Community Forums

conniep · 04-14-2016, 10:58 AM

Hello, from Denver.trying to decide if pulling through the mountains is going to make a huge difference in mileage $$ Deciding if we should get the Tiffin Bus 45OP or 45UP.

Skip426 · 04-14-2016, 12:09 PM

Welcome to iRV2.

The old Drag Racing adage applies ; Speed Costs... how fast do you want to go?

I'm on the road at 31,500 lbs GCW. and 300 hp. and get everywhere I want to go, most members will agree that a ratio of 1HP to 100Lbs of combined weight , Motor home and toad or trailer, is a good target. It won't be the fastest thing on the road but it'll get you there.
The 450 HP coach will perform just fine up too 45,000 lbs of GCW. You'll always be faster than a loaded semi on the hills.
The 600 HP, will get you over the summit faster; unless you're rolling at 60,000 lbs; but , you'll be feeding the extra ponies to do it.
As far as actual MPG between the two, I'll let members who own them comment on that.
Here's a pdf on what factors determine fuel economy. This one is from Caterpillar, but Cummins produced a similar document , that said mostly the same things. Driver and speed are the biggest factors in economy.

Cranemec · 04-14-2016, 12:17 PM

You will be fine with the 450.

Gordon Dewald · 04-14-2016, 12:55 PM

We are running combined at 53,000 and have the ISL 450.

For us it is very adequate. I am not concerned about going up the hills a bit slower. We are not passed by many semi's going up hill.

MSHappyCampers · 04-14-2016, 01:37 PM

Welcome to IRV2! We're sure glad you joined the gang!

Good luck, happy trails, and God bless!

Crasher · 04-14-2016, 04:38 PM

You won't "Need" the 600 hp as the 450 gets our 53,000# coach/trailer over the pass just fine. I tell my wife that a 600 would be nice, but if I had that, I would want 800 hp. On the level running the 600 will get about the same economy as the 450 and maybe a little better due to torque curves. However, if you put your foot into a 600 to get up the hill quicker get ready to buy more fuel at the next stop.

loisjop · 04-14-2016, 04:52 PM

There's no comparison. I've owned both and the ISL is adequate, but the ISX is really fun to drive.
At 65 the isl is turning about 1800 rpm while the isx is about 1400. The fuel mileage has been about the same, but I haven't been in the mountains with the isx.
By the way I wouldn't buy either one of the Tiffins. I've owned two and spent way too much time in Red Bay Al.

Dutch Star David · 04-14-2016, 05:08 PM

Quote:

Originally Posted by loisjop

There's no comparison. I've owned both and the ISL is adequate, but the ISX is really fun to drive.
At 65 the isl is turning about 1800 rpm while the isx is about 1400. The fuel mileage has been about the same, but I haven't been in the mountains with the isx.
By the way I wouldn't buy either one of the Tiffins. I've owned two and spent way too much time in Red Bay Al.

I couldn't agree more. On Entegra ISL runs 4.88 rear end; ISX is 4.30. I've had both and if I keep my foot out of it, the mileage is about the same.

conniep · 04-15-2016, 11:35 AM

Thanks for your response. Did you buy your Tiffin new or used? What year and model? What kind of problems did you have? Do you still own a Tiffin?

loisjop · 04-15-2016, 01:05 PM

Quote:

Originally Posted by conniep

Thanks for your response. Did you buy your Tiffin new or used? What year and model? What kind of problems did you have? Do you still own a Tiffin?

Bought both new, first was a 2007 40qsp second 2012 43qgp. Problems were everything from roof leaks, steering issues, rotted slide and wet bay floors, roof radius cracks and a couple hundred other issues.
No I do not still own a Tiffin. Bob Tiffin is a great guy unfortunately I don't think the sons are from the same cut.

Larrikin · 04-16-2016, 10:58 AM

We have a 2007 Tiffin Allegro Bus, 42 ft tag axle, Freightliner chassis w 400 hp Cummins. With toad we weigh in at About 41,000 pounds. The 400 hp has pushed us over Hoosier Pass, Wolf Creek Pass, and many others. Only problem in 5 years was east of San Diego on I-8, on a 100 degree day, where engine temp management was critical. Many trucks were at 20 mph, we could hold 35. If we had ever lost our momentum we probably would not have gained it back.

Extra horses are great, and don't really affect your mileage (you only use X hp to push your rig at a given weight, speed, and frontal drag), but come with a purchase price and weight penalty. You decide. Pay attention to radiator size and installation as well.

BTW, our bus was 4 years old when we got it. 2 years later Tiffin covered all the stuff mentioned in the previous blog about issues, plus other vendor part issues that they did not cause. The family name is on the bus. You will not get that kind of care from a bus manufacturer that is publicly held and led by an itinerant CEO. They have very short term, bonus oriented agendas where customer care is not a quantifiable metric.

JMonroe · 04-16-2016, 11:43 AM

The 450 in our Revolution certainly gets the job done. Am I looking forward to driving the new coach with the 600? Heck yea!

Mr_D · 04-16-2016, 11:50 AM

Quote:

Originally Posted by Skip426

The 600 HP, will get you over the summit faster; unless you're rolling at 60,000 lbs; but , you'll be feeding the extra ponies to do it.
As far as actual MPG between the two, I'll let members who own them comment on that.

Our ISX running with close to 55,000#'s gets almost the same mileage as our ISC 350 did with 36,000#'s in our '02 Dutch Star. But the performance is very different with the ISX being much better.
But the 450 will get you there.

conniep · 04-17-2016, 09:36 AM

Quote:

Originally Posted by Larrikin

We have a 2007 Tiffin Allegro Bus, 42 ft tag axle, Freightliner chassis w 400 hp Cummins. With toad we weigh in at About 41,000 pounds. The 400 hp has pushed us over Hoosier Pass, Wolf Creek Pass, and many others. Only problem in 5 years was east of San Diego on I-8, on a 100 degree day, where engine temp management was critical. Many trucks were at 20 mph, we could hold 35. If we had ever lost our momentum we probably would not have gained it back.

Extra horses are great, and don't really affect your mileage (you only use X hp to push your rig at a given weight, speed, and frontal drag), but come with a purchase price and weight penalty. You decide. Pay attention to radiator size and installation as well.

BTW, our bus was 4 years old when we got it. 2 years later Tiffin covered all the stuff mentioned in the previous blog about issues, plus other vendor part issues that they did not cause. The family name is on the bus. You will not get that kind of care from a bus manufacturer that is publicly held and led by an itinerant CEO. They have very short term, bonus oriented agendas where customer care is not a quantifiable metric.

Thank you for your response. I am unaware of a weight penalty, please elaborate.