I haven't been doing any math, so help me figure out if the effort would be worth the possible gains in mpg and savings of this theory in a scientific way. What are the highway mpg improvements to be had by using a small displacement engine: less pumping and frictional losses, price, and better tuning for its purpose.
I want to find the hp required to cruise at 50mph and 65mph for a 95 civic dx/cv/vx. And cross reference it to the fuel consumption at that hp for the donor engine. It has to be cheap, and it doesn't matter where it comes from such as motorcycle, moped, light industrial etc as long as its fuel efficient. The optimal engine would be the Loremo 20hp turbo diesel but i couldn't find the specs for that engine.
Here are just the first examples i could find but I can't translate the fuel consumption of these engines from g/hph or litres a kilowatt hour.
http://www.alibaba.com/product-gs/52...ll_V_Twin.html
http://www.alibaba.com/product-gs/50...el_engine.html
http://engines.honda.com/models/model-detail/gx630