I have an HPI rotostart installed on my Rapida (Himoto) Team Infinity .18 engine. You need a different one way bearing for it. It works like a charm. Starts up fast. I also put a tube on the muffler heh to port all the oil out the backside of the car. A little loss in power, but at least my rear wheel doesn't get covered with oil and I spend all my time cleaning oil dirt goop out of the car. RO tubing works perfectly