Cummins vs. Powerstroke Connecting Rods
#46
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Since the most torque is required to start the load or keep the load moving on a steep incline, that is where the Cummins is superior because an I-6 has heavier engine components and more main bearings to withstand the stress while generating more torque. When starting a load the engine speed is at a low rpm, thus the stress on engine components from generating that stump pulling torque is excessive, because at low rpm there is no inertia built up in the flywheel. V8 engines need an automatic transmission's slippage to allow the engine to speed up and develope much inertia in the flywheel before applying the grunt to move the load. With more inertia in the flywheel there is less torque force on the engine componets which are lighter in a V8. The I-6 is just better designed for heavier pulling. The I-6 is better balanced also.
#47
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Greater inertia inherent in a higher mass reciprocating assembly retards the engine's rate of acceleration, or ease of revving... but provides much more energy to transmit through the powertrain to the drive wheels.
Don't forget to consider the effect of the energy pulse on each combustion stroke, which is why the V-8s typically make their power at comparatively higher RPMs.
Torque is the rotational energy transmitted to the crankshaft.
Horsepower is the rate at which torque is applied, or produced.
Don't forget to consider the effect of the energy pulse on each combustion stroke, which is why the V-8s typically make their power at comparatively higher RPMs.
Torque is the rotational energy transmitted to the crankshaft.
Horsepower is the rate at which torque is applied, or produced.
#48
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I-6 grunts at low rpm while V8 stalls out with max fuel.
Greater inertia inherent in a higher mass reciprocating assembly retards the engine's rate of acceleration, or ease of revving... but provides much more energy to transmit through the powertrain to the drive wheels.
Don't forget to consider the effect of the energy pulse on each combustion stroke, which is why the V-8s typically make their power at comparatively higher RPMs.
Torque is the rotational energy transmitted to the crankshaft.
Horsepower is the rate at which torque is applied, or produced.
Don't forget to consider the effect of the energy pulse on each combustion stroke, which is why the V-8s typically make their power at comparatively higher RPMs.
Torque is the rotational energy transmitted to the crankshaft.
Horsepower is the rate at which torque is applied, or produced.
If a V8 was fueled appropriately at lower rpms it could be made to produce higher torque at the same low rpm that peak torque is develped in an I-6. The reason the design engineers do not fuel a V8 in greater quanties at lower rpms is due to the fact that an excessive load resistance could result in damaged engine components that are lighter fabricated than those in an I-6. A V8 probably would stall out if loaded heavy at low rpm without an automatic transmission unless the clutch is slipped (burned).
Engine configuration dictates the maximum efficiency and torque from a given amount of fuel. The stroke in a V8 is not as much as in an I-6 resulting in a lower mechanical advantage, plus at slower engine speeds the rotational geometry of one cylinder bank slightly opposes that of the other cylinder bank during part of the crankshaft rotation and has more of a negative effect on power. V8 engines with a standard transmission do not produce enough torque to pull hard a low rpms as it could damage the light components. Lighter V8 components can rev faster than heavier I-6 components, so V8 engines are more suited to take advantage of the slip in an automatic transmission to rev to an engine speed that will not require the components to withstand as stressful a force in torque that and I-6 can withstand.
#50
I know I have the actual ad somewhere, but here are pics that I had and pasted them onto one .jpeg pic. Ford 5r110 input shaft is courtesy of Suncoast's website, the allison input shaft is a picture I took when I built mine, and the 48re input is from an ATS build on Pirate4x4.
Not looking to argue or anything, take it for what its worth, I just saw that people were looking for this.
Ill keep looking for the ad itself.....
ben
Not looking to argue or anything, take it for what its worth, I just saw that people were looking for this.
Ill keep looking for the ad itself.....
ben
#52
Registered User
No wonder you need a billet input shaft for boost launches in the Ram!
The 48RE looks like my pinky,
the 5R110 looks like my thumb,
and the LCT-1000 looks like... well, I don't have anything that big
Is the Allison a much larger tranny than the 48?
The 48RE looks like my pinky,
the 5R110 looks like my thumb,
and the LCT-1000 looks like... well, I don't have anything that big
Is the Allison a much larger tranny than the 48?
#53
ben
#55
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I know I have the actual ad somewhere, but here are pics that I had and pasted them onto one .jpeg pic. Ford 5r110 input shaft is courtesy of Suncoast's website, the allison input shaft is a picture I took when I built mine, and the 48re input is from an ATS build on Pirate4x4.
Not looking to argue or anything, take it for what its worth, I just saw that people were looking for this.
Ill keep looking for the ad itself.....
ben
Not looking to argue or anything, take it for what its worth, I just saw that people were looking for this.
Ill keep looking for the ad itself.....
ben
As for practical experience with the Allison, I had a 5-speed.
Pros:
Excellent shift management and engine braking in tow/haul mode
Easy to replace external spin-on filter
Cons:
Heavy
Power would not come on for a few seconds after shifting into gear
Power would be disrupted when going over bumps
Parking pawl was very clunky
In comparison, my experience with the 48RE:
Pros:
Smoother shifting
No pause when shifting into gear or going over bumps
Cons:
4-speed has wider gearing
Hunts for gears occasionally
No fluid pressure to TC in Park
All in all, I'd say that the 48RE is easier and better to drive around town, but the Allison was better for towing. Considering I do mostly unloaded driving, I'm fine with that.
#56
Thanks for posting that. Looks like the Allison's input shaft is about as over-engineered as the Cummins engine is.
As for practical experience with the Allison, I had a 5-speed.
Pros:
Excellent shift management and engine braking in tow/haul mode
Easy to replace external spin-on filter
Cons:
Heavy
Power would not come on for a few seconds after shifting into gear
Power would be disrupted when going over bumps
Parking pawl was very clunky
As for practical experience with the Allison, I had a 5-speed.
Pros:
Excellent shift management and engine braking in tow/haul mode
Easy to replace external spin-on filter
Cons:
Heavy
Power would not come on for a few seconds after shifting into gear
Power would be disrupted when going over bumps
Parking pawl was very clunky
TCM is really finicky and always making sure you arent trying to hurt the trans whenever you shift it, its annoying. I notice if Im going forward reverse forward quickly, like backing into a parking space, it will just kick itself in neutral because it thinks you are trying to go from reverse to drive while moving. Good thing I guess is that its not really possible for the driver to do something stupid...you can put it in reverse at 65mph on the highway.
speed bump thing is annoying, I think its the way the valve body is plumbed, to not let the trans completely "free wheel" in the lower gears.
parking pawl is very clunky, I hate when I back up into a parking space perfectly, then put it in park, and letoff hte brake only to have the truck "roll" forward or backward 2". Doesnt bother me that much tho I guess, the GM parking brakes SUCK so its good to know that there is a huge parking pawl holding the load there.
also, the grade braking is awesome but sometimes mine is retarded, just flat out doesnt work. Something to do with the complicated algorithm in the TCM?? It downshifts at the correct time maybe 80% of the time.
more ally parts with size references next to them.
ben
#59
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The 6.0 is IH's VT365 which is used in their medium duty trucks.
http://www.internationaldelivers.com...t365detail.asp
http://www.internationaldelivers.com...t365detail.asp