By Paul Bertorelli

Power Shift: Cirrus and Tornado Alley

In 2007, more than half of all the turbocharged singles sold will be powered by systems built by a little shop in Oklahoma. Here’s why we think that’s a big deal.

It’s not much of a reach to posit that the entire survival of piston general aviation pivots around the exhaust valve, a $100 part that lives a miserable existence being slammed against a hardened steel seat 10 times a second swirled in a gale of white hot combustion gas. When an engine tanks prematurely or needs a midstream top overhaul, it’s often something to do with exhaust valves—bad guides, leaky seats, cracks around plug bosses originating near the exhaust valve.The engine makers and airframers have tried to meet these problems head on with mixed success.