6.0 Powerstroke vs. 5.9 Cummins

[D808]

I'm reading a Cummins publication from 1957 titled "Driving Cummins Diesels. " It says to "find the gear that gives you the right road speed at 10% to 15% below the governor. " Also, when ascending hills, it says to "always operate in a gear low enough to allow the engine to accelerate to, or maintain, governed RPM when you advance to full throttle. " I believe these rules will still apply to our new 2003's. I know that lugging is hard on all engines, especially Diesels. I believe that lugging is particularly detrimental to rod bearings in a Diesel. Perhaps someone out there can tell us exactly what type of damage lugging does to a Diesel engine.



Federal Man

 

[pkennedy]

The information you read is exactly right for a NT or NTC 855 CI engine until the big cam series came out ( 1980 ) at which time they started to play with widening the power band. The engine your reading about had a very shallow band 1800-2150 RPM and the big cam engines 1600- 2100. Big cam IV's were supposed to work from 1450-1800 on economy versions, our little B's will start to produce manifold pressure at about 1450-2500 with the problem of heat being generated at the low side pulling hard. One can compensate for this by watching his guages (pyro, manifold PSI and water temp) and adjusting foot on accelerator accordingly at diifernt RPM's (lower the RPM the quicker the heat comes up). Electronic engines stock will not do this as ECM controls the fuel rate,timing rate and monitors engine function at 10k pulses per second eg: holding foot to floor on 24 valve engine on hill at any RPM wont matter as will lugging it down. The performance will be less than tolerable and you will change RPM to suit. ON mechanical engines it is rule of thumb to maintain highest possible manifold PSI without smoke and high EGT's by backing off throttle as RPM drops and you will feel bottom of power band and shift gears. Hope this gives you a little help finding the right power bands. PK

 

[jimnance]

Exactly, Caterpillar was one of the first to push the peak torque down well below max governed RPM.



Drivers familiar the the old Detroit 2 stoke engines will tell you that they had to be wound up tight to pull a hill. Although the Cummins of it's time was a four stroke it also needed to be wound up though the governed speed of a Cummins was a couple hundred RPM below Detroit.



All these manufacturers found that one of the secrets to fuel economy was to make peak torque at a low RPM and drive them that way.



Interestingly, amongst the most efficient diesels are the slow speed variety found in ships. They produce thousands of horsepower yet only turn 40 to 60 RPM.

 

[Jeremiah]

Originally posted by federalman

I'm reading a Cummins publication from 1957 titled "Driving Cummins Diesels. " It says to "find the gear that gives you the right road speed at 10% to 15% below the governor. " Also, when ascending hills, it says to "always operate in a gear low enough to allow the engine to accelerate to, or maintain, governed RPM when you advance to full throttle. " I believe these rules will still apply to our new 2003's. I know that lugging is hard on all engines, especially Diesels. I believe that lugging is particularly detrimental to rod bearings in a Diesel. Perhaps someone out there can tell us exactly what type of damage lugging does to a Diesel engine.



Federal Man [/QUOTE



Does the publication tell us what "below the governor" means?

 

[jimnance]

In the older mechanical fuel pump systems a mechanical governor in the fuel pump controls max RPM. Depending on the engine it probably varied between 2100 RPM and 2500 RPM. To the best of my memory I thing the Detroits were around 2500 RPM (maybe higher) and the Cummins were around 2200 RPM. Again, it varied by model as well as manufacturer.



In the good 'OL days drivers would mechanically adjust rail pressures up to get more power. Depending on the pump and driver they would sometimes also jack up the RPM. Naturally, the trucking companies did not like this because it shortened engine life as well as lowered fuel economy.



The new electronic pumps make it harder for drivers to monkey with the pump. If they can find a friendly tech at a dealer they could probably get it turned up as all they do is flash new parameters into the system. However, I'm sure there is a maximum value that can be programmed in. Beyond that I'm sure the computer won't accept the code.

 

[Jeremiah]

Aha! That makes sense. As an old airplane pilot, I am familiar with red lines and know better than to exceed them regardless of where they are found. It's clear to me that the red line on the '03 tach could be exceeded easily either by down-shifting or running through it on the other end.

 

[jimnance]

What did 'ya fly? I'm a T210 Driver.

 

[bmaxey]

Skylane N97300

 

[jimnance]

My T210 SUV has 310HP and goes over 200 MPH and over 1,000 miles on one 90 gallon tank of gasoline.



How 'bout them numbers!



Bet you even a CTD can't make the run from L. A. to Portland in four hours and fifteen minutes.

 

[Jeremiah]

Flyin' low

I flew a 210 (non-turbocharged or pressurized) for a construction company, Beech Barons for a couple of oil companies, and - depending on need - a 310, Bonanza or Navajo Chieftain for the City of Shreveport. I also flew an old Twin Bonanza that was set up in tri-gear configuration. I loved the sound of that plane! It was the only plane I ever flew that had a geared prop, meaning the pilot retarded the rpms after takeoff before reducing manifold pressure.

 

[jimnance]

Very cool, I've a few hours of dual in twins, but never got the rating. Decided that for personal use a T210 is all I wanted to pay for. You understand about the jump to twins. Have to have the need and the $. Every so often I get the urge, but maintenance and insurance hold me back. The recurrency requirements for the T210 are bad enough, for any twins or pressurized aircraft you can pretty much count on having to go to Flight Safety annually. As it is I have to have an IPC every year.



Sorry guys, I promise to stop talking airplanes and start talking CTD.

 

[geusterman]

The Cummins 5. 9 is classified as Medium Heavy Duty diesel. Both the Duramax 6. 6 and Ford 6. 0 are classified as Light Duty diesels. Take your pick. George

 

[Jeremiah]

Originally posted by jimnance

Very cool, I've a few hours of dual in twins, but never got the rating.

Getting a multi- rating is the easiest of all ratings. All you have to do is demonstrate an ability to fly the thing on one engine. But flying a plane is also similar to running a diesel engine: If you do it right you monitor EGT, boost pressure, fuel flow, etc.

 

[jimnance]

Yeah, I know. In a weekend I could have the rating, but then I'd have to buy a twin... ... ... .

 

[agoldbach]

Getting back into the original topic of this post, Has anyone read part one of the Diesel Pickup Shootout on pickuptruck.com yet? You should really give credit where credit is due. The new Powerstroke smoked the Cummins when paired with equivalent manual transmissions. Dodge doesn't even offer an auto which will stand up to the Allison and TorqShift yet. The numbers don't lie. The Cummins may be a monster when spending thousands on aftermarket upgrades, but out of the box, bone stock, the Powerstroke ate it's lunch. This only adds to my discomfort levels about buying a CTD since reading all the postings from those who felt that their test drives were less than impressive. I want a Cummins, but it always seems to come out on bottom of any new comparison test. Can anyone offer me some substantiated words of encouragement to remain in the Dodge camp?

 

[geusterman]

agoldbach--how about mileage, longevity, reliability, price, resale, proven design. An HO with 6spd will last forever. Maybe you have some other needs that overshadow these values and so be it. I just love capitalism. George

 

[Badunit]

Might want to wait for the second half of the article when they pull a load up a hill. My guess is that the Cummins will rule in that test, at least in high gear. The others will need higher RPMs.



All we've seen so far is a drag racing test. I wonder if the hemi would have done better than any of the diesels tested in the drag races. I bet it would have but it still wouldn't make it the better engine for towing.

 

[Wiredawg]

Another 2 cents worth

Fellow Rammers



I posted early in this thread I'm a diehard Dogde/Cummins fan. Here's som more of my opinion after reading pages of repplies:



I don't really care about drag racing the trucks, loaded or unloaded. I care about longevity, dependability and ease of maintenance. I STILL vote for Dodge/Cummins.



After some of you go out and buy a Ford or Chevy, please do come back and let us know how you like your rides and how they are holding up. And please do come to our rallys and dyno with us. You and your friends will always be welcome.



Dodge forever!



Wiredawg

 

[Jeremiah]

Originally posted by agoldbach

Getting back into the original topic of this post, Has anyone read part one of the Diesel Pickup Shootout on pickuptruck.com yet? You should really give credit where credit is due. The new Powerstroke smoked the Cummins when paired with equivalent manual transmissions. Dodge doesn't even offer an auto which will stand up to the Allison and TorqShift yet. The numbers don't lie. The Cummins may be a monster when spending thousands on aftermarket upgrades, but out of the box, bone stock, the Powerstroke ate it's lunch. This only adds to my discomfort levels about buying a CTD since reading all the postings from those who felt that their test drives were less than impressive. I want a Cummins, but it always seems to come out on bottom of any new comparison test. Can anyone offer me some substantiated words of encouragement to remain in the Dodge camp?

I can try. How many days do we spend trying to out-smoke somebody else's truck? I'd rather put 100 Powersmokes against 100 Cummins engines and come back 400,000 miles later and see how many of each are still around. MY test drive went quite well and convinced me the CTD was the truck to buy. Of course, I didn't challenge any Powersmokes, but I wouldn't be doing that anyway.



How did I do?



Jeremiah Joiner

 

[D808]

If I race another truck, I start out in second gear. The 3. 73 axle ratio then gets me pretty far down the road before it's time to shift into third. Then, if I still loose, I just reminisce about the 1966 GTO 4-speed that I once owned. It would beat every Chevelle 396 that I took on! That Pontiac 389 was one heck of an engine!!!

Federal Man