MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Topic: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd. (Read 1293 times) previous topic - next topic

MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

October 07, 2023, 01:49:05 pm

Definitely not a deal breaker but curious if the shorter 34' U270 has any advantage over the longer coaches considering weight in MPG? What are you seeing? This coach would take care of my needs but longer world have more opportunity.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #1 – October 07, 2023, 02:00:58 pm

Think the 2 feet would not make a noticible difference.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #2 – October 07, 2023, 02:02:39 pm

Physics says very little difference in MPG on flat ground, as aerodynamic drag is by far the largest factor.

Yes, on grades, weight does play a significant role.

So, someone living in a flat place will have different results than someone living the mountains in the west.

But, for a short answer, the driver (speed, anticipation of driving conditions, etc) is certainly more of a factor that 34 vs 36 or even 40'.

Now, if your toad is a Hummer and you live on the west side of Colorado-- different.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #3 – October 07, 2023, 02:04:17 pm

I'm not aware of any 34' unicoaches but someone who's been on the scene longer will hopefully chime in and correct me if they do exist. 36' U270s are definitely out there however.

I doubt the reduced weight will make a difference given that these are giant bricks driving down the highway. None the less, the difference in mpg will be 100% unnoticeable in the midst of all the other costs of ownership with these rigs. Literally a drop in the bucket. Plenty of good reasons to buy a shorter coach but I wouldn't let fuel economy be one of them.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #4 – October 07, 2023, 02:09:20 pm

Our '93 U280 has the mechanical 8.3L and 6-speed Allison. We weigh just under 30,000 pounds in travel condition, and we pull a 4,000 pound towd combo. I have found 8 mpg is a reasonable average fuel consumption figure for range calculation.

I would guess most U270 models would fall pretty close to that consumption figure, regardless of length.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #5 – October 07, 2023, 02:13:14 pm

Quote from: Elliott – October 07, 2023, 02:04:17 pm

I'm not aware of any 34' unicoaches but someone who's been on the scene longer will hopefully chime in and correct me if they do exist. 36' U270s are definitely out there however.

I doubt the reduced weight will make a difference given that these are giant bricks driving down the highway. None the less, the difference in mpg will be 100% unnoticeable in the midst of all the other costs of ownership with these rigs. Literally a drop in the bucket. Plenty of good reasons to buy a shorter coach but I wouldn't let fuel economy be one of them.

Randy has one

Routing Information PA and NJ enroute to Maine

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #6 – October 07, 2023, 02:16:06 pm

Quote from: Elliott – October 07, 2023, 02:04:17 pm

I'm not aware of any 34' unicoaches...

Check 1998 and 1999 U270 floor plans in the Forum Wiki:

Media [ForeForums Foretravel Motorcoach Wiki]

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #7 – October 07, 2023, 03:02:40 pm

34' would have more opportunity for finding parking spaces, a big advantage especially in National Parks. . .

A very desirable limited-production length. Is engine computerized ISC or Simplified C8.3?

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #8 – October 07, 2023, 03:44:29 pm

We have a 34' which we absolutely love. When we started looking for a Foretravel, we were coming from a 27' class C and wanted the smallest we could find because the size and perceived decrease in maneuverability was intimidating.

With the benefit of hindsight, I would probably go with a 36'. The amount of additional storage in the bays is significant. The HWH components hanging from the ceiling eat up a lot of space, and that additional 2 feet more than compensates for it. Secondly, since they are a relative rarity, they command a higher price on the used market. You have less choices at a higher price.

I wouldn't want to go much bigger that 36 because a smaller rig allows more flexibility in State and National Parks which often have limited space for large motorhomes. But as far as drivability, our fears were much greater than reality.

We typically get 8.0 to 8.5 MPG at 60 MPH towing a little Geo Tracker. I don't think that's much better than the larger rigs achieve.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #9 – October 07, 2023, 04:07:12 pm

We have a 98 36' U270 with all mechanical C8.3 towing 5400 pound toad. Average is 8 mpg at 65 and under with lots of mountain miles. We are pushing 34,700 GCVW.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #10 – October 07, 2023, 05:06:45 pm

About 8 for us also, unless my foot gets a little heavy, or bucking a head wind

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #11 – October 08, 2023, 01:17:00 pm

8 for us also. And having a Grand Villa with the sloped nose apparently doesn't make the difference you'd think it would. Dang it.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #12 – October 08, 2023, 01:39:11 pm

I've been getting 10+ mpg since I bought it, over the last 10 years I've watched my mileage and it hasn't changed.
I run at 62 as an ideal pace, I can't speak to other engine and size combinations specifically. Hard to put into words however if the engine is sufficient for the coach size the only variable is the nut behind wheel, under powered means more aggressive throttle, lots of power raises the opportunity to go faster. The faster you go the more fuel you use.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #13 – October 08, 2023, 04:07:57 pm

OP is specifically asking about observed 8.3L MPG in different length coaches, so yer big block Cummins and CAT, nice as they are, be nonrelevant.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #14 – October 08, 2023, 04:17:00 pm

Quote from: Bob & Sue – October 08, 2023, 01:17:00 pm

...having a Grand Villa with the sloped nose apparently doesn't make the difference you'd think it would.

It DOES make one big difference...it looks mucho KOOL!!!

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #15 – October 08, 2023, 04:44:49 pm

There's me thinking he was talking about expected/projected mileage and how length of the coach might affect fuel consumption. Sorry didn't realize this was for Cummins owners specifically 8.3, is there much difference between the 5.9BT6, the old triple nickel and the 8.3 ? Always ready to up my education.

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #16 – October 13, 2023, 08:35:00 am

We have a 36' 350hp no slide and tow a Jeep Cherokee, at 60 mph we average 8 mpg at 67 mph we average 8.5 according to our Silverleaf,

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #17 – October 13, 2023, 11:45:05 am

We have the 8.3 ISC no side towing a Jeep trailhawk Im on a coast to coast trip across country so far I have put 4150 miles I have been on flat roads and up and down hills and mountains, interstate 70 out Denver for example, on the Silverleaf I'm averaging 9.5 mpg but if I figure it by hand 8.3 mpg fatefully drive at 60 mph or 100 ks and I do not Idle an engine. The old days a diesel engine it was better to idle them leave them idle all day or night at 1200 rpm not at 700 rpm . but the new computer engine you don't idle then especially the ones with DEF. I was told by the time you come of the Interstate down the ramp drive down the road at 30 mph to your stop go thought a parking lot crawling 5mph park. the engine or turbo has cooled down shut it down . Before I leave a campground I do what I have to do before start the engine and getting on the road when it's time to go I start the engine build air up and go take my time till operation temperature is 180 degrees then go.
Don't For get to account for how often you're using your generator I have at time use my generator to operate the roof air condition while driving you can forget about fuel mileage with that on but 99% of the time the dash gives cool air to keep me and wife comfortable but we do stop for lunch and I turn it on Dürer factors in getting good mileage
I drove Tractor trailer most of my life some long haul some locally and I has payed a bonus each month for not going over 65 mph and not idling the truck and the smoother the takeoff to speed and a smoother braking to a stop helps a lot to getting good mileage and life of your vehicle it all boils down to good driving habits .

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #18 – October 13, 2023, 12:01:10 pm

Silverleaf

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #19 – October 13, 2023, 03:54:57 pm

We had poor mileage at 6 to 6.5 mpg from our 2002 U295. Only on one tank I got 7.0.

I have tire pressure monitors and the left rear duals always would get pretty warm.

Paul Ogle told me about a cracked rotor on his (same year, same model). I took mine to a brake place in San Antonio and found that both rotors were cracked and the brakes had been dragging, probably since I bought it 5 years or more before. The pad guide pins get sticky and don't retract properly. This causes premature wear and cracked rotors.

I replaced the pads, rotors and calipers. I now routinely get 7 to 7.5 mpg. The engine is quieter since it's not working as hard now.

Check your brakes if your mileage is poor!

Randy Moody
2002 U295
2018 GMC AWD Tow

Re: MPG looking at a 1998 U270...34' 8.3L Cummins Allison 6 spd.

Reply #20 – October 13, 2023, 04:01:19 pm

Think you need to stay on the forum and look up slide pin maintenance,did they rebuild the calipers or just replace?

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