FishOnOne wrote:
ShinerBock wrote:
Travlingman wrote:
ShinerBock wrote:
FishOnOne wrote:
ShinerBock wrote:
Both engines can easily and reliably make well over factory power levels
I hear this statement from time to time but I have to ask why did Cummins change the internals to handle the 1,000 ft/lbs. I would have expected no internal changes if this were true.
What internals were changed? My Cuumins Quckserve shows the same internals. The main thing that changed was a CGI block to shave weight and a CP4 to increase fuel pressure to allow more power while meeting emissions. CGI blocked allows you to use less material due to it being a stronger material pound for pound so less can be used while having the same strength similar to how less "high strenght" material is being used in the frames.
The other reason for these changes may also be for future performance gains similar to how Cummins made to the 5.9L and 6.7L over the years by only changing engine tuning, fuel systems, heads, and turbo without changing any internals.
If it wasn't for these emissions requirements and future CAFE regulations coming to HD trucks that are bring mpg requirements to these truck classes. There are plenty of current 6.7L engines making well over 1,000 lb-ft with hundreds of thousands of miles on the clock.
Here are some changes according to their press release:
The new Cummins I6 is now 60 lbs lighter than before, according to Ram. A new cast-iron cylinder head includes new exhaust valves and springs, and new rocker arms. Pistons are redesigned and include new low-friction rings and connect to the crankshaft via newly design forged connecting rods and new bearings. An all-new exhaust manifold houses an improved variable-geometry turbocharger that can deliver up to 33 psi of boost pressure.
New Ram
I show the same part numbers on my Quickserve when comparing a 2016 engine serial number to a 2019 engine serial number on everything under the head(which is what is classified as internals) aside from the block. Any changes made was to reduce internal friction to decrease parasitic engine losses, not to increase strength to handle the added power.
As I told Roy in our other debate, the internals of the 6.7L can and has handled more than 1,000 lb-ft torque that the Ram puts out even in other stock applications. One example is the marine version of the 6.7L that shares the exact same internals and puts out 550 hp/1,250 lb-ft.
Also, the 6.7L computer controlled turbo has always been able to deliver up to 33 psi and can deliver even more, but the stock tune would not allow it to go that high.
According to Lead Engineer - Cummins Truck Engines quite a bit has changed to support the 1000ft/lbs upgrade:
1. CGI block
2. Stronger crank shaft
3. Stronger connecting rods
4. Stronger main bearing caps with larger bolts
5. Stronger flex plate
6. Larger piston wrist pin
Link
According to my Quickserve, the part numbers are to same which they will generally change part numbers if anything has been changed.
Also, the 2018 and below internals already handles well over 1,000 lb-ft(1,250 lb-ft to be exact) in other applications such as the marine version. The only difference between the marine QSB 6.7L and the on road ISB 6.7L is injectors, turbo, head, and the lack of EGR. All internals are the same as what is in the pick up truck version.
