best speed for fuel economy - Printable Version
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RE: best speed for fuel economy - ron skeen - 09-14-2012
(09-14-2012, 06:50 PM)Express1 Wrote:Do you mean cruise set has more power? On our model coach the mode on mean less shifting.(09-14-2012, 05:48 PM)Richard Wrote: On some of the bus conversion forums, they make reference to the DDEC responding differently when the cruise is on. It is actually possible, and common, that the engine is programmed to have more HP and torque when on cruise to encourage the truckers to run on cruise (aka to drive the speed limit)
I swear my engine pulls hills on the cruise without shifting, that it will not pull without shifting when I am the cruise control.
Richard, I took note of that today going west on I80. Now doubt with cruise off and mode button on, performance feels stronger..
RE: best speed for fuel economy - prairieschooner - 09-14-2012
I like 59 MPH it gives me about 10 MPG up a hill, own a hill, towing or not towing about 10 MPG.
RE: best speed for fuel economy - Richard - 09-15-2012
Yes, cruise on seems to have more power to me. This is independent of the mode button on the Allison tranny. Maybe, it's my imagination. It's not my imagination that it the DDEC can be programmed that way. I have never had my DDEC "read" so I don't know if mine is that way or not.
RE: best speed for fuel economy - lbrachfe - 09-15-2012
What tranny "mode" ? Some have "Econ" and others "Perf". The "Perf" is for hilly terrain... I prefer free wheeling for better mileage
RE: best speed for fuel economy - Johnc - 06-04-2013
Some people pretty high up in the engine OEM food chain have confirmed the 'more-power-in-cruise' set-up. The logic being that the computer can better control the engine.
Watching the space shuttle on approach is a classic example of our caveman reaction times. When the computer 'flies' the shuttle approach, the landing is always near perfect, not so when humans are at the controls.
RE: best speed for fuel economy - encantotom - 06-04-2013
today we decided to drive 55mph for 200 miles since it was totally flat in east new mexico and west texas.
i reset the prodriver as we left and it says we got 9.2mpg.
when we do lots of grades, i am more at 7.
now i see why some of you have said you get 8 or so. it is on flat and level terrain.
anyway. i am thrilled spitless to get 9mpg in this beast.
tom
RE: best speed for fuel economy - Erniee - 06-04-2013
I usually get 5. Going to Montana last week, uphill with 50 mph head wind- got 3. Talk about going thru fuel~
RE: best speed for fuel economy - folivier - 06-04-2013
Tom did you compare the prodriver mileage with your vmspc?
Heading west from Steve Bs the prodriver showed about 6.5 but I hadn't reset it. We had headwinds all the way with the hills.
The vmspc showed higher but don't remember. This was driving about 60-62
Heading up I25 from Colorado Springs the vmspc showed 8+. This was steady with no headwinds. I need to reset the prodriver when I get back.
RE: best speed for fuel economy - encantotom - 06-04-2013
i have been doing an entire trip including the 160miles of mountains in az so the vmspc is lower.
tom
RE: best speed for fuel economy - Express1 - 06-05-2013
Yep, same for me, 63 = 8+ on _______ w/tow.
I can't get into High Gear @ 55?