what blower on 640 cu.in
#2
Platinum Member
Platinum Member
Best not to spin a roots blower over 8,000 rpm for any length of time. Whips up more heat than boost.
At 6000 motor rpm, you can overdrive 30%.
An 8-71 at 30%over will give around 14 pounds of boost in a 640. An 8-71 at 15% over will give around 9 pounds. At 1:1 is will be about 4 pounds.
A 10-71 at 1:1 will do about 7 pounds in a 640. At 10% over will do around 10 pounds.
A 14-71 at 1:1 will give you probably 10+ pounds.
These are just guidelines. Each motor, how well its heads flow, carb size, cams, etc will affect the outcome.
I'd say a 10-71 is minimum for that motor, but you could really stretch an 8-71 and make it work.
At 6000 motor rpm, you can overdrive 30%.
An 8-71 at 30%over will give around 14 pounds of boost in a 640. An 8-71 at 15% over will give around 9 pounds. At 1:1 is will be about 4 pounds.
A 10-71 at 1:1 will do about 7 pounds in a 640. At 10% over will do around 10 pounds.
A 14-71 at 1:1 will give you probably 10+ pounds.
These are just guidelines. Each motor, how well its heads flow, carb size, cams, etc will affect the outcome.
I'd say a 10-71 is minimum for that motor, but you could really stretch an 8-71 and make it work.
Last edited by mcollinstn; 02-07-2004 at 08:20 PM.
#3
Registered
Join Date: Oct 2002
Location: Morgan Hill, CA
Posts: 50
Likes: 0
Received 0 Likes
on
0 Posts
timucin, I have a 621" BBC with a 14-71 blower and I get about 9 psi boost (at 6,300 rpm) running 12% over. I would run a 14-71 on anything bigger than 600". Hope this helps.
Keith
Keith
#4
what the heck are you build'n now
did you get that Hemi car you were looking at?
did you get that Hemi car you were looking at?
__________________
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
Thread
Thread Starter
Forum
Replies
Last Post
CigDaze
General Boating Discussion
21
06-18-2003 08:26 AM