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slowmover · 04-25-2013, 08:05 PM

There is a substantial set of Cummins guys who claim high MPG while driving 40 MPH

BigDave, I've seen you make this same statement on FORD forum threads. I've never come across it. Hard enough to find anyone who doesn't speed (runs 60-mph plus) or who keeps the average mpg updated. Now, if you meanAverage MPH your comment may be on track.

Trucks are a compromise. And part of that compromise is poor handling/braking. A propensity to roll-over where cars just spin out. Trucks are geared to run 55-65/mph most efficiently. And highest mpg claims are within this range. The foolishness of running a truck faster than this has no place in any discussion of performance, or from any angle. It is beyond the pale.

When I claim no less than 24-mpg at 58-mph @ 1,725-rpm that is over tens of thousands of miles. My truck spec, climate and terrain comparisons with others makes this consistent (with those others who keep records). I've also run over 1k miles in town at 23-mpg, but this was in practicing hypermiling techniques. And I've seen just above 30-mpg in a run across southernmost Louisiana on a road where the limit was 50 for many, many miles. A fluke, in any case.

If you've other sources to cite, start a thread on the topic. FORD is at the back of the pack for good reasons . . but all turbodiesel trucks have some magic to discover in re fuel efficiency. We're all friends around here, so let's not muddy the water.

The OP has his work cut out for him in establishing the best mechanical baseline. Sounds great here at the beginning (pics seem to show an unmolested truck), but at over 20-years it's time to go through it all in re systems.

I'd start by weighing it. A CTD is fairly impervious to weight changes, but getting the weights for each axle and each wheel where the truck has driver, full fuel and any permanent supplies aboard is the adjusted empty weight over vehicle manufacturer shipping weight numbers. IOW, a weight that will never go lower. Truck tire pressure is within manufacturer specs (especially FF/RR bias) and then according to load. Accurate steering and braking is not helped by overinflation, etc. Baseline, to know how it feels when it is to spec.

The underhood electrical harnesses and then dash harness would be my main concern in where to get reliability back to new. Get the service manuals, identify the harnesses and work hard to get those OEM parts. Dealers and parts stores start eliminating stuff for 15-yr old vehicles and they then become incredibly difficult to find (at a similar level of quality). It might cost $$$, but every penny will be earned back.

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04-25-2013, 08:05 PM	#7 (permalink)
slowmover Banned Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,442 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,422 Thanked 737 Times in 557 Posts	There is a substantial set of Cummins guys who claim high MPG while driving 40 MPH BigDave, I've seen you make this same statement on FORD forum threads. I've never come across it. Hard enough to find anyone who doesn't speed (runs 60-mph plus) or who keeps the average mpg updated. Now, if you meanAverage MPH your comment may be on track. Trucks are a compromise. And part of that compromise is poor handling/braking. A propensity to roll-over where cars just spin out. Trucks are geared to run 55-65/mph most efficiently. And highest mpg claims are within this range. The foolishness of running a truck faster than this has no place in any discussion of performance, or from any angle. It is beyond the pale. When I claim no less than 24-mpg at 58-mph @ 1,725-rpm that is over tens of thousands of miles. My truck spec, climate and terrain comparisons with others makes this consistent (with those others who keep records). I've also run over 1k miles in town at 23-mpg, but this was in practicing hypermiling techniques. And I've seen just above 30-mpg in a run across southernmost Louisiana on a road where the limit was 50 for many, many miles. A fluke, in any case. If you've other sources to cite, start a thread on the topic. FORD is at the back of the pack for good reasons . . but all turbodiesel trucks have some magic to discover in re fuel efficiency. We're all friends around here, so let's not muddy the water. The OP has his work cut out for him in establishing the best mechanical baseline. Sounds great here at the beginning (pics seem to show an unmolested truck), but at over 20-years it's time to go through it all in re systems. I'd start by weighing it. A CTD is fairly impervious to weight changes, but getting the weights for each axle and each wheel where the truck has driver, full fuel and any permanent supplies aboard is the adjusted empty weight over vehicle manufacturer shipping weight numbers. IOW, a weight that will never go lower. Truck tire pressure is within manufacturer specs (especially FF/RR bias) and then according to load. Accurate steering and braking is not helped by overinflation, etc. Baseline, to know how it feels when it is to spec. The underhood electrical harnesses and then dash harness would be my main concern in where to get reliability back to new. Get the service manuals, identify the harnesses and work hard to get those OEM parts. Dealers and parts stores start eliminating stuff for 15-yr old vehicles and they then become incredibly difficult to find (at a similar level of quality). It might cost $$$, but every penny will be earned back. . Last edited by slowmover; 04-25-2013 at 08:22 PM..