Re: Dual exhaust, side thread to what 4bbl
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Re: Dual exhaust, side thread to what 4bbl



Regarding the carb synchronizers, I had a Dan Dvorak synchronizer and used it to tune ol LeRoar.  It was amazing how well it worked.  I would do a show and tell at cruise night and car shows where I would mess up the carbs where it ran rough and nasty. Then I would tune with the synchronizer. People were amazed how the engine smoothed out and purred with that simple device. It's the way to go when tuning multiple carbs. Not unlike using a vac gauge to tune a single carb.

Rich Kinsley '64 Dodge Polara 4dr LeRoar 324 poly w/less goodies 


On Thu, Jan 16, 2014 at 11:31 AM, <stevec@xxxxxxxxxxxxxxxxxxxx> wrote:
I think of the engine as a pump - it can put a set volume of fluid (in this case air and fuel) through it depending on the limitations of the "pump" - be it exhaust, port size, valve lift, carburetor, air filter, etc.  For any given combination, one of the aforementioned parts will be the bottleneck, restricting further flow.  Upgrading that particular component improves flow (performance) and the next most restrictive part becomes the bottleneck.

Looking back at dual quad and six-pack options, the factory definitely made those intakes and carbs capable of flowing more than the rest of the combination.  But being as how they ran (at low throttle openings) on either the primaries of one carb (normally the rear) or the center carb in the case of a six-pack, low speed driveability was not compromised.  At WOT, the engine took what it needed, limited only by the exhaust, port size, valve lift, etc. of that particular combination.  That's why cars equipped with those induction systems responded well to exhaust and camshaft upgrades - the induction system was ready!  

So really, the engine isn't forced to accept the 1000-1200 cfm of the multiple carb systems, it simply takes whatever it can take - could be just 600 cfm, maybe 800 or 900, but since the fuel is metered in relation to the air flowing at WOT, it all works, which was good enough for most folks, and allowed the cars to perform well even with production tolerances and tuning variances.

So could a well-tuned 650 or 750 cfm carb outperform a dual quad?  Probably, unless the dual quad was properly matched and as well tuned as the single carb.  If you're running a dual quad, be sure to read Dan Dvoraks' treatise on multiple carburetor tuning linked from here:


If you don't already have one, by all means get one of his synchronizers - you won't believe what you've been missing without it.

SC


    Dodger7998@xxxxxxx Jan 14 11:05AM -0500  

    Looking for opinions here, several days ago Gary H. made a
    statement,,,,,dual exhaust will not change (carb) air flow needed , this got me
    thinking,,,,,,, please correct me , in my opinion dual exhaust will increase the
    amount of air flow especially during WOT, the benefit of a dual exhaust other
    than sound is it's ability to flow more exhaust fumes, that being said
    during that split second when both exhaust and intake valves are open the
    scavenging effect will increase the HP, by clearing the cylinder better and
    drawing more air and fuel into the cylinder,,,,,,,,,,so my question,,has it
    changed the needed size of CFM carb needed?

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Rich Kinsley '64 Dodge Polara 4dr 318poly w/goodies

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Please address private email -- email of interest to only one person -- directly to that person. That is, email your parts/car transactions and negotiations, as well as other personal messages, only to the intended recipient. Do not just press "reply" and send your email to everyone using the general '62-'65 Clubhouse public email address. This practice will protect your privacy, reduce the total volume of mail and fine-tune the content signal to Mopar topic. Thanks!
 
1962 to 1965 Mopar Clubhouse Discussion Guidelines:
http://www.1962to1965mopar.ornocar.org/mletiq.html and http://www.1962to1965mopar.ornocar.com/general_disclaimer.html.
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You received this message because you are subscribed to the Google Groups "The 1962 to 1965 Mopar Mail List Clubhouse" group.
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