Have any of you had your Cummins ISC 315 HP w/6 speed Allison turned up to 350 HP? My coach has a 4.30 rear end. I know it will be necessary to call Allison and Eaton to make sure the final drive will handle the additional torque from 950 to 1050 lb-ft. I would like to hear about your results.
Back when diesel was near $5.00/gal. I owned a Peterbilt 387 with a C15 Cat, 475 HP and 1650 torque. I had the Caterpillar computer reprogramming done to take the engine to the max of 525 HP. That was all I could get with the computer. The dealership had to verify that the tractor had the heavy-duty drive line. The increased HP took the torque to 1850, and resulted in two-tenths of a mile per gallon improvement in fuel consumption. That may not sound like much, but the tractor was a team truck averaging 250,000 miles/year. Per my calculations, each tenth improvement in fuel economy was worth about $12,000.00 in savings. The additional 2000 lb-ft torque improved the performance of the tractor significantly.
The downside...when the engine was down in the low RPM range on a long pull, we had to watch the pyrometer to keep from cooking the turbo charger.
I am considering making the change. What do you think?
Randy & Sheron
2000 Monaco Diplomat 38D, 315 HP, 1998 Jeep Cherokee Sport 4X4
1993 Rockwood Embassy E6321, diesel pusher