speedmater 1.31 vs 1.48 ratio

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07-20-2016 | 11:18 AM

crazy canuck

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speedmater 1.31 vs 1.48 ratio

How much more horsepower does it take to turn a 1.31.ratio over a 1.48 ratio at the same engine rpm ?

07-20-2016 | 12:18 PM

Griff

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It would be about 3" of prop pitch difference. Prob would take about another 100hp to spin the same prop with the gear change.

07-20-2016 | 12:25 PM

jmoore1225

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Really takes the mid range pull out as well....

07-20-2016 | 12:28 PM

crazy canuck

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So what you are saying 3" less prop pitch 100 more hp to achieve same engine rpm and mph? So why you would run a 1.31 ratio

07-20-2016 | 12:41 PM

crazy canuck

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Does it have to do with prop pitch availability in big horsepower applications ?

07-20-2016 | 12:52 PM

jmoore1225

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Yes, smaller props are more efficient as well.

07-20-2016 | 01:05 PM

crazy canuck

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Thanks for the info reason for asking looking for ssm v"s to put in my scarab kv with 900hp

07-20-2016 | 06:04 PM

Griff

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Quote:

Originally Posted by crazy canuck

So what you are saying 3" less prop pitch 100 more hp to achieve same engine rpm and mph? So why you would run a 1.31 ratio

No, One or the other. 3" less prop pitch OR add 100hp to spin the current props at the proper rpm

07-20-2016 | 06:07 PM

crazy canuck

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meant to say 3"less pitch or 100 more hp

07-20-2016 | 06:10 PM

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crazy canuck

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thx

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