#1  
Old 07-24-2000, 04:07 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

The following post was written by a friend of mine who occasionally reads postings here but is not a registered user. He has a flow bench and has done some experimenting with the Pontiac Tri-Power.

The 65 center carb flows 278cfm, the outside carbs and the 66 carbs are 435cfm. The 2 barrel carbs are flowed at 3 in. of Mercury and 4 barrels are at 1.5 pressure drop. 1 inch of Mercury equals 13.6 in. of water. To convert 2 barrel cfm rating to a 4 barrel you need to divide the 2 barrel rating by 1.414. So a 66 trip flows 923 four barrel cfm's The biggest improvements to the tripower is to take the air cleaners off and put a 1" phenolic spacer under the carbs. The air cleaner base must be left on the carb. These mods. on a 65 goat with a 9:1 400 picked up a half second in the quarter mile. 3/10s for the air filters and 2/10s for the spacers. A 4 barrel setup will out perform the tripower only because the manifold is better not the carburation.
Headgaru

__________________
Tim Corcoran
  #2  
Old 07-24-2000, 04:07 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default More info Re: Tri-Power

The following post was written by a friend of mine who occasionally reads postings here but is not a registered user. He has a flow bench and has done some experimenting with the Pontiac Tri-Power.

The 65 center carb flows 278cfm, the outside carbs and the 66 carbs are 435cfm. The 2 barrel carbs are flowed at 3 in. of Mercury and 4 barrels are at 1.5 pressure drop. 1 inch of Mercury equals 13.6 in. of water. To convert 2 barrel cfm rating to a 4 barrel you need to divide the 2 barrel rating by 1.414. So a 66 trip flows 923 four barrel cfm's The biggest improvements to the tripower is to take the air cleaners off and put a 1" phenolic spacer under the carbs. The air cleaner base must be left on the carb. These mods. on a 65 goat with a 9:1 400 picked up a half second in the quarter mile. 3/10s for the air filters and 2/10s for the spacers. A 4 barrel setup will out perform the tripower only because the manifold is better not the carburation.
Headgaru

__________________
Tim Corcoran
  #3  
Old 02-22-2023, 11:15 PM
MidnightAuto's Avatar
MidnightAuto MidnightAuto is offline
Chief Ponti-yacker
 
Join Date: Jul 2018
Location: NY
Posts: 521
Default

just dug up this old one. why would keeping the bottom air cleaner pan help?

and is it fair to say that a spacer might help 1/4 mile and higher rpm- but would hurt low end and stop light to stop light?

  #4  
Old 02-23-2023, 02:37 PM
pfilean's Avatar
pfilean pfilean is offline
Ultimate Warrior
 
Join Date: May 2007
Location: West Des Moines, IA
Posts: 1,932
Default

Bases on factory air cleaners generally have a curved entry into the air horn not an abrupt 90 degree. This gives smoother air flow into the carb and thence likely more air flow with less or no turbulence through the venturi.

  #5  
Old 02-23-2023, 07:40 PM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 31,294
Default

2 BBL carbs are tested at 3.0" of Mercury or 40.78 inches of H2O

4 BBL carbs are tested at 1.5" of mercury or 20.392 Inches of H2O

So agree there.

We know the 1966 center 2BBL carb has a smaller Venturi diameter but a larger
Throttle Blade diameter vs the 1965 center carb. And as posted several times,
The air horn entry is better on the 1966 center carb.

The Pontiac TRI-POWER air cleaner (Big Car) was a very good piece.

What Flow Bench does he have Tim??

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
  #6  
Old 04-30-2023, 11:07 AM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

Hi Tom, he made his own flow bench but it's calibrated same as any other but I know there are still variations between benches even the professionally made ones.

__________________
Tim Corcoran
Reply

Thread Tools
Display Modes

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

Forum Jump


All times are GMT -4. The time now is 08:44 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017