DragStuff

I got a P.M. from a friend (Jim) the other night which i don't know the answer to. He inquired as to whether or not we had run our 598 motor with the powerglide transmission on a chassis dyno. He was at a guys shop that had a Dynojet and had a high powered car strapped down that had unusual data readings being recorded. He said the guy had put a very tight converter in the car and the Dyno and the guy's data logger were showing more driveshaft speed than engine speed on both units. Another good friend (Don) had recently asked if i knew what the high gear ratio was in a powerglide. He said his transmission builder had told him it was overdriven at about .92-1 in high. Any thoughts on this abnormal situation? I take it the car is a shootout 10.5" tire car and needs the tight converter.

Unless his glide is some new prototype that is no longer a glide, the output shaft cannot turn any faster than the input shaft. Due to the slippage in the converter when under load, the engine will always turn faster than the driveshaft. When decelerating, the driveline will turn faster than the engine, again due to the slippage in the converter. In hi gear, the clutches lock the input shaft to the output shaft and 1 to 1 is all you can get.