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CARB AIRFLOW ?

Posted By: chagjr

CARB AIRFLOW ? - 09/16/11 01:20 AM

What is the cfm increase you get by removing the choke plate? AVS 800 cfm (Thunder Series).

Is this good or bad to do? I have heard conflicting opinions.

Any data around showing increases?
Posted By: lewtot184

Re: CARB AIRFLOW ? - 09/16/11 01:22 AM

in reality, probably little to nothing gained.
Posted By: ahy

Re: CARB AIRFLOW ? - 09/16/11 01:40 AM

On anything except a pure 100% race car I wouldn't want to have to fight it to start and warm up on a cool day. Its a PITA and can be hard on the engine. Not worth it to me.
Posted By: RapidRobert

Re: CARB AIRFLOW ? - 09/16/11 01:45 AM

if you can get by WO it as in a drag eng that gets fully warmed up before use or a street car in a very warm climate I think it'd b OK but any less than that which is most of us you have to goose the throttle more or less till it warms up to a certain point & I'm not a fan of excessive raw fuel from the AP being dumped tho prob not a deal breaker just one of my pet peeves. It does take some space in there tho prob couldn't feel it on the butt dyno but small changes add up & keep you in the mindset of being meticulous/making changes/experimenting that youre opponent may not be willing to do
Posted By: chagjr

Re: CARB AIRFLOW ? - 09/16/11 01:55 AM

A lot of the other guys are doing it. I have read several different opinions, but there is no real concrete info saying Yeah! THATS THE HOT TICKET.
If everyone who is like minded as me (more strip than street)is doing this, why?
Posted By: joedust451

Re: CARB AIRFLOW ? - 09/16/11 05:06 AM

Quote:

in reality, probably little to nothing gained.



What he said.
Posted By: greg_moreira

Re: CARB AIRFLOW ? - 09/16/11 03:03 PM

You especially see this frequently done with the holley 477X series of double pumpers. The choke flap gets removed, and the whole choke tower gets milled off.

Guys say it can be worth as much as 30 CFM, which is a pretty negligible difference in most cases.

You figure its gotta be worth at least a hair because when it comes to the race bred carbs....they designed a different main body without a choke tower to begin with(take a look at a holley hp for instance).

If it was literally zero difference...the smart money wouldnt have designed an entirely different main body. BUT...the gains that you do see are never really anything to write home about. A very small gain that'll show up on an ET clock, but nothing that'll jump out at you just having fun driving on the streets
Posted By: Just-a-dart

Re: CARB AIRFLOW ? - 09/17/11 12:32 AM

I would test at the track with, and without back to back and watch MPH to see.
Posted By: BSB67

Re: CARB AIRFLOW ? - 09/17/11 12:46 AM

Harry, is you question; will air flow go up and how much, or will the air flow increase make a difference in power? Not that I know the answer to any of those questions. I would think air flow would go up.

My opinion - If the carb is your biggest limiting factor in make more power, I would think it would help. If it is your intake, maybe not.

How much more power do comparable A12 FAST cars have? I would think that difference is nearly all in the induction.

Have you called the guys at Diamondback Engines?
Posted By: joedust451

Re: CARB AIRFLOW ? - 09/17/11 03:05 AM

I would just remove the choke flap & assembly, at that point milling off the tower IMO won't gain you much to speak about, then you have a carb that can't have a choke anymore , You can get bigger air flow in booster changes/modifying or opening up the venturies.
Posted By: drago

Re: CARB AIRFLOW ? - 09/17/11 12:00 PM

Hi,
If this is a racecar and your rules allow you to delete the choke, you should do it.
The word "choke" says it all.
Posted By: JohnRR

Re: CARB AIRFLOW ? - 09/17/11 02:21 PM

Harry , do you have the HP book on the carter carbs , lots of race tips in it , I started on an HP 750 carter back before the ebrock 800's came out . they talk about streamlining the boosters to gain CFM , there is a shop that specializes in race avs, they should be abloud to eek a little more out of that carb.
Posted By: RapidRobert

Re: CARB AIRFLOW ? - 09/17/11 06:23 PM

Quote:

the HP book on the carter carbs ,they talk about streamlining the boosters to gain CFM.

I remem that. Could section an extra booster if you have a parts carb 2 see how far you can go, they reduced the dia of the horizontle leg as it is a restriction and they reduced the dia of the throttle shafts & iirc slimmed the thickness of the throttle blades/& a bit on the screws also. EDIT I would do what Joe451 said just remove the choke plate/rod. I'm sure the rest (airhorn) would b beneficial but it'd b quite a bit of work MORE EDIT they also tapped the other end for a dual inlet
Posted By: John_Kunkel

Re: CARB AIRFLOW ? - 09/17/11 10:11 PM


I doubt if removing the choke increases airflow per se but I'm sure it affects the dynamics of airflow.
Posted By: joedust451

Re: CARB AIRFLOW ? - 09/17/11 10:43 PM

Quote:


I'm sure it affects the dynamics of airflow.



Yep.
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