Flowing carbs
Moderator: Team
Flowing carbs
We are racing in a stock spec style class. The carb is the restriction in the intake. I have started flowing them at 28 inches. Is the standard for carb flowing at a different depression? With the carb being the restriction should it be flowed at high depression? The head loses 30% of flow once the carb is bolted on.
Re: Flowing carbs
factory 4Bbl's are flowed at 1 1/2 inches of mercury, and 2Bbl are flowed at 3 inched of mercury. I believe 1 1/2 inches is equal to 20.6 inches of water
-
- Guru
- Posts: 4607
- Joined: Sun Sep 18, 2011 11:31 am
- Location: Heading for a bang up with Andromeda as we all are.
Re: Flowing carbs
The above 20.6" H2o is correct for a 4 bbl, the 3" test point for a 2 bbl is twice that at inches or water.
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
Re: Flowing carbs
It's a nit-picky kind of thing, but 1.5" HG is 20.4" water. Do your rules allow any carb spacers? That could help with pressure recovery , and that could help get a little more flow. Norm
Competition Fuel Systems Birch Run,MI. www.compfuelsystems.com/index.html 520-241-2787
-
- Guru
- Posts: 4607
- Joined: Sun Sep 18, 2011 11:31 am
- Location: Heading for a bang up with Andromeda as we all are.
Re: Flowing carbs
Bingo!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
-
- Guru
- Posts: 2651
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
Re: Flowing carbs
---here's a link to some of my Holley 2barrel flowtesting---that might give you some ideas
http://www.ryanbrownracing.com/Bill_Jones_Page_27.html
http://www.ryanbrownracing.com/Bill_Jones_Page_27.html
-
- Pro
- Posts: 279
- Joined: Tue Sep 03, 2013 3:03 pm
- Location:
Re: Flowing carbs
Flowing 1 venturi at a time, and then adding the flows together, will usually give a lower total airflow, that flowing the whole carb. It depends on your flow bench fixtures, and how good the pressure recovery is when flowing one venturi, as opposed to what it is when flowing the whole carb on its appropriate fixture. You would want to flow each venturi at 40.8", more to see if they are close to equal flow, than to determine total flow. Norm
Competition Fuel Systems Birch Run,MI. www.compfuelsystems.com/index.html 520-241-2787