Booster Signal

[GTO Geoff]

RHD,
I know this is the H section but I didn't [ & still don't ] read Shrinker's comments as being brand specific. Unless I missed it, the word Holley is nowhere to be seen.
He says 'hello hot rod' & 'a carburetor' in the very first line.
I took that to mean:

[1] Hello hot rodders, wherever you are & whatever carb you are using
and
[2] a carburetor means just that a carb, any carb, any brand.

[GTO Geoff]

The 6214 & 6464 Holley 4500 carbs have holes in the metering block on the float bowl side that feed feed fuel directly into the idle-intermediate system.

[GTO Geoff]

Rgalajda,

I agree with a lot of your comments in your last post.

And let me congratulate you on using MVA to give the engine the proper ign timing at idle that the engine wants. So many just don't get it....

Disagree that 4 corner idle is needed. A quote from the late, great John Passini says it best in his quaint English way: 'Idle can only suffer from richness; there is always sufficient range on the mixture screw to deal with weakness [ leanness ]'

Carter patented the 'Economizer' concept. Carter AFBs, AVS, TQ, Rochester QJ & 2bbls use it. Not sure about Stromberg & others. Also called the idle down channel [ IDC ]. It is a jet that controls [ volume ] the A/F mix available to the transfer slot. Sometimes the IDC needs to be increased with big cams etc to avoid surging at cruise. Extremely hard to access on Carters above. On the TQ, it is buried in the air horn, about 1 1/4" in & requires long drill bits. QJ is very easy to access. As far as I can tell, brand H & clones just have a large-ish hole in the met block & not really specifically sized, just made 'big' to cover all possibilities. It is my opinion that this omission by H to properly size the IDC orifice is what makes them gas guzzlers.

Tailing off of the idle cct as the main cct starts, getting it correct. You would use the IAB to do this.

[Right hand drive]

[GTO Geoff]

RHD,
Thanks for posting that. Very interesting, but some of Shrinker's comments are his opinion, as he states. The first diagram of the booster looks wrong to me because once fuel starts to flow from the booster, & then the throttle is closed, the signal at the booster stops. But looking at that diagram, fuel would continue to flow [ siphon ] because there is no air brake [ kill bleed or MAB ] that is connected to the booster well. The MAB needs to be able to act directly on this fuel to break the flow.
Also, MAB size controls the start of the main cct. Smaller MAB starts earlier, as stated in the Holley book, opposite to what S said. I presume Holley know how their carb works.

[Right hand drive]

[Right hand drive]

[Right hand drive]

Following from previous post regarding larger i/d annular boosters, a question hopefully Mike and/or Mark can answer.

With .600” i/d annulars which would you expect to pull fuel earlier, 1) a lot of smaller discharge holes such as the BLP 16 hole or 2) fewer but larger discharge holes such as std Demon and I think Holley with eight holes?

(Sorry don’t know the discharge hole size for the latter, but definitely larger than the BLP 16 holes)

[mike laws]

[Right hand drive]