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Mystery · 12-24-2012, 03:44 PM

Is there an optimum power to weight ratio or torque to weight ratio for obtaining best mpg performance or acceleration? I have a 2002 Dutchstar 3852 with a 330 cat 3126E. My average mpg over 68,000 miles is 7.4. I do run genny a great deal of the time when driving and drive in NC mountains quit a bit. Seems as weight of coach goes up so does engine size. So does an Essex with 500hp and 1650 torque perform better than my coach? I am not comparing options or luxury. I imagine the Essex would drive and ride better and be much more comfortable. Love to hear some experienced opinions since I am new to rving and this is my first coach.

Mekanic · 12-24-2012, 03:58 PM

Horsepower - aero drag = top speed
Torque -weight = Acceleration (and hillclimbing)
Also proper Gearing is a factor for both

Mr_D · 12-24-2012, 04:02 PM

The only two Dutch Stars I've really had a chance to compare were our 2000 with FL chassis and 3126 and our present 2002 with Spartan chassis an ISC 350/1050 (now 435/1200).
The stock 350 had more torque, 1050 vs 860 and it was noticeable in the mountains on the west coast.
Usually more is better and there usually isn't much, if any mileage penalty as the bigger engine is working less and at lower rpms.
They usually say 100#'s per HP. We weigh 32,000#'s and have 435 hp, thsi puts us ahead of that and it does show in performance.

Also remember that HP is calculated from torque and rpm, nothing more. It's actually a fictitious figure dreamed up to show how much work a steam engine could do in relation to a horse to sell the newfangled steam engines. It favors higher rpm engines.

Mystery · 12-24-2012, 04:07 PM

Mr D did you raise hp and torque to your stock 350 ? Or do you have different coach? I am sure my kitty is maxed out.

Mystery · 12-24-2012, 04:10 PM

My 3852 at Newmar scale was 25,500 in 2007 full of all fluids and has carrying capacity of about 5000 lbs so I sb about right with 330. Right?

Mr_D · 12-26-2012, 09:04 PM

Quote:

Originally Posted by Mystery

Mr D did you raise hp and torque to your stock 350 ? Or do you have different coach? I am sure my kitty is maxed out.

MH info is in my sig. We have the ISC 350 and I put a Banks kit on it. But the real gain is not in the peak HP/torque change, it's in the much wider power range. The stock engine has 1050 ft lbs at only it's peak of 1400 rpm, the modified engine never gets that low till 2100 rpm. Even at it's lowest rated rpm of 1200 rpm it's about 1100 ft lbs.

Mystery · 01-02-2013, 07:38 PM

Mr D. Thank you very much for the input. We are new to rving and love it. We have a houseboat at 68 ft long and tell our dock mates that this is a houseboat that can go to different lakes. A couple of buddies commented on mpg and I had to laugh. BC the houseboats are measured at gallons per mile. Lol

Mr_D · 01-02-2013, 07:45 PM

Quote:

Originally Posted by Mystery

Mr D. Thank you very much for the input. We are new to rving and love it. We have a houseboat at 68 ft long and tell our dock mates that this is a houseboat that can go to different lakes. A couple of buddies commented on mpg and I had to laugh. BC the houseboats are measured at gallons per mile. Lol

Sold the boat well and boat along with the "hole in the water" at the yacht club and dropped that membership too. Just didn't use it enough and cruising up and down the Columbia River got old.