Community Forums

**TonyDi** · 01-07-2017, 02:30 PM

To me, the engine in a motor home is like a TV. I've never heard anyone say "I should have bought a smaller one".

tropical36 · 01-07-2017, 02:36 PM

Quote:

Originally Posted by TonyDi

To me, the engine in a motor home is like a TV. I've never heard anyone say "I should have bought a smaller one".

Are there really that many choices for engines in most like coaches, as there weren't any in the year models that we had picked out.
Seriously though, I don't see the need for a larger one and have been pretty impressed, coming from an older gas coach.

Mr_D · 01-07-2017, 02:43 PM

Quote:

Originally Posted by tropical36

As said many times, about 10HP per foot, is considered more than adequate for most coaches, so anything above that, is gonna be better. On the used market and I'm always looking, I've not seen over 400HP in a 40ft coach, but I imagine they're out there in the new or newer models.

Newmar uses the ISL 450/1200 in their Dutch Star line.

tropical36 · 01-07-2017, 03:05 PM

Quote:

Originally Posted by Mr_D

Newmar uses the ISL 450/1200 in their Dutch Star line.

Well, again and since it's in all their coaches, regardless of length and weight, then the 43 ft models are going to feel inadequate by comparison to the 37 ft model with the same engine and even though 450HP is over the 10hp per foot rule for the entire selection. In fact the 37 should be a real rocket and qualify as king of the hill.

Kodiakan · 01-08-2017, 02:56 AM

No one has any concerns about the history of motors having higher failure rates at the top end of their HP spectrum? Its pretty much a given.
Just curious.

AndyE_ · 01-08-2017, 05:39 AM

I agree with Mr_D. I'm in an Entegra Anthem with the 450hp. I have a lead foot and do 72-75 when on the highway. The coach weighed in loaded and full water and fuel at 43k lbs. I average 7 mpg. A friend has the Cornerstone 600hp rig. He, at the same speeds gets 6.8-7.1 so effectively the same mpg. The difference is I'm doing 1950-2100 rpm at speed and he's doing 1700. Keep in mind, thermodynamically speaking, HP is HP on a Diesel engine and whether it's a 300 hp engine or a 600 hp engine it takes a certain amount of horsepower to push 43k lbs up a 6% grade. Caterpillar had a good write up on this. We do 52-55 mph up a 4-6 % grade towing a 4200 lb Jeep Wrangler 4dr. I'm ok with that. He has a Buick SUV and goes 65 up same grade, prob could go faster. For me I couldn't justify the 115k diff in price tag from Anthem to Cornerstone. We live in Alabama so believe it or not it's hilly here, up north. We have a 6% BIG grade to climb in Anniston AL area. If I start at the bottom around 60 or better I'm fine at 52 mph. There is a traffic light close to the bottom going up. If I hit a red light I can only do 45 going up. I've done that specific hill about 10 times now. It's about 3 miles then levels then climbs again for about 2 miles. One big thing is the ISX is 15 gallon oil changes. I considered a 2014 Cornerstone but ejected on a new 2017 Anthem because of the exact floor plan we wanted and the significant modern improvements. We're very happy.

BattleWagon · 01-08-2017, 08:35 AM

Andy, That is just the sort of real world performance numbers that is helpful for me to assertain the difference.

What of the modern features drove your decision toward the 2017?

BTW: I'm originally from Birmingham so I'm familiar with the long grades you are talking about. Roll certain team! (I'm new to Irv2 but extrapolating out the Irv2 rules to mean they don't want us talking religion, politics or ...... in Alabama ..... football! Lol)

Many thanks to everyone for such helpful comments!
Chip Battle

Agaveguy · 01-08-2017, 10:37 AM

We have a 40' with the 6.7 ISB, 360hp/800tq. The coach is right about 33k and tow an offroad car on a flat trailer, I think we're close to 37,500 when gassed up and full of water towing the trailer. We can go up any hill we wish to go up, just a push of the down arrow on the shift panel is all it takes to keep the engine in the power band.

Going down the highway at 65-68 mph the engine runs at 2000rpm, and gets near 10mpg. We definitely slow down to 35-40 for a 6% grade but the 6.7 always have enough power to get you to the top.

Diesels usually do not accelerate but rather gain momentum. Getting stuck in the rt lane behind a slower moving rig makes it near impossible to move to the left and pass. Sometimes that is unavoidable though. Diesels were engineered to run at 100% for many hours at a time but I like to keep on the conservative side most of the time.

Had we to do it over again, the 450 ISL would be the engine of choice. I wouldn't upgrade just for the engine though.

petrel · 01-08-2017, 11:59 AM

The more hp you have the more you "drive" in the mountains and the less you "slug it out." If I was in a hurry, I'd fly. However, it is still nice to see the mountains in the distance and just see them as another part of the drive, not an obstacle to overcome. No matter how patient you are, if your rig struggles in the mountains, it must diminish the experience. You can certainly grind it out in the right lane with the loaded semi's, with most any decent diesel setup, but it couldn't be much fun.

Of course, I've been watching videos about the 750hp Volvo and thinking about what a cool conversion it would make

Mr_D · 01-08-2017, 12:15 PM

Quote:

Originally Posted by Kodiakan

No one has any concerns about the history of motors having higher failure rates at the top end of their HP spectrum? Its pretty much a given.
Just curious.

The '07 EPA model of the 650 ISX like I have has a dismal record of failures due to design errors on Cummins part. I know of about 8 that have broken a valve in #6.
But, how many ISL failures were there do to the wrist pin problems? It took Cummins some years to admit it, and come out with an interim warning system. But now they have extended the warranty for the life of the rig to those in the affected range. You have to do some digging but there is a letter from the Cummins attorneys stating that.
Hopefully they will step up to the plate and do the same with the older ISX. The newer SOHC 2010 EPA models don't have the problem like the older DOHC ones do. Guess they learned their lesson from the older one!

slickest1 · 01-08-2017, 12:54 PM

Quote:

Originally Posted by Dutch Star Don

As usual, those with small motors defend on how well they work!!! I've got a 450 ISL in a 37K coach pulling another 5K. Does it climb grades, sure, so does a moped. I won't buy another coach at this weight unless they at least bump the engine to the small ISX. Tiffen is already doing it. The Allegro Bus, typically powered by an ISL is now being offered with an ISX.

People seem to think that just because they're willing to climb a grade at 30mph behind a garbage truck, everyone else is. Another issue is that many east coast people don't see the grades that the west coast RVers see several times in one trip.

Lastly, those little engines don't offer the braking power of the larger engines (exhaust brake versus engine brake). My 400ISL in a lightweight DP, (31K) was a rocket, but was a nightmare to manage on down hills with an exhaust brake.

Any before any of you even say it, going down a major grade at 35 mph is dangerous. Modern semis can now negotiate those down hill grades at 55-65 mph without issue. So some coach doing 35mph is a danger on the road.

These semis may go down these hills at that speed but if something happens in front of them they are not going to stop very fast.

I have driven trucks for years starting with 200 hp right up to 600 hp. Yes the ISX engine brake is phenomenal at holding back on a down hill but you still have to be able to stop in a safe distance.

Big power is nice to have but not everyone needs it or can afford it, so we will be the garbage trucks in your way on the hill. We will probably wave at you as you fly by!!

cruzbill · 01-08-2017, 01:17 PM

Was climbing Stevens Pass in Wa state this summer, 5-6% for miles. I was doing pretty well, doing about 50 mph and passing semi's, when out of nowhere, a new Newell (600 hp, my guess) flew by me....My foot wasn't in it as I let torque push me up the hill, and I drive 55-60 as its more comfortable for me at that speed. But more hp will win the race every time.
2005 Beaver Patriot Thunder, 525 hp Cat C-13.
Bill

SpaceNorman · 01-08-2017, 01:20 PM

When it comes to engine size - it really comes down to what options are available to you and what will fit your budget. Let's not kid ourselves - "This coach is simply way overpowered!" - said no one! Ever!

tropical36 · 01-08-2017, 01:34 PM

Quote:

Originally Posted by cruzbill

Was climbing Stevens Pass in Wa state this summer, 5-6% for miles. I was doing pretty well, doing about 50 mph and passing semi's, when out of nowhere, a new Newell (600 hp, my guess) flew by me....My foot wasn't in it as I let torque push me up the hill, and I drive 55-60 as its more comfortable for me at that speed. But more hp will win the race every time.
2005 Beaver Patriot Thunder, 525 hp Cat C-13.
Bill

Very, very difficult to be the king of every hill, if that might be your purpose.
Even this Newell owner probably bought it for other reasons, as well. As for affordability, we could have bought a late 90's Newell for the price we paid for our present coach, but felt that we did the best we could with balancing quality and newness to fit our budget.