I have heard that shifting manually can lower your et, but I don't want to mess up my transmission, so I figured before I tried it, I would ask here first. When should I shift? I have a zz4, with a 700R4 auto (shift kit, billet servo 1800 stall) and 2.73 gears as well as stock tpi setup on the zz4.

 

try 5000 rpm, it depends on where the engine pulls hard to, on stock tpi setup probably 4800-5000, it wont hurt, and it will definitely be better in the quarter mile