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Old 02-10-2020, 03:45 PM   #361
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Diesel engines are designed to run most efficiently at a specific RPM. By simply lowering the RPM, you might be bypassing that "sweet spot" that the engine likes. I remember when the speed limit was set at 55 MPH, and all the truckers lost fuel mileage due to losing their sweet spot. Lower RPM does not guarantee better mileage. It just means more available top speed.
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Old 02-10-2020, 03:49 PM   #362
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I had some issues with getting the right combination of operating system and driver and application... but after enough tries I've got it all working in a virtual machine.
Will the adapter that you have work with Bluefire or Silverleaf?

I would like to get the 6th unlock done but don't want to have to buy two J1708 adapters.
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Old 02-10-2020, 04:08 PM   #363
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I doubt it works with those tools. Would be interesting to look at their APi and see if it could do the same job with some custom code though.
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Old 02-10-2020, 07:18 PM   #364
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Originally Posted by harleydoug View Post
Diesel engines are designed to run most efficiently at a specific RPM. By simply lowering the RPM, you might be bypassing that "sweet spot" that the engine likes. I remember when the speed limit was set at 55 MPH, and all the truckers lost fuel mileage due to losing their sweet spot. Lower RPM does not guarantee better mileage. It just means more available top speed.
Is there a better way to find this sweet spot instead of burning a lot of fuel in trial and error?
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Old 02-10-2020, 08:22 PM   #365
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No one is mentioning if they are running with the "mode" button on or not. We just completed a 1,000 mile Gulf Coast trip with a 40' Thomas, 3126 and 5.67 gears. I ran the mode button the whole trip, when possible on interstates I ran 75+ and when all was said and done and filled up at home and averaged the two fuel buys we got 8.927 MPG. I think if I paid attention and lightened up on the right foot a little an even 9.00 is possible. The "mode" button is economy mode and the 3060 upshifts a little sooner and downshifts a little later, in theory keeping the RPMs slightly lower for better fuel economy.
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Old 02-10-2020, 08:45 PM   #366
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oops wrong thread!
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Old 02-10-2020, 08:52 PM   #367
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I usually use the economy mode, though on my runs it wouldn't have made much difference since there's only a few stop lights anyway. It made more of a difference before the unlock as the transmission was used to indiscriminate, foot to the floor driving. As part of the unlock, the shift point adaptions were reset and now it better matches my more lax driving style. Shifts so much smoother too.
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Old 02-11-2020, 09:06 AM   #368
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When I press my mode button it just turns it to manual. I see no other options. Sometimes I press mode for manual going down long hills. Wasn't aware of any other use for it.
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Old 02-11-2020, 09:24 AM   #369
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My mode button specifically says Economy on it. I wish it would default to "On".
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Old 02-11-2020, 09:30 AM   #370
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Quote:
Originally Posted by harleydoug View Post
Diesel engines are designed to run most efficiently at a specific RPM. By simply lowering the RPM, you might be bypassing that "sweet spot" that the engine likes. I remember when the speed limit was set at 55 MPH, and all the truckers lost fuel mileage due to losing their sweet spot. Lower RPM does not guarantee better mileage. It just means more available top speed.
This.

Lowering rpm should theoretically gain you mileage. But occasionally that gain will be so small it's negligible. Especially if 6th lowers your rpm too much.

If anyone wants to gain fuel mileage, Read this. https://www.prevostcommunity.com/PDF...%20economy.pdf

Read it again if you have to, maybe even a 3rd time. There is a lot of data in there that you should understand if you're wanting good fuel economy.

There is also a lot of info in here if you want to read it. https://www.irv2.com/forums/f124/3126b-mpg-75162.html

But the end result is that 7-9 mpg is about what you should expect to achieve.
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Old 02-12-2020, 12:34 AM   #371
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My route is from the Sunco at Washington Dulles International Airport onto Route 28 south to Interstate 66 west. Take Interstate 66 to Interstate 81 north. Interstate 81 to Route 7 east. Route 7 to Route 28 south. Then jump off at Washington Dulles and refill at the same pump.
I know all those roads, some really well despite being born and raised in Silver Spring. I do not miss them one little teensy bit, no sirree!
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Old 02-12-2020, 01:24 AM   #372
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Quote:
Originally Posted by matthews2001 View Post
When I press my mode button it just turns it to manual. I see no other options. Sometimes I press mode for manual going down long hills. Wasn't aware of any other use for it.
The function of the mode button is programmable for different functions. I can't remember what the other options are at the moment. Getting old sucks I have never seen one with any function other than economy but have read about them in Allison documentation.

Mine is set up for economy and that suits me.
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Old 02-15-2020, 02:23 AM   #373
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Question about communicating with TCM to unlock 6th gear. Family friend works for Allison Transmission. He's been out twice to try and unlock my sixth gear on my 2001 Amtran International DT466/Allison MD3060 skoolie. Using the round Deutsche connector under the drivers seat, he's tried numerous times to communicate with the TCM. No connection. Tried the connector in the engine compartment, no luck. Spoke to several 40+ year veterans at Allison, but can't communicate with the TCM. Any suggestions? Bus runs and drives great, so clearly working. Thinking the connector or wiring is bad. I'm not too technical here, but happy to provide more info. This guy calibrates Allison transmissions for a living, but we are stumped.
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Old 02-15-2020, 10:50 AM   #374
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Quote:
Originally Posted by Booyah45828 View Post
This.

Lowering rpm should theoretically gain you mileage. But occasionally that gain will be so small it's negligible. Especially if 6th lowers your rpm too much.

If anyone wants to gain fuel mileage, Read this. https://www.prevostcommunity.com/PDF...%20economy.pdf

Read it again if you have to, maybe even a 3rd time. There is a lot of data in there that you should understand if you're wanting good fuel economy.

There is also a lot of info in here if you want to read it. https://www.irv2.com/forums/f124/3126b-mpg-75162.html

But the end result is that 7-9 mpg is about what you should expect to achieve.

my Allison 545 to Allison 1000 (6 speed) install netted me a whole lot of fuel economy gain.. HOWEVER when I first programmed the transmission to get into 6th gear as soon as possible I LOST fuel economy over my program which ran 6th gear completely disabled.. (5th only).. my best MPG currently is allowing my 6th gear to operate during lighter throttle conditions and only over 62 MPH.. my 0 throttle shift-Up to 6th is 63.. my Cruise control operates 6th gear at light load conditions and pulls it out when the cruise drips to 2 below setpoint or engine load reaches 75%..



my bus is geared Too Tall (the opposite of what most skoolies have here)... its important to know when and when not to use it.. the MD3060 has the capability of running 6th or turning it off at your will with the up / down arrow buttons..



know when to use it and when not.. also I will say in Navistar-Land that updating the ECM calibration helps transmission shifting in the E engines.. installing a newer ECM that has a full program update greatly helps the transmission and engine to pick the right gear for the job..



my year 2000 ECM with the original calibration was terrible with the allison 1000.. when I ran it through NavKal(NavKal is the software I subscribe to which allows downloads of programs from Navistar's dealer Cloud network.. yes its expensive.. yes its worth it to me).. it updated the calibration and the base firmware... my shift optimization got better.. when I bought a used year 2004 ECM and loaded my VIN / engine serial number and ran it through NavKal so it had the correct info for my Bus, my shift opimization got to a near perfect state.. in effect navistar had improved their end of things as well.. the ECM I purchased was the current replacement-part number as indicated to me by the navistar dealer.. the original part number had been discontinued and superceded by the new one.. there were things in the newer ECM that didnt get updated by just running it through NavKal.



that said, i still need to gear down from 3.54 to 4.10 to really have the perfect setup in my bus..



** Most diesels like to live a few hundred (500-700) below their governed RPM **


if your computer tells you your engine load factor, its best to run it at 75% or below except when climbing inclines..



I mention all this as lugging down a diesel will result in just as bad of fuel economy as spinning it too fast.. learn your engine.. if you unlocked 6th gear to gain speed because you are running against your RPM governor.. you will gain that speed but will gain no MPG (probably lose it)..



if you enabled 6th so that you can drive the same speed but run the RPMs a few hundred below RPM governor you'll likely gain a good amount of MPGs..


if you enabled 6th when your engine was running already in the "sweet spot" you may very well lose MPGs as you could be lugging the engine in all but perfect conditions..



if your engine sounds and feels Labored it probably is..



the up / down arrow buttons on your shift pad are your friend.. just like driving a stick-shift, pick the right gear for your weight / terrain / WIND-CONDITIONS / speed


-Christopher
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Old 02-17-2020, 10:32 AM   #375
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Originally Posted by cadillackid View Post
** Most diesels like to live a few hundred (500-700) below their governed RPM **

if your computer tells you your engine load factor, its best to run it at 75% or below except when climbing inclines..

I mention all this as lugging down a diesel will result in just as bad of fuel economy as spinning it too fast.. learn your engine.. if you unlocked 6th gear to gain speed because you are running against your RPM governor.. you will gain that speed but will gain no MPG (probably lose it)..

if you enabled 6th so that you can drive the same speed but run the RPMs a few hundred below RPM governor you'll likely gain a good amount of MPGs..

if you enabled 6th when your engine was running already in the "sweet spot" you may very well lose MPGs as you could be lugging the engine in all but perfect conditions..

if your engine sounds and feels Labored it probably is..

the up / down arrow buttons on your shift pad are your friend.. just like driving a stick-shift, pick the right gear for your weight / terrain / WIND-CONDITIONS / speed


-Christopher
Everything you said is 100%. 6th only helps if you're not in the "sweet spot" already. If you're already there, 6th won't do much, and can actually hurt.

What rpm are you at if you were running 55mph?

Christopher, if you're so inclined, I'd suggest that you consider a turbo upgrade in your future on your redbyrd bus. I'm finding more and more that diesel engine efficiency is heavily tied to turbo efficiency. Which makes sense because most of the power that your modern diesel engine can achieve is based off the additional air provided by the turbo.

And turbos have advanced light years in design in the last 20 years. Even just a wheel upgrade on your current compressor can net you a more efficient engine.
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