transamz9
Lawrenceburg Ky
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Hannibal wrote:The Cummins 5.9 and 6.7L are rated for 3400 and 3300 rpm in marine applications. Cringe doesn't cause excessive engine wear. Strange how people brag about how tough their diesels are yet they believe running them in their normal operating rpm range will hurt them.
Who's saying it will hurt them? There is just no need in it now days. They make so much power down low there is very few times they have to be run in the higher RPM range.
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Hannibal
Tampa Bay Area
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transamz9 wrote:
Who's saying it will hurt them? There is just no need in it now days. They make so much power down low there is very few times they have to be run in the higher RPM range.
There is if you need the additional horsepower (rear wheel torque) to get the job done in the time you desire to do it (miles per hour).
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transamz9
Lawrenceburg Ky
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Hannibal wrote:transamz9 wrote:
Who's saying it will hurt them? There is just no need in it now days. They make so much power down low there is very few times they have to be run in the higher RPM range.
There is if you need the additional horsepower (rear wheel torque) to get the job done in the time you desire to do it (miles per hour).
The job gets done at 2000 RPM or lower and on occasion short burst of 2500. I've never "had to" go over 2500 rpm to hold a respectable speed and I tow over my listed GCVWR and well beyond the GCVWR of a comparable hp gas truck.
Like I've said before, 2000 rpm is going to be half the wear of 4000 rpm. If you say that today's engines have 0 wear at 4000 rpm then I am getting negative wear at 2000 rpm.
Take a gas truck with 325 hp and hook a high profile 18,000# load to it and take it up and down the road for 100,000 miles holding the posted speed 95% of the time and tell me how she's doin' after the 100,000 miles. Then try it with 25,000#.
I know that most RVers don't pull that kind of weight but this thread is gas verses diesel, right?
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rhagfo
Portland, OR
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transamz9 wrote:Hannibal wrote:transamz9 wrote:
Who's saying it will hurt them? There is just no need in it now days. They make so much power down low there is very few times they have to be run in the higher RPM range.
There is if you need the additional horsepower (rear wheel torque) to get the job done in the time you desire to do it (miles per hour).
The job gets done at 2000 RPM or lower and on occasion short burst of 2500. I've never "had to" go over 2500 rpm to hold a respectable speed and I tow over my listed GCVWR and well beyond the GCVWR of a comparable hp gas truck.
Like I've said before, 2000 rpm is going to be half the wear of 4000 rpm. If you say that today's engines have 0 wear at 4000 rpm then I am getting negative wear at 2000 rpm.
Take a gas truck with 325 hp and hook a high profile 18,000# load to it and take it up and down the road for 100,000 miles holding the posted speed 95% of the time and tell me how she's doin' after the 100,000 miles. Then try it with 25,000#.
I know that most RVers don't pull that kind of weight but this thread is gas verses diesel, right?
LOL!
Getting on the freeway with my five speed, I may wind the Cummins up to 3,000, but towing and pulling hills at speed (55 to 60 on state highways) most of the time not over about 2,300 rpm in 4th (direct drive) with 3.55's moving 19,000#+ with less than 270 hp! Do that with a gaser!
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Bedlam
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I've owned both the Powerstroke and the Cummins. Those of you used to the I6 diesel definitely run at lower RPM's (I'm still getting used to mine). Now, I am running 1500-2000 RPM while cruising and 2250-2750 RPM when passing on a grade. When I had a V8, the diesel was making peak torque at 2000 RPM and peak horsepower at 3300 RPM. I used to run 1750-2250 RPM while cruising and 2750-3250 RPM when passing on a grade.
I would guess that there is half the friction surface in a diesel than gasoline engine due to the lower revolutions, but you are operating at twice the pressures which causes wear elsewhere.
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Hannibal
Tampa Bay Area
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transamz9 wrote:Hannibal wrote:transamz9 wrote:
Who's saying it will hurt them? There is just no need in it now days. They make so much power down low there is very few times they have to be run in the higher RPM range.
There is if you need the additional horsepower (rear wheel torque) to get the job done in the time you desire to do it (miles per hour).
The job gets done at 2000 RPM or lower and on occasion short burst of 2500. I've never "had to" go over 2500 rpm to hold a respectable speed and I tow over my listed GCVWR and well beyond the GCVWR of a comparable hp gas truck.
Like I've said before, 2000 rpm is going to be half the wear of 4000 rpm. If you say that today's engines have 0 wear at 4000 rpm then I am getting negative wear at 2000 rpm.
Take a gas truck with 325 hp and hook a high profile 18,000# load to it and take it up and down the road for 100,000 miles holding the posted speed 95% of the time and tell me how she's doin' after the 100,000 miles. Then try it with 25,000#.
I know that most RVers don't pull that kind of weight but this thread is gas verses diesel, right?
Since the little Cummins makes peak torque at 1600rpm, why do you gear it to run 2000rpm and 2500rpm on the grades? Why not gear it to run 1600rpm no matter the load?
Where did I say 4000rpm produces zero wear? Quote please.
Sure! We'll pull a grade at 2000rpm. Then let's do it again at 5k rpm and see which engine survives. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
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64thunderbolt
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the fight continues I see. Buy what you want & drive it like you stole it. LOL
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RUFFSTUFF
Kingsland, GA
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All I know is my Powerstroke on a Hot Damn Tow tune pulls my trailer nicely. A Gasser wouldn't even be an option for me... that would just be stupid.
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trcgolf
western NY
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so a 2006 6.0 Ford Turbo Diesel should be avoided?
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AlanAdams
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My choice is Diesel
1. More Torque
2. Pulls more ( Rig is 18k )
3. Truck maintains more value on trade
4. Getting a Ram 3500 since it has a In-Line 6 vs V-8 ( Like all new OTR trucks )
All the above is IMO
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