Is it possible for a Mac 91, 92, or 93 to hit 12000 RPM on the straightaway with proper gearing?
bill
Top Mac RPM
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Bill Hermsted
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Scott Kneisel
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Re: Top Mac RPM
14-15K I would think is doable.
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steveohara
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Re: Top Mac RPM
Bill,
I ran my IKF legal stock Mc91B1s to 12,800 to 13,000 back in the late 70s and won 36 consecutive one hour enduro races over a three year period without a single engine failure. The gear ratio on most tracks was 4.1 to 4.2. Had I been running sprint events I would have geared for higher peak rpm.
The 101 series motor cannot take the same peak rpm and I normally geard the 101s at 3.75 and they topped out at 11,800. These days when running vintage events on sprint tracks using stock 101s I gear to limit the 101s to 13K at the end of the longest straight and it will only run there for a few seconds per lap.
Steve O'Hara
I ran my IKF legal stock Mc91B1s to 12,800 to 13,000 back in the late 70s and won 36 consecutive one hour enduro races over a three year period without a single engine failure. The gear ratio on most tracks was 4.1 to 4.2. Had I been running sprint events I would have geared for higher peak rpm.
The 101 series motor cannot take the same peak rpm and I normally geard the 101s at 3.75 and they topped out at 11,800. These days when running vintage events on sprint tracks using stock 101s I gear to limit the 101s to 13K at the end of the longest straight and it will only run there for a few seconds per lap.
Steve O'Hara