Hello Everyone,

As many of you know I have a steam bicycle. On the steam bicycle is a 2 cylinder single acting westinghouse type Stuart Sirius. This engine is capable of speeds up to 4000 rpms and has a 1" bore x 1" stroke. This engine isn't the torqueist engine, but because of high engine rpms it is geared 15 to 1 or so maybe I'm a little off. I calculated using the hp= torquexrpm/5252 that my engine: ~.85hp*5252/2600rpm =torque or 1.7lbft torque. This is at 250 psi and its weight is only 6.5lbs.

I was planning on building a bike before I acquired the steam bike I have now. I was gonna use a PM research engine #6CI. I believe this engine would have been too big, but it was 1.5" bore x 2.5" stroke and claimed a 1/4hp and weighed 35lbs, no mention of psi, but at say 100rpms the engine would make 10-11lb feet of torque after pump loses.

Now I'm curious what everyone thinks would be better a torquer, but much slower engine that is larger or a faster, but less torquer engine that is smaller. They both have advantages and disadvantages, there have been steam bikes/motorcycles built both ways.

Does anyone have any thoughts as to which is better in their opinion ultimately there probably is no right or wrong answer as long as the system meets all needs.