Schizophrenic 7.3L
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Tuned
Joined: Oct 2020
Posts: 411
Likes: 284
From: Northern Sierra Nevada
Steve SBD:
Your new F-series will feel like an old shoe, compared to the 5.9L Cummins.
Very similar torque splay with both having great low end torque.
Much better throttle response with the gasser. Is yours 7.3 or 6.8?
I'll stick with ONE mpg less with the F-350 gasser as the average.
There are caveats.
The sweet spot for mpg with the camper on the Ford is 63 mph, on the flat with no headwind. If hilly or windy 58-60 mph is a better bet. Good thing as I'm old, and not in a hurry anymore.
The slower you go with the Cummins, the better the mpg. Doing the Mojave Road (124 miles of 2-track old wagon road across the desert from Barstow to the Colorado River) at 20 mph netted us great, and I mean great mpg with the Cummins. The Cummins has gobs of torque all the down to idle. Au contrare, the faster you go with the Cummins, the worse the mpg becomes.
With the camper on, wind is the most egregious enemy. Our camper is always on, so I don't even know what mileage the truck gets without the camper aboard.
As with other Cummins and Subaru owners, our CTD is now in the hands of our son and his Lance 845 chateau.
Your new F-series will feel like an old shoe, compared to the 5.9L Cummins.
Very similar torque splay with both having great low end torque.
Much better throttle response with the gasser. Is yours 7.3 or 6.8?
I'll stick with ONE mpg less with the F-350 gasser as the average.
There are caveats.
The sweet spot for mpg with the camper on the Ford is 63 mph, on the flat with no headwind. If hilly or windy 58-60 mph is a better bet. Good thing as I'm old, and not in a hurry anymore.
The slower you go with the Cummins, the better the mpg. Doing the Mojave Road (124 miles of 2-track old wagon road across the desert from Barstow to the Colorado River) at 20 mph netted us great, and I mean great mpg with the Cummins. The Cummins has gobs of torque all the down to idle. Au contrare, the faster you go with the Cummins, the worse the mpg becomes.
With the camper on, wind is the most egregious enemy. Our camper is always on, so I don't even know what mileage the truck gets without the camper aboard.
As with other Cummins and Subaru owners, our CTD is now in the hands of our son and his Lance 845 chateau.
Mountain Pass
Joined: Feb 2024
Posts: 168
Likes: 153
Steve SBD:
Much better throttle response with the gasser. Is yours 7.3 or 6.8?
The sweet spot for mpg with the camper on the Ford is 63 mph, on the flat with no headwind. If hilly or windy 58-60 mph is a better bet. Good thing as I'm old, and not in a hurry anymore.
The slower you go with the Cummins, the better the mpg.
Much better throttle response with the gasser. Is yours 7.3 or 6.8?
The sweet spot for mpg with the camper on the Ford is 63 mph, on the flat with no headwind. If hilly or windy 58-60 mph is a better bet. Good thing as I'm old, and not in a hurry anymore.
The slower you go with the Cummins, the better the mpg.
Yes I get the best MPG with my 98.5 running 55mph on state routes (21.5 MPG without camper). Running 70mph, the mileage drops to the mid to upper teens. With the camper on, I can only run 65mph at the max, and get around 13mpg. I'm in the Colorado mountains, so the terrain is a factor.
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Tuned
Joined: Oct 2020
Posts: 411
Likes: 284
From: Northern Sierra Nevada
We used to get 15-19 mpg with the Cummins HO/ NV5600 4:10's with no load and rolling 35's.
So, again it boils down to a mile or two per gallon difference whether gas or diesel considering GVW, speed, and wind resistance with the camper on.
We never had a problem with the NV5600 which had the tallest overdrive of the 5 or 6 speed manual trannies.
1st gear was 5.61:1 and overdrive 6th gear was 0.73:1(27%) with low range at 2.62:1 reduction.
It was rated at 26K pounds.
That sucker weighs in at 360 pounds wet with it's cast iron case and aluminum top cover.
I'm glad that noise is gone. Jeanie and I can actually converse on long trips, and she likes to drive the 10 speed auto trans.
So, again it boils down to a mile or two per gallon difference whether gas or diesel considering GVW, speed, and wind resistance with the camper on.
We never had a problem with the NV5600 which had the tallest overdrive of the 5 or 6 speed manual trannies.
1st gear was 5.61:1 and overdrive 6th gear was 0.73:1(27%) with low range at 2.62:1 reduction.
It was rated at 26K pounds.
That sucker weighs in at 360 pounds wet with it's cast iron case and aluminum top cover.
I'm glad that noise is gone. Jeanie and I can actually converse on long trips, and she likes to drive the 10 speed auto trans.
Tuned
Joined: Nov 2023
Posts: 431
Likes: 247
It has been said the 6.8 is focused around fleet sales What if it is the more reliable motor and the 7.3 failures were fixed for the fleet purchasing power???
I know crank this and crank that but when is last time you you saw any crank fail? How many lifters fail? Lifters are what seems to be most common failure.
The thing with 6.8 is the 10L100 tranny. Which is a an unknown.
I know crank this and crank that but when is last time you you saw any crank fail? How many lifters fail? Lifters are what seems to be most common failure.
The thing with 6.8 is the 10L100 tranny. Which is a an unknown.
Mountain Pass
Joined: Feb 2024
Posts: 168
Likes: 153
It has been said the 6.8 is focused around fleet sales What if it is the more reliable motor and the 7.3 failures were fixed for the fleet purchasing power???
I know crank this and crank that but when is last time you you saw any crank fail? How many lifters fail? Lifters are what seems to be most common failure.
The thing with 6.8 is the 10L100 tranny. Which is a an unknown.
I know crank this and crank that but when is last time you you saw any crank fail? How many lifters fail? Lifters are what seems to be most common failure.
The thing with 6.8 is the 10L100 tranny. Which is a an unknown.
Tuned
Joined: Nov 2023
Posts: 431
Likes: 247
Like I said, it's just too new, so I don't have enough real world reports to go on. For someone like me who buys vehicles to keep 15+ years, I won't buy early production anything. It could very well be the better of the two engines. I've seen some youtubers posting some great MPG videos with the 6.8, so it definitely has promise. Some might notice that my 98.5 Dodge Cummins was the first production run for the 24 valve engine, but I bought it when it was 6 years old, and we already knew it's pain point (the lift pump) and upgraded that immediately.
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