Kumho have launched their new Extreme Performance Ecsta V730.
Looking at the thread pattern, which looks similar to the older V720, but grooves are more shallow.
Outer shoulder...
cut it short,let's say i upgrade to a bigger injector,and there's a show of lean fuel.by avoiding using supplementary injector,just using bigger cc injector,let's say 750 or 1000cc injector, do i still need to...