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Compression / Compression Ratio
Chart
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MM's or Degrees ATDC =
Duration
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Desired Compression Ratio - (UCCR)
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If the exhaust opens @ MM's ATDC
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The exhaust opens @ degrees ATDC
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Total Exhaust Duration (degrees)
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11:1
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12:1
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13:1
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14:1
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15:1
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16:1
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17:1
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18:1
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19:1
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Approximate Fuel Octane Requirement
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92
|
100
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108
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118+
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Does not include deck height measurement
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Approximate Static Compression At Sea Level
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42
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91.1
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177.8
|
150
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163
|
176
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189
|
201
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214
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227
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240
|
253
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|
41
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89.5
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181
|
147
|
160
|
172
|
185
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197
|
210
|
222
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235
|
247
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|
40
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87.9
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184.2
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144
|
156
|
168
|
181
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193
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205
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217
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230
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242
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39
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86.3
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187.4
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141
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153
|
165
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177
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189
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201
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213
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224
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236
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38
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84.8
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190.4
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138
|
149
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161
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173
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184
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196
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208
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219
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231
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37
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83.2
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193.6
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135
|
146
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157
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169
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180
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191
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203
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214
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225
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36
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81.7
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196.6
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132
|
143
|
154
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165
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176
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187
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198
|
209
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220
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35
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80.2
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199.6
|
129
|
139
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150
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161
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171
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182
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193
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204
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214
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34
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78.6
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202.8
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126
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136
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146
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157
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167
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178
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188
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198
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209
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- 246.3 cc / 66 mm Bore x 72 mm
Stroke
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Volume Needed @ TDC To Achieve Above
Compression Ratio - CC's
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24.6
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22.3
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20.5
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18.9
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17.6
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16.4
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15.4
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14.5
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13.7
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Head Gasket Thickness (mm)
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.25
|
.50
|
.75
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1.0
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1.50
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Gasket Volume (cc's)
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.86
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1.7
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2.6
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3.4
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5.1
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269.2 cc / 69 mm Bore x 72 mm Stroke
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Volume Needed @ TDC To Achieve Above
Compression Ratio - CC's
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26.9
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24.5
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22.4
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20.7
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19.2
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17.9
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16.8
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15.8
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14.9
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Head Gasket Thickness (mm)
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.25
|
.50
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.75
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1.0
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1.5
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Gasket Volume (cc's)
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.93
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1.9
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2.8
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3.7
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5.6
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293.1 cc / 72 mm Bore x 72 mm Stroke
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Volume Needed @ TDC To Achieve Above
Compression Ratio - CC's
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29.3
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26.6
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24.4
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22.5
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20.9
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19.5
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18.3
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17.2
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16.3
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Head Gasket Thickness (mm)
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.25
|
.50
|
.75
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1.0
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1.5
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Gasket Volume (cc's)
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1.02
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2.0
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3.0
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4.1
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6.1
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