350 HP ICE vs. 350 HP Diesel?

hardtobe wrote:

RMIGHTY1 wrote:
OK, newbie here and aspiring RV'er. What comments can be made about the advantages/disadvantages of a 350 HP internal combustion engine vs. a 350 HP diesel engine in a class A camper (assuming all other variables are equal)?

the 350HP diesel will most likely be a Diesel pusher which is considerable heavier than a gasser therefore its hard to compare
as a 350 gas motor would not be viable in such a unit for many reasons
that being said though I personally would prefer the diesel(if there was such a motorhome made) because of the larger torque value because I drive the mountains all the time
and the diesel will pull loads up steep passes at way less RPM and stress.
Anyone whom says they don't need a exhaust brake or better yet a compression brake is not the brightest bulb in the room/
YES u can get away without one and be safe but why if u don't need to?
I can safely decenda "steep" pass at 50MPH wiith a engine brake.TRY that with your old DP and just air brakes!!!
Now every diesel pusher MH made of recent(2000) onward have them so people who don't have old old MH
I just don't see the point of the arguments here trying to compare 1/4 mile pickup drags to a 40 foot diesel pusher 4 slide mH with 350
and more HP because its just simply not the same worlds
Try and imagine a 38-39+++ 2-4 slide Diesel pushers units with a 410HP
dodge hemi engine running the unit.Its would be the sickest running MH out there and another thing the guy with the 502 A class MH towing 18000 lbs did not go up a 6% grade at 80MPH.that is so much BS its ridiculous(unless he hit the hill at 100MPH and it was short 6% grade)

I don't think he's running a stock 502. When he said he could pull 18,000 pounds up the grade, he did not mean his coach AND 18,000lbs, he meant combined.

zb39 wrote:

OhhWell wrote:

Daveinet wrote:
The reason no one looks at torque to weight ratios is because it doesn't tell you anything. Fact is, at one point in my life I could leg press over 1000 lbs. So hook me up to a bicycle peddle and let me power your RV.

For it to have any meaning at all, you have to factor in RPM. Any mount of torque can be achieved by gearing. In first gear, I'm putting over 12,000 ft-lbs off the line on my front axle and 6000 ft-lbs of torque once the TC couples fully. I shift out at 50 mph. Whats in your wallet?

I've said it and you've said it. Many others have said it on other threads in the past but some are just not going to get the simple fact that Torque can be multiplied through gearing. It's pretty pointless to keep saying it but what the heck right?

Look at the ISL and ISM engines from Cummins. The different power levels offered only differ in HP, the TQ rating stays the same. Now they obviously must be complete fools right since the torque rating is all that matters?

Oh, also... the Gas engine will start right up in single digit weather :p

ISM has more tq than ISL.

I'm sorry, I should have qualified that by saying within the same line. The different levels of ISL engines have different HP ratings but the same TQ and same for the ISL line.

OhhWell wrote:

Daveinet wrote:
The reason no one looks at torque to weight ratios is because it doesn't tell you anything. Fact is, at one point in my life I could leg press over 1000 lbs. So hook me up to a bicycle peddle and let me power your RV.

For it to have any meaning at all, you have to factor in RPM. Any mount of torque can be achieved by gearing. In first gear, I'm putting over 12,000 ft-lbs off the line on my front axle and 6000 ft-lbs of torque once the TC couples fully. I shift out at 50 mph. Whats in your wallet?

I've said it and you've said it. Many others have said it on other threads in the past but some are just not going to get the simple fact that Torque can be multiplied through gearing. It's pretty pointless to keep saying it but what the heck right?

Look at the ISL and ISM engines from Cummins. The different power levels offered only differ in HP, the TQ rating stays the same. Now they obviously must be complete fools right since the torque rating is all that matters?

Oh, also... the Gas engine will start right up in single digit weather :p

ISM has more tq than ISL.

rgatijnet1 wrote:
I appears that the consensus is that if everything is stacked in favor of the diesel engine, it will beat the gas engine. :B

You might be right. I can't figure out why those dumb manufacturers
keep putting in diesel engines. They must have not read this thread.

zb39 wrote:

rgatijnet1 wrote:

tempforce wrote:
one thing they forgot to mention above and in the test...
how long the engines will last and how much fuel each used to perform the test...

the diesel will usually last between 750,000 to 1 million miles before overhaul... the gas engine should last around 150,000 - 200,000 miles...
also the diesel engine will usually get 1/3 to double the mileage of the gas engine, with the same gearing/load ect.

Yep, I'm sure that Motor Trend could have modified the test so that the diesel performed better. Maybe change the gearing, load the gas coach more, etc. Since you brought up mileage, according to the test, the diesel got 18MPG max and the gas engine got 17mpg max. Not a huge difference, especially since diesel fuel costs more The OP asked for a comparison with all variables being equal. The Motor Trend test was pretty equal as to comparing the two different types of engines.

They tested pick ups not coaches. I have never run my coach in a 1/4 mile and never will.

I do on some on-ramps to busy highways.

zb39 wrote:

rgatijnet1 wrote:

tempforce wrote:
one thing they forgot to mention above and in the test...
how long the engines will last and how much fuel each used to perform the test...

the diesel will usually last between 750,000 to 1 million miles before overhaul... the gas engine should last around 150,000 - 200,000 miles...
also the diesel engine will usually get 1/3 to double the mileage of the gas engine, with the same gearing/load ect.

Yep, I'm sure that Motor Trend could have modified the test so that the diesel performed better. Maybe change the gearing, load the gas coach more, etc. Since you brought up mileage, according to the test, the diesel got 18MPG max and the gas engine got 17mpg max. Not a huge difference, especially since diesel fuel costs more The OP asked for a comparison with all variables being equal. The Motor Trend test was pretty equal as to comparing the two different types of engines.

They tested pick ups not coaches. I have never run my coach in a 1/4 mile and never will.

I start every trip with the first quarter mile. When leaving a stop light on an uphill incline, I am using maximum acceleration for the first quarter mile and then some. My gasser can handle it and I'll bet that your diesel can also. If you say that you have never held your foot down to the floor for even a quarter mile, at any time in your travels, I believe you.
My current coach will soon be topping 100,000 miles, as did most of my previous coaches, including the DP I previously owned. As I said in my first post, floor plan is more important than engine.

rgatijnet1 wrote:

tempforce wrote:
one thing they forgot to mention above and in the test...
how long the engines will last and how much fuel each used to perform the test...

the diesel will usually last between 750,000 to 1 million miles before overhaul... the gas engine should last around 150,000 - 200,000 miles...
also the diesel engine will usually get 1/3 to double the mileage of the gas engine, with the same gearing/load ect.

Yep, I'm sure that Motor Trend could have modified the test so that the diesel performed better. Maybe change the gearing, load the gas coach more, etc. Since you brought up mileage, according to the test, the diesel got 18MPG max and the gas engine got 17mpg max. Not a huge difference, especially since diesel fuel costs more The OP asked for a comparison with all variables being equal. The Motor Trend test was pretty equal as to comparing the two different types of engines.

They tested pick ups not coaches. I have never run my coach in a 1/4 mile and never will.

You sure as heck don't need a Jake brake. They are nice to have I imagine especially with all the extra weight of a DP. I still have to fight the urge to pump the brakes in a hard stop even though I have had ABS systems for years. Rgatijnet1 makes a darn good point about reliance on a system like that.

If someone has no idea how to downshift and pick a safe speed to descend a steep road, then they would benefit from an exhaust brake setup greatly. The newer F-53 chassis with tow/haul mode overcomes this as well by forcing a downshift when the brakes are hit. You can overheat your brakes on a passenger car on some grades if you don't downshift.

dubdub07 wrote:

wny_pat wrote:

rgatijnet1 wrote:

dubdub07 wrote:

rgatijnet1 wrote:

JetAonly wrote:
Now on to the next part of the discussion. How much "Brakeing" HP does a gas engine develop. You know the kind of HP that keeps you from using your brakes down hill?

Who cares? They put brakes on a vehicle for a purpose. I use them. Never had a problem on any Western mountain ranges. :R

For safety sake I am going to chime in. This is NOT a correct statement. If I used my brakes only without my exhaust brake I wouldn't have a MH anymore as it would have been impailed in the side of a mountain or off a cliff long ago. There are statements that should not be made in general and this is one of them. Sorry, just making sure that those that don't know better don't come to my beautiful state thinking that the brakes won't fail them because if you are not REAL careful, they will.

Bill

It was a correct statement when you consider that many of us, me included, DO NOT have an exhaust brake and learn how to safely drive the mountains without one.

Makes me wonder how I survived my last twenty years of my commercial driving, hauling petroleum products, in the hills of northwestern Pennsylvania without a jake brake or any type of engine brake. Only once did I have the brakes get to hot to stop and that was my fault!!! But did get it stopped without mishap. To hear some of the experts around here, I should have died in a trucking accident long ago.

Look at the quote! They put brakes on a vehicle for a purpose and I use them. If you throw that statement out there and are heading down the west side of Wolf Creed pass figuring your BRAKES ALONE are going to do the trick with heavy weight, you are sadly mistaken. Everyone is an expert I guess, everyone but me. I don't think absolute statements do anyone any good at all.......

Yes, LOOK at that statement. We go up and down mountains all of the time and do not have an exhaust brake to assist us. We also have found out through YEARS of driving that we DO NOT need an exhaust brake to safely navigate the mountain roads. I guess it all depends on your own abilities and if YOU need an exhaust brake, then good for you. I said that I have brakes and I use them. Obviously I, and thousands of other drivers, have used their brakes properly and make it down the mountains with a fully loaded RV safely. If you cannot do that, and MUST HAVE your exhaust brake, then maybe you need to take a course to educate you on how to descend a mountain without an exhaust brake. Some day your exhaust brake may fail, and from what you say, you will be in deep manure.

wny_pat wrote:

rgatijnet1 wrote:

dubdub07 wrote:

rgatijnet1 wrote:

JetAonly wrote:
Now on to the next part of the discussion. How much "Brakeing" HP does a gas engine develop. You know the kind of HP that keeps you from using your brakes down hill?

Who cares? They put brakes on a vehicle for a purpose. I use them. Never had a problem on any Western mountain ranges. :R

For safety sake I am going to chime in. This is NOT a correct statement. If I used my brakes only without my exhaust brake I wouldn't have a MH anymore as it would have been impailed in the side of a mountain or off a cliff long ago. There are statements that should not be made in general and this is one of them. Sorry, just making sure that those that don't know better don't come to my beautiful state thinking that the brakes won't fail them because if you are not REAL careful, they will.

Bill

It was a correct statement when you consider that many of us, me included, DO NOT have an exhaust brake and learn how to safely drive the mountains without one.

Makes me wonder how I survived my last twenty years of my commercial driving, hauling petroleum products, in the hills of northwestern Pennsylvania without a jake brake or any type of engine brake. Only once did I have the brakes get to hot to stop and that was my fault!!! But did get it stopped without mishap. To hear some of the experts around here, I should have died in a trucking accident long ago.

Look at the quote! They put brakes on a vehicle for a purpose and I use them. If you throw that statement out there and are heading down the west side of Wolf Creed pass figuring your BRAKES ALONE are going to do the trick with heavy weight, you are sadly mistaken. Everyone is an expert I guess, everyone but me. I don't think absolute statements do anyone any good at all.......and just because someone does it doen't mean it is safe. In Turkey they ride a family of 7 on a moped and yet it isn't illegal and few die because of it. Does that mean it is safe? I am done chiming in, just a precautionary statement. Use it, don't use it. But to try and prove my good intentions wrong is mean spirited.

AND on edit....the reason I said anything is the number of people I do stop and help with smoking brakes every year.....and none of them had Colorado plates.