DX3 driving power question

[jkoenig24]

Brian, can you say what the difference in fuel economy is from the original settings to the performance settings? What did the Allison shop charge to reprogram? TIA!
John

[bkballard3]

John,

As far as mileage I don’t think it is even noticeable. I get anywhere between 6-9 mpg. The fee was around a $100. They actually call Allison to approve the program change that took longer than the actual reprogram.

Brian

[murraym]

Originally Posted by 4DayJeep

I have been reading lots of these threads - I plan on using our unit on order DX3 37TS to go cross country. Do these units have plenty of power to pull the grades?? Not looking at going 70 MPH over the grades on Hwy 80 or ones like the grapevine on I-5, but don't want to drop to 30 MPH either. Wondering since I saw you could upgrade to the M2-112 chassis and get another 100 horsepower and 250 more ft/lbs of torque.

2015 DX3 37BHHD M102 pulling a loaded up 26' trailer. Go back and forth between Philly and Indianapolis often. It pulls up the grades just fine, and comes down just as easy with the engine braking. There is only one grade that makes it work for it. I know where it is by terrain and know that when I get there, I just get a little bit of a running start up to about 75-80 for about a mile and it makes it up without getting below 55. If I hit it at 55mph because of heavy traffic or I'm not paying attention, then it will drop down to about 30-35 and I just move over to the right out of everyone's way just like the trucks. It makes it with ease though.

[bkballard3]

Hi there,
Similar to you I only drop to about 35 mph on the steepest hills without the extra run to the hill. In these cases I am always towing a ram 1500 4x4. Hope this helps!

Brian

[FOURWHL]

Originally Posted by tnrzryd

Hey FOURWHL - what rpm do you like to hold as a minimum when climbing? I’ve always watched the tach and manually downshifted to hold the rpms up to prevent overheating. The sweet spot on my last coach was 1500.

A lot of the time I just let the Allison do it's thing. Will lose a little momentum but always stay above 40. If I want to try and sustain 45 or 50 I'll usually think about downshifting in the 1300 to 1500 range. That usually bumps it up near 2k I think. Hard to drive from memory though

[bkballard3]

Yes as I recall it will shift on its own at about 1300 -1500 rpm. The sweet spot I believe is about the same.

[FOURWHL]

Sometimes I've watched it go down as low as 1000 which like I said is fine, but does result in a little bit of momentum loss that you likely won't get back until cresting

That said it's nothing in comparison to getting stuck behind somebody doing 20 and then trying to reaccelerate!

[tnrzryd]

Originally Posted by FOURWHL

Sometimes I've watched it go down as low as 1000 which like I said is fine, but does result in a little bit of momentum loss that you likely won't get back until cresting

That said it's nothing in comparison to getting stuck behind somebody doing 20 and then trying to reaccelerate!

All this sounds familiar. When driving and facing long uphill hauls, a good run at it never hurt. Sure hope we can afford to order our DX3 sometime in the very near future.