Diesel more sluggish than gas?

[Mostovi]

New to the site, so hello to everyone. Will be moving into the motor home world soon. I had pretty much settled on DP or large super C, but I've read several posts here where some folks said some diesels are actually more sluggish than gas. Contrary to all I've ever heard. Can those of you with more experience than myself please explain? Thanks!

[Executive45]

Our 40' Dynasty had a 300HP Cummins and I thought it to be underpowered. It was sluggish off the line and when trying to pass slow moving trucks. Like Mark said, once the speed falls off, it takes awhile to get it back to speed. The Exec has a chipped ISM which comes in at 525HP and it does make a big difference. Our coach weighs in at 49,500 pounds and while it won't give you a 'push you back in the seat' feel when you leave the light, it's much easier to get moving. The other thing to realize is pulling up large hills. The Eisenhower tunnel is at 12,000' elevation. Pulling up that grade, my coach rarely got out of fifth gear and I held it close to 55mph all the way. You'll find the diesels are much heavier coaches and will be easier and more fun to drive especially in high windy conditions. The tag and air suspensions are huge pluses...there's an old saying, "Don't drive a diesel unless you're ready to buy one"....Dennis

[MRUSA]

It is not just a matter of power. The big diesel pushers are upgraded in many other ways compared to their gas cousins. The big diesel pushers tend to have better suspensions, bigger fuel, water and waste tanks, and better amenities than the gassers. They ride and handle better as a result of the better long-wheelbase chassis that they are built upon, and tag axles on many of them. Bigger generators and more batteries with big inverters for generator-free operation of electronics without shore power. There is a lot more to consider than just the increase in pulling power.

[Mr_Mark1]

Our first coach had the 425 HP Cummins with 1,200 lb. ft. of torque weighing 40,039 lbs. The problem was not at start off but at passing on hills. I had no problem climbing the steepest hills, when I was not able to pass a very slow truck because of traffic, once my speed fell, it was hard to get it back to pass.

Our current coach has 1,750 lb. ft. of torque with 500 HP at 55,500 lbs. Even with the additional weight, I can pass a slow moving truck much better in this coach. As mentioned previously, torque is what moves the weight.

Safe travels,
MM.

[smlranger]

Mostovi wrote:

darsben1 wrote:
Rather than consider the original question I have one for you. What are your plans with the rig? Lots. of miles? Stay stationary? Some other answer. Then we might be able to guideyou to a good decision.

I appreciate all of the info. I will be retiring soon and we plan to hit the road, with extended stays wherever we want to be. We plan on doing significant traveling. I had read some threads with comments that gas actually pulled hills and mountains better than diesel, which is what prompted the question.

Based on your plan to hit the road and 'doing significant travel', I would want a diesel. This is especially true if you plan to travel in the western US and through the beautiful mountains.

That said, your focus should be on getting a floorplan that you can enjoy and meets your living needs.

A diesel pusher will also provide benefits in terms of ride comfort, handling, cargo and towing capacity. This may not always be true in some of the lowest cost entry level DP's, but will be the case in many situations.=

[wa8yxm]

Well most folks think HP HP HP (Horse power) And like TIM Taylor (TV Show: Home Improvement) MORE POWER.....

Actually it is torque that gets you moving,, HP keeps you moving.

Diesels generally have more torque at low RPM However a good transmission (Allison) can make up for it.

Now: Another thing is this, Torque is aq function of HP to some extent so if you have say a 450 HP engine, and the guy beside you has a nearly same weight but only 350 HP.. Yes. His will be sluggish, compasred to yours

But if you put a 425 HP Diesel against a 425 HP gas... Well I can't tell you who will finish the quarter mile first.

I can tell you the fastest RV in the USA is gas.. but it's not .. exactly.. Stock... It isd a vintage GM that has been er. slightly modified. You don't want to know the Horse Power rating (or perhaps you do) on that big engine.

[Dutch_12078]

Keep in mind you'll spend far more time living in your motorhome than you will driving it. Make sure you select a floor plan that you, and especially your wife, will be happy with even if the power plant isn't exactly the one you prefer. All of them will get you where you want to go, so make sure you'll be comfortable when you get there.

[Bruce_Brown]

Mostovi wrote:

darsben1 wrote:
Rather than consider the original question I have one for you. What are your plans with the rig? Lots. of miles? Stay stationary? Some other answer. Then we might be able to guideyou to a good decision.

I appreciate all of the info. I will be retiring soon and we plan to hit the road, with extended stays wherever we want to be. We plan on doing significant traveling. I had read some threads with comments that gas actually pulled hills and mountains better than diesel, which is what prompted the question.

We're on our 5th MH. The first 3 were gassers, the next 2 have been diesels. I don't see us owning another gasser - ever.

One thing I would caution, and this may be where your info came from, don't get a too small diesel. The number to look at with a diesel is torque. HP sells stuff, torque is what gets the job done. Bigger is always better.

For example, common Cummins engines are the ISB, ISC, ISL, and ISX.

10 years ago they offered an ISB that was 300HP, 600 # torque. They also offered the ISC as 300HP, 950# torque. With all else being equal which one do you think would be the better performer?

Our first diesel was 330HP, 720# torque and it did a wonderful job. Our current one is 400HP, 1200 # torque - it's a lot more fun to drive. :B

[gutfelt]

Mostovi wrote:

darsben1 wrote:
Rather than consider the original question I have one for you. What are your plans with the rig? Lots. of miles? Stay stationary? Some other answer. Then we might be able to guideyou to a good decision.

I appreciate all of the info. I will be retiring soon and we plan to hit the road, with extended stays wherever we want to be. We plan on doing significant traveling. I had read some threads with comments that gas actually pulled hills and mountains better than diesel, which is what prompted the question.

I would be interested in reading those threads; the thing is you have to keep in mind as I said earlier you can get away with a 340-60 HP gasser in a 20-25 K MH but once you get into MH with freightliner and Sparton chassis 3-4 slides 39++ft motor homes that weigh north of 30K there all going to be diesel powered and for good reasons as explained already
I have a 41 ft DP with a 425ISL loaded and pulling small toad iam well over 36K lbs I can pull mammoth mountain at 49-51 MPH
at its steepest and 8200 ft; I can guarantee you a 35-38 ft gasser 3 slide loaded and towing will be at 35 MPH on the same pull
we will both make it no doubt but if anyone was silly enough to put the gas engine in my unit ? well you can well imagine why they don't make such a animal

[Mostovi]

darsben1 wrote:
Rather than consider the original question I have one for you. What are your plans with the rig? Lots. of miles? Stay stationary? Some other answer. Then we might be able to guideyou to a good decision.

I appreciate all of the info. I will be retiring soon and we plan to hit the road, with extended stays wherever we want to be. We plan on doing significant traveling. I had read some threads with comments that gas actually pulled hills and mountains better than diesel, which is what prompted the question.

[Johno02]

When you start driving a motor home, you will be quick to find that it is not a sports car. You are driving a house, fully equipped with furniture, personal items, dishes, glasses, packaged foods, and liquids. Unless you have someone standing in the aisle to catch things, you will find that jack-rabbit starts and hard braking are not really smart things to do. And you will learn to allow plenty of room around your rig to prevent sudden changes or rapid movements. And all of that stuff really needs to be secured as much as possible. The same applies even more so to a trailer behind you.

[cruz-in]

"I would not worry about what fuel the motorhome uses or what powerplant it has from a performance standpoint."

Cold not disagree more...

[STBRetired]

I frequently travel with a friend who has a DP. My gasser is 38' and about 25K when loaded for travel, including toad. His DP is 38' and weighs about 31K when loaded for travel. I can beat him off the line and can out run him on the flat if I want to be stupid enough to run that fast. He easily out climbs me on hills and gets much better fuel mileage. I have a Ford V10, he has a CAT 360HP. We usually get where we are going at the same time.

I would not let "who can beat who in a drag race" weight very heavily in the purchase decision process.

[darsben1]

Rather than consider the original question I have one for you. What are your plans with the rig? Lots. of miles? Stay stationary? Some other answer. Then we might be able to guideyou to a good decision.

[Ivylog]

Once you go above 36' you need a diesel to get enough power. Put the same engine in a 32' MH and it will blow the doors off a gas rig if you start the race from 10 mph. The turbo on a diesel needs 2000+ RPMs before it makes a lot of power...making it sluggish off the line.

[mc_cc]

I drive a 2007 37 foot Super C diesel with a group that I sing with. I also own a 2016 newer 36 foot Class A gasser. The weight comparison of both rigs is close. Here is the difference. The Super C diesel gets about 10 miles per gallon of fuel where my gasser gets about 6-7. The Super C has more power on hills and takes them at lower RPMS. The only downside to the diesel is that it heats up more on the hills than my gasser. The gasser is louder because of it's requirement to downshift more frequently than the Super C. The diesel is not more sluggish. I would recommend the diesel if the cost is not prohibitive.