Where's the rest of my engine mods ? – Dragster Mayhem - Top Fuel Sim Review

How do I get the rest of my engine mods ? I have 6 spots to fill. In the engine, tire and Frame category. How is it one night I do my burnouts to a certain % and run 3.147-3.189 then a few days later with the same burnouts I can't get no lower than 3.218 ? Not to mention I am moving my burnout % up and down to get a faster time but can't seem to. But all the other driver are running faster ? Plus I have all my engine mods now. And the engine blue print doesn't do anything for me. I run faster without it.
Review by trp2000 on Dragster Mayhem - Top Fuel Sim.