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Stock - 17 HP @ 7000 RPM
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Modified - 25 HP @ 8000 RPM
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Modified - 29 HP @ 8400 RPM
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Modified - 33 HP @ 8700 RPM - Long Rod
68 mm Bore (207 cc)
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Output data
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Intake - 9
Transfers - 6.3
Exhaust - 10.8
Exhaust Blowdown - .4
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Intake -11
Transfers - 6.9
Exhaust - 12.3
Exhaust Blowdown - .6
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Intake -11.9
Transfers - 7.2
Exhaust - 13
Exhaust Blowdown - .7
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Intake -12.8
Transfers - 7.5
Exhaust - 13.7
Exhaust Blowdown - .8
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These numbers are not the "as measured" areas of
this engines ports. They are what Bimotion
determined would be necessary to produce 17 HP @
7000 RPM.
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These numbers are a reflection of what is
necessary to produce the given power at the RPM I
entered. it is easy to see that more time area is
needed for more HP. These output numbers are easily
understood. I can tell there is a multiplier
involved or else they would be more like .00011 or
.00007. It is usually 1000 for all ports and 10000
for blowdown. This is done to make the numbers more
friendly.
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Exhaust Port Data - (as measured from
BDC)
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Port height - 24 mm - opens @ 91.5 ATDC
Port Duration - 177 degrees open
Port width - 43 mm
Percent of bore - 64.7 %
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Port height - 25.5 mm - opens @ 88.5 ATDC
Port Duration - 183 degrees open
Port width - 43 mm
Percent of bore - 64.7 %
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Port height - 26 mm - opens @ 87.3 ATDC
Port Duration - 185.4 degrees open
Port width - 45 mm
Percent of bore - 67.7 %
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Port height - 27 mm - opens @ 85.5 ATDC
Port Duration - 189 degrees open
Port width - 46.5 mm
Percent of bore - 69.9 %
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Squish Area Data - MSV (Maximum Squish
Velocity) Expressed in m/s
(Meters/Second)
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Volume Trapped @ TDC = 22.4 cc
Uncorrected Compression Ratio (full stroke) =
9.8:1
Corrected Compression Ratio = 6.1:1
Squish Band Width = 17 (76% of bore)
Squish Band Thickness = 2.7
Maximum Squish Velocity = 21.6
Max Squish Pressure Ratio of 1.048 occurred @
14.5 Degrees BTDC
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Volume Trapped @ TDC = 17 cc
Uncorrected Compression Ratio (full stroke) =
12.6:1
Corrected Compression Ratio = 7.4:1
Squish Band Width = 11 (55% of bore)
Squish Band Thickness = 1.1
Maximum Squish Velocity = 30.1
Max Squish Pressure Ratio of 1.082 occurred @
10.5 Degrees BTDC
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Volume Trapped @ TDC = 15.5 cc
Uncorrected Compression Ratio (full stroke) =
13.8:1
Corrected Compression Ratio = 7.9:1
Squish Band Width = 10 (51% of bore)
Squish Band Thickness = 1.0
Maximum Squish Velocity = 29.4
Max Squish Pressure Ratio of 1.085 occurred @
10.3 Degrees BTDC
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Volume Trapped @ TDC = 15.4 cc
Uncorrected Compression Ratio (full stroke) =
14.4:1
Corrected Compression Ratio = 8:1
Squish Band Width = 9 (46% of bore)
Squish Band Thickness = .9
Maximum Squish Velocity = 27.6
Max Squish Pressure Ratio of 1.089 occurred @
9.5 Degrees BTDC
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Boost Bottle Information - Data is CC's
based upon stock 26 mm carburetor. Tuned for 5000
RPM.
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Boost Bottle Information - Using 34 mm
carburetor.
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Boost Bottle Information - Using 34 mm
carb & other changes.
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Bottle Volume = 495
Tube Diameter = 12.7 mm
Pipe Length = 98
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Bottle Volume = 517
Tube Diameter = 12.7 mm
Pipe Length = 93
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