I'd never seen actual dyno test data of a "CorvAircraft" engine, even though we all had a pretty good idea of the power output. I mentioned this on the CorAircraft list one day and Eric Tingey emailed me the following data.

Eric dyno tested his 2700cc with .030" oversized pistons and cylinders back in Sept 2006. He knows a little something about this, as he was working at the dyno shop at the time. His engine uses a Marvel Schebler carb and OT-10 camshaft, which is common among Corvair engines intended for flight.

Here are the numbers, taken with 28 degrees of total ignition advance. Note the air/fuel ratio is set for max power. My takeaway from this is that we've all been a little optimistic on our power estimates for the Corvair. Also, running the Corvair at high RPM doesn't get a huge power increase with this configuration. William Wynne calls his version of the Corvair a 90 continuous HP engine at 3000 RPM on his website, and that jives perfectly with this dyno run. He also refers to it as 100 HP @ 3150 RPM, but that may be a bit optimistic, and the test run shown above shows about 95 HP @ 3150. I'm not sure how you'd get 10 HP from 150 RPM, but I'm sure he could explain it.

Still, this is pretty impressive for an engine that GM calls a 110 HP engine (or 95 HP with the weaker cam) at 4400 RPM. Now that I mention it, this dyno run shows it at 113 HP at 4400 RPM, and that's probably the price of spinning the stock fan. So it's not that we're performing such a miracle getting so much power at a low RPM, it's that the GM configuration just doesn't do much improving between 3000 and 4400 RPM! GM's dyno chart, along with some other performance info, is located at http://www.n56ml.com/corvair/specs.html.

Return to Mark Langford's Corvair Engine website.