diff. of power commanders?

[dirtyred]

this might be a dumb question, but whats the diff. between a power commander IIIR AND a power commander III usb. Noticed people were selling the power commander IIIR on ebay and wasnt sure what it is.

 

[Blue Streak]

PCIIIR does timing and it adjust the fueling every 500 RPMs the USB does not do timing (it will if you buy an ignition module also) and adjust fueling every 250 RPMs.

 

[BusaWizard]

A lot guys with turbos use the PC3R, to retard timing.