Running A 671Blower On A Eng. That Already Has 12.5:1 compre
03-03-2009, 03:49 AM
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Running A 671Blower On A Eng. That Already Has 12.5:1 compre
My de-stroked 400 chevy w/ domes. What pulley set-up should I run w/ 12.5:1 compression. Was going to slow the blower down guite a bit, just not sure which pulley to use. This engine is an alky injected eng. currently. The car is a Front Engine Dragster. This is a street blower kit. Wieand is only helpful on strock. Any suggestions. Kris
03-03-2009, 02:46 PM
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8mm or 13.9/14mm drive pulleys ?
also IMO you are on the high side of the static compression .i think i would ask myself how much final compression would i want to make then back into the pulleys..after you figure this i can give you some pulley ratio's etc...
here is a formula to determine final compression ratios from BDS
Final compression Ratio (FCR)=[(boost /14.7)+1]xCR
Boost = Max blower boost
14.7= psi @ sea level
CR= engine compression ratio
also IMO you are on the high side of the static compression .i think i would ask myself how much final compression would i want to make then back into the pulleys..after you figure this i can give you some pulley ratio's etc...
here is a formula to determine final compression ratios from BDS
Final compression Ratio (FCR)=[(boost /14.7)+1]xCR
Boost = Max blower boost
14.7= psi @ sea level
CR= engine compression ratio
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Bjuice..
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03-03-2009, 04:23 PM
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671 blower
Bjuice, I have a wieand setup w/ 1/2"pitch, just a street blower. Not trying to compete just doing the nostalgia shows every now and then. But when I go I got to go. Have 39,35,32,38,33tooth pulleys. Normally I run the right piston for the application. Though I do hear of some folks running high static and just just taking (ALOT) of speed out of the blower.
03-03-2009, 05:12 PM
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Re: 671 blower
Originally Posted by kbartley
Bjuice, I have a wieand setup w/ 1/2"pitch, just a street blower. Not trying to compete just doing the nostalgia shows every now and then. But when I go I got to go. Have 39,35,32,38,33tooth pulleys. Normally I run the right piston for the application. Though I do hear of some folks running high static and just just taking (ALOT) of speed out of the blower.
39 38 2.7 overdriven
39 33 18.2 overdriven
39 32 21.9 overdriven
39 35 11.4 overdriven
32 39 20.5 underdriven
if you want anymore combo's let me know which ones and i will post it.
Brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "
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03-03-2009, 05:53 PM
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haha.. im sure your runnin 8mm and a 1440 belt? 52ish on top and 44-48 on bottom or in that ball park. you could probably run it close to 1to1 since its alky injected but we will see for how long? Be carefull that it doesnt rip the front of the crank off.
