Pony_car

If I tune my car, then change the tire size or suspension later, do I need to re-tune? I know that when ordering tunes, they ask for tire size. If I'm at 17s now, then move to 18s later, does that effect tune enough that I need to tune again? Also, does changing suspension and lowering car mean I need to tune again? Thanks for the info...

28HopUp

Yes, you will need to reflash your car with your handheld tuner if you change tire diameter or gears (lowering the car will not affect the tune though). With my SCT xcal2, it offersprompts to change different parameters, including tire revolutions per mile. You will need to determine that number for the new tire, which you can get from the tire manufacturer or tire resellers like TireRack. Once you make the necessary changes, then you need to load your desired tune (and it can be the same tune you were running before changing tire size).

If you can play a video game, then you can adjust the settings on a handheld tuner.