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John Baker (Bus_john_bus)

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Posted on Monday, April 24, 2006 - 5:07 pm:   

I know, I know, if you have to ask, you can't afford it. But, there are a couple threads I'd like to see a thought or two on.

First, across the full range of models and types, what are you guys really getting in fuel milage. Name your bus and power train... but no tall tales please. I'm in need of a reality check.

Second, if any of your Eagle drivers are reading, how can I squeeze the miles out of my Eagle. It's currently grounded. Powered by an 8v92T with a 5 speed, it's not going anywhere right now, so I have time to ponder how long a payback in fuel savings might take. So if anybody can report what their Eagle set-up does for mileage, and ANY and all ideas for maximizing mileage while enjoying he ride (engine, transmission, rear end, amazing additives...) I'd find it interesting reading.

When I put my Eagle on the road, I'd like to go places, and $500 a trip if I could increase mileage would add up fast....

So how are you guys doing? Anybody ready to convince me to switch?

Thanks, and happy busing.
Doug Wotring

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Posted on Monday, April 24, 2006 - 5:14 pm:   

59 4104 fresh 6-71 (50k from crate) 4 spd spicer ( Suburban gearing)....................7-12 depending on my foot and cruising speed.

75 MC-8, 8-71 Allison 6 spd........8-10 depending on the foot

78 4108 8-71 V730............5-7
Paul Tillmann (Paultillmann)

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Posted on Monday, April 24, 2006 - 5:53 pm:   

1978 MCI MC-5C 8V-71 4 spd manual: 7.5-8.5 MPG
1980 GMC T6H-5307N 6V-71 V730: 7 MPG
2003 VW Jetta TDI: 47-49 MPG w/Trip Rewards Card for discounted overnight stays @ any of hundreds of Super 8's across America which is by far the cheapest way to see the sites these days.

(Message edited by paultillmann on April 24, 2006)
Henry Bergman

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Posted on Monday, April 24, 2006 - 5:54 pm:   

1974 Crown Super Coach 40 foot 3 axle 10 wheeler with Big Cam Cummins 250 with Roadranger tranny...10 to 12 mph at 55 to 60 mph cruise.
Phil Smith (Phil_smith)

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Posted on Monday, April 24, 2006 - 6:19 pm:   

1980 RTS- 40ft- 8v-71N w/N-65 & adv.timing, 4:10 gears,V-730 weighing in at 29,700 w/4 adults, 85 gals of water, empty waste tanks, full fuel 125 gals. Gets 6-7 mpg at 68-73mph ( that's where it likes it! - the sweet spot )..
BTW- The saying 'If you have to ask - you can't afford it' went out with the HIGH FUEL PRICES of today ! Today it's 'If you don't ask - you're foolish'...

(Message edited by Phil_Smith on April 24, 2006)
Jack Conrad (Jackconrad)

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Posted on Monday, April 24, 2006 - 6:20 pm:   

MC-8 with 8V71, Allison 740, and Rockwell 3.73 rear axle. Bus weighs 34,000 loaded ready to travel. We have kept fuel records since we purchased it. When we first used it as an empty shell (steel tent) we were getting about 7.5-7.9 MPG. We are now averaging about 6.2-6.8 mpg. We used to run the interstastes at about 70-75 (6.2 MPG). We are now running bacvk roads at about 60-65 (6.8 MPG). We have seen an increase in MPG. and the ride is much more enjoyable. These are the roads to travel to really see America. Jack
Dan West (Utahclaimjumper)

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Posted on Monday, April 24, 2006 - 6:29 pm:   

Some of you guys with good looking milages whould not be so good out here at 5 to 6 thousand feet in the west half of the country.>>>Dan
John MC9

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Posted on Monday, April 24, 2006 - 6:33 pm:   

The latest choices at the fuel pump were:

Cash?
Credit?
Home Equity?
Doug Wotring

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Posted on Monday, April 24, 2006 - 6:56 pm:   

Several Cross rockies trips showed no decernable difference in MPG in the 4104

wanted to add the follwing stats.

1985 mercedes 300SD...........28mpg
1998 Ford F-150 Supercab 5.4 Auto...14 city/16 hwy
2004 Foooord F-250 6.0 Diesel Auto 14 city/24-26 hwy
Jerry Liebler (Jerry_liebler)

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Posted on Monday, April 24, 2006 - 7:40 pm:   

Dan is right! When I was going through Wyoming I got about 5 mpg but that includes lots of climbing.
While through the relative flats of the central US I get 8+ cruising at 70 MPH. in a 4107 with 4 speed Spicer.
On a related topic I have a digital fuel guage with very high resolution (.1 gallon) and accuracy (read 101.1 gallon change when I add 100 gallons) and I've found that what I'd call a full tank varies by over 10 gallons on this guage. The sender for my fuel guage is very near the center of the tank in both directions so tilt effects are small. This variation in filling is, I suspect, making mileage calculations vary a lot for most bus owners. When I started to add or subtract the guage readings after fillup my milage became much more constant and is 8.3 Mpg East of the Mississipi (virtually all freeway at the speed limits).
Regards
Jerry 4107 1120
Kevin Hatch

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Posted on Monday, April 24, 2006 - 7:42 pm:   

1970 GMC PD-4905, 8V71, 4spd manual, not sure on the gearing, loaded with a five piece band and all the musical gear and luggage for a month long tour.

Last I checked it was getting 9-10 running 65-75 with the Generac 7.5Kw genset running the whole time.
Gary Stadler (Boogiethecat)

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Posted on Monday, April 24, 2006 - 8:18 pm:   

'62 Crown raised roof 29,000# turbo Cummins 220, 9 speed w/ overdrive. 5:29 rear, 11R22.5 donuts

anywhere I go, no matter what I do or where I drive, 10-11mpg. Cruzes mostly at 75

Hey Henry where ya been lately? Hanv't seen your name pop up in a long while...

(Message edited by boogiethecat on April 24, 2006)
Steve Zona (Highwayrunner)

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Posted on Monday, April 24, 2006 - 8:35 pm:   

82tmc 6v92ta, 315/80/22.5 tires not sure of gearing 740 allison. close to 35.0000# 200 gal fresh,115 gal black, 115 gal. grey water. towing vw vanagon 5.500# 7kw deisel genset. averages eight mpg at around 65 mph
Jim & Linda Callaghan (Jimc)

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Posted on Monday, April 24, 2006 - 8:50 pm:   

I get between 7.5 and 8.1 with a GM4106
871/auto and 4.1 gears, cruising the midwest at about 62-65 mph
Jim
R.C.Bishop

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Posted on Monday, April 24, 2006 - 8:59 pm:   

Consider yourself very fortunate, Gary.....I'm in there with Henry, and I only have a 10 spd RR., also a 220 Turbo (265). Usually travel under 65 nowdays....just to get the mileage. Have gotten 12, but can't count on it as a regular thing. 10 on the ground 12R22.5, transaxel.

Ditto, Henry...nice to see you back.

RCB
'62 Crown Supercoach ( HWC )
Brian Elfert

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Posted on Monday, April 24, 2006 - 9:11 pm:   

1995 Dina Viaggio with Series 60 11.1L and Allison B500 auto (5 speed version)

On my trip home recently I filled up at Gary, Indiana all the way to the brim. Terrible wind from the West. I then drove between 55 and 65 MPH through Chicago (Lots of construction). Once I was headed north out of Chicago I set the cruise at 68 MPH per my GPS unit. I almost got blown off the road twice.

I filled up to the brim again at home. 7.8 MPG. I expect closer to 8.5 MPG once a few problems get fixed and without the wind.

Brian Elfert
R.J.(Bob) Evans (Bobofthenorth)

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Posted on Monday, April 24, 2006 - 10:20 pm:   

8-92 10 spd RR 36,000# 1981 LeMirage
unsure of the gears but it turns about 1700 @ 70 MPH in 10th
6.3 MPG per Canuck gal over 2 years & 25,000 miles, all fuel in (including gen & Webasto usage) running 70-80.

Last trip 7.4 MPG (Canuck gal) running 50 towing my Ford Exploder Trucklet
Bob Belter

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Posted on Tuesday, April 25, 2006 - 12:14 am:   

Ahoy, Busnutz,

My -01 Eagle with a 400 hp M-11 Cummins, Fuller Roadranger 10 spd overdrive RTO1110, and 3.33 rear axle has a life mileage -- all the fuel ever put in it -- (~~24,000 miles)of 9.74 mpg. All west coast in the mountains. Cruise at 65-75 mph. Some small part of the fuel went into the genset and heater. They are now separate. Bus weight was ~~24,000 lbs, now ~~28,000 lbs.

Enjoy/s/Bob
james dean boggs (Jd_boggs)

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Posted on Tuesday, April 25, 2006 - 1:17 am:   

1981 Flex 6V92TA/730 Allison tranny, 4.56 gear ratio weighs 26,450: 7MPG at 65mph, 8MPG at 50MPH
Marc Bourget

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Posted on Tuesday, April 25, 2006 - 1:41 am:   

Mr. Belter forgot to add a comment about his better aero from the custom formed aluminum front cap he constructed for his bus.

It's got to help!
Ron Rutledge Thunder Coach

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Posted on Tuesday, April 25, 2006 - 1:49 am:   

1981 Crown Super Coach...Big Cam 400 HP..Power steering...Hyd FAN...Allison 644...4:11...12.22.5...75 Gal Water...Wastes tanks emt. most of the time(2-45 gal)...125 fuel full when leaveing and when I return...All way broke until the mail get here...Runs the Interstate 65-70 up and down the hills...9.7-10.3..Loves the backroad 50-60...much better milage 11-12..I have been run West Coast...Washington, Oregon, Upper Idaho and 200 miles into Montana...Looking to go B C and up into Alaska this Summer..Ron
TomNPat

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Posted on Tuesday, April 25, 2006 - 1:58 am:   

Sure wish I could afford to fill up so I could give you a figure!!!!!!!!!!!!

But, as long as I don't fill, it reduces demand which increases supply and therefore reduces price. Bought $179.90 (less than 60 gallons) today and should cover my next three weeks. Don't thank me, just join me!

About 6 back when I could afford to fill on MC9, 6V92, Allison 740.

TomNPat
Brian Brown (Blue_velvet)

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Posted on Tuesday, April 25, 2006 - 2:15 am:   

4106: 8v71N stock, 4-speed, 26,000# no toad, (six trip avg.)8-9mpg @ 70mph on the flats , a bit less than 8mpg in the mtns.

4108: 8v71N w/ 65Cs, V730, 26,000# no toad: 7.5mpg @ 68mph on the flats (one trip), haven't done mtns. yet
Casper4104

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Posted on Tuesday, April 25, 2006 - 9:07 am:   

’58 PD4104 with freshly out-of-frame OH’ed 6-71 & 4 speed, empty tanks, lighter conversion – 11mpg

’83 Mercedes-Benz 240D, 2.4L 4cylinder diesel, 4 speed – 32mpg (best car I’ve ever owned)
’97 BMW Z3, 1.9L 4 cylinder, 5 speed – 32mpg
’94 Ford Explorer-Sport (2-door), 4.3L 6 cylinder, 5 speed – 22mpg when I drive, 18mpg when daughter drives.
’86 Honda Shadow (motorcycle) 500cc 2 cylinder, 5 speed – 65mpg.
Carroll Sasscer

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Posted on Tuesday, April 25, 2006 - 9:47 am:   

83 MC 9 - 6v92 turbo allison 4 speed automatic 5.7-6.3 mpg

58 4104, wore out 6v71 4 speed splicer 7.5-8.5 mpg

Carroll 4104
Geoff (Geoff)

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Posted on Tuesday, April 25, 2006 - 10:14 am:   

I get from 7.5 single to 6 mpg towing my trailer. I just figure it is going to cost me about $.50 a mile to drive my bus, and that hurts! The good point is I can live in the bus cheap when I stop, as long as I avoid the high priced RV parks.

--Geoff
'82 RTS AZ 350HP 6V92 TA 4.10 gears V730 32,000lbs. +7500 lb trailer
Paul Klyczek

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Posted on Tuesday, April 25, 2006 - 10:36 am:   

Seems like a big veriable is cruise RPM,diesel engine consumption is all RPM and load. So how fast You spin it and how far Your foot is in it.So I guess I would like to know what the RPM people are spinning.



Paul and Dawn Klyczek
PD 4107-870
Platteville Colorado
Mark R. Obtinario (Cowlitzcoach)

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Posted on Tuesday, April 25, 2006 - 10:48 am:   

1969 Crown Supercoach 40' 10-wheeler with a Cummins 262 and Allsion HT70 and top speed 72 MPH: 6-9 MPG

1973 MCI MC-7 with DD 8V-71 and Allison HT740 and top speed 73 MPH: 3-6 MPG

1979 Crown Supercoach 35' with a DD 6-71T and 5-speed, 5th direct and top speed 62 MPH: 9-12 MPG

1993 Setra S215 with DD Series 60 with Allison HT748 and top speed faster than I ever wanted to go (80+ MPH): 6-12 MPG

We usually figure the fuel consumption on a ski run to be about twice the normal fuel consumption. The high end numbers were for straight highway runs, usually with no passengers.

We are located in WA state so we have very little in the way of flat straight roads.

The average MPG readings on the '69 Crown were always less than the '79 Crown. I suppose if we kept the '69 poking along at 62 MPH it would have raised the MPG to be more similar to the '79. But who wants to poke along if you can run with the big dogs?

The average MPG readings on the MC-7 were usually less than 5 MPG.

The high end MPG readings on the Setra were when we were operating last fall in LA after Katrina and Rita. (I wonder how many miles will go by before you won't notice the dye in the fuel tanks?) The low end readings were on ski runs with normal operations right at 8.5 MPG.

Mark O.
gg04

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Posted on Tuesday, April 25, 2006 - 10:50 am:   

1960 4104, 6L71ta ddecII , spicer 4spd..11.00X24 tires..26,000lbs..5,000lb toad..1800 rpm cruise..41/8 gears.. Last 50,000 miles..avg of 10.83mpg...with best tank of 13.3 and worst of 9..uphill down hill away we go..gg ps : most of the time we weigh around 30,000..just near empty weight of 26..
niles steckbauer (Niles500)

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Posted on Tuesday, April 25, 2006 - 11:43 am:   

8v92 - DDEC II - 755 ATEC - aerodynamics like a brick - gotta be pushin the 46k GVW - 5mpg (leadfoot)

Ford Excursion 12.?? highway - city mpg will make you cry

Paul has the right idea - keepin it around RJ's 1700 rpm on the 92's seems to be a sweet spot
captain ron (Captain_ron)

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Posted on Tuesday, April 25, 2006 - 1:44 pm:   

1978 mci 8 with 8v92 and allison 740a 5.3 mpg no matter what I do. I can't seem to increase it by slowing down and it's killing me. cost me about $1000 in fuel from Fort myers to Green Bay
Mark Scott

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Posted on Tuesday, April 25, 2006 - 2:04 pm:   

1985 MCI 102A3, 8v92TA,Jake Brakes, Allsion 740, standard rear gearing, fully converted.
A trip from Cleveland, OH to Daytona Beach,FL averaged 6+ miles per gallon. I pulled a 24' enclosed trailer, loaded to 10,000lb GVW.
This trip was 50% hills, including I-77 thru WV to Columbia,SC and 50% flat thru I-95 to FLA.
We averaged 65-70mph on the flats, and probably 55mph in the hills, some mountains as slow as 35mph and downhills at 65mpg. Anyone who wants to travel over 70mph in a coach needs to be very careful. Mark
R.C.Bishop

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Posted on Tuesday, April 25, 2006 - 2:53 pm:   

It appears the Crowns, pretty much lead the pack in fuel mileage....:-) My RPM usually 16-1700. I'm learning to enjoy the trip with a softer foot at about 1500 RPM...that's when the coach can get up to 12+ MPG. Above that it drops back around 10-11, depending on how much Webasto use.

The coach drives best at 70-75...unknown top speed. I've had it to 85 and figured that was more than good enuf. We live in the Southwest....lots of wind and long straight roads. Wind is definitely a factor. Travelling to Dallas via I-10 and I-20, lots of change in terrain will usually get 10+.

FWIW
Brian Brown (Blue_velvet)

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Posted on Tuesday, April 25, 2006 - 4:37 pm:   

So as the CROWNed champions of MPG, what's their secret?? Lower RPMs, non-DD engines (for the most part), aerodynamics?? Seems like they weigh as much as MCI's and Eagles.

Curious...

Cap't Ron... you missin' your old '05 about now?? Anyways, you're doing a great job with your warp-speed conversion, bud.

bb
Don Ripley

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Posted on Tuesday, April 25, 2006 - 5:56 pm:   

85 Prevost,8v92,allison 748,fully loaded 40,000ibs.Over 30,000 miles in three years,6.3mph.I usually run 1600 to 1700 rpm's.I started to drive 1400 to 1,500 rpm's and my millage went dowm.I guess it's true about the dd's like to run at 1,700rpm,s.We will be travelling about 8,000 miles so I hope prices start to even off soon.
Frank Allen (Frank66)

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Posted on Tuesday, April 25, 2006 - 6:31 pm:   

i have a 4106, with a 8/71 730, 7.5 mpg, when i had the spicer it got 10 or better all the time, just the facts.
Frank Allen
Jarlaxle

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Posted on Tuesday, April 25, 2006 - 6:53 pm:   

Ford B-700 school bus, rebuilt & supertuned gas 460, ~7MPG.

1979 F-350 SuperCab 4x4, Cummins 6BT conversion: 19-20MPG
1979 Coupe de Ville, Cad stroker & OD trans, 18MPG
1995 Caprice wagon, 260HP 350 LT1, 22MPG, just coughed up $54 to fill the tank.

Wife's 1988 Ford Festiva, 1.3/4-speed, 43-45MPG.

I need a diesel Rabbit.
JW Smythe (Jwsmythe)

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Posted on Tuesday, April 25, 2006 - 8:49 pm:   

Paul has it right. It's going to vary a lot by driver, as well as equipment and conditions.

The moving van I drove across the country (way overloaded 26' + car trailer, gas engine) got about 4mpg on the flat areas, and a lot less on the mountains. It averaged out to about 3mpg, driving the length of I-10. If it hadn't been overloaded, and I didn't have to stand on the gas to keep it moving, it would have probably done better.

I have no idea what my bus gets, but the $125 bill to just top the tank off kinda reminded me that gas is expensive.

My '00 TransAm WS/6 gets 26mpg with the cruise set to 80, A/C on, and windows up, assuming hard acceleration on the onramp, and not stopping until it's out of gas again. It typically get 24mpg controlling the gas myself on the highway, roughly 15mpg to 20mpg in the city, and about 5mpg racing.
david anderson (Davidanderson)

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Posted on Tuesday, April 25, 2006 - 9:26 pm:   

1985 Houston Metro Eagle 10. 36,000 wet. 6v92 315hp (I think), Voith 4 spd auto with retarder. 24.5 wheels, 3.36 rearend, 70@1950, 80@2100, 18psi turbo boost @ 2100. Completed 2003, 31,000 miles. 6.2 average.

David Anderson
Greg Peterson

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Posted on Tuesday, April 25, 2006 - 11:39 pm:   

Captain Ron do you know what injectors and what is the horsepower rating of your 8v-92?

I see from your fuel mileage post you are getting less mpg than my 8v-92 averaged when I ran it down to Florida. I was in the 8mpg range but was light with no seats in the bus. Maybe you are heavier since you have much of the conversion completed or maybe the air drag is less on my 102a3.

I have 9f80 injectors and have a 400hp rating. This is the rating that was the original MCI factory spec.

I am going to have my engine tuned up and have been considering putting in bigger injectors for more power. I would think that if you were not using the extra power the engine would not use any more fuel. Maybe the efficiency of the engine drops with larger injectors for a given horsepower rating. With DD having little interest in the 2 strokes and most knowledgeable mechanics retiring, this information is harder to find these days than getting information for atomic bomb construction.

Thanks for any information
Greg
R.C.Bishop

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Posted on Tuesday, April 25, 2006 - 11:40 pm:   

Brian.....no secret that I am aware of. When I purchased the coach from Northern AZ Univ in Flagstaff (original owner) they told me the coach would get 12 MPG. Hard for me to believe, but alas, it's true, but things must be just right.

I do think that keeping the rpms low is a key. The ten speed RTO is a real blessing and knowing when and how to use the gears in the upper range seems to make a difference. In the winter, the Webasto really takes it's toll, however. A half gallon of fuel per hour,+- can make a real difference,especially if one is in the mountains at very low temps.

Don't know the exact weight just now, but suspect it is 30K plus.

RCB
John MC9

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Posted on Wednesday, April 26, 2006 - 12:04 am:   

Greg -

Don't go the "bigger injector" route. You'll have to have it
re-racked for the bigger injectors, and you'll still have a
major black smoke problem each time you accelerate. It'll
be a pain in the butt... And you can expect it to run hotter
pulling hills or running up against the governor for miles
on end... You wanna' go faster? Buy a Porsche..

I was looking for smaller, OE injectors for mine, and would've
considered a swap, until I heard the price to re-rack...
Buswarrior (Buswarrior)

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Posted on Wednesday, April 26, 2006 - 1:06 am:   

Hello.

1975 MC8, stock roof, two roof airs
8V71 in stock 280 HP settings
governed at 2100 RPM, 70 mph
HT740
3.7 axle

3242 miles round trip Canada to Florida for Jack's party, (cold weather) running at flank speed both ways: 6.25 mpg average (US gallons)

The tank that included coming off the highway and driving onto the Mall in Washington DC, and then cutting through the town to get out the north end was degraded by approximately 1 mpg over the rest of the tanks used for primarily Interstate "get me there and home" travel.

I fill it to the rim for fairly consistant calculations.

One of these years, we'll be ready to leave on time and be able to run this trip throttled back to 60 mph to see the difference. On shorter stuff up here in warm weather, indications are that 7 mpg US when driving at more leisurely speeds is within reach for my rig.

happy coaching!
buswarrior
Marc Bourget

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Posted on Wednesday, April 26, 2006 - 5:08 am:   

Bob Belter or Dave Galey wrote an article for an early BC Mag issue showing MPG at various speeds, IIRC, dropping from 68-70 MPH down to 52-55 MPH improved mileage something on the order of from 5.8 to 9.3 total MPG.
David Dulmage (Daved)

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Posted on Wednesday, April 26, 2006 - 10:00 am:   

1976 MC 8 with 8V-71 and 740 Allison transmission. On a recent 300 mi. round trip to Syracuse, NY I averaged about 5 mpg (US gal) at about 60 mph. It seems be be lower than I was getting. I paid $3.039/gal for diesel fuel at Longways Mobil just north of Waterown, NY

DaveD

(Message edited by DaveD on April 26, 2006)

(Message edited by DaveD on April 26, 2006)
Steve (Steve)

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Posted on Wednesday, April 26, 2006 - 10:47 am:   

1981 mic9 170,000 miles on rebuilt long block 6V92@ 350HP@ 2300RPM, HT740, 3.33 dif.
11:00x 22.5 aired to 120psifront, 100psidrives,90psitag,
complete stewart&stevenson tuneup-
1. High exhaust back pressure-muffler out pipe baffels clogged up and 3"outlet, should be 5" outlet-cut muffler open installed 5"outlet.
2. High vacuum on air inlet 12"-Removed stock inlet in front of radiator and opened air box inlet from the side-4"now.
3.New injectors N90 part# R5226410
4.New fuel pump and lines and fittings
5.New Rocker Arms
6.New Bridges
7.New Fuel Tubes
8.Remove Rack Delay Valve for full fuel at green light.
9.Set Bridge Clearence,cold
10.Set Valve Clearence,cold
11.Set Injector Height,cold
12.Adjust Rack
13.Adjust Gov.
14.Set top RPM @2300
15.Oil Change 40w 6Gal.
16.Transmission pan removed- Inspected and re installed,pressure check, new filters.
17.Adjust down shift cable,Check air box pressure and check valves! copper seal washers on generator mount studs. No oil leaks./ except airbox check valve tubes at idle-small spots.
13.Installed Fuel Pro Fuel/Water Seperator
14.New second fuel filter
15.Rebuilt driveshaft and balance.
16.Inspect Drive axle-Input Shaft seal and adjust preload,New Brakes on all axles,seals,drain and refill oil.
17.True and Balance all 8 wheels and tires,-Shaved and Balanced on coach.

23 people on board with luggage from San Antonio to Sturgis, South Dakota- running 65mph 7.2-6.8 going up, 3 people Sturgis to San Antonio no luggage running 75
6.8-7.9mpg slight black smoke hammer down,
Oil Used 5000miles-2 quarts
18. Return to Stewart& Stevenson for HOT tuneup.
drive train 98% tops

19.Bus now being converted.
Mark R. Obtinario (Cowlitzcoach)

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Posted on Wednesday, April 26, 2006 - 11:43 am:   

Brian Brown has asked why the Crowns consistently get such good MPG compared to other buses.

I really do not have any real definitive answers as to why the Crowns are the mileage "champs". Any answer I give would be a shot in the dark colored by my prejudice for the Crown Supercoach.

But I will make a few guesses.

My DD powered 35' gets 2-3 more MPG than my Cummins powered 40' 10-wheeler. The fact the 40' has an automatic and the 35' has a stick may have more to do with the difference than anything else. So the question as to whether 4-stroke or 2-stroke is better, I don't know. And since neither of my Crowns have coach air it is hard to make a direct comparison to my coaches that do have coach air. The coach A/C compressor uses up a lot of fuel.

I think the better fuel mileage is due in large part more to the shape than anything else. A brick with curved ends is going to go through the air better than a flat brick. Plus a brick that is two to three feet shorter than other bricks won't be pushing as much air as the taller bricks.

I think the fact the body on all of the Supercoaches is made of aircraft aluminum also has a direct impact upon fuel consumption. This may have more of an impact at low speeds than highway speeds. I know that Crowns were always the fuel mileage champs in school service.

The last thing that I think makes a difference is all of the Crowns with the pancake engines had inline engines. I think inline engines put out more usuable power to the wheels than any V-design engine. If you don't have to bury your foot all of the time to go up hill and down dale you will use less fuel.

Are my answers the definitive answers? I doubt it. But they do sound plausible however.

Just my two cents worth (and by today's fuel prices my two cents worth is going to cost a whole lot more).

Mark O.
R.C.Bishop

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Posted on Wednesday, April 26, 2006 - 9:02 pm:   

Mark....I always thought it was that Cummins was the engine of choice (mpg)....:-) Interesting, your remarks.

RCB
Steve (Steve)

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Posted on Thursday, April 27, 2006 - 8:49 am:   

Yep I had a red top N14 525hp @ 1850ft lbs. 13 speed double over trans with 3.55 rear with 24.5 wheels with tall rubber and horsepower control system installed and tuned by diesel injection service It was putting 720 hp on the dyno @ 2250 ft lbs. But the trans and drive line was only rated for 1850ft lbs. The nice thing about it was, when running empty I could turn it down to a 350hp and when running at 80,000 gross I could turn it up anywhere from 350hp to 720 hp. It helps to get the software from the engine manufacturer, and they don't give that to the customer so you can't keep resetting the information to keep it in warranty. My wife got a ticket 65 in a 35 pulling the grape vine in Cally. with 38000lbs on going up hill in the number one lane. $1600.00 The cop said he had never had to write a truck driver a ticket for going that fast up here. I laughed my @#$ off and he wrote me a ticket for the log book $800.So anyone with ECM Engines Should look into the control system, could save ya some dough on fuel.

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