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Griz43 · 12-15-2017, 12:35 PM

Looking at 2018 Discovery XLE 38K with 6.7 Cummins Diesel. Specs say 800 ft lbs of torque. Will it have enough power to pull 2012 GMC Terrain over the mountain passes of Montana and Washington at 55 mph? Currently have a 2009 33 ft Winnebago Adventurer with Triton V-10 and I know it does NOT.

MisterT · 12-15-2017, 12:58 PM

the LXE is a beautiful model coach, and I've delivered a few to dealers. The ISB with 360hp will suit you fine, as it's the same rear engine design as the 44H tag axle version, though it has an ISL. The allison 3000mh is also a nice upgrade to many other similar length coaches.
I don't think you'll have any regrets, and no problems handling the mountains - but whether you can do it always at '55'mpg stands to reason - what you're towing(weight), your stuff(weight), and the weight of the onboard liquids, such as the water tank, diesel fuel, etc.

Bigd9 · 12-15-2017, 01:03 PM

Well, this is a hard question to answer. I've towed a Honda CR-V over some of those areas, but doing 55mph? I doubt it. But then I only have a Cat C7 330 hp w/ I think 860 ft-lbs of torque in my Discovery. I will say I normally can pass 18 wheelers if I really want to, but I normally don't. Looks like you would need to step up to the 40D to get the larger engine.

paddler1954 · 12-15-2017, 06:06 PM

You will running about the same speed as you did with the V10. The reason, the Discovery weights 10k lbs more than your old gasser.

brian-nicola · 12-18-2017, 06:57 PM

Don’t mean to be a spoiler, but why not look for a new 40e 2017? If pricepoint is an issue. Then you get all the power and tranny you want and yes 2’ makes a difference. Buy your last MH first.

Fiesta48 · 12-19-2017, 07:24 AM

Any engine can go up a mtn, hill at 55. It depends on how much gas/fuel you want to use. My prior V10s could do it if I want 2-3 mpg spinning like crazy. My DP will do it and get 4-5 at a more relaxed pace. Do I? Never. I usually crest at 35 (steep) to 45 moderate hills.

Happy Pat · 01-15-2018, 12:49 PM

So what do you think about the 340 HP in the new Pace Arrow? Looking very seriously at one and you have raised my curiosity...

Bigd9 · 01-15-2018, 03:27 PM

Well, for comparison the new 2019 Ford Mustang Bullitt has a Ripping 475-HP, 430 ft-lbs of torque pushing the light weight body to 165 mph! I'd get one but it only comes in two colors, neither of which I like very much.

The Cummins at 340-HP sounds kind of punny doesn't it?

To seriously answer the question, if it was me facing that choice I would thinh the 340HP would be OK. My present 330-HP Cat pushing roughly 26,000 pounds including the toad is plenty big enough for me. But, I'm retired and I'm never in a hurry any more.

tropical36 · 01-15-2018, 04:40 PM

Quote:

Originally Posted by Griz43

Looking at 2018 Discovery XLE 38K with 6.7 Cummins Diesel. Specs say 800 ft lbs of torque. Will it have enough power to pull 2012 GMC Terrain over the mountain passes of Montana and Washington at 55 mph? Currently have a 2009 33 ft Winnebago Adventurer with Triton V-10 and I know it does NOT.

Generally speaking, 10HP/foot is about right and one that translets into torque.
At 400HP and 1150ftlbs, speed control set at 57, we do pretty well over the terrain and seldom ever, out of 6th gear, but doubtful that we'll top over long 6% grades at 55mph in any gear, without manually pushing the limits. Doubtful that you will either, so being king of the mountain, is probably out of the question.

anav8or · 01-15-2018, 06:38 PM

The Discovery LXE models all have a Cummins ISL - the 44H has a 450hp variant, the rest are 380hp. We have a 2017 Discovery LXE 40G and the power is ample towing our Honda CR-V.

The non-LXE Discovery models have the ISB. Our previous coach, a Jayco Seneca, had the ISB (340hp variant) and I found it a bit under powered on hills.

Good luck with your search!

Clayobx · 01-16-2018, 05:07 AM

No.....but neither will my ISL 450 pulling my Ford Edge with all my “stuff” maxed out CCC. However, properly maintaining your rpm’s at 1900 to 2000K will get you their with no issues, just “not” 55!

Fiesta48 · 01-16-2018, 12:37 PM

If you want to know if a specific engine has more power than another do the weight to torque ratio.
Take gross weight and divide by the ft lbs. The one with the lower no. wins.
Gearing is a minor consideration since OEMs do a good job engineering this for every vehicle.

LBear · 01-25-2018, 10:08 AM

I have a 2015 38K expedition. 360 hp. And tow a Jeep. Probably 3500 Steep hills 45 mph. Coach fully loaded. 55 not a problem until you hit about 5 or 6% grade

V3600 · 01-25-2018, 10:36 AM

I deliver motorhomes as a part-time job. They are new, empty, and aren't towing anything. Most, to me, seem to be only adequately powered.

Recently I drove a Fleetwood Excursion that had the 300 HP ISB Cummins and it could hardly get out of its own way. The 340 HP ISB Pace Arrow seemed better powered.

Yesterday I drove a new Allegro Bus 45' OPP from Phoenix to Tucson. It has the standard 450 HP/1250 Torque ISL Cummins. I was cruising 65-75, due to traffic, and it seemed slow to accelerate from 65 to 75. Guess I was expecting more performance. Tiffin does offer an optional ISX15 605 HP/1950 Torque, which should offer better performance.