4x4ord
Alberta
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^^^ You may have been happy with a 6 speed transmission but the shape of the 2015 Cummins torque curve was very similar to that of the Powerstroke ..... 250.lbft less but more or less parallel. Yours has a torque rise of 106 lbft over 1200 rpm. The torque rise of the 2021 HO Cummins is 287 lbft over 1000 rpm.
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4x4ord
Alberta
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Torque rise is often expressed as the percent rise in torque from the torque at rated engine speed (torque at rpm of peak hp) to that at maximum torque.
Expressed that way the Power Stroke and Duramax both have a 9% torque rise.
Me Again’s 2015 Cummins has a 15% torque rise.
The 2021 HO Cummins has a 36% torque rise.
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Grit dog
Black Diamond, WA
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......![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/scratchead.gif "scratchead")
"Yes Sir, Oct 10 1888, Those poor school children froze to death in their tracks. They did not even find them until Spring. Especially hard hit were the ones who had to trek uphill to school both ways, with no shoes." -Bert A.
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Me Again
Sunbird(Wa)/snowbird(Az)
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4x4ord wrote:^^^ You may have been happy with a 6 speed transmission but the shape of the 2015 Cummins torque curve was very similar to that of the Powerstroke ..... 250.lbft less but more or less parallel. Yours has a torque rise of 106 lbft over 1200 rpm. The torque rise of the 2021 HO Cummins is 287 lbft over 1000 rpm.
I hardly ever turn high RPM even towing a 24,500 combine on the Hilly West Coast.
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Cummins12V98
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Me Again wrote:Hum, I have known that for 5+ years now!
I have known this since September 2011 when I bought my first DRW.
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4x4ord
Alberta
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Grit dog wrote:......
Consider the torque rise as an engine resists a load. If a truck is pulling a heavy load up a hill you downshift and get your rpm up. As you start climbing, the hill causes the engine to slow. The Cummins has enough torque rise that it can pull down to about 2100 rpm in direct (4th) where it is putting about 1030 lbft of torque out the back of the transmission. After the shift the engine revs to 2800 rpm where the engine torque is only 788 lb ft. The 3rd gear ratio (1.33:1) increases that torque to 1048 lbft and the torque carries on rising as the engine continues to pull down in third gear. The Powerstroke, with its 10 speed would pull a hill the best running in the 2400 to 2900 rpm range.
It is interesting to view the rpm range where the different engines should run at looking at their HP graph. Here is a HP graph generated from the torque graphs that I posted earlier:
![[image]](https://i.imgur.com/Sgz7KQcl.png)
![[image]](https://i.imgur.com/tzljO6Xl.png)
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Grit dog
Black Diamond, WA
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^ I understand the concept and terminology. I'm simply confused as to what your point is.
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4x4ord
Alberta
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^^^ Maybe I'm just kind of rambling, I don't know. My point is simply that this 2021 Cummins has a higher percent torque rise than previous models and much higher percent torque rise than the competition. It really is tuned perfectly to be mated to the gear ratios of the Aisin transmission.
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spoon059
Just north of D.C.
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Grit dog wrote:^ I understand the concept and terminology. I'm simply confused as to what your point is.
So is he.
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4x4ord
Alberta
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spoon059 wrote:Grit dog wrote:^ I understand the concept and terminology. I'm simply confused as to what your point is.
So is he.
I didn't think I was confused but now I'm beginning to think I must be.![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/smile.gif "smile")
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