It wasn't so long ago that Cummins owners were being told that high RPM's simply wasn't a possibility with a factory ECM. In short, you either had to put up with 4,000 RPM and power robbing defuel or run an aftermarket ECM setup - PERIOD.
That was certainly one of the first myths to be broken by EFILive, with 5,500 RPM and adequate fuelling being achieved on the 5.9L ECM even before our first public release.
Moving forward 18 months, high RPM and full fuelling on the factory ECM has simply become an expected industry feature, and the day of workarounds are long, distant memories for the 06-07 5.9L Cummins crowd, but remained a highly requested agenda item (and high development priority) for the 07-09 6.7L Cummins segment.
Like all development, if it was an easy addition, customers wouldn't be requesting the feature, simply put other companies would have delivered a solution a years ago. But hitting those limits requires dedicated development time and a dedicated test truck with the right modifications to support these features, and lots of software revisions.
November 2012 finally delivered the progress that has been so long in the making. The Cummins 6.7L is finally over 4000 RPM's with full fuelling. With Rich from Doghouse Diesel behind the wheel of the Garmon's Diesel Performance 6.7L, using our latest beta software revision this truck became the first 6.7L with a factory ECM to break 3,850 RPM's. Sure you'll hear others claiming they have already done this, but have they? High RPM is common when switching 5.9L electronics over to the 6.7L, but with a full factory OEM setup this simply hasn't been possible.
Public release is scheduled for December 2012, but ensure your mods will support these new features or a winter rebuild may be next on your agenda!