O.S makes a great engine! I only used O.S in my Airplanes! But, in R/C cars and trucks I think you can get more for your money out of some of the others out there! The O.S engines cost a ton to rebuild compared to many of the others out there! As far as power the Ofna Force .25 and the Hyper 8 port put out about the same as the OS RZVO1B! Now whether the power is as usable as it is in the O.S I could not say but, for the money it cost to buy one RZVO1B I could get 2 Hyper 8 ports!
Please don't take this the wrong way! I know that O.S engines are of a better quality but, when you beat and bash the way I do your going to be rebuilding or replacing engines no matter what you buy!
Originally posted by TODD MARSH
I am sticking with my .21 OS RZVO1B, built in boost chamber, 2.4HP super durable, reliable, and forgiving to some degree tuning wise. For a engine thats straight out of the box, this is a pretty hot engine. Makes GREAT power at 5,500 feet of elevation (Denver, Colorado) and runs super at 250F, but can safely run around 300F for insane power output. I can only imagine the power this unit makes at sealevel! These sell for $270-$395 depending on who you buy from. OS has been making Nitro engines for over 20 years, they aren't some new company. Alot of airplane modelers swear by OS only. I like mine so much I bought another one NIB, for replacing the first one. I would guess it will be quite a while before I need to replace it though, I expect 10 gallons of excellent performance at least.