in the old days it used to be you had to double the Cubic centmeters to be =.

A lot depends on the plane and overall performance you are looking for.

I will tell you that in the Saito engines that there is certain ones to buy like why buy a .91 when the 125 is close to the same weight. of the saito's

i will only buy the 40, 82, 125 or the 220.

no reason to buy the 1.80 when the 220 puts out more and is the same weight.


most four strokes dont like to turn much past 10,000 as a general rule. I have turned some of the saitos past 12,000 though in the air.

the saito 40 is 10.5 ouncs
from the 56 to the 82 there is only 1.5 ounces difference so why buy the smaller ones the 82 is almost as strong as the 91. the 91 is only 2.3 ounces more than the 82. the next engine of choice is the 125 with a weight of 21.9 ounces only 3.5 ounces more than the 91. So kinda see what i am talking about with my choices on which of the saito 4 strokes to buy.

saito 40 on most 30 size planes and smaller
saito 82 on small to med size 45-55 size planes
saito 125 on large 45- med size 120 planes
saito220 on large 120 size to 30 cc planes


If need more power can run more nitro. i have run all my saitos on 45% with no problems