Carburetor Tuning Thread for B Series

[cbevis]

You should move that pump back towards the tank. Electric pumps do best pushing, not pulling.

What fuel pump?

 

[spock345]

What fuel pump?

The electric pump bolted to the side of the block.

 

[cbevis]

The electric pump bolted to the side of the block.

oh....old picture. That's long gone.

 

[BreckVelo]

I'll post what I am running thus far. But I'm really just getting into tuning this engine. Just got this car/engine combination running this winter.

1966 122S with a B20 and M41 and overdrive conversion. I'm located in Colorado at 9-10,000' elevation. So that is affecting my tuning quite a bit.

Engine:

• B20B bored to .040" over, decked to 0.0" +/-
• Lightened flywheel
• .036" Cometic HG with same tight squish +/-
• E Head with 38/44mm valves, mild porting, double valve springs, 45cc chambers, 11:1 compression???
• Tinus Tuning TT4N cam, with his lifters and pushrods
• 4:2:1 header into 2 1/2" exhaust
• Stock SU manifold
• Open Cone filters
• 123 Distributor

Carbs:

• 42mm dual Mikuni's
• 22.5 Pilot, air screw 2.5 turns out
• 180 Main
• Y6 needle jet
• needle raised 1 notch (richer)

Running 17d advance at idle, max 34d
Just installed a wideband O2 and AFR gauge, still trying to figure out where I want to be with this motor at 10k elevation. It's idling around 14:1, WOT is in the 12-14 range, light throttle cruising it seems to be running rich right around 11:1