to go, and I had reset the trip odometer at the same time I reset everything else. What happened is that before we ran out and actually had to stop for gas, the "miles til empty" counter went to zero. We got something like 420 miles on that tank and the "miles until empty" counter went to zero right as we crossed the 400 mile mark. It made me think that the onboard computer is not designed to go over 400 miles on a tank, with respect to calculating fuel mileage and "miles until empty"

Anyway, I thought it was strange, thought I'd share it here, and maybe it's all BS. I'll have to cross check mileage to see if the car is making me delusional.....

Wow I was in high school when this thread was started. My advice is to use the computer as a comparison tool because it has NEVER been accurate with my fuel comsumption. It is usually off by 1-3mpg. I went from the bay area to Sacramento and back. Probably about three hundred miles round trip. At about 70mph all freeway. I filled up and calculated 27mpg.

Looks like the OP posted this 7 years ago.

:rofl3: Second time I have seen this in 2 hours?

Now that the topic is brought up...

The best MPG I have gotten is 24.1 and the worst is 17. The thing that seems weird is that the on board computer is not accurate at all; I have noticed that it is actually off by nearly 50 percent? For example, it will say I have 21 miles and after going about 10 miles it will say like 4 miles? Nothing big as my manual calculation comes out to the above numbers, which seem normal, but was just wondering why my OBC is so off?

In the couple of weeks I've had my m3 the I've seen a relatively significant difference in the two road trips. 20ish vs 24.3 Same distances, same driving style. The only difference was I got 24.3 driving at night without ac.

Just some random input.

Generally my experience has been pretty consistent with several of the posts here with 28mph highway and 20ish city. On average, I get around 310 miles on every refil (13.8 gallons) which equates to 22.4mpg.

best i've pulled out of a full tank was 358 miles. When I refill the computer said I should get 380 on the next tank. I never seem to get there. From what i remember reading the on board computer is suppose to calculate your next tank based off your driving style.

to the OP...there was a posting within the last month on this topic and speed to MPG was calculated and printed...do a quick search to check it out...:thumbsup2:

I think the OP is now somewhere around 90 years old.:lolhit:

Generally my experience has been pretty consistent with several of the posts here with 28mph highway and 20ish city. On average, I get around 310 miles on every refil (13.8 gallons) which equates to 22.4mpg.

No WAYYY !! Iget 250-260 miles out of a tank!!! but that is strictly city driving ONLY.. as of now Istarted driving more on the highway and I get about 320.330 just like you say... what tupe of driving are you refering to ??? ohh and by the way whenI refuel I get in about 16 galons!! 16.2 or someting to be exact!