Reviewed By Pavel B (Albuquerque, NM) Reviewed for a 2004 GMC Yukon —2/7/2008 10:33 PM
I bought HyperPAC hoping to achieve some performance gains and for the various diagnostics programs it offers. Installation is simple and straightforward, uploading performance tunes takes less than 5 minutes. Performance gains are consistent with the dyno charts Hypetech has on their website - modest but noticeable. I tow a trailer and acceleration from standstill and throttle response are better. My benchmark is a steep grade on I-25 before Santa Fe. With the stock tune the rig tops at 50mph on 2nd; after installing the premium fuel tune I was able to take it at 60mph. With this tune engine seems to develop more hp after 4000rpm than with the stock tune. I also like the engine monitor program which allows me to check on transmission temp. I also used the dyno program but you need to weight your truck for accurate results. Regarding fuel economy, there seems to be a modest improvement (14.2 city vs. 13.9 with the stock tune on winter gas-ethanol mix). In sum, I find this product to be useful and fun to use but do not expect miracles.