Welcome to Harris Performance, this site dealing with the TPI Tune Port Injection system used by GM from 1985 through 1992. I have posted pages to help those with these systems overcome the limitations of those systems and point out what those limitations are. While I specialize more in the daily driver type fuel injection aspects rather than full fledged race cars, most of my advice is going to be geared towards a nice daily drivable vehicle but with TPI to be a race system a lot of these changes will apply there as well.