Cummins beefs up ISX ratings

COLUMBUS, Ind. (Sept. 7, 1999) — Cummins Engine Co. has added two new ratings to its 15-litre ISX engine line and is set to roll into full production on the complete range by Oct. 1.

The new ratings are a 475-horsepower engine and a 475-hp ST2 “Smart Torque” version. The straight 475 develops 1650 pound feet of torque at 1200 rpm, while the ST2 does the same and then adds another 200 pound feet in the upper two gears. Cummins says fuel economy should be the same with either engine.

Built on the same platform as the premium Signature 600 (launched in 1997), the two 475s — like all ISX models — also have a killer engine brake built in. In this case the Intebrake, designed by Cummins and then refined by Jacobs, builds as much as 500 retarding horsepower. The company also said that a six-position retarder switch will be standard fare on ISX and Signature engines.

The rest of the double-overhead-camshaft ISX range offers ratings from 400 to 600 hp. Interestingly, Cummins will produce for the Australian market a Signature rated at 650 hp and 2250 lb ft — in that case mated to Mack’s beefy triple-countershaft transmission, the only one so far that can handle all that torque. Cummins said it could go higher if there were drivetrain components strong enough to take the stress.