Carburetor idle air bleeds

[Tom Goldman]

If its the approved S/SS NHRA replacement carb , I believe it can only have the primary idle circuit adjustable , and has a non adjustable secondary idle circuit .
Not 100% sure on that , but pretty certain.

[jmarkaudio]

As delivered the secondary is adjustable with short mixture screws, they must be plugged once in competition. They supply lead plugs, much like the emission carbs had the idle screws plugged off. Not real sure why, it offers no real advantage having 4 corner idle.

[Jeff Lee]

Originally Posted by jmarkaudio

As delivered the secondary is adjustable with short mixture screws, they must be plugged once in competition. They supply lead plugs, much like the emission carbs had the idle screws plugged off. Not real sure why, it offers no real advantage having 4 corner idle.

That is correct. I wonder what thought process went into "we'll give them this Holley replacement but hinder them by making the secondary mixture screws adjustable just once"
I guess they wanted to make sure your not driving through the pits at a proper a/f mix if you drive different elevation tracks?

[astikhossw]

Jeff did you have any idle issues with your QF carb.if you did how did you cure the problem, i've seen your dyno video.By the way are you going to make the division race next week.

[Jeff Lee]

Originally Posted by astikhossw

Jeff did you have any idle issues with your QF carb.if you did how did you cure the problem, i've seen your dyno video.By the way are you going to make the division race next week.

The engine was never much below 1500 on the dyno so I don't know what it will be like around 900 or so RPM. Finally installing engine today so we can get final pinion angle factored in and final weld the axle tubes to perches. Spent over a day completely redesigning / machining all parts related to the Browell TO bearing collar to get all parts inside the bell working right. All that stuff ads up to a lot of work!
I will be at Vegas this week. Hopefully Wednesday for TNT

[Philip Baise]

Try this, On the sec. shaft there is a screw that will help adjust the idle. With a 3/32 allen wrench turn this screw 1/4 turn counter clockwise, then adjust your idle on the primary side to compensate for that . Mixture screws in the sec. should be 1 and 1/2 turns out. The primary screws can be 1 or 1 1/2 out (which ever is best for you. And the bleeds were staggered on purpose, 73 pri, 68 sec. Hope that helps.

[astikhossw]

So is there going to be a problem by me swapping over air bleeds,68 fronts,73 rear, for now it idles better and i have control of the mixture screws.I also backed down on the secondary allen screw.

[Tom Goldman]

Originally Posted by jmarkaudio

As delivered the secondary is adjustable with short mixture screws, they must be plugged once in competition. They supply lead plugs, much like the emission carbs had the idle screws plugged off. Not real sure why, it offers no real advantage having 4 corner idle.

We know that , but this is NHRA were talking about .
Their reasoning is the OE didn't have it so neither can you .