Not familiar with the FDR in the XB4, but I'm running that same motor in my Tekno EB410 with 24/81 gearing and it's by far the fastest car at my club... guys with the Tekin Spec-R motors aren't happy and are saying I must be cheating, ha! I bought mine from Team Eric Anderson Motorsports, so it's not certified, but Eric tuned the motor for me so I can't say exactly what the timing is set to, but it kinda looks close to 46°-47° if I had to guess:



*** It's also worth noting that I noticed my fast lap time increased 0.4 sec this past week, so I rebuilt the car and found a crunchy bearing that needed to be replaced, hopefully I get that time back next race day