Running A 671Blower On A Eng. That Already Has 12.5:1 compre

Old 03-03-2009, 04:49 AM
  #1  
kbartley
Senior Member
EXPERT BUILDER
Thread Starter
 
Join Date: Oct 2007
Location: Staunton,VA.
Posts: 251
Default 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
kbartley is offline  
Old 03-03-2009, 03:46 PM
  #2  
bjuice
Administrator
RACING JUNKIE
 
bjuice's Avatar
 
Join Date: Apr 2003
Location: Greenville s.c.
Posts: 3,239
Default

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
__________________
Bjuice..

"I'M YOUR HUCKLEBERRY ! "
bjuice is offline  
Old 03-03-2009, 05:23 PM
  #3  
kbartley
Senior Member
EXPERT BUILDER
Thread Starter
 
Join Date: Oct 2007
Location: Staunton,VA.
Posts: 251
Default 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.
kbartley is offline  
Old 03-03-2009, 06:12 PM
  #4  
bjuice
Administrator
RACING JUNKIE
 
bjuice's Avatar
 
Join Date: Apr 2003
Location: Greenville s.c.
Posts: 3,239
Default 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.
Bottom upper
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
__________________
Bjuice..

"I'M YOUR HUCKLEBERRY ! "
bjuice is offline  
Old 03-03-2009, 06:53 PM
  #5  
kwkracing
Senior Member
RACING JUNKIE
 
Join Date: Dec 2004
Location: austin texas
Posts: 729
Default

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.
kwkracing is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service