My Cherokee has an 8.5:1 O-360 with autogas STC for 91 minimum. You could get
a 6-cylinder version of the same engine (O-540 straight-valve) STC'd for 91 in some
planes. The Comanche hydrolocked the carb on autogas (Peterson told me that), so it
couldn't pass.... it's a combination of engine and airframe.

That said, if you run premium an O-540 at 8.5:1 and 2700 rpm is 260 HP on
autogas. If you keep it sufficiently cooled and well cowled, you could reduce the
vapor locking problem. I don't know of any fuel-injected Lycomings that can be STC'd
for autogas, so the O-540 is probably the biggest. If you run 7:1 compression for 235
HP (e.g. PA-28-235), it runs happily on regular 87.

-Cory

John Skorczewski wrote:
: I appreciate the info--- but I still have questions. Say, I wanted to
: built an RV-10 with a 260 lycoming engine. How do I find out if it can
: be stc-ed for autogas??? ---and if not what is the biggest lycoming
: engine that can burn autogas? Who has info like this??

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering Ph.D. Graduate Student *
* Virginia Polytechnic Institute and State University *
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