On Thu, 30 Oct 2003 03:59:54 GMT, clare @ snyder.on .ca wrote:

On Thu, 30 Oct 2003 03:50:22 GMT, Orval Fairbairn
wrote:

In article ,
Roger Halstead wrote:




I wonder why they use such a low compression ratio? Even car engines
running regular usually run 8:1. This one is 6.3:1.
It would reduce the stress on the parts, allowing less expensive
materials than a reliable high compression engine.


They use such a low compression ratio so they can use Russian gasoline!
No. They use the low compression ratio because the Walther LOM engine
has a centrifugal engine driven supercharger. ANy higher CR would be
dangerous under boost.

US turbo'd engines use either 8 or 8.5:1 and my 300 HP IO540 uses 10:1
I'd think it would have a lot to do with the gas they are designed to
use and well as durability and manufacturing cost.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2).