Originally Posted by Muggs
The V-8 would need to really bump MPG to justify change or I would need bigger unit (not likely).
Thatís not ever going to happen in my opinion. The new V8 ďmayĒ get slightly greater fuel economy due to its higher compression ratio, lower friction, and improved breathing, but these can only be incremental improvements in the Premium ďpowerĒ tune. The reasons large and heavy motorhomes get crappy fuel economy is mostly because of the amount of power it takes to move them, not because their engines are that inefficient.
As Iíve stated before, V10 technical data shows that the V10 engine is reasonably fuel efficient in the right power range. Iím certain Ford did not replace the V10 with the new V8 just to save fuel. Thereís no way the new V8 can save enough fuel over a V10 to justify upgrading a motorhome solely for that purpose.
The new V8 has significant ďpotentialĒ over the V10 which has nothing to do with fuel economy. I believe the driving force (no pun intended) behind the new V8 was to reduce costs. The new engine is simpler so should cost less to manufacture and repair/rebuild. Itís also physically smaller, so can fit in tighter spaces and/or have better cooling over the exterior of engine. A smaller RV doghouse should be a welcomed improvement.
What I like best about a V8 is that itís not a V10. My V10 may have just over 200,000 miles now, but itís never been smooth or quiet. A V10 is not inherently balanced, so requires a balance shaft. Beyond that, I have never driven a single Triton engine that wasnít loud. Even a 4.6L V8 in an F-150 was louder than old OHV V8s from the past, particularly at higher RPMs.
P.S. ó For the size RV Iím interested in, I still think the 7.3L is too large for optimum efficiency. A +/- 5-liter engine should have greater chance of 12 MPG at 60 MPH in a smaller motorhome.