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  • Dub
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Economy mode
Just ran 1025 miles getting to St Augustine Fl and ran the coach in economy mode like Brett recommended and got 8.9 mpg vs the 7.5 in performance mode. Ran steady 65 mph. Couldn't be more pleased with results.wasnt towing anything but still...

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Re: Economy mode
Reply #1
Dub,
One other thing is, you can have Allison change the ECM to default to economy mode (or you could in the past). You will have to push the button to make it go back to performance mode.

Mike

Re: Economy mode
Reply #2
I never could figure out if there was any difference.  Please explain the benefits of Eco mode and how to tell which mode your coach defaults to.
And what is the maximum rpm for the M11 engine?

Re: Economy mode
Reply #3
 folivier,

Here is a link to what Brett has wrote up.
technical:transmission:econ [ForeForums Foretravel Motorcoach Wiki]

This is better than me trying to explain.
Mike

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Re: Economy mode
Reply #4
Just ran 1750 miles and used the mode button. Haven't figured the mileage yet, need to fill the tank to get accurate number.

Larry

Re: Economy mode
Reply #5
Short answer to "difference in MPG" is THERE IS NO SIMPLE ANSWER.

On totally flat ground (say, I 10 across Louisiana) it will make zero difference, as the transmission will stay in 6th gear all the way across.

Move west on I 10 to the hill country...

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Re: Economy mode
Reply #6
Here is what Cummins says about M11. 400 and 450 HP
1,450 pound force-feet (1,966 N⋅m) @ 1200 rpm, 400 horsepower (298 kW; 406 PS) (246 kW) electronically governed at 2,100 rpm
1,450 pound force-feet (1,966 N⋅m) @ 1200 rpm, 450 horsepower (336 kW;...

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Re: Economy mode
Reply #7
Roger I didn't realize that we had that much torque. Was thinking it was in the 1100 pd range. No wonder I can just chug on past the big rigs, let alone the SOB's

Larry

Re: Economy mode
Reply #8
I usually use economy mode (mode light on) except in real mountain driving.  It is my impression that when the transmission is in the economy mode it will sometimes "dither" between gears going up a hill.  That is it will downshift to 5th, for...

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Re: Economy mode
Reply #9
Long term  user posted here .4mpg  increase using the mode.  Just  shortshifts the motor.

I agree it feels like 1100 torque. 

George your shifting results reported seem backward. 

I wonder if someone set your trans to mode as the default?

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Re: Economy mode
Reply #10
So what would be the preferred rpm on a steep climb?
I find that if I keep the engine at about 2000 rpm then the temp. stays pretty constant, but if I'm at 1500-1800 rpm the temp. will start to rise.  I usually try to keep it at 2000 rpm.
Doesn't...

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Re: Economy mode
Reply #11
Motor has weak torque.  So the hp can go slightly faster up grades.

If we could raise the torque we could sixth gear all the interstate grades....

Re: Economy mode
Reply #12
Using the gear that results in the lowest throttle opening will usually result in the best fuel use.  There is a fixed amount of torque required to climb a grade. Divide that torque  value by number of piston strokes.. Use 6 gear, lower number of...

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Re: Economy mode
Reply #13
I think it's funny to hear you guys with 1,450 lb-ft of torque crying about your "weak" engines, when I get along fine with a measly 820 lb-ft.  8)

  • Dub
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Re: Economy mode
Reply #14
 In performance mode mine would down shift every time I pressed resume on cruise control even if at the speed I had it set on. Mine would downshift at times where there was absolutely no need. Stopped that nonsense now and get decent mpg. I...

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Re: Economy mode
Reply #15
We feel that to get higher MPG, it comes from loading engine more before it changes gears. Lower gear ratios use more fuel, but also lower engine loads. We use power mode 100% of the time as we figure it helps our engine.  It takes power to move...

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Re: Economy mode
Reply #16
If you want an excellent insight into RPM for best MPG, LISTEN TO THE 18 WHEELERS.  All (certainly all the privately owned ones who pay for their own fuel) climb those grades (yes, with more than twice our weights) JUST ABOVE PEAK TORQUE RPM. ...

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Re: Economy mode
Reply #17
As to the mode which the trans defaults to with the key on, I believe it depended upon the original purchaser's preferences. Ours starts out in economy mode and the label above the mode switch says "Power". When the red light above the mode...

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Re: Economy mode
Reply #18
In what year did Allison introduce the 6 speed with the "economy" - "power" -(normal )? Options? Don't recall reading about it in my manual.

Re: Economy mode
Reply #19
All Allison 6 speeds have power/economy mode. Certainly true on our 1993 U240.

Look at your Allison shift pad-- upper right corner for the button and light.

Re: Economy mode
Reply #20
FT.. do you not have a "mode" button on your Allison keypad ?

Re: Economy mode
Reply #21
Yep
Mode is there

Re: Economy mode
Reply #22
It would be EXTREMELY RARE for the Allison ECU to be programmed with economy mode as the default (selected each time the coach is started). Could a previous owner have had an Allison dealer reprogram it-- sure.

So, easy test to verify:

On a clear...

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Re: Economy mode
Reply #23
Your good then,  mode on for the rolling hills.
 We just retuned from the Texas hill country and I went through the 5th to 6th thing.  Wish this thread would have started before, I think I already new about the mode thing but spaced it.

Re: Economy mode
Reply #24
This morning I left Watson Lake, Yukon and drove to Carcross with the mode ON in economy.  Big difference in the mountains here, no gear hunting going uphill.  Ambient temp was in the 40's so didn't notice any difference in engine temps.  Too...

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