Why do they sound that way? Learn the principles of the flat-plane crankshaft in this entertaining and educational video. 

As we never get tired of saying here at Mac’s Motor City Garage, we appreciate plain, simple technical pieces, and when we find them we like to share them. Here’s a first-rate video by Chris Kuhn of 3D Performance Tech exploring the basics of the flat-plane aka 180-degree crankshaft. The graphics are pretty cool, and it’s more than worth your time and consideration. However, there are a few points we would like to expand upon:

+  The flat-plane crank depicted in the excellent animation has its throws arrayed in an up-down-up-down (UDUD) configuration, the same type used in Ford’s recent Shelby Mustang GT350 V8. However, there is a second, more traditional flat-crank design with the journals arranged up-down-down-up (UDDU) like a familiar inline four. Both are true flat-crank V8s but there are some differences when you drill down, mainly in tuning.

+  At one point the video almost seems to suggest that the flat-crank V8 fires every 180 degrees. Just to clarify, both 90-degree (cross-plane or conventional) and flat-crank V8s fire a cylinder every 90 degrees, or eight firing events per four-stroke cycle. The difference is the flat-plane crank fires each bank at equal intervals, for better intake breathing and exhaust scavenging, at some sacrifice in smoothness.

These fussy little quibbles aside, here’s an illuminating and entertaining primer on the flat-crank V8. Among other things, here folks can see why a cross-plane V8 sounds burbly and muscular, while a flat-crank V8 sounds sharp and crisp. Please enjoy.