2011 Heavy-Duty Hurt Locker: Fuel Economy

Fuel-economy
Words by Mike Levine, Mark Williams and Kent Sundling, Photos by Ian Merritt

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Fuel Economy

Our final test of the three heavyweights was fuel economy, because every time you have to stop to refuel, you lose time and money.

We measured fuel consumption over almost 2,000 miles of travel with the trailers behind the trucks the entire time. The results exclude segments where we were testing the trucks, such as on the mountain climbs and at Chrysler’s proving grounds. As we’ve seen in earlier tests, the Ford F-350 had the best fuel economy while towing, at 9.5 mpg. The GMC was close behind at 9.1 mpg, or a difference of $22 over 2,000 miles. The Ram had the worst mileage, at 8.5 mpg, costing $115 more to operate than the Ford.

Download Detailed Mileage Comparison Chart Acrobat-icon

Ford’s and GMC’s DEF systems – used to scrub nitrogen oxide emissions to meet federal regulations – allow the engines to operate more efficiently with less exhaust gas recirculation than the Ram. While DEF runs about $2.99 a gallon and the Ford and GMC have DEF tanks that hold about 8 gallons, it’s well worth the cost. We started out with full DEF levels in both trucks and never had to refill during the trip, and no low-DEF warnings came on.

Our past measurements show DEF consumption at about 2 percent of diesel fuel, though it might have been higher because of the heavy loads and high stress we were putting on the trucks.

Driving

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Comments

Why didn't you measure DEF consumption?
It is the only equilizer between the Ram and its competition. Ram advertising makes a big deal of it as well.
I doubt DEF consumption would offset the Ram's MPG but it should of been measured.
Probably a mote point since 2012 will most likely have Ram's on DEF.

Way to go Ford!

You couldn't top off the dpf? That's low budget.

2% On flat ground maybe at times during this test you were pulling much more than 10% Dpf

Lou: The entire tank only uses $24 worth of DEF, and the test run was $115 more expensive on the Ram (fuel only). Even if they consumed the entire DEF tank (which they didn't), that would make the Ram $91 more expensive to operate. If, as it appears, they only used 2% of the DEF tank over 2,000 miles, then they consumed 0.8 gallons of DEF, or adding less than $3 to the cost of the run on the Ford and GMC.

@Buddy: Agree. 2% usage on average. What we were doing was kind of far from average.

Gk
under severe conditions you could use up your dpf in as little as a few tanks of diesel. These were full power runs of less than 12 mi and 1/4 mi average out over 2000 mi.
Every body gets good down hill milage. But if your regular route is Eisenhower pass dpf is going to kill you.

I live in a valley passes on all sides hard climb both in and out. Hard on dpf

My guess?
Dodge will have dpf next year and nobody wants dpf results from tests like these released.

@Buddy-"But if your regular route is Eisenhower pass dpf is going to kill you."
The extra fuel used to clean the LNT is always worse, whether in Nebraska or at Eisenhower. General acceptance, combined with the economy deficit must certainly be part of Ram switching P/U's to SCR. There may have been excessive warranty claims, too.

Mr

not true ram switching because of the extra expence of two types of systems and they have to have dpf on 4500's. I think this move will hurt them. 1 mile/Gallon doesn't mean much when you are already in the low teens while pulling.
And a lot of people switched to ram because of no dpf.

And for this test rams penalty was expressed in the milage figures. The dpf penalty was hidden by the purposeful failure to measure it's usage.
Up those grades dpf was disappearing like Casper.
Your statement doesn't add up

Mr
dpf system is also cheaper for manufacturer because of the cost for rare earth that is required. The manufacturers are passing the expense to the buyer when using dpf

I know guys who have gone to Ram to avoid DEF, and I know guys hanging on to their pre-DEF trucks for the same reason. DEF consumption should of been measured even though it wouldn't of been a significant overall cost disadvantage.

Lou,
The numbers would have scared people. It's like the eco boost thing. Numbers look nice until you start towing heavy. And why have a diesel if you are not heavy towing or driving a 100,000 miles a year?

The excuse to buy diesel is the mileage. The ford v10 has all the power anyone needs outside of the commercial driver.. Diesel lost the cost per gallon race years ago.

Considering the upfront costs. The v10 is the better purchase for the average driver. Gasoline engines can easily last 200,000 miles

Especially when considering that the evap controls are tried and tested on the v10. Not so for the diesels.

@Buddy- quick terminology refresher:
DPF- Diesel Particulate Filter- these catch soot, and have been (required) on trucks since 06. They regen with diesel fuel.
DEF- A Urea solution used to make ammonia to regenerate some after treatment systems.
SCR- Selective Catalytic Reduction- after treatment device that uses ammonia to convert NO into CO2 and Water.
LNT- Lean Nox Trap uses rare earth metals as a catalyst to convert NO under lean burn conditions.
Diesel Options cost as follows-
GM- $8400
Ford- $7800
Ram- $8300
Especially between the Ram and GM, the cost difference is small, and you might argue the Cummins costs more than the D-max.

Thanks Lou, I meant DEF not dpf in my above posts.


Q. Do trucks equipped with scr have a Diesel particulate filter (Dpf)?
a. Yes they do. The DPF serves a different function than the SCR; it helps
remove soot from the exhaust. For 2011, the range between Duramax
DPF regeneration cycles has been lengthened by 75% and is now up to
700-miles. This improves fuel economy performance since less diesel fuel
is required to clean the DPF. (Based on GM testing.

Mr.
Thanks, got my abrevi
Q. Do trucks equipped with scr have a Diesel particulate filter (Dpf)?
a. Yes they do. The DPF serves a different function than the SCR; it helps
remove soot from the exhaust. For 2011, the range between Duramax
DPF regeneration cycles has been lengthened by 75% and is now up to
700-miles. This improves fuel economy performance since less diesel fuel
is required to clean the DPF. (Based on GM testing.

Thanks MR.
got my abbreviations mixed up

Mr.

There was a 1 mpg difference between Ford and Ram. .5 mpg between Duramax and ram.
The cost of DPF can be more costly than diesel. Approaching 5 dollars/gallon by the jug. If not more in many places.

The best one can say about the dpf mileage is that it is a toss up with the Rams.
Blame that on PUT.com They new it would be asked about it. Never-the-less they failed to test it.
I say there is a reason for this failure.

cummins needs to make the switch to def just like in their 4500. It is a proven fact that the less egr the better for your engine. as well as better mpg, its a no brainer, and thats why they will have it next year for 2500/3500

If the Ram was $94 more costly to operate over 2000 miles that extends to $2,350.00 every 50,000 miles. That is a lot of money and a proven loss. The possibility of Ford spending more money on brakes is not proven. However, $2,350.00 is more than enough money for brakes and then some! More should of been made about Ram's operating costs with fuel and less of Ford's and less of the possibility of extra braking costs with Ford which was never proven.

DEF- lot of emotions here. This is my experience. I have 8k on my Chevy. I have added DEF a few times to total about 8.5 gallons. The average for everyday driving and some towing is right at 1000 mpg. A loaded trip to Utah in the heat and very mountainous driving up to 11,000 feet resulted in slightly higher burn rate- say 800 mpg.

I seem to buy 2.5 gallons of Peak for about 12 bucks. So not a huge expense. I almost go through that amount of windshield wiper fluid.

It is a slight pain in the ass to access the intake on the Chevy under the hood. So is changing the oil and fuel filter which every car suffers from. The lack of smell coming out the tailpipe is also a big bonus.

When talking to Reid he told me the Rams will get DEF after the 2013.5 range. Like the split build for the 07's. That might only apply to Canada though.

2011 cab&CHASSIE ALREADY HAVE D.E.F



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