Ok so I have a 2013 fx4 ecoboost. Ran a friend of mine 2012 gmc about 6 times. The first 2 races was amazing I kept pulling and left him behind. After the 2 races I noticed he was starting to keep up better. On the 4th run he actually beat me and the 2 after that too. We raced back to back no rest on trucks. I'm guessing the turbos were hot? My temp gauges looked ok inside though. We did several runs from stop and 20 and 30 rolls.