Piston Motion Simulator

With our Rod Speed / Piston Motion Simulator you can clearly visualize changes for your engine build.

While the simulation is running, use the number 2 or 8 keys on your number pad to decrease or increase your connecting rod length. Number keys 4 and 6 decrease or increase the stroke of the crankshaft. Keys “a” and “d” will (a)ccelerate or (d)ecelerate the simulation speed. And at any time hit key 5 to clear the graphs. “q” will go back to the previous page.

So key in your favorite combination and compare the position and displacement to “ideal” in the lower sine chart. And watch the motion of the piston as you increase or decrease the stroke or rod length.

You can have some fun here and create impossible situations. Try out an 82mm stroke with a 41mm rod. That’s about as extreme as you can get and notice the piston dwells at the bottom for 270 deg, then all the motion is contained within 90 deg of crank rotation. Vs. the ideal fully utilizing the full 360 deg crank rotation for all that motion. However, there are some advantages to longer stroke and shorter rods. Aside from packaging, you get higher piston velocities which can dramatically increase your volumetric efficiencies especially at lower rpms where these engines, especially turbos, need it! Notice also going from the stock 76.4 / 127mm rod length to our “cookie cutter” 80.4 / 125mm rod length setup there’s barely 1 deg difference in the max rod angle.

Let us know what you come up with!