I have 20 inch wheels with a gear ratio of 4.10. I bought the car like this. I am looking for more acceleration off the line. In the future I want to switch to 18s as I can feel the weight of these wheels. What gear ratio do you guys recommend with a 20 inch wheel?
4.10’s are a good gear for naturally aspirated GT’s looking to maximize the use of their first 4 gears in the quarter mile (trap speed <111mph assuming stock tire+wheel height). If you are naturally aspirated, I’d hold what you got. To get more acceleration you need to drop weight, improve the tires &suspension, or add more power. As an example - I still have stock 3.27 gears because I have a stock height tire, stock redline, and a higher trap speed because of my blower. More power solved my acceleration problem.
Here is an example chart for stock size rims and tires (245/45/17), 5 speed TR-3650 tranny (dunno what you have but this is a good starting point to see the difference between the gears):