37' Allegro Bus

Question

The 2015 37' Tiffin allegro Bus RV comes with an Cummins ISL 450 HP diesel engine. The larger 45' version of this RV offers the Cummins ISX 600 HP diesel. Obviously the longer the more heavier unit demands more HP but why isn't such an engine available on the 37' 0r 40' tag axle version? Forget the fact there's no tag axle (37'version) to handle excess weight is this simply a structural issue in that the RV is not set up to handle the extra weight/torque or is it simply HP overkill that not too many RV owners want/need?

The reason I'm asking is in today's auto/truck world we have massive HP availability not only in the pick up truck arena but passenger cars also. In that Americans crave more of everything.

In a motor home it's been my experiences that more HP is better even though there's the added cost.

mr_mark1 · Answer

In my opinion, it's simply a cost issue. The big 600 hp Cummins will need the larger Allison transmission. I would imagine that Tiffin is trying to meet a price point. I would think that option would be at least a $25,000 upgrade.

And talking about eating up your CCC in a 37 ft.!

MM.

dsdp_don · Answer

They probably don't want the 37' to be able to do wheelies!

We have the 40' Dutch Star with the 450 ISL. In my opinion, when towing, it's just about maxed out. They just changed the frame and made the entire floor, including FWS all tile. It bumped the weight another 3K. I think they'll now be forced to put the smaller ISX in it to make the coach reasonably powered. As "Mr.Mark" stated, the ISX and 4000 Allison then add another level of additional weight.

gmandjm · Answer

I can't image there'd be much consumer demand for it. RV builders build what sells. (Not sure about that "Americans crave more of everything" statement, btw.)

Can you imagine a 37' tag axle with a 650? Absolutely NO basement storage but you could tow a tank.

ivylog · Answer

The 1 HP/100 lbs is a pretty good rule of thumb for MHs. My combined weight is pushing 45,000 lbs and 99% of the time I'm happy with my ISL 400. To gain 100 HP you are probably looking at 3,000 extra lbs in the engine/tranny, larger radiator/coolers, larger frame members, and usually a couple more feet in length so you have only gained 70 hp in performance.

bobged · Answer

All of the new Allegro Buses come standard with a 450HP/1250 lb torque Cummins.  The ISX 600 is available for the 45OP and 45UP models only, and I believe the up charge is around $65,000.

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37' Allegro Bus

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