As I've posted elsewhere, and these dyno graphs confirm, according to my rump dyno the 300 kit drops peak horsepower to about 8000, peak torque to about 7000. Still almost the same horsepower at 9000 as stock, but power dives right after 10,000, right before the valves float, where the 250 was still pulling another 500rpm or so before the valves float.
SpudRider, you are so right about how well Zong has the Delphi set up for the RX3. Using a slight up hill to control driveline slop, I can slow idle under load, 1500rpm, in 6th, crank the throttle WFO, and the Delphi does such a good job with the air/fuel ratio not a beat is missed, 80mph top. I've never had any vehicle with such command of the mixture.
All I've done to make the Delphi perform this well is nothing. Zong set it up perfect for the 250, Delphi set itself up perfect for the 300. Took a few miles each time, more than adapting to a different valve setting or motor oil, but those improve, too.
Rolled over 10,000 miles yesterday. Still running the original spark plug. Never missed a beat. When is a change due?
