Quote Originally Posted by SgtMarshal View Post
the biggest problem with your dyno numbers is the fact that you did the pulls in 2nd gear. 3rd gear is the 1:1 ratio and will give accurate hp/tq readings. and another thing to consider is the 103 plugs, they don't last very long, like 3000 to 5000 miles.
doing a dyno pull in 2nd or 3rd gear won't change the measured power significantly. Regardless of the gear, a chassis dyno is measuring the horsepower delivered to the drum / rollers, and deriving a torque value from that power measurement. In a 2nd gear pull you can run up to engine redline at a reasonable wheel speed, and probably see peak HP. The difference in 3rd from 2nd is that you have a more constant load on the engine to run through, maybe different powertrain loss, but at the risk of a higher wheel speed as you try to run up to a peak HP number as torque is falling off in the upper RPMs.