Attention: TDR Forum Junkies 
I read the post below with interest. I always find comparison tests and discussions interesting. This one forces me to offer my own opinion.
https://www.turbodieselregister.com/forums/showthread.php?t=160415
I don't dispute the accuracy or honesty of the test but would like to report my own experience.
About three months ago I was pulling a medium-sized fifth wheel from IN to to Washington State. I spent the night at a Flying J along I-80 at Lasalle, IL. When I left the following morning a woman transporter with a new Chevy-Duramax with the latest and highest power rating was following me. She was pulling a slightly smaller and slightly lighter conventional travel trailer. As we headed west all day I was in the lead and we talked on our CB radios. As we crossed western Iowa we encountered a series of rolling hills, some of them fairly steep. I was still driving my 2001 Ram with manual six speed and 3. 54 gears. My truck had over 300,000 miles on it at the time. The woman's new Chevy was equipped with six speed automatic and 3. 73 gears and smaller diameter tires which made her differential gearing more like 4:1 compared with my Dodge. Her new Chevy had the most powerful engine offered, rated at 660 ft. lbs. or torque, I think.
I was running along at about 62 mph in 6th gear with cruise control engaged. For the entire life of the truck I allowed it to pull steep grades in 6th gear. If EGT did not exceed 1350 degrees and engine rpm did not drop below 1600 rpm I let it pull. I know many consider this wrong or abuse but that was my driving style. I saw no damage. The truck still runs great and is now owned by family members.
As we pulled the grades on I-80 I would notice the Chevy falling off and the distance would open significantly as we started up the grades then would close somewhat as we climbed but never close the initial gap between the trucks. I called the woman driving the other truck on the CB and asked her what her engine rpm was. She didn't have a clue what I was talking about so I asked her to look at the big round gauge beside the speedometer and tell me what number the needle was pointed at.
What I learned was the big Chevy would start up the grades running about 1600 rpm as my truck was but couldn't hold speed. Her truck would struggle along for awhile opening the gap between us then the mighty 660 ft. lb. Isuzu would force a two gear downshift to 4th/direct, rev the engine to about 2200-2300 rpm, then it would slowly close the distance.
My opinion: First, the big Chevy-Duramax performs best in the sales brochures distributed in dealer showrooms. The engine may (I emphasize the maybe) produce 660 ft. lbs. of torque but not at 1600 rpm like a Cummins, it has to be revved like a V8 gasser. I think it probably puts less torque to the rear wheels than a Cummins. Second, the six speed Allison automatic is more GM hype. The truck (when loaded) will only run in overdrive on flat ground. When it starts up a grade it will force a downshift to 4th and buzz the engine.
I've had similar experiences with Fords. Many a time I've been loafing along down an interstate at around 60-65 mph in 6th gear with cruise control engaged, the tach showing around 1600-1800 rpm and looked in the mirrors to see a Ford closing. Then I start up a grade. For some unexplained reasons the Fords always disappear.
If the magazine testers could find a Dodge, Ford, and Chevy with their highest rated turbodiesel engines and each equipped with manual six speed transmissions and test them with similar loads under similar conditions I am convinced that the Cummins-powered Dodge will outpull each of them every time.
The Cummins is an inline 6 cylinder torque motor. It's strongest point is low rpm torque. V8 configurations, gasoline or diesel, don't produce a lot of torque at low rpm. They require higher rpm. Revving the engine to higher rpm burns more fuel and increased the rate of wear.
Stepping down off my soap box..... it is a personal choice. I was a Ford owner for many years but no longer. Ford Motor Company could get me to drive one if they provided it at their expense and agreed in writing to pay to have it towed in when it broke and pay me for lost wages while it was being repaired, but I wouldn't drive one on my money. Same with the Chevys. Honest transporters will tell you they have to replace the injectors every 30k miles and sometimes the failed injectors take out the entire engine.
Just my own personal anecdotal evidence and my own personal opinion.
Harvey
https://www.turbodieselregister.com/forums/showthread.php?t=160415
I don't dispute the accuracy or honesty of the test but would like to report my own experience.
About three months ago I was pulling a medium-sized fifth wheel from IN to to Washington State. I spent the night at a Flying J along I-80 at Lasalle, IL. When I left the following morning a woman transporter with a new Chevy-Duramax with the latest and highest power rating was following me. She was pulling a slightly smaller and slightly lighter conventional travel trailer. As we headed west all day I was in the lead and we talked on our CB radios. As we crossed western Iowa we encountered a series of rolling hills, some of them fairly steep. I was still driving my 2001 Ram with manual six speed and 3. 54 gears. My truck had over 300,000 miles on it at the time. The woman's new Chevy was equipped with six speed automatic and 3. 73 gears and smaller diameter tires which made her differential gearing more like 4:1 compared with my Dodge. Her new Chevy had the most powerful engine offered, rated at 660 ft. lbs. or torque, I think.
I was running along at about 62 mph in 6th gear with cruise control engaged. For the entire life of the truck I allowed it to pull steep grades in 6th gear. If EGT did not exceed 1350 degrees and engine rpm did not drop below 1600 rpm I let it pull. I know many consider this wrong or abuse but that was my driving style. I saw no damage. The truck still runs great and is now owned by family members.
As we pulled the grades on I-80 I would notice the Chevy falling off and the distance would open significantly as we started up the grades then would close somewhat as we climbed but never close the initial gap between the trucks. I called the woman driving the other truck on the CB and asked her what her engine rpm was. She didn't have a clue what I was talking about so I asked her to look at the big round gauge beside the speedometer and tell me what number the needle was pointed at.
What I learned was the big Chevy would start up the grades running about 1600 rpm as my truck was but couldn't hold speed. Her truck would struggle along for awhile opening the gap between us then the mighty 660 ft. lb. Isuzu would force a two gear downshift to 4th/direct, rev the engine to about 2200-2300 rpm, then it would slowly close the distance.
My opinion: First, the big Chevy-Duramax performs best in the sales brochures distributed in dealer showrooms. The engine may (I emphasize the maybe) produce 660 ft. lbs. of torque but not at 1600 rpm like a Cummins, it has to be revved like a V8 gasser. I think it probably puts less torque to the rear wheels than a Cummins. Second, the six speed Allison automatic is more GM hype. The truck (when loaded) will only run in overdrive on flat ground. When it starts up a grade it will force a downshift to 4th and buzz the engine.
I've had similar experiences with Fords. Many a time I've been loafing along down an interstate at around 60-65 mph in 6th gear with cruise control engaged, the tach showing around 1600-1800 rpm and looked in the mirrors to see a Ford closing. Then I start up a grade. For some unexplained reasons the Fords always disappear.
If the magazine testers could find a Dodge, Ford, and Chevy with their highest rated turbodiesel engines and each equipped with manual six speed transmissions and test them with similar loads under similar conditions I am convinced that the Cummins-powered Dodge will outpull each of them every time.
The Cummins is an inline 6 cylinder torque motor. It's strongest point is low rpm torque. V8 configurations, gasoline or diesel, don't produce a lot of torque at low rpm. They require higher rpm. Revving the engine to higher rpm burns more fuel and increased the rate of wear.
Stepping down off my soap box..... it is a personal choice. I was a Ford owner for many years but no longer. Ford Motor Company could get me to drive one if they provided it at their expense and agreed in writing to pay to have it towed in when it broke and pay me for lost wages while it was being repaired, but I wouldn't drive one on my money. Same with the Chevys. Honest transporters will tell you they have to replace the injectors every 30k miles and sometimes the failed injectors take out the entire engine.
Just my own personal anecdotal evidence and my own personal opinion.
Harvey
