Diesel Horsepower Needs...seriously. - RV-Dreams Community Forum

DEWhit · RV-Dreams Family Member

Diesel Horsepower Needs...seriously.

TRAILERKING · RV-Dreams Family Member

DEWhit wrote:

I have been looking at and inspecting various used and new Class A RV models.
I have read remarks and heard several individuals in person express that they feel they need more horsepower.
I am in the class 8 truck transportation industry and have not heard or read any explanations for increased horsepower in standard manufactered RV units that really make any sense.
My experience has been that most all company truck drivers would like more power and torque and greater ranges in transmission choices and rear ends, but trying to explain the company policy of extracting 80% of the engines potential is the goal and also considering the regional demands of the equipment. It is usually met with an attitude of the company set equipment spec's being to the "cheap " side instead of based on maximizing the drivetrain. Fuel is never a consideration by company drivers.
Now, that being said, I am wondering why RV owners would make the same demand for more horsepower when it seems the actual time under mid to full power is not very significant. The mileages I am seeing on many of these coaches just do not seem to support the need for more power from a standpoint of usage. Most of them are not built for major mileage and spend more time idling or parked than under load.
To this point I have been silent and listening, but really do wonder if many of the RV owners really understand the needs of their rigs and seem more concerned with grade power and cruising speed than braking ability and mass stability. This is also an observation from an individual with a commute that is seeing more RV drivers engaged in some seriously bad control of some rigs that are not built for stability. Then there are those towing that are even more reckless than the first category.
My question is : Do you feel most owners you interact with actually understand the size and the build structure of what they are handling ? Do many owners actually get under their rigs or know the frame rail specs or cross member numbers ? It seems there is so much money wrapped up in these coaches with the owners not knowing what the creature comfort is riding on or really caring.

How many really feel they are underpowered to the point of being a safety hazard as they are not on a route schedule ?
I think some of the used RV equipment I am looking over may be in better shape than the understanding and operation of the people that own some of them.
There are other equipment issues I am hearing, but the horsepower remarks are adding up. No one speaks of their braking system much or suspensions.

-- Edited by DEWhit on Sunday 11th of May 2014 09:47:18 PM

Your right on some of that. I have my class 1A but there are so many that have very little knowledge and jump out of their mini-van and hop behind the wheel of an air brake equipped coach with not a clue.

I've witnessed on a few forums, individuals with lack of knowledge, operating air brake equipped vehicles. I'm not sure why they are not required to have training, knowledge, and proper endorsed drivers licenses to pilot such vehicles down the road?

BiggarView · RV-Dreams Family Member

DEwhit, as a relative newbie to vehicular operation of anything larger than a Siverado pickup... a couple of rented Class C's and a 20' Uhaul moving van, I/we are on the lookout for knowledge from the more experienced about such things before we hit the road full time. When we do, we may consider a larger class A DP or a 5er with one of the current iterations of dually 1 ton diesel pickups. We may look into an HDT as a tow vehicle alternative but not until we are both comfortable with the idea. Whatever we get, we both intend to take a course in driving safety and systems for such vehicles.

What, in your opinion, represents sufficient HP in a class A or an HDT in the case of a 5er? While I/we want to get up the hills as much as the next person, we recognize A) we are not in a hurry and more importantly B) we want to be able to safely stop such a large (relatively) setup. You say, there not much talk of braking and suspensions, what in your opinion are desireable features for such rigs either as standard or recommended upgrades?

I, for one, do not think we need gobs and gobs of HP(which could be a function of industry hype) but I also have no idea what a bare minimum needed to do the job is either. Safety will be a top focus in any rig we buy.

Brian

-- Edited by biggaRView on Monday 12th of May 2014 05:35:19 AM

-- Edited by biggaRView on Wednesday 14th of May 2014 04:49:46 AM

Lucky Mike · RV-Dreams Family Member

I think alot of the horsepower issue comes from those that have never experienced some of the larger mountain passes and exspect to climb them at 70 mph ....also coaches are getting larger and larger!

I have the same feelings as" Trailer-King".......as units grow in size and systems get more complicated operators are allowed to climb out of their little passenger vehicles into these machines without proper knowledge....yet if I go from my coach to a motorcycle it takes a special lic. and a road test confuse confuse ...

I think the problem is bigger / better syndrome!!!!!.....and way to much Tim Allen & Tool Time...Harr- Har !!

As stated in other posts across several forums.......the majority of crashes in RV's is operator error and not understanding the equipment they operate nor the safety & maintenance that comes with it as a whole.......IMHO

-- Edited by Lucky Mike on Monday 12th of May 2014 06:43:10 AM

BiggarView · RV-Dreams Family Member

Lucky Mike wrote:
I think alot of the horsepower issue comes from those that have never experienced some of the larger mountain passes and exspect to climb them at 70 mph ....

They must still be commute mode... rushing to get from campsite A to campsite B to "beat the traffic". It's the rush hour mentality, hard habit to break

Brian

WestWardHo · RV-Dreams Family Member

DEWhit,

Those are very good questions and I think it's great you addressed them. You'll find several on this forum who address build structure and frame rail specs such as Jack Mayer, Howard, Bill & Linda, &. Lucky Mike. They, in particular, emphasize safety and structure and caution. I'm sure there are a few others but those come to mind quickly.

Interesting, we, being novice RVers compared to so many, were in a shop recently with several new large MH owners. We were kind of stunned at how little a couple of them really understood and how they bragged about highway speed. When we asked about stopping they kind of just blinked at us.

We're having our suspension and brakes upgraded as we speak.

We find this forum the best at getting GOOD information and as Howard says, "Do your own research from more than one expert".

Sherry

The Bear II · RV-Dreams Family Member

As others have indicated...the need for speed. Unfortunately, these RV'ers want to stay at 70 MPH no matter the load or the grade.

I'm perfectly happy going up a 10% grade at 25MPH. It gives me a chance to feed the squirrels as they run alongside.

Lucky Mike · RV-Dreams Family Member

confuse I could never understand why it takes 500 horsepower under the hood , But only 1 jack-A wink wink behind the wheel to operate it !!.... biggrin

Barbaraok · RV-Dreams Family Member

A few states do require license endorements for those with heavier/bigger rigs. And a lot of fulltimers will purposely then choose South Dakota because they are afraid they can't pass the driving tests in their new rigs. Test requirements should be nation-wide.

Would you really want an ISB 275 hp trying to push 40,000 pounds up say Monarch pass? Do we need 500 hp, probably not, but it is often a sales pitch as much as anything else. After all, if you are spending $500K+ for a rig, you want the bigger engine option for that 45 ft motorhome pulling the 30 ft trailer with everything including the kitchen sink in it.

Barb

TRAILERKING · RV-Dreams Family Member

Barbaraok wrote:
.......... And a lot of fulltimers will purposely then choose South Dakota because they are afraid they can't pass the driving tests in their new rigs. Test requirements should be nation-wide.

Agree 110% there. Not foolin' anybody but yourself thinking you have the right to pilot the rig down the highway without knowing what you're up against. Look pretty neat when have a brake issue and mow somebody over......

Air brakes are air brakes and has nothing to do with only for CDL's. If it has them you better be trained and licensed no matter what place you drive or what you drive.

Bill and Linda · RV-Dreams Family Member

If I may comment on just a couple of things: Horsepower works both ways. It can give you more safety if you know how to use it wisely to control your rig; Class A MH or a 1-ton truck pulling a fiver. Some, not all, larger engines also have very effective exhaust brakes, including some pickups, not all, which are extremely effective in controlling and stopping a vehicle even out of the mountains. It saves brakes and keeps the rig “tight.” I personally really don’t care to tow without an effective exhaust / turbo brake if I can avoid it. I also know driving underpowered vehicles can be dangerous as you have fewer options. It depends. I’ve been there.

In my state you need a Class A, non-CDL license to operate a vehicle over 26,000lbs, RV or not. In some even a 5er above 16,000lbs GVW. The test required in my state, written and driving, is the same as the CDL but without the commercial regulations. Is it that hard? No, not all that hard. But you do have to learn a few things you really need to know; especially when operating some of our rigs that exceed 30,000lbs single or combined weight. That’s pretty big frankly. And some of those rigs have air brakes and they are not the same as your Ford Explorer.

My only point is that education and training are a good thing and sometimes taking a test will help you learn them. Like many things, lots of horsepower can be a problem or an asset. It depends on the skill and knowledge of the individual behind the wheel as to its proper application. If you don’t have the knowledge and skills there is training available. It is also important, as was noted above, to learn something about your equipment beyond just turning the ignition key to start the engine. It is very advisable to get it before you hurt yourself or someone you love.

My 2 cents

Lucky Mike · RV-Dreams Family Member

You do know that a BIG Air-horn or Train-horn Makes the trip down the hill alot easier!!!!

Of course Diesel isnt always necessary to get the rig down the road....I have a 454 with a banks system that loves to putt along and the V10 Triton s are nothing to laugh at either............and unless your planning on putting 250,000 miles on your coach you could probably save 20 to 30 k by looking into this ......

-- Edited by Lucky Mike on Tuesday 13th of May 2014 05:26:10 PM

DEWhit · RV-Dreams Family Member

The statement by Lucky Mike about the big air horn reminds me of an old grizzled veteran truck driver that told me there were two items needed in steep downhill grade descents while loaded that I needed to learn.

The first was a good light switch for night descents so the lights could be cut off briefly to ascertain wether or not another truck was climbing so both lanes could used by us descending around mountain bends.

The other item was the need for a good working air horn on descents.
I asked him if that was to alert other drivers if we came out of gear and the brakes were overheating and he said ,
" No , you need a good horn to drown out the screaming in here if we can't keep her slowed down getting off this mountain. "

I don't remember if I chuckled or not, but it made an impression.

I would render the advice that cooling temps and a transmission running high and hotter on a loaded descent are not such bad things as long as the brakes are still responding.

Jakes are a blessing and equipment saver if the drivers know how to limit their rpm's thru the transmission gear choice before applying the brake.

-- Edited by DEWhit on Tuesday 13th of May 2014 05:51:06 PM

MarkS · RV-Dreams Family Member

Please explain the difference between air brakes and hydraulic brakes.

TRAILERKING · RV-Dreams Family Member

http://digitalcollection.gov.mb.ca/awweb/pdfopener?smd=1&did=20528&md=1

All I can suggest is read and flip through this manual then most will begin to understand why there are "Air Brake Training Courses" and not really "Hydraulic Brake Training Courses".

-- Edited by TRAILERKING on Tuesday 13th of May 2014 10:23:38 PM

Sushidog · RV-Dreams Family Member

Torque is what is required to pull a heavy load, while HP, which is torque applied over a given period of time, determines the speed at which you can go.
Torque is determined by the engine, which generally produce diminishing levels of torque as the RPMs rise, limiting HP. Turbo's increase an engine's torque and extend the torque curve up the rpm scale, greatly increasing HP. Thus, turbocharged diesels have a flatter torque curve, giving you more usable torque without one of those fancy 8+ speed transmissions. The overall gear ratio also multiplies the available torque at the wheels. A higher numerical ratio, indicating lower gearing, is what you will need if choosing a smaller, less powerful engine. However, since your engine is turning a higher rpm at a given speed with this lower gearing (higher numerically), your fuel mileage will suffer.

I chose a Ford 6.4l (350 HP, 650 lb/ft TQ) with a 3.78 rear axle ratio to pull an 11,000 lb trailer. This should prove more than adequate, though there are many tuners available that allow more turbo boost to significantly increase the HP and TQ for this dual sequentially charged engine, should it prove necessary with only minimal effects on reliability unless you get crazy, adding hundreds of HP and TQ on top of the stock tune. Most turbo diesels will respond similarly to minor tweaks in tuning should you find yourself needing more power for a short time, such as cresting the next hill - just as long as you keep an eye on your exhaust gas temps and back off when they start to climb excessively.

If I were planning on a heavier load, I'd either go for a more powerful engine or lower gearing - possibly both, though many get by moving twice as much weight with far less power. They just do it slower, especially on steeper grades, which is OK too. It takes fuel to make power - no way around that small Phun Physic Phact. You wanna play, you gotta pay. If you watch the big truckers with a much poorer HP to weight ratios, they accelerate on the bottom of the downhills to make it up the next rather than trying to maintain a steady speed, conserving both momentum and fuel. This is a wise practice, as far as it is safe to do so. Coast more; spend less. They also use other tricks to conserve momentum, such as using their gears to stay in the sweet spot of their torque curve; as well as planning their accelerating and braking as far ahead as possible and traffic allows. They also use tricks to improve their aerodynamics - requiring less power at highway speeds too. All these tricks allow a lower powered engine to do more - if it is driven properly. So if you're a good driver, less HP is needed. Sorry, there's no simple answer to your question as there are many factors involved, not the least of which is your driving skills and preferences.

Chip