what CR for my l92 422???
08-13-2007, 08:33 AM
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what CR for my l92 422??? like the title says...what CR should i plan for the shortblock...i plan on running the new 235 tfs heads or ETP 240 heads...any help would be appreciated
08-18-2007, 01:14 AM
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How much do you want to spend for gas, and what are you doing with this car.
If you want to pay $8.75 for 100 unleaded race fuel, go with 12.5:1 and make some big power. If this is a pump gas driver, better keep it below 11 or it will knock until the pistons go south. What you really need to calculate is dynamic compression that uses the intake valve closing point. That runs near 3.0 below static compression. Keep the static below 8.0 and you can use 92 octane.
If you want to pay $8.75 for 100 unleaded race fuel, go with 12.5:1 and make some big power. If this is a pump gas driver, better keep it below 11 or it will knock until the pistons go south. What you really need to calculate is dynamic compression that uses the intake valve closing point. That runs near 3.0 below static compression. Keep the static below 8.0 and you can use 92 octane.
08-18-2007, 10:36 PM
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11:75 to 1 compression is very doable on 93 octane, a good tune, and as long as your dynamic compression ratio is in check around 8.6 to 8.7 to 1. This is also about as high as will want to go on 93 octane and of course will make great power! 
Last edited by Chicago Crew UnderBoss; 08-20-2007 at 04:07 PM.