Rod ratio vs reversion
#32
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Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
heres another article on this topic. That math is over my head to try and do comparions. Pipemax helps make it easier. It be cool to be able to simulate from graphs based on the math results
http://www.epi-eng.com/piston_engine...ion_basics.htm
http://www.epi-eng.com/piston_engine...ion_basics.htm
#33
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Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I think the reality of it, for us boaters, is pick a rod that fits in the box. We aren't building engines that are competing to the tenths. Heck, the majority of us here, are so undercammed and undervalved (except guys like 14apache lol), chasing rod length is over the top, from power production standpoint. I mean, guys are building 598ci NA engines, with .630 lift hydraulic cams, and 2.25 or 2.3 valves. So far from what the engine actually wants/needs from an airflow demand standpoint, a change in piston acceleration from rod length, is almost microscopic in the grand scheme of things. When you look at what the top engine guys are running for valve lift, and valve diameter, that are making big power on motor, its a world away from what most here are running. none the less, pretty interesting topic.
#34
I think the reality of it, for us boaters, is pick a rod that fits in the box. We aren't building engines that are competing to the tenths. Heck, the majority of us here, are so undercammed and undervalved (except guys like 14apache lol), chasing rod length is over the top, from power production standpoint. I mean, guys are building 598ci NA engines, with .630 lift hydraulic cams, and 2.25 or 2.3 valves. So far from what the engine actually wants/needs from an airflow demand standpoint, a change in piston acceleration from rod length, is almost microscopic in the grand scheme of things. When you look at what the top engine guys are running for valve lift, and valve diameter, that are making big power on motor, its a world away from what most here are running. none the less, pretty interesting topic.
#36
Pump gas engines without trying different props 110.7 Think it needed a little les pitch. It had a bunch of trim in it. Without a lot of trim good water 105.
Props 17x31 15*rake 5blade For got to say NA engines
Props 17x31 15*rake 5blade For got to say NA engines
Last edited by 14 apache; 04-11-2017 at 08:08 PM.
#37
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Joined: Jul 2004
Posts: 11,332
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From: chicago



