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22 Posts
Discussion Starter · #1 · (Edited)
By performing a simple calculation, I've discovered that the 2014 Power Wagon, although with a more powerful engine, will still have less torque at the wheels compared to a '13 model or older. The reason it will have less torque is that it is losing torque multiplication from the 4.10 axle ratio. Even with the additional 29 torque at the engine, the 4.10 gears, just can't compare to the 4.56 gears. Below is theoretical calculation I've created based off the pickup's weight in tons, that demonstrates the max torque at the wheels per transmission gear ratio. **This calculation doesn't factor in mechanical slippage, wind, and other environmental factors.

Max torque at wheels per transmission gear= (transmission gear ratio)x(axle gear ratio)x(max engine torque)/(vehicle weight in lbs./2000)

Transmission gear ratios are 3, 1.67, 1.5, 1, 0.75, 0.67
Vehicle weight is 6350 lbs (approximately)
2013 and older max torque is 400
2014 max torque is 429
2013 and older axle gear ratio is 4.56
2014 axle gear ratio is 4.10

Here are the values per transmission gear for 2013 and older models, and 2014 models (expressed in torque at wheels per vehicle weight in tons)

2013 and older, 2014
1st 1723.46, 1661.95
2nd 959.4, 925.15
3rd 861.73, 830.98
4th 574.49, 553.98
5th 430.87, 415.49
6th 384.91, 371.17

You can see that the 2013 and older models actually have a higher maximum torque at the wheels than the 2014 models, just due to its higher (4.56) multiplier. I'm hoping the 6.4 L engine will have a flatter torque curve, thus possibly allowing more torque at slower engine RPM's. This calculation only demonstrates max torque. This is only a simple calculation, and if anybody has any additional formulas to add, let me know. I've compared many vehicles in Microsoft Excel using the above formula, and from what I've calculated, the 2014 Ram 1500 5.7 L (w/ 8 Speed) has very high torque per vehicle weight numbers. Here they are with a 3.92 axle ratio:
1st 2822.49
2nd 1881.66
3rd 1258.43
4th 1000.75
5th 773.04
6th 599.25
7th 503.37
8th 401.50

Those numbers would eat a Tundra alive ;)

22 Posts
Discussion Starter · #3 ·
Arth, haha yes! My predictions were correct! Note on my first post I didn't mention that there may be weight differences in the 2014's engine, rear end (11.5), and coiled rear springs (versus leaf springs) compared to the older models.

817 Posts
Man oh man. Back in the 70's, I used to swap rear gears in and out of my sports car as my racing days progressed (we had only 4 speed manuals then with 4th being 1:1). The 4.56 gears were dramatically tighter than the 4.11's. Actually, the 4.56's were only good for the track and could not be run on the street without winding the engine so tight, I became concerned of possible wear and heat issues. 4.11 was the tightest rear ratio I finally would run on the street.

If you are truly into monster towing, then just throw a new rear 4.56 gear set into your pumpkin and you''ll be pulling buildings off their foundations. Not too expensive at all.

But for sheer torque multiplication, you cannot beat 4.56 gears (with posi).

22 Posts
Discussion Starter · #5 ·
The numbers on my first post are slightly off.

Transmission gear ratios should be 3.23, 1.84, 1.41, 1, 0.816, 0.625 (66RFE) instead of
3, 1.67, 1.5, 1, 0.75, 0.67. I pulled them off of Wikipedia at the time, but I see there is now a correction.

Here are correct the values per transmission gear for 2013/2012 models, and 2014 models (expressed in torque at wheels per vehicle weight in tons)

2013/2012, 2014
1st 1855.60, 1791.91
2nd 1057.06, 1020.78
3rd 810.03, 782.23
4th 574.49, 554.77
5th 468.78 , 452.69
6th 359.06, 346.73
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