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Rod ratio vs reversion

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Old 04-11-2017 | 06:54 PM
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wtf.... lol
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Old 04-11-2017 | 06:55 PM
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Originally Posted by kvogt
From Flatlander racing, The piston rod diagram didn't paste over.
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
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Old 04-11-2017 | 07:04 PM
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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.
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Old 04-11-2017 | 07:51 PM
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Originally Posted by MILD THUNDER
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.
Ya and that's why my sh!t is in buckets.... LOL
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Old 04-11-2017 | 07:54 PM
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Originally Posted by 14 apache
Ya and that's why my sh!t is in buckets.... LOL
lol..but how fast do they push that 41 Apache to?
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Old 04-11-2017 | 07:58 PM
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Originally Posted by MILD THUNDER
lol..but how fast do they push that 41 Apache to?
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

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Old 04-11-2017 | 08:21 PM
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Originally Posted by 14 apache
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
Thats humping. Prob wouldn't happen with some 310cc heads and 651 crane cams.
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Old 04-11-2017 | 08:33 PM
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Boat ran around 106 with 351 brodix ovals that head will haul the mail and still have bottom end. Head hunter 383mc hurts the bottom to plane off. But they run like a bear.
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Old 04-11-2017 | 08:41 PM
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I'd much rather have good head vs having a longer rod,
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Old 04-11-2017 | 08:51 PM
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A long rod you get more enjoyment from the small end to the big end. Lol
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