Edelbrock 1407 off idle bog

[Baker7888]

Did getting aggressive with the accelerator pump make any sort of difference?

It didnt help the off idle bog. Not sure what it made for a difference honestly other than when i punch it from a rolling cruise it did hit harder.

Changing the linkage setting to richest (did this a while ago) did help, but not cure.

I will try the vac gauge on takeoff. Should help narrow down what’s going on.

 

[Baker7888]

Did getting aggressive with the accelerator pump make any sort of difference?

In doing some general reading, others are suggesting bending the linkage rod? Citing that there’s slack in the linkage and the pump shot comes in too late. Thoughts ?

 

[Baker7888]

How do I determine that bowls are staying full? Just dawned on me that i have a fuel pressure drop when the car warms up. I installed the regulator and gauge after thinking my pressure may be too high (wanted to stall coasting around certain corners)

 

[Rt Jam]

Before you bend anything. Check for pump shot the moment the throttle blade moves. It must be instant.

Yes, the bowl needs to be full since the accelerator pump feed is high in the bowl on Edelscraps. < I've had an easier time tuning in Holley squarebores.

 

[Baker7888]

Before you bend anything. Check for pump shot the moment the throttle blade moves. It must be instant.

Yes, the bowl needs to be full since the accelerator pump feed is high in the bowl on Edelscraps. < I've had an easier time tuning in Holley squarebores.

Thanks RT Jam. How do I determine bowls are staying full?

 

[Wageslave]

Dumb question, but are you running a ported or manifold vacuum source to your vacuum advance? Your setup sounds like one that would really prefer a ported source.

 

[Baker7888]

Dumb question, but are you running a ported or manifold vacuum source to your vacuum advance? Your setup sounds like one that would really prefer a ported source.

Running manifold

 

[Wageslave]

Running manifold

I would try a ported source and see if that helps. It will give you less advance at idle and still keep all of your top end advance.

 

[Baker7888]

Okay I have some results and could really use some insight.

Idle is about 16” of vacuum. Goes up to about 25 with throttle (no load)

Under heavy load it drops to about 5.

Okay. Now for the clutch release. Drops to about zero. Engine falls on its face.

Try again with half choke. Drops to 5+ and takes off beautifully. No clutch shudder either.

Did this multiple times. Went from heaviest to lightest springs. No real change. Bent linkage for less stroke. Ran worse. Took measurements first. Bent linkage back to original. Back at square one. Pump shot is and was immediate. Waiting on rods and jets i ordered so i can only try so much with what i’ve got on hand right now.

So i drove around on ~1/2 choke and man she runs good. Like a whole nother animal. Smooth. And smooth power transition.

I am thinking this is too much carb (air) as much as i hate to say it. I dont know if its possible to tune it out. Need advice!

 

[ELCAM]

When you get the zero vacuum what is the engine RPM?