Many people don't about this, but Jim Testa made a simple program a long time ago that used Joe Lubrant's data. Much better than all the online calculators and lets you compare inject %, hp, slip%, ET, mph real quickly. I use it all the time, its called TRX Performance.
I attached the program as a .dat file. Save it and rename to .exe and enjoy. Don't worry, not a virus. I would have provided a link to download it but I don't see it anywhere online. Hopefully the attachment works, let me know.
Thanks Jim and Joe!