Bonneville America Forums Forums Off Topic Discussion Forums Lounge Why MPG?

I have decided that maybe MPG is almost a completely fake measurement. After all how can they say that a vehicle gets 40 MPG? What RPMS were they runng? What speed were they going? Were they going uphill or down hill? They do not say how they cam up with that number. "City" MPG is a completely fake number. How do they define "stop and go"? HOw long were they sopped? How long, what speed and RPMs while going? I am starting to think that fuel efficiency should be GPH (gallons per hour). Think about it, MPG is really only good if you can maintain a steady pace. In todays city (including interstae) driving, it is stop and go. Usually that is more stop than go, and when stopped you are burning fuel while idling. Sometimes the interstate is moving only about 5 mph for a few miles. I have noticed that sometimes I might use the same anount of fuel to go 10 miles in half an hour as it would 40 miles in half an hour. However, it all depends on the road, speed, and most importantly RPMs.

So I think we need a new way to measure fuel effiency, something based on time and RPMS.

Soren

Okay, Soren me boy! I think you may be taking that ol' saw..."Time is money"...and puttin' a whole new twist on the thing.

BUT, you MAY just have a point here, my friend. Let me think about this for a while, and I'll get back to you on this.

Cheers,
Dwight
(but I better not take TOO much TIME though...This COULD cost me more MONEY than I can afford)

You think you've got it tough? Try living in a metric country and figuring out what km/100L is in meaningful terms! It's actually easier to convert everything back to imperial and use MPG.

Point of interest... your MPG will be different to people in UK/AU/NZ etc, as the US gallon's slightly smaller.

As I understand it, the Federal Trade Commission (or some other flakes in a government office) have a "standard" profile of partial highway and partial city roads that the manufacturers are suppose to test their vehicles on.

Consumer Reports (a US-based magazine) has been pressuring the government to update its profile as, like us, their actual 216-miles mixed road testing gives consistantly lower MPG than the manufacturers place on their pre-sales data sheet.

I prefer MPTF.

Miles per tank full. I like to keep a check on how many miles i get to a tank in both the car and the bike. Works quite well i think and then you can always work out an average.

Oh, i guess should point out that i fill the bike when i turn the tap turns from main to reserve and i fill the car when the orange light comes on.

Just another statistic people calculate... I think there's us a standard EPA sort of obstacle course that they run on, or a "loop". Whatever the car gets on that loop they call the EPA extimate. So as for real world, your results may vvary.

"consumer reports" is the shizznit. totally consumer driven, non-profit, no advertisements- ever.

http://www.consumerreports.org/cro/aboutus/mission/overview/index.htm

I'm with you Soren. I've had this debate with others, often over "Brand A fuel gives me better MPGs brand B." There are too many variables to pin it down to a few hundred miles on this then that in real world conditions. I usually get in the low 40s on my Speedmaster, but on a recent long haul, I was clocking MPGs in the low 30s, for a number of reasons, mostly related to slab speeds and a tremendous amount of wind during most of the trip.

I contend there's no way to know accurate MPGs without a very lengthy comparison for starters.

The EPA method of determining MPGs for autos (measuring exhaust discharge while on a dyno, performing a programmed run) is very close to worthless IMO when compared to real world vehicle operation.
http://www.nytimes.com/2006/01/11/automo...nyt&emc=rss

The method to determine comparative MPGs that seems to be the most reliable is to operate vehicles in controlled conditions, then weigh the remaining fuel at the end of the runs.

I've got it! If you like the way your vehicle uses fuel, you get 'good' mileage. If you don't, you get 'bad' mileage.

We had a 3 cylinder Subaru Justy, with the snowmobile type constant velocity belt drive variable pulley size drive train deal. (A very weird but good while it lasted car) I could get low 50s if I kept it to around 55 MPH tops. My wife got low 30s, all the time. She drives as if clawing for the lead in a Baja Rally, 24/7.

The best mileage I ever got was riding through Yellowstone Park a few years ago. The speed limit throughout the park is 45 mph. I was probably doing slightly extra-legal speeds, but nothing where I couldn't dodge a stray elk or grizzly bear on the road. Anyway, I got over 50 mpg. I thought it was a fluke, but I got the same on the next tank too.