It is not the horsepower that is the problem, but the compression ratio. There
are 230 horse engines for which an STC exists and is quite easy to use. There
are sub-100 horse engines for which no STC exists today, and which will either
have to be derated in some way OR have an engine modification to reduce the
compression ratio (which does an automatic derating). If the airplane cannot be
flown derated (not enough horses for the job) then an engine change to a lower
compression, more horsepower engine may be the only solution.

Understand that AOPA and other groups "working on the problem" are being torn
two ways. One is to keep their majority constituency that COULD use premium
fuel in a derated engine happy. The other is their well-heeled minority
constituency who are happy with the way things are, thank you, and will continue
to block the use of autogas at the expense of the majority.

Of course, the folks producing TEL could end the debate in a month or so if they
wished. As noted, though, if there is a market for TEL, and unless the EPA bans
the import of TEL, anybody with a class in high school chemistry could open a
plant in a third world country and start selling the stuff in barrels at a
mighty good profit if this happens.

Jim



(John Skorczewski)
shared these priceless pearls of wisdom:

-I am new to this group. I know that many low hp engines can get an
-autogas stc.
-My question is this: How hard is it to run autogas in 200+ hp engines-
-say 200 to 300 hp? Both physically and legally?

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com