Shiftpoints with gear change

[Jay Dee]

I'm changing from 3.55 gears in my 16 auto gt to 4.09 gears. I bracket race the car at the dragstrip. It has basic bolt ons and a dyno tune with the shift points around 7200rpm and rev limiter at 7800 rpm. I want to put off until the spring getting the dyno tune updated for the gearing change (shift points). I know the speedo isn't affected due to the placement of sensor on these newer mustang. I only have one race left and my question is:
where do you think the car is going to shift at rpm wise with the 4.09 gear before doing an updated dyno tune for the gear change? Before 7200 rpms or after 7200 rpms???????

 

[86GT351]

Too generic of a question. You would really need to experiment with that. Drive it and feel the performance. You will feel it if the engine is being revved too high. It will start to lay over slightly.

 

[MrBhp]

Surely you will be able to do a few tune runs before the next event. Tracks are usually open several hours before the actual event. Start with shifting at whatever you currently shift at. That should be your baseline. Or maybe you are letting it shift automatically? In that case not much is going to change. Your best torque usage is going to be very close to what it was.

 

[JEWC_Motorsports]

Its a 6r80, its going to shift where its commanded to shift. My 6r80 is commanded to shift at 8200. Do you let it shift or are you using selectshift?