Originally posted by AMGRacer
There is no mystery really. IFMAR and ROAR I believe limit the amount the exhaust port can be take out to 4.5mm. Also there is a limit to what you can do to the crank, a single "turbo" cut which does not enter the central feed passage in the crankshaft. I think the RTO has a bi-turbo cut and the exhaust port is taken out too much beyond the 4.5mm.
Ahhh thanks AMG !
So are there any rules on increasing the timming ?
Also if we are already going illegal with the RTO would it be any advantage to increase the pipe stinger size and then port and time the engine to the modified pipe ????