MPG Calculation, What methods do you use? , beating a dead horse I know.

[neoneddy]

I've seen some threads around on this where everyone checks in with MPG, which I am curious about.  I've done two measured runs so far.

1982 MCI MC9 6V92TA - running AC from an inverter pulling from the main alternator, so there was some draw there.

One of 600 miles or so with mixed idling, traffic and hwy, trying to stay with traffic hitting 75 in the flats, that ended up around 6-6.5 mpg

Last one was 220 miles, mostly hwy, some traffic in St. Paul construction during rush hour, gah!   This time around I didn't care if I got passed, I took it up to 70 on the down hills, but then let it settle in around 60-65 depending -  8.5 mpg

How do you calculate  your MPG?

Are there things you can hook up to measure live data / fuel consumption? in a bus like mine?   Right now I just take miles traveled and divide by fuel used.  But because I have no odometer I use Google Maps after the fact to measure my route.

How to Improve MPG?

Obviously the biggest factor is your right foot.  But then what?

• Air Filter? (not sure when mine has been cleaned, messing with it at all has me nervous in reading technomadia's experience of losing the engine to it getting sucked into the intake)
• Tire Pressure? - I'm running mine at a mix of 110 to 90psi, my home compressor won't fill much past 90, thinking of using the cus air line in the rear right as a fill once the main pressure hits 120psi.  I'd like to run all my tires around 110.  I know the ride might not be as nice but I'd love to hit 9 mpg or so.
• Fuel Filter? - Not sure if mine have been changed, I suppose I should. 

[windtrader]

I think around 6mpg is a good average. Beyond that the saying goes, "If you gotta ask, you can't afford it" lol

[neoneddy]

re: if you gotta ask, you can't afford - If Warren Buffet lives in a normal small house and doesn't throw 100's out his window for the fun of it, I can too.

Nothing wrong with being efficient :-)

[windtrader]

The bottom line is there is not much to work with. I mean a 10% improvement from 6.0 to 6.7 mph doesn't show up much at the pump. So instead of paying $330 for some diesel you now pay $300. Sure, every bit helps but at least for me that difference doesn't dry many tears. LOL

[Geoff]

If you don't have an accurate odometer using google maps is not accurate.  I get 8 mpg in my 6V92TA @ 350HP and 4.11 gearing.  I can go 80mph @ 2350 rpm.  I have a tachometer, and that is the tool to get the best fuel milage.  If I can keep it below 1800 rpm's which ends up being 62 mph I can get easily 8mpg, maybe better.  I just don't like driving that slow so I go 70-75, and still get 7.5.  Towing my pick-up drops it down to 6.5 mpg, towing a 20' 10k trailer has me at 4.5 -5 mpg.

--Geoff

[luvrbus]

If you are in the 6.5 range you are ok, the 740 is a 1:1 final ratio unlike Geoffs V730 that is a 3 speed with a OD ratio of .875:1 your foot and the load will dictate your fuel mileage

[J_E]

I was able to load my bus into the Fuelly.com account that I use for my other vehicles.  Open up the site on the phone, and enter data as I fill up, or get the receipt and write the odometer reading down so I can enter it later.  I don't do anything special to determine my fuel economy, just drive normally.  I can usually account for MPG changes driving type/style/towing/speed.

Adding the odometer to your MCI shouldn't be much more difficult than finding the parts.  Once you have the odometer, any method that you choose for tracking will work better.  And it will help you track some maintenance items better.

http://www.fuelly.com/truck/motor_coach_industries/102a3/1991/jasons/632074

[neoneddy]

Thanks for all the replies everyone.

lovrubus: mine is a 4 speed automatic, no idea what beyond that.

In 3rd it tops out around 50, the. 4 or OD I have no idea top speed, been above 75 down a hill but I  don't like it much.

[bevans6]

What is this MPG you speak of?     I have a hub meter that reads in something close to KM's travelled.  I have a fuel gauge that seems to stay full until it jumps to a half a tank, then goes to 1/4 in a few miles.  I have no clue what my fuel mileage is.  I just fill up every day or two on a trip, and give the bill to my wife.

[neoneddy]

Re fuel gauge, I know right? I was thinking "sweet 300 miles down only used an 1/8th tank .... And I'm at 1/2"

[windtrader]

Yeah, I was warned that the gauge in mine only went to 3/4 when full so not all that accurate. I just topped it off and watched it go down and topped up to learn about how much fuel was used/left. After a few times I have a good sense of where it is now. Like how much $$$ to fill from that point. LOL

[Zephod]

I write down how much fuel I put in, the odometer reading and the date. After 1,000 gallons I add up my mileage and divide by gallons to get a reasonably accurate all around figure.

The key is to know if your odometer and speedometer are correct. For this, a gps speedometer is useful. If the speed on gps does not match road speed then you're probably using tyres that aren't the right size rather than any mechanical problem.


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[HB of CJ]

Divide the gallons, (US) into the miles traveled and get a figure.  That would give you the ROAD MILEAGE.  APU or generator usage will not enter into the road mileage but will affect the usage.

My old Crown Supercoach got around 10.5 mpg at 55-60 mph.  About 1500 rpm at 60 in 10th gear.  Twinkie.  Pretty slick at a moderate speed.  But if pushed to 75 or flat out 80 I imagine it was poor.

If you sit at a Boon Docker non improved camping site for months while Campground Hosting, divide your usage into the days sitting and get a figure for usage.  Not MPG.  Gallons per day.

If parked in the shade and if you spare the house bank, you might not need to run the APU that much.  All electric coach?  But on washing/recharge day or when hot and muggy, high consumption?

Separate considerations for diesel fuel consumption.  But overall, both must be added together.  For propane use I do not know.  Perhaps all added together to get a monthly $money$ expenditure?

[muldoonman]

3.53 rear end, 5 speed 755CR trans, 8V92TA and 40,000 lbs, pulling a 2013 Ford Super Crew. 5 MPG.

[lostagain]

LOL !

My fuel mileage goes like this: when the gauge gets close to 1/4, or I've gone 500 to 800 miles, I pull in to a gas station and fill it, give lots of money, and be on my way. Nothing else you can do... If I was so concerned about fuel mileage, I would go on a bicycle holiday instead...

JC