MI Pulley Black and Red Colors!

[CrankyOldMan]

Originally Posted by cali yaris

Lightweight rotating elements, like pulleys, flywheels, and wheels/tires, confer more responsiveness and feel than actual measurable horsepower, but it is a noticeable difference.

Doh. I oversimplified the result. You're not actually adding horsepower, you're just removing parasitic losses. The net result is that your acceleration curve as a function of time has a steeper slope. I don't think it would show up on a dyno, since that is hp/torque vs RPM, not time.

For racing purposes this means reaching the power band sooner--so your elapsed times will decrease. For daily driving, this means less energy spent spinning up the pulley--decreasing fuel consumption.

I frequently have issues with acceleration wheel spin (outside of ideal road conditions) and my only other engine mod is a drop-in high-flow filter. I can only imagine what a lightweight flywheel and I/H/E would do. Perhaps it would require me to add that magical LSD?