Author Topic: Mixing recipes for idle, primary & secondary circuits?  (Read 2015 times)

Offline beertracker

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Mixing recipes for idle, primary & secondary circuits?
« on: February 16, 2013, 03:38:24 PM »
Being new to q-jets I wanted to ask if you experienced guys ever mix recipes?  By this I mean using recipe #3 for idle circuit and a different recipe for primary & secondary circuits.   Or do you use the same recipe for all circuits?

I am using recipe #3 for the idle circuit.  Should I use recipe #3 for the primary & secondary circuit?  :-\

Setup:
Pontiac 400 cid, 8.6:1 CR, slight head porting, headers, dual exhaust, auto trans, 17057274 q-jet, 2200 rpm stall, Summit 2802 cam:  Cam Style: Hydraulic flat tappet  Duration at 050 inch Lift: 224 int./234 exh.  Valve Lift with Factory Rocker Arm Ratio: 0.466 int./0.488 exh.  Lobe Separation (degrees): 114.

Application is weekend street.  Factory HEI dist.  Ignition advance kit.  Engine has lope at idle before carb work.  My throttle base is NOT drilled for air.

bt


Offline Cliff Ruggles

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Re: Mixing recipes for idle, primary & secondary circuits?
« Reply #1 on: February 17, 2013, 05:50:45 AM »
Nice carburetor, I use the same part number on my 455.  It doesn't need a lot of help in too many places, but will need a lot more idle fuel for your appliation.

Every carburetor should be set up EXACTLY for where it is going to be used.   

Having that much cam in a low compression 400 is going to mandate a lot of idle fuel.  I'd use recipe #3 from the book. 

I'd get one of our kits, and I can spec out the correct jets and metering rods at the same time, so it would be basically "plug and play".....Cliff