Community Forums

efstewart · 05-31-2019, 07:22 AM

We are looking at a 2010 Dutch Star model 4010, for sale that we like. It has the 360 HP Cummins engine. On our former Dutch Star, model 3817, we had a Cummins 400 Hp, and we had plenty of power pulling our toads up and down mountains.

I know that this one has a little lower Torque, and I am wondering if anyone has the 360 and can share their experiences and opinion.

twogypsies · 05-31-2019, 02:12 PM

We were in the BIG mountains out West all the time with our 370 Cummins. So what if you go up a little slower? Enjoy the scenery on the way.

tom chelbana · 05-31-2019, 05:59 PM

There are 6.7 B engines and 8.9 L series engines that have 360 HP. The difference is the torque for each engine because that is what gets you up the mountain. You need more information then just HP. If the engine is the 6.7 B engine you will be going up the mountains here in the west maybe 25 MPH. You don't need the X15 605 HP with 1950 ft. pounds of torque like a LA, but at least 1000 would be nice.
Newmar Man

jbikes1 · 05-31-2019, 07:21 PM

I came from F250 with the 6.7 diesel pulling the 5th wheel which was plenty of pulling power but the coach is about 6 ton heavier. I agree that the 6.7 engine with about 800 pounds torq would be way under powered.

I have the larger engine that will develop 1050 pounds. I just don't push it that hard. I try to keep it about around 800 - 900 pounds max torq going up passes at no slower that 45 mph. I know I could go faster but now that I'm retired, I just don't care that much about how fast I run up the hill. I was worried about the power weight ratio when looking at it but am satisfied. Pulling a Jeep I am at about 31000 pounds. Don't know what your pulling or the weight of the 4010.

docj · 05-31-2019, 07:35 PM

Quote:

Originally Posted by tom chelbana

There are 6.7 B engines and 8.9 L series engines that have 360 HP. The difference is the torque for each engine because that is what gets you up the mountain.

With all due respect, it's horsepower that governs the speed you can maintain when going up a hill. Horsepower is energy delivered to a load in a unit of time.

Torque is the rotational analog of force and it governs how quickly you can change the rotational speed of your driveshaft, in other words, how quickly you can accelerate, particularly when trying to accelerate up a hill.

Diesel engines can be tuned to develop different amounts of HP, but torque is pretty much a function of the engine size. So the 6.7L ISB engine has ~800 ft lbs of torque whereas an engine twice that size (IMX, C-12, etc) will have roughly twice the torque.

tom chelbana · 05-31-2019, 08:33 PM

If pulling a step grade with a 40K pound load I would be much more prefer to have 400 HP and 1650 lbs. of torque then 500 HP and 1100 lbs. of torque. Love the new X 15 with 1950 lbs. of torque.
Newmar Man

docj · 05-31-2019, 09:34 PM

Quote:

Originally Posted by tom chelbana

If pulling a step grade with a 40K pound load I would be much more prefer to have 400 HP and 1650 lbs. of torque then 500 HP and 1100 lbs. of torque.

As long as no one gets in your way and forces you to slow down, the larger HP MH will climb the hill at a faster pace every time. That's simply physics.

The real-world issue is that if someone gets in your way and you have to slow down and lose momentum the extra torque will make it easier to accelerate while continuing to climb that hill. Greater torque translates into faster acceleration.

jbikes1 · 06-01-2019, 05:00 AM

I know your point about horse power. I didn't clear state my point that I have experience with the 6.7 which was a great pickup engine at 400 hp and did well pulling 20,000 pounds but I dont think nearly as well with 31,000. I know there are coaches running that smaller engine, I didnt want one and therefore wasnt recommending one. I would take 360/1050 over 400/800 every day of the week. I know the magic ratio of 100 hp per 1000 pounds of weight and seems to work 'OK' with my setup at GVW of about 31000 pounds. It seems like a marketing song and would prefer a ratio of 125 or 150 to 1000. But people tend to be satisfied with what they have. That said, it seems the small engine gives better MPG than the bigger one.... unless people lie about MGP which never happens.

This is my opinion and my experience. Everyone's is different.

Quote:

Originally Posted by docj

With all due respect, it's horsepower that governs the speed you can maintain when going up a hill. Horsepower is energy delivered to a load in a unit of time.

Torque is the rotational analog of force and it governs how quickly you can change the rotational speed of your driveshaft, in other words, how quickly you can accelerate, particularly when trying to accelerate up a hill.

Diesel engines can be tuned to develop different amounts of HP, but torque is pretty much a function of the engine size. So the 6.7L ISB engine has ~800 ft lbs of torque whereas an engine twice that size (IMX, C-12, etc) will have roughly twice the torque.

docj · 06-01-2019, 05:51 AM

Quote:

Originally Posted by jbikes1

I would take 360/1050 over 400/800 every day of the week.

So would I!

I basically agree with everything you said and I often try to make the same points on this forum. I own a MH with 425/1550 and love it! I was simply correcting the physics of the issue.

tom chelbana · 06-01-2019, 10:32 AM

When we talk about HP in motor homes/trucks we need to include torque. When motor homes get to 31K plus weight it should have either the C or even better a L series engine with a 1000 plus pounds of torque minimum. The B series engine is great for 34 ft. coach's but not 40 ft.
Newmar Man