Community Forums

cageyone · 11-16-2008, 06:17 AM

Iam looking at a 40' RV with a 330 horsepower Cummings. Is this enough power for this RV? I see some have a 360 H.P. Which to me is relative. Probably the same torque. I am new at RVing and would like some input from someone who has drove a 330 or 400 or 450?

Thank You for your time.

Carol

cageyone · 11-16-2008, 06:17 AM

Iam looking at a 40' RV with a 330 horsepower Cummings. Is this enough power for this RV? I see some have a 360 H.P. Which to me is relative. Probably the same torque. I am new at RVing and would like some input from someone who has drove a 330 or 400 or 450?

Thank You for your time.

Carol

BigSkyBob · 11-16-2008, 07:45 AM

Depends on the coach weight. The generally accepted rule of thumb is 1 HP per 100 lbs of coach weight. Personally I wouldn't accept less.

Jestme13 · 11-16-2008, 07:57 AM

Carol, a good running coach usually has a rule of thumb Horsepower formula of, 10HP per foot of coach, (40 ft = 400HP) the absolute mininum, 350HP. There is nothing worse then an underpowered coach as they are also safty hazards in my opinion. HP is costly with diesel engines, but in the long run it pays off in spades with driving comfort and safety.
Good luck

Glen41 · 11-16-2008, 08:34 AM

If you line up two identical RVs with the two different diesels and stomp on it, I would bet you could not tell the diffference. Unless the HP just happened to be measured at the same RPM with the same rear end gear ratios in identical transmissions. Add to that HP figures are often figments of the sales department's imagination and you get the idea. See if you can drive them both and then decide.
Give me the choice between hp and torque and I'll take torque every time.

GaryKD · 11-16-2008, 10:41 AM

Hi Carol,
Welcome to iRV2. My signature tells you what I have. I am pleased with the coach being able to move when I want it to, cruise all day in the hot summer, climb the Rocky Mtns and after 44K miles get an average of 8.4 MPG.

All other things being equal, it is the weight of what you are moving down the road that makes the difference. Like previously posted, drive the coach and determine what meets your requirements.

cageyone · 11-16-2008, 03:39 PM

Gary

Thanks for your response. I see you have a 39'10" DP. The one Iam looking at is 40'10". One foot should not make much of a difference. It has the same engine yours has, same torque also. GVWR is 33,000. What Iam looking at is a 2006 Monaco Knight.

Georgia Flash · 11-17-2008, 04:43 AM

Amen to GARYKD. I have had no problems with 330 hp Cummins in my Bus.

GaryKD · 11-17-2008, 05:38 AM

The weight mentioned in my signature is the actual weight. The coach travel weight is a little over 29K. The toad is a little over 5K. The GVWR for the coach is 34K and the GVWR for the toad is 6.2K. The coach combined GVWR is 44K.

From this you can see the coach travel weight is about 5K below its' GVWR. The toad is about 1K below its' GVWR. The combination is about 10K below the CGVWR. I would not say we travel light. We take what we need. We do have storage that has never been used.

A few observations after 44K miles.
1. The engine temp never moves off about 180 degrees, unless climbing mountains. It has risen to 210 degrees on long mountain climbs.

2. I manually downshift the transmission, when climbing to keep the RPM around 2K. This means my uphill speed is whatever 2K delivers in the gear that keeps the engine temp around 210 degrees.

3. Fuel mileage is solid as a rock, when measured over several thousand miles. It started around 7.2 MPG and has risen to 7.4 MPG at 40K miles. I travel the Interstate highways at 60 MPH. This seems to be the sweet spot for MPG. At 40K miles I started adding Stanadyne Performance Formula to the fuel. It adds about 10 cents per gallon to the cost of fuel. The MPG has jumped to 8.4 MPG. I have 4K miles using Stanadyne. I'm going to use it all next year to see if the good results continue.

I am meticulous about drive train maintenance. Fluids and filters all get changed according to the mfgs schedule.

digNbubbs · 11-18-2008, 07:58 AM

I have an '06 40' Knight with the 330 ISC. I have found that I have wanted more horsepower a couple times a year - when going over the Rockies and going over the Sierras. Typically, my bottom speed going over the Rockies is 40mph-ish, which isn't so bad. Sierras about the same. I did go over a pass in Utah that slowed me way down, but I think it was a 10% incline on a two-lane road, so I didn't have much in the momentum department to help

I bought the coach new and have burned 2935.9 gallons of diesel for an MPG of ~7.63. We pull a 4-door Wrangler now, 2-door last year.

I don't think I would take anything less than the 1hp/100lbs, and the Knight GVW is 33k lbs, which puts it right at the limit. I run pretty full (fulltimer), and really have no complaints. It has decent acceleration on the onramps, and does fine in the hills.

I love my Knight - the floorplan is what pushed us to the Knight, and we have been extremely happy with it. I have found that we are parked way more than we are driving, so I think the floorplan has been the most important aspect of this rig. However, I always look forward to getting on the road. She is a pleasure to drive

--kevin

cb5300 · 11-18-2008, 10:56 AM

Alway remember you can never have to much horse power or torque.

Moder2 · 11-18-2008, 11:05 AM

I have a cat 330 in my 40 foot winnie.

Sure, I'd love more HP, do I need it... No. It pulls fine, and I am 29k plus a 7k toad.

Yes, when I get in the mountains, I gotta hold it back a bit, but there is really plenty of power, I need to downshift to keep the fan moving air through the stupid rear radiator...

In all honestly, my friend has a 400 cummins in almost identical coach, maybe a bit heavier, but not much, and I would much rather have my almost 8mpg than his barely 6 mpg...

And there are a lot of Big trucks on the road that don't even have 330, and they are all licensed to haul 80k gross. When I started driving It was with an old wore out cummins with a million+ miles, it was rated at 230hp and I am sure it didn't have that anymore... I got by.

John

cb5300 · 11-20-2008, 06:22 AM

May be...but I went from a 400 cummins in a 2007 Dynasty to a 600 cummins in my 2008 Signature and the difference is day and night. I set the cruise at 70 (or whatever the speed limit is) and off we go. I don't slow up the flow of cars when I'm going up mountains and it's a more enjoyable trip (at least for me). The mileage is only slightly lower with the 600.