blt2ski
Kirkland, Wa
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Fortunately, I90 at snocrummy is a pretty mile pass, along with low at 3000'.......
But as one former poster liked to point out. The army must not agree with some of you, as they took out the 2000/4000 diesel motors, and put 2000/400 rated turbine motors in the Abrams tanks, they BOTH go just as fast, with the tubines doing a bit faster IIRC.
At the end, the turbin always at 10 or 20K r's, pushing/running a hydraulic system, was better than a higher torque motor pushing a set of gears, reving up and down etc as one shifted. The drive traain behind the motor will also effect the how good a particular engine is. BUT< at the end of the day, 350 hp is 350 hp, both motors be them 350 at 2000 rpm or 350 at 20,000 rpm, if both have the drive train to get the max to the ground, both should be going the same speed with the same wt etc. The issue with trucks, reality is, gas and diesel are not really setup to compare equally. BUT, if one is willing to run a gas motor at 4000 rpm, with 350 hp behind it, vs a diesel at 2000 with 350 hp......you should be able to be going the same speed. Like a lot of things, it may not happen with current teck drivetrains in twucks!
marty
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rhagfo
Portland, OR
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hutchman wrote:Uhhhhhh, 350 HP at 1800 rpm is the same as 350 hp at 4,000 rpm..........
It's 350 hp.
And just so you know, I used to drive tankers over Snoqualie Pass in WA State loaded at 105,500# with a 350 Cummins. 350 hp will get the job done.
Yea 350 HP is 350 HP, but how much torque were you producing with the 350HP????
This is where the real difference between Gas and Diesel comes out!
My Cummins with the DS Power Puck produces about 285 HP, but 610 ft. lbs. of torque, with a 360 cu in engine.
I can move my 12K 5er at 55 up 5 to 6 percent grades with 3.55 gears, try that with a gasser, at any RPM of the same HP!
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hutchman
Kennewick, WA
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It's really pretty simple....
HP = Torque X engine rpm/5252
It doesn't matter whether it's a diesel or a gasser.
Diesels make lots of torque at low engine rpm and therefore more low end HP than a gasser does. Gassers don't make as much low end torque and rely on engine rpm for producing HP. However, 1 HP = 550 ft-lbs/sec......
You might want to ask yourself where peak HP is generated in your diesel if rpm doesn't mean much?
I'm sure the discussion will never cease...
2012 Ram 3500 CCLB dually, auto, Max Tow, 4.10s
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Hannibal
Tampa Bay Area
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400 ft/lbs of torque applied at 4000 rpm through 2:1 gearing = 800 ft/lbs output and 300~hp at 4000rpm.
800 ft/lbs of torque applied at 2000 rpm through 1:1 gearing = 800 ft/lbs output and 300~hp at 2000rpm.
345 hp 365 ft/lbs will out tow 250 hp 460 ft/lbs any day of the week. It works on paper and I proved it with two Rams identical except for the engines and transmissions towing a 10, 040 lb 5th wheel.
Diesels are stronger. Not necessarily faster. Diesels make better heavy tow rig engines for several reasons. Higher horsepower at lower rpm is the most attractive to rpmaphobes. If you're scared of 4k rpm, then the diesel is for you.
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OhhWell
Florida
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Madhatter1 wrote:Hannibal wrote:You need to put it into perspective. A 350 hp tractor engine running at it's peak hp rpm of 1800~ is at it's peak hp rpm. A 350 hp SB gas V8 in a pickup truck running 1800 rpm is almost 4k rpm under it's peak hp rpm and is likely making less than 120 hp.
If you think those 350HP enines are equal for moving a big load you are way off. The tractor is over 1000 lbs torque at 1800 and the gas is at 300 lbs at 4K (using your example numbers). Another BIG factor is the tractor is makeing big HP numbers at lower RPM's and the peak torque is going to be much higher than 1K. You guys are doing a dis-service to posters looking for info on gas vs Diesel. Even if us Diesel guys post they are not as fuel efficient, as reliable, or as cost effective as they used to be the gas fans still neeed to say "mine can pull the same load through gearing". Might be able to do the job (which is an inportant fact for those that need a truck more for a daily driver than towing) but a low RPM Diesel has a big advantage pulling a load. Get off your high horse and talk facts to help out posters looking for some real world info. I drive a 4X4 3500 Dually Diesel but can recognize that is not what everyone else needs. I pull a 14.5K to 15K trailer all over. Off road a lot. Still not gonna tell someone who pulls the same load 100 miles to a paved campground they need the rig I went with. And you "engineer math guys" need to drive a truck with a load on it. Your calc's do not work out in the real world. If they did a pair of 260HP 350CI gas engines could equal the 260HP Cummins 360CI in my boat. They would never be expected by any marine designer to even get the boat to plane off. What??? I thought HP was HP. 350 HP at 1800 RPM in a whole different animal than 350HP at 4K or 5K. Flame away.
They have been talking facts, and proven science backed up with math. If it werent for things like math and science and engineers, you wouldn't have your truck to begin with.
I have seat of the pants experience with high horse power and high torque engines in light duty vehicles. I love the feeling of a high torque motor and agree, it does have that "seat of the pants" benefit.
Still, max output power (Horsepower) is just that. It's the most you have. If you are powering down the highway or up a mountain, you are now in the realm of horsepower. That's why they make larger horespower OTR truck engines for more demanding applications. If two engines of any kind were in two identical trucks going up the same infinite uninterupted incline pulling the same load, whichever one had more horsespower would eventually go faster.
This even works comparing two diesel engines. The one with more horsepower will be capable of a higher top speed not matter the torque.
I've posted this quote before and I will post it here again:
From Diesel Power Mag:
http://www.dieselpowermag.com/features/1111dp_king_of_the_hill_rematch/viewall.html
"
The first time we put the 800-lb-ft Ram into gear, the extra torque felt obvious. We found ourselves checking to see if the transfer case was in low range. Yet when we got up to highway speeds, a few things became clear. The first was that even though the Ram matches the Ford (and beats the GMC) in torque production, towing this much weight at highway speeds is a test of horsepower—not torque. The Ram showed its 50hp deficiency attempting to keep up with the Power Stroke and Duramax everywhere we went."
I know no one wants to listen to some silly "Math engineer guys" on a forum but something tells me the people at that publication kinda know what they are talking about.
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OhhWell
Florida
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hutchman wrote:It's really pretty simple....
HP = Torque X engine rpm/5252
It doesn't matter whether it's a diesel or a gasser.
Diesels make lots of torque at low engine rpm and therefore more low end HP than a gasser does. Gassers don't make as much low end torque and rely on engine rpm for producing HP. However, 1 HP = 550 ft-lbs/sec......
You might want to ask yourself where peak HP is generated in your diesel if rpm doesn't mean much?
I'm sure the discussion will never cease...
Nope, it wont cease but that's good because it is a fun distraction at times and is pretty well kept in this monster thread.
You bring up a good point. Alot of the diesel fanatics claim that since they are able to pull their heavy rigs at highway speeds around 2,000 rpm easily, they therefore have power to spare. Well, that may not be true. A high torque number means that you are putting out your engine's max horsepower at lower rpms. Depending on your power curve, you may not really have all that much left.
Another interesing thing is the current push for horsepower in modern diesel engines. I think this is great as it truley makes the modern diesel engine all around better power wise for towing. Who really needs more than ~400 horespower for towing a RV? The interesting thing however is that Fuel Efficency is dropping. This is part due to emmissions crippling "features" but also because (except for increases in engine efficiency) more power takes more fuel.
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Ram4Sam
Redlands, Calif
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Hannibal wrote:400 ft/lbs of torque applied at 4000 rpm through 2:1 gearing = 800 ft/lbs output and 300~hp at 4000rpm.
800 ft/lbs of torque applied at 2000 rpm through 1:1 gearing = 800 ft/lbs output and 300~hp at 2000rpm.
345 hp 365 ft/lbs will out tow 250 hp 460 ft/lbs any day of the week. It works on paper and I proved it with two Rams identical except for the engines and transmissions towing a 10, 040 lb 5th wheel.
Diesels are stronger. Not necessarily faster. Diesels make better heavy tow rig engines for several reasons. Higher horsepower at lower rpm is the most attractive to rpmaphobes. If you're scared of 4k rpm, then the diesel is for you.
It was never the screaming gas engine that scared me, it was the single digit 6 and 7 miles per gallon mpg's when towing......now that is scary!
Sam
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OhhWell
Florida
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Madhatter1 wrote:Hannibal wrote:You need to put it into perspective. A 350 hp tractor engine running at it's peak hp rpm of 1800~ is at it's peak hp rpm. A 350 hp SB gas V8 in a pickup truck running 1800 rpm is almost 4k rpm under it's peak hp rpm and is likely making less than 120 hp.
If you think those 350HP enines are equal for moving a big load you are way off. The tractor is over 1000 lbs torque at 1800 and the gas is at 300 lbs at 4K (using your example numbers). Another BIG factor is the tractor is makeing big HP numbers at lower RPM's and the peak torque is going to be much higher than 1K. You guys are doing a dis-service to posters looking for info on gas vs Diesel. Even if us Diesel guys post they are not as fuel efficient, as reliable, or as cost effective as they used to be the gas fans still neeed to say "mine can pull the same load through gearing". Might be able to do the job (which is an inportant fact for those that need a truck more for a daily driver than towing) but a low RPM Diesel has a big advantage pulling a load. Get off your high horse and talk facts to help out posters looking for some real world info. I drive a 4X4 3500 Dually Diesel but can recognize that is not what everyone else needs. I pull a 14.5K to 15K trailer all over. Off road a lot. Still not gonna tell someone who pulls the same load 100 miles to a paved campground they need the rig I went with. And you "engineer math guys" need to drive a truck with a load on it. Your calc's do not work out in the real world. If they did a pair of 260HP 350CI gas engines could equal the 260HP Cummins 360CI in my boat. They would never be expected by any marine designer to even get the boat to plane off. What??? I thought HP was HP. 350 HP at 1800 RPM in a whole different animal than 350HP at 4K or 5K. Flame away.
Opps, sorry. Missed that part. Despite bringing a boat to a truck fight, I will address this. A high torque engine in a boat amkes a much better direct drive powerplant than a low torque engine obviously. That's why gas inboard engines often have transmisions. No way a low torque gas engine is going to turn a large prop easily at low RPM. That's what a high torque rating is for.
Big heavy boats and big heavy trucks are well served by high torque slow turning diesel engines. If you want speed, that's more the realm of gas and horsepower, especially in boats.
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OhhWell
Florida
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Ram4Sam wrote:Hannibal wrote:400 ft/lbs of torque applied at 4000 rpm through 2:1 gearing = 800 ft/lbs output and 300~hp at 4000rpm.
800 ft/lbs of torque applied at 2000 rpm through 1:1 gearing = 800 ft/lbs output and 300~hp at 2000rpm.
345 hp 365 ft/lbs will out tow 250 hp 460 ft/lbs any day of the week. It works on paper and I proved it with two Rams identical except for the engines and transmissions towing a 10, 040 lb 5th wheel.
Diesels are stronger. Not necessarily faster. Diesels make better heavy tow rig engines for several reasons. Higher horsepower at lower rpm is the most attractive to rpmaphobes. If you're scared of 4k rpm, then the diesel is for you.
It was never the screaming gas engine that scared me, it was the single digit 6 and 7 miles per gallon mpg's when towing......now that is scary!
Sam
hahaha, yeah. That's for sure. Watching my gas guage hit 1/4 tank out in the middle of nowhere on the interstate pulling with a gasser is pretty scary too. It also sucks pulling into a truck stop and not being able to use those nice huge diesel pump lanes. Looking over at the Clusterf**k that is the gas lanes is scary with a large TT.
Shoot, good thing your old 12 valve is reliable. The new diesels are not too good on gas from the testimonials we are hearing. Power is awsome though.
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hutchman
Kennewick, WA
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I have about 5000 miles on my new Dodge and it is averaging about 12.5 mpg. That is mostly in a suburban area with mixed highway and city driving. My old 6 liter gasser averaged about 13 in the same mix. The Dodge gets about 10 towing and the gasser got about 8.5 over the same route with the same trailer....
The real difference is that I did not run the gasser at 4500 rpm up the hill for two reasons:
1. The fuel mileage decreased dramatically trying to maintain 60 on the hills.
2. I did not like the engine running at 4500.
Watching how fast I ran the gasser up the hills while towing made it easier to live with in my opinion. The new Dodge is easier to drive while getting better economy towing. Balancing my desire for a new truck, the fact that I do like the Cummins engine, and the fact that it tows my trailer at a lower engine rpm over the mountians, make it a good choice for me.
When you add in the additional cost of the new Dodge over a 5 year old Chevy gasser though, it makes the decision tougher. With the added emissions junk on these new diesels, I do not think the decision is as clear cut as it used to be. They burn more fuel and have more systems that will need repair and maintenance over the years.
The newer gas engines are a viable alternative when towing light to moderate loads. I think there is no question that a diesel wins as the loads get heavier though.
At least that is my humble opinion...
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