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I was waiting for this. Good find.

The normally aspirated gas engine handed it to the Cummins at 11,000 ft elevation.

They were pretty gentle with the summary but there were several tough comments like "the Cummins was slower than we anticipated" and "the gas version could exceed the speed limit but we couldn't do that in the Cummins."

Cummins took 10:30 time to complete at 3.7mpg.
Gas took 9:44 time to complete at 3mpg.
 

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If an XD is underrated, it's the 5.6. They could give it the 1000lbs it lacks to the cummins, and then some. The only thing to be concerned with was braking. I'd like to see the actual braking instances.
 

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Sad really. A turbo 5L diesel versus a NA 5.6L gas at 11k in elevation and lost. I think Cummins needs to find another 20% HP/TQ in this motor ASAP.
 

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Exactly... give it a tune and there will be a totally different result. My 2006 5.9 and my 2011 6.7 were both dogs until I tuned them up. Then they passed everything in site. A Gas pot could not keep up mind you running 40PSI of boost does that lol.

Diesels are not rockets ships until you tune them... but If you were to tow and pull weight all day long the diesel will win longevity 100% of the time. For me my XD is not the fastest(Yet) but it sure will last longer because the engine isnt running at 6500RPM.

Just my 0.02
 

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Wow, I just realized the diesel was pulling a lighter trailer. Both weighed in at the scales at 11,120lbs (truck, trailer, & people) but we know the diesel is around 900lbs more so they must have lowered the trailer weight. That makes it even more sad.
 

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Exactly... give it a tune and there will be a totally different result. My 2006 5.9 and my 2011 6.7 were both dogs until I tuned them up. Then they passed everything in site. A Gas pot could not keep up mind you running 40PSI of boost does that lol.

Diesels are not rockets ships until you tune them... but If you were to tow and pull weight all day long the diesel will win longevity 100% of the time. For me my XD is not the fastest(Yet) but it sure will last longer because the engine isnt running at 6500RPM.

Just my 0.02
i drive my 5.6 like a total sh1t head and the motor is totally fine living in 3-6k rpm. its everything else that fails. like my radiator, clutch fan, and thermostat. at the dealership now lol. 112k miles.
 

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My XD P4X 5.6 likes to run in the 2500 to 4000 range. i have pulled 5k with a thousand pound golf cart in the bed and had zero concern. Truck actually sat right at or just under level, had no bounce, no roll and plenty of power. This was without a weight distribution hitch. I can tell you that this truck is much more comfortable and confident, pulling a medium load than my buddies' Fords or Chevy 1/2 tons, which I feel is the true idea behind the XD. Have I told y'all that I love my truck!!
 

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Wow, I just realized the diesel was pulling a lighter trailer. Both weighed in at the scales at 11,120lbs (truck, trailer, & people) but we know the diesel is around 900lbs more so they must have lowered the trailer weight. That makes it even more sad.
I didn't see that but it add more shock value.

I guess we shouldn't be too surprised as this result is just a continuation of some of the early reviews with drivers reporting it felt under powered or as if dragging an anchor. Something isn't quite right but that's to be expected for a first model year. Maybe Nissan will increase the HP/TQ and/or cut the fat.
 

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There's a rule of thumb for normally aspirated engines losing horsepower at elevation. Some say it's ~3% per 1000ft. If so the gas XD was down almost 130hp at 11,000ft. Of course the XD Cummins loses HP at elevation too, just not at the same rate.
 

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Well, for 1, you should never tow with a "hot" tune in a diesel. You're just asking for trouble. The tow tunes don't push any extra boost or timing. They mainly just focus on fuel delivery and shifting. That said, the 5.6 would still win every time. 2, if the cummins needs a hot tune just to keep up with little bro gas burner, that's laughable. Put the hottest tune on it and the 5.6 will still blow it's doors off, in a unloaded run at sea level.
 

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The 5.6 is a great motor even the original versions will keep up with most of the current trucks out there. That said the diesel did fine, diesels are not meant to be speed demons. Their meant to provide good steady grunt power with a greater longevity and economy then a gas motor when towing heavy on a regular basis.
 

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Discussion Starter #16
Ssls6, that weight was not including the trucks.

The 7 speed still had trouble finding the sweet spot. 2rd gear was running 5500 rpm at around 50 mph (maxed out for that gear) , then it would drop way down to 3500 rpm in 3rd gear. If the truck had 4.10 gears, it could stay at 4000 rpm or higher at probably hold 60 mph.
 

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@Biga - A Ram 2500 with the lower output 6.7 did the run in 7:30 with more weight if I remember correct. There is just too much of a gap between this engine and even the lowest output 6.7L
 

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Wow, I just realized the diesel was pulling a lighter trailer. Both weighed in at the scales at 11,120lbs (truck, trailer, & people) but we know the diesel is around 900lbs more so they must have lowered the trailer weight. That makes it even more sad.
So the trailer only weighs 2500lbs?

Trailer, people and cargo were 11120lbs not with truck.

Funny thing is back when they first tested the xd back in winter with only a few hundred less lbs of trailer weight it beat those times up the hill by alot. I wonder the mileage difference on the actual truck is the difference. As like myself and others have commented with miles on these trucks they really wake up.
 

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So the trailer only weighs 2500lbs?

Trailer, people and cargo were 11120lbs not with truck.

Funny thing is back when they first tested the xd back in winter with only a few hundred less lbs of trailer weight it beat those times up the hill by alot. I wonder the mileage difference on the actual truck is the difference. As like myself and others have commented with miles on these trucks they really wake up.
The difference is the trailer, more weight, and warmer, less dense air. This trailer was like pulling a sail.
 

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I am not a diesel pro by no means but if they were running the xd at full throttle as shown couldn't that have hurt the numbers? I thought this engine had a torque sweet spot of 1800 to 2500 rpms? I could be wrong and am open into interpretation...
 
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