Ford HP & Torque


If you study the performance curves you will see two major benefits of GearSplitting; increased horsepower and multiplied torque. As an example, we’ll use the E40D/4R100 trans chart with a 4.10 rear and both the 7.3DI Diesel and Fords new high rev V-10. For the diesel engine the ability to keep the engine in a narrower band is even more important than the gasoline powerplants because of the lower rpm range where power is made. Gaining a 4.92 multiplier plus the ability to drop only 500rpm on-shift instead of a thousand makes a dramatic difference. Notice if you rev to 3400rpm (way above the power) in 2nd and then shift to 3rd your engine speed drops to 2210 rpm. With the GEAR VENDORS you can rev to just 2650 with great hp and torque and a 20% greater torque multiplier in 2nd-over and drop to only 2200rpm onshift to 3rd.

As an example, with the new High Rev V-10 since gears are multipliers of torque at 4000 rpm in 2nd-over the torque multiplier is 4.92 where without the GEAR VENDORS you would get into 3300rpm in 3rd-direct at 4.10. The difference in engine torque is only 10lb ft. but the difference in the multiplier is 4.92 vs 4.10. That’s 20% more working torque (net). At this same moment horsepower at 4,000rpm is 300 instead of 250 @ 3300 which is 20% more horsepower with all the reliability of your stock powerplant.

To figure the drop in rpm or torque multiplier from one gear to the next, calculate as follows: Final Drive Ratio of gear you are shifting to, divided by the gear you are shifting from, minus 1, times 100. The difference from 1st-over to 2nd is even more dramatic.

This is why if you are towing or loaded heavily, the best way to reliably improve performance is with the GEAR VENDORS UNDER/OVERDRIVEâ„¢. It’s the same reason the big 18 wheelers have 2 and 3-speed auxiliaries for 10 to 15 gears.

Click on graphs to enlarge.


Ford 5.4L PN102


Ford 7.3L V-8 IDI
Navistar Diesel


Ford 6.8L V-10


Ford 7.3L V-8
(Non Turbo)
Navistar Diesel


Ford 7.3L V-8 DIT
Navistar Diesel


Ford 7.5L E/F E4OD