The AEconoguide specification provides a piston with a skirt bearing area which, depending mainly on skirt length, is from 45% to 70% less than normal without detriment to lubrication or guidance. Such pistons can only be produced by diamond turning on special machines.
The lower friction associated with AEconoguide has either increased power or reduced fuel consumption in 5 gasolene and 4 diesel engine tests to date. Power was improved by (1.8 ± .4)% and fuel economy by (3.4 ±.6)% at part load in those engines, expressed as (mean ± r.m.s. error of mean)%.