LOL yes for Phil!!!

Hot Rod mag did a great test of these theories a few years back. They built 2 motors of same displacement. One big bore, one big stroke and they were.....The same on the dyno. Cube is a cube unless your rev very high which is not big in the boat world. Great article. Wish i could post it.

I'd beg to differ on said opinion, as the stroker engine would have a slight advantage over the big bore engine, piston speed being the advantage and if you look at an engine as what it really is (a pump) you will find that the longer stroke increases the piston speed which in turn increases the air volume of said pump... beyond that of the big bore engine... however, with that being said, if you rev the BB (big bore) engine to a point that the piston speeds match then you'd have a stroker crusher!!! as that BB engine would dominate over the stroker
says the oldest student in med school!!!

OH NO!!! WHO DUNIT!! :hitfan: someone kicked over the hornet's nest!!! :angry-smiley-044:

Well think about friction of stoker compared to not, I would use big piston less stroke due to shrouding and friction... Less up and down = less friction

Piston speed, yes, is faster with more stroke.

But.....what about rate of displacement, again, if both motors displace the same.

I thought she said piston size doesn't matter................

being that this is relative to boats lets say the big bore is happiest at 8000 rpm and the big stroke is happiest at 6000 rpm. what effect of prop and drive ratio selection would be optimal would you be giving up too much prop to spin the motor to 8?

that's a bit unrealistic as the piston speed differential in a .250 stroke differential would be considerably less than 2000 rpm

well this thread does make one think now doesn't it? lol FYI I'm a fan of the bore VS stroke, but hat to put that out there just for chits and giggles!!!