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Old 08-19-2018, 10:04 PM   #1
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New Aire Fuel Economy

Our 3433 New Aire is not even broken in yet (odometer showing about 3,800), but already showing much better fuel mileage than the prior DS 4369:

Trip #1 about 450 total miles towing 3,200# trailer across southern Idaho, about 10 mph headwinds on the return trip. Maintained 62mph on cruise control. Overall mileage shown on the dash computer and confirmed by my own “old school” calculation was 8.2 mpg.

Trip #2 about 1050 miles from central Idaho up through western Montana to Flathead Lake, return through north Idaho back down eastern Washington and Oregon. Cruise control set at 62. Lots of steep uphill climbs, freeway and 2-lane highways, towing Jeep Wrangler 4-door. On several longer grades top speed dropped to 42 mph. Overall fuel consumption 8.1 mpg.

Disappointed with lack of uphill pulling power, about 8-10 mph less than the DS up same grades, but nice trade-off on the fuel consumption side of the equation, at a leisurely 62 mph.
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Old 08-20-2018, 02:04 AM   #2
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What is the approximate weight of your NA?
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Old 08-20-2018, 04:52 AM   #3
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I think my 37' is about the same weight (37000 + /-) but has the 450. On our last trip around 8k miles, we averaged 8.1 (confirmed by calculation) for the entire trip. 65 mph towing the Wrangler most of the time with stints at 70. When I ferst got it, mileage was around 7, but seems to have broken in now.
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Old 08-20-2018, 07:08 AM   #4
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Originally Posted by lostinfla View Post
I think my 37' is about the same weight (37000 + /-) but has the 450. On our last trip around 8k miles, we averaged 8.1 (confirmed by calculation) for the entire trip. 65 mph towing the Wrangler most of the time with stints at 70. When I ferst got it, mileage was around 7, but seems to have broken in now.


Thank you, was trying to make a relative comparison, my 18 DS weighs in at close to 42,000 pounds and I have gotten 7.2 MPG towing a 4 dr Jeep Wrangler. I’d say on a weighted comparison (pun intended) the mileage 7.2 vs 8.1, +/- 5,000 pounds, it’s pretty even. Stuart
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Old 08-20-2018, 01:52 PM   #5
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Originally Posted by Johnidaho View Post
Our 3433 New Aire is not even broken in yet (odometer showing about 3,800), but already showing much better fuel mileage than the prior DS 4369:

Trip #1 about 450 total miles towing 3,200# trailer across southern Idaho, about 10 mph headwinds on the return trip. Maintained 62mph on cruise control. Overall mileage shown on the dash computer and confirmed by my own “old school” calculation was 8.2 mpg.

Trip #2 about 1050 miles from central Idaho up through western Montana to Flathead Lake, return through north Idaho back down eastern Washington and Oregon. Cruise control set at 62. Lots of steep uphill climbs, freeway and 2-lane highways, towing Jeep Wrangler 4-door. On several longer grades top speed dropped to 42 mph. Overall fuel consumption 8.1 mpg.

Disappointed with lack of uphill pulling power, about 8-10 mph less than the DS up same grades, but nice trade-off on the fuel consumption side of the equation, at a leisurely 62 mph.
My NA 3343 is providing about the same milage as yours but due to speed sensor issue my cruise was not working and most was without cruise and speed was at 65 to 68 which is faster than normal. I agree with the lack of uphill power but still better fuel milage than my previous 4304 DADP. My weight is about 33,000. Great driving coach.
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Old 08-20-2018, 02:06 PM   #6
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Thank you, was trying to make a relative comparison, my 18 DS weighs in at close to 42,000 pounds and I have gotten 7.2 MPG towing a 4 dr Jeep Wrangler. I’d say on a weighted comparison (pun intended) the mileage 7.2 vs 8.1, +/- 5,000 pounds, it’s pretty even. Stuart
Makes sense since most of the horsepower at 65mph goes to aerodynamic resistance. So frontal area is a bigger factor that weight.

Now have 10,000 miles on the New Aire. Most of it towing the 4 door Wrangler. All up weight around 39,000 lbs. Average fuel economy since new is 7.52 mpg.

Based on my recent trip if most of my mileage was east of the Rockies (rather than west), my average fuel economy would be closer to 8 mpg. Going up and down big grades out west seems shave about .5 mpg from the fuel economy. I have a hunch frequent use of the VGT turbocharger for braking eats up the fuel economy numbers.
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Old 08-21-2018, 04:15 AM   #7
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Why would using the engine break use fuel/decrease mileage?
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Old 08-21-2018, 05:44 AM   #8
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Extra economy is available by activating the second shift schedule mode on the Alison transmission. Works well well on the flats and traveling less then 62 mph. The main shift schedule does not allow gear 6 at 55 mph. This is why many people report better economy at higher speeds. In the Midwest at 55-58 mph in 6th gear we got 9.2 mpg. I’m very pleased with that.
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Old 08-21-2018, 06:14 AM   #9
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My original 2001 NewAire 2801 is getting 13.5 MPG in the midwest flat towing a Honda CR-V. The old girl is equipped with a Cummins 5.9 ISB (chipped) and an Allison T-2000 transmission. GVWR is 24,000 pounds.

On a long flat trip I think I can get north of 14 MPG at 2000 RPM and 62 MPH.
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Old 08-21-2018, 06:50 AM   #10
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Originally Posted by thomaspryan View Post
My original 2001 NewAire 2801 is getting 13.5 MPG in the midwest flat towing a Honda CR-V. The old girl is equipped with a Cummins 5.9 ISB (chipped) and an Allison T-2000 transmission. GVWR is 24,000 pounds.

On a long flat trip I think I can get north of 14 MPG at 2000 RPM and 62 MPH.
Those original New Aire’s are very cool, so far ahead of there time!
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Old 08-21-2018, 07:29 AM   #11
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Originally Posted by turbopilot View Post
Makes sense since most of the horsepower at 65mph goes to aerodynamic resistance. So frontal area is a bigger factor that weight.




I also have to feel that the larger contact patch of the larger tires plus the additional tag wheels also have to cost some energy. Motorhome fuel economy is interesting, when numbers like .7 can represent a 10% improvement. Not a lot to work with[emoji4]
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Old 08-21-2018, 08:09 AM   #12
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Why would using the engine break use fuel/decrease mileage?
Just a theory. The whole purpose of the VGT turbocharger is to provide resistance to the mass of the coach moving down hill versus just a free coast.

I know for sure that my NA will get .5 mpg less fuel economy when going up and down big grades. Up the grades I might be down 40 to 45 mph and down the grade using VGT braking doing 45 to 50 mph. Running on level ground at 45 to 50 mph I would easily get up to 1 mpg more than average. So given the speed in the actual fuel penalty is much larger operating on steep grades.
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Old 08-21-2018, 09:32 AM   #13
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What is the approximate weight of your NA?
Have not weighed it recently or as loaded for that trip, but just the normal load of fuel, water and basics for two adults and our dog. Well under GVWR and GCWR.
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Old 08-21-2018, 09:39 AM   #14
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Originally Posted by thomaspryan View Post
My original 2001 NewAire 2801 is getting 13.5 MPG in the midwest flat towing a Honda CR-V. The old girl is equipped with a Cummins 5.9 ISB (chipped) and an Allison T-2000 transmission. GVWR is 24,000 pounds.

On a long flat trip I think I can get north of 14 MPG at 2000 RPM and 62 MPH.
No such possibilities for the new coaches, particularly In this new age of tighter regulations and DEF. Driving on flat roads over 50 or so mikes, my computer shows about 9.2 mpg, but hilly or mountain terrain definitely take their toll.
I agree with (based on current experience) with Turbopilot’s comments above...the average mpg reading steadily clicked down a tenth at a time when ona lengthy uphill grade.
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