When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The idle circuit? Venturi effect from the idle ports at the base of the carb near the butterflies.
No, you and I were both wrong on this. Sorry, it's been so many years since I studied the Holley technical literature, I just forgot some of the details. I don't have any of those books now, but here's an excerpt from one of the Edelbrock manuals. Their idle circuit is similar in operation, and they clearly state that manifold vacuum pulls fuel out of the idle port. In other words, if the butterfly was positioned between the idle port and transfer slot, then sealed around its edge so no air could flow, vacuum below the carb would still pull fuel from the idle port. Velocity through the bore isn't needed. The transfer slot also uses vacuum to pull fuel, not velocity.
[QUOTE=454Luvr;1591043884]No, you and I were both wrong on this. Sorry, it's been so many years since I studied the Holley technical literature, I just forgot some of the details. I don't have any of those books now, but here's an excerpt from one of the Edelbrock manuals. Their idle circuit is similar in operation, and they clearly state that manifold vacuum pulls fuel out of the idle port. In other words, if the butterfly was positioned between the idle port and transfer slot, then sealed around its edge so no air could flow, vacuum below the carb would still pull fuel from the idle port. Velocity through the bore isn't needed. The transfer slot also uses vacuum to pull fuel, not velocity.
You said: "Blah blah blah, here we go again. The double pumper will work fine."
Did you forget that?
That's not an inaccurate statement. It will work fine on a daily driver. I don't see why some people hate the DP so much where they have to belittle people. It will work just fine. I did not forget it, and I stand by it. for cryin' out loud I (and most of my friends) had these in High School, we were able to tune them with our limited experience. Why some people say they can't work on a street car is beyond me.
How about doing the obvious; remove that silly 750 cfm double pumper that is only intended for track racing and install a street carburetor that has AVS or vacuum secondaries?
When well-meaning (but ignorant) people put track racing carburetors on street engines a stall at a low rpm full throttle is what happens. Put a street carburetor on it that has AVS or vacuum secondaries and a stall won't happen. The problem only gets worse when a mechanical secondary carburetor is combined with a large plenum single plane track racing intake manifold as the air velocity thru the carburetor and runners drops to near zero. Use the right parts and it won't bite you!
That's not an inaccurate statement. It will work fine on a daily driver. I don't see why some people hate the DP so much where they have to belittle people. It will work just fine. I did not forget it, and I stand by it. for cryin' out loud I (and most of my friends) had these in High School, we were able to tune them with our limited experience. Why some people say they can't work on a street car is beyond me.
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Originally Posted by toobroketoretire
When well-meaning (but ignorant) people put track racing carburetors on street engines a stall at a low rpm full throttle is what happens. Put a street carburetor on it that has AVS or vacuum secondaries and a stall won't happen. The problem only gets worse when a mechanical secondary carburetor is combined with a large plenum single plane track racing intake manifold as the air velocity thru the carburetor and runners drops to near zero. Use the right parts and it won't bite you!
It doesn't. a) An engineer understands why. b) Any person with a technical background should understand why c) Anyone with a serious interest in how things work should understand why. So, where do you fit in? d) None of the above.
Just to let you know because you have always failed to mention this, vacuum secondary carbs can bog also. When carbs bog, you tune the fuel circuit causing the bog to eliminate it. Double pumpers included. Hard to believe, eh?
Bneezey ... here's something else to consider. I had a '70 Coupe with the 350/350 engine. It developed a problem of when I would stomp on it ... engine seemed like it would shut off until I got off the pedal. It also had another symptom. If I stopped the car when it was hot and then tried to re-start it moments later, it wouldn't fire but would start after it cooled down. It turned out to be the ignition coil. An engine diagnostic test quickly showed the coil was going bad and not providing enough spark. Service tech said it takes a hotter spark to fire a rich mixture than a correct or lean mixture. The under hood heat spike when I shut it off also was enough to degrade the spark to where it wouldn't fire to re-start. A new coil fixed all symptoms.
this whole statement doesn't even make sense. Maybe you can convince F22, COOLTED, diehrd, bluedawg, 427Hotrod, etc., but not me. 
