Forum Discussion
ShinerBock wrote:
FishOnOne wrote:
No official links but my cousin mentioned that the service department has received several complaints on fuel economy on the '19 trucks are noticeably lower when either pulling or running empty. Also I spoke with a hot shotter who I know that handles a lot of our material handling between our sites reported lower fuel economy compared to his 4 gen. It maybe a bit too early but it sounds like something is going on.
Also as a reminder and that you said on this site one of the reasons the cummins makes better fuel economy vs the other 2 diesels is because of it's higher compression and that it makes the engine run more efficient.
Hmm. Again, I have been hearing the opposite. My BIL just got a new 2019 service truck that replaced his 2016. Same specs and all and he said his posted less fuel economy at first, but then started to climb to what his previews truck was getting after around the 2nd oil change. Lavon Miller and a few other stated roughly the same thing in their blogs. This is common for most engines until they are fully broken in.
I guess we will have to wait and see who is telling the truth when we get more records on Fuelly. So far, it is lower than the 2014-2018 Cummins trucks, but having a lower than previous years average is normal for most vehicles posted on fuelly until they start getting more miles recorded.
How could a lower compression engine make the same fuel economy?ib516 wrote:
ShinerBock wrote:
FishOnOne wrote:
This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.
Can you please post any links where you have been hearing these reports? I would love to read them because some new Cummins owners like Lavon Miller at Firepunk diesel has been doing video blogs about his new 2019 Cummins he just bought with dyno and others tests comparing it to his 2017 stating otherwise.
His stock 2019 Cummins rated at 400 hp/1000 tq made 392 hp and 896 tq at the wheels on the dyno. He says his 2016 truck (385 hp rating) made 342 hp at the wheels.
VIDEO results start at 8:52 in the linked video.
385 hp rated made 342 hp.
400 hp rated made 392 hp.
15 hp increase in rating but 50 more hp on the dyno? Is Ram sandbagging the numbers?
If this new cummins HP is understated then one can say that about the Duramax used in this test.ShinerBock wrote:
FishOnOne wrote:
This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.
Can you please post any links where you have been hearing these reports? I would love to read them because some new Cummins owners like Lavon Miller at Firepunk diesel has been doing video blogs about his new 2019 Cummins he just bought with dyno and others tests comparing it to his 2017 stating otherwise.
His stock 2019 Cummins rated at 400 hp/1000 tq made 392 hp and 896 tq at the wheels on the dyno. He says his 2016 truck (385 hp rating) made 342 hp at the wheels.
VIDEO results start at 8:52 in the linked video.
385 hp rated made 342 hp.
400 hp rated made 392 hp.
15 hp increase in rating but 50 more hp on the dyno? Is Ram sandbagging the numbers?FishOnOne wrote:
No official links but my cousin mentioned that the service department has received several complaints on fuel economy on the '19 trucks are noticeably lower when either pulling or running empty. Also I spoke with a hot shotter who I know that handles a lot of our material handling between our sites reported lower fuel economy compared to his 4 gen. It maybe a bit too early but it sounds like something is going on.
Also as a reminder and that you said on this site one of the reasons the cummins makes better fuel economy vs the other 2 diesels is because of it's higher compression and that it makes the engine run more efficient.
Hmm. Again, I have been hearing the opposite. My BIL just got a new 2019 service truck that replaced his 2016. Same specs and all and he said his posted less fuel economy at first, but then started to climb to what his previews truck was getting after around the 2nd oil change. Lavon Miller and a few other stated roughly the same thing in their blogs. This is common for most engines until they are fully broken in.
I guess we will have to wait and see who is telling the truth when we get more records on Fuelly. So far, it is lower than the 2014-2018 Cummins trucks, but having a lower than previous years average is normal for most vehicles posted on fuelly until they start getting more miles recorded.- Torque multiplication of the Ram Aisin 6-speed w/ 4.10
1st- 3.75 x 4.10 x 1,000 lb-ft= 11,275 lb-ft
2nd- 2.00 x 4.10 x 1,000 lb-ft= 8,200 lb-ft
3rd- 1.34 x 4.10 x 1,000 lb-ft= 5,494 lb-ft
4th- 1.00 x 4.10 x 1,000 lb-ft= 4,100 lb-ft
5th- .77 x 4.10 x 1,000 lb-ft= 3,157 lb-ft
6th- .63 x 4.10 x 1,000 lb-ft= 2.583 lb-ft
1-3rd are under-drive gears, 4th is direct, and 5-6 are overdrive.
Torque multiplication of the GM Allison 10-speed w/3.42
1st- 4.70 x 3.42 x 910= 14,627 lb-ft
2nd- 2.99 x 3.42 x 910= 9,305 lb-ft
3rd- 2.15 x 3.42 x 910= 6,691 lb-ft
4th- 1.80 x 3.42 x 910= 5,602 lb-ft
5th- 1.52 x 3.42 x 910= 4,731 lb-ft
6th- 1.28 x 3.42 x 910= 3,984 lb-ft
7th- 1.00 x 3.42 x 910= 3,112 lb-ft
8th- .85 x 3.42 x 910= 2,645 lb-ft
9th- .69 x 3.42 x 910= 2,147 lb-ft
10th- .64 x 3.42 x 910= 1,992 lb-ft
1-6 are under-drive, 7th is direct, and 8-10 are overdrive.
The Duramax was winning the torque to the wheels battle even with a 3.42 and it was also winning the horsepower battle according to the manufacturers ratings. ShinerBock wrote:
FishOnOne wrote:
This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.
Can you please post any links where you have been hearing these reports? I would love to read them because some new Cummins owners like Lavon Miller at Firepunk diesel has been doing video blogs about his new 2019 Cummins he just bought with dyno and others tests comparing it to his 2017 stating otherwise.
Also, reduced compression is likely due to the increase in fuel pressure coming from the CP4.
No official links but my cousin mentioned that the service department has received several complaints on fuel economy on the '19 trucks are noticeably lower when either pulling or running empty. Also I spoke with a hot shotter who I know that handles a lot of our material handling between our sites reported lower fuel economy compared to his 4 gen. It maybe a bit too early but it sounds like something is going on.
Also as a reminder and that you said on this site one of the reasons the cummins makes better fuel economy vs the other 2 diesels is because of it's higher compression and that it makes the engine run more efficient.Cummins12V98 wrote:
The 10 speed with lower combined load should have stomped the measly 6 speed with 6 tires dragging the road.
Same downhill braking. GM should have been better with lighter load and higher revving engine to give more braking HP.
Heavier combined load but better economy.
How many here still think the “BRANDED” 10 speed is the Savior???
The 10 speed just made up for the economy rear gear.
Guess all that extra drag from the dually and Rams AUTO MODE made up for the higher revving Braking HP.
Savior? No, but they did prove that the 10 speed made up for the 3:42 axle. Care to rerun that load with a SRW Ram with a 3:42 axle?
There are several things I don’t like about the new GM HD twins. Looks is the 1st, they are just ugly! 2nd I don’t like that Chain drive PTO. I don’t need a PTO and don’t want that chain. 3rd I would rather have the 3:73 gears (or 4:10) than the 3:42. I just don’t drive unloaded highway miles. If you do then it’s great, I don’t.
Just glad I have my 18.FishOnOne wrote:
This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.
Can you please post any links where you have been hearing these reports? I would love to read them because some new Cummins owners like Lavon Miller at Firepunk diesel has been doing video blogs about his new 2019 Cummins he just bought with dyno and others tests comparing it to his 2017 stating otherwise.
Also, reduced compression is likely due to the increase in fuel pressure coming from the CP4.Cummins12V98 wrote:
Too funny on these AISIN "SLOW SHIFTING" comments and the such. Not sure what it's supposed to do. Mine works flawlessly with ZERO dead pedal or shifting issues.
I suppose for the '19 trucks Aisin didn't make improvements to the shifting for no apparent reason.ShinerBock wrote:
RCMAN46 wrote:
Actually the Duramax reaches max torque (1600 rpm) at 200 rpm less than the Cummins (1800 rpm). Both engines produce max horsepower at the same 2800 rpm.
True, but the Cummins produces 90 lb-ft more torque at 1,800 rpm and more than likely produces the same amount of torque as the Duramax does at 1,600 rpm.
The other thing is that the Cummins is more of a natural torque at lower rpms while the Duramax is boost assisted torque at lower rpms. This does mean much in a wide open throttle situation where the short stroke Duramax shines, but at part throttle under normal driving conditions you can feel that Cummins has a lot more natural torque between 1,100 and 1,600 rpm without the need of the turbo spooling that much to make it.
If you have ever driven a Duramax(or Powerstroke) and a Cummins back to back then you will know what I mean. My Cummins(even stock) will just pull me up a long hill close to my house at 1,250 rpm at 60 mph the whole way up with little boost while my cousins tuned LML would build boost and then eventually downshift half way up to maintain 60 mph. My Father in laws new 2018 Powerstroke would do the same, but will hold 6th a little longer. This is probably why people say that the Cummins pulled like a train because it does so with little effort at low rpms versus many other diesels I have driven.
Not saying that it is a bad thing tat a Duramax has less natural torque, it is just a product of it's design and how these two engines drive different under normal driving conditions. Wide open throttle, the Duramax will win especially if the Cummins has a slow shifting Aisin behind it. The thing feels like it takes forever to shift under wide open throttle versus my 68RFE.
This conversation should be about the Duramax L5P and the current cummins with the CP4 and reduced compression. I'm hearing reports that the latest cummins is making less fuel mileage than the previous generation and maybe requiring more turbo boost now to make equivalent power.
As for performance of these two trucks they're overall performance is essentially the same. V8 or I6 doesn't matter with the end result.
