Originally Posted by Baddad53
I got 7 to 8 mpg with DP - I am getting 8 to 10 mpg with V10.
My wife hated the size while traveling and liked it when it was parked. Only thing we gave up was washer/dryer. Plus she is driving it to releave me on trips ...she would never do that in the DP. Yes it was about size and costs. But my wife and I thought that the Axis/Vegas was just the right size (tanks and living space for us) MB based B's and C's. The ones with room we wanted had no capacity for GVWR.
That's quite an improvement.
If Cummins is correct about their 20 to 40 percent improvement over a V10, it would suggest your 8 to 10 MPG could become 10 to 14 MPG if an Axis-size motorhome had a 5.0L diesel V8. And that sounds realistic compared to Winnebago Class A on Sprinter chassis that reportedly get as high as 17 MPG (granted they are slightly smaller and lighter than Axis).
What I don't get about diesels is buyers' acceptance of low power-to-weight ratio compared to many gas motorhomes. For example, this new Tiffin with 275 HP for 23,500-pound GVWR would be the same as Ford installing a 3.2L 185 HP inline-5 in an Axis. That would also make an Axis close in power to a 3.0L Sprinter V6. Would that seem adequate after driving a 305 HP V10?
By the way, I agree the larger Mercedes Class A on Sprinter chassis is a little low on GVWR for the way it's built. I also don't like the narrow rear track for such a tall motorhome, or the limited places to get it repaired. We do like the overall size and build quality which appear very good; although higher quality should be expected at that price.