Hi Guys,

I'm after some information on what sort of fuel economy you're getting from Weber fed 12As. Mine is shocking and with petrol in Aus hovering around the A$1.20 mark, I want to do something about it.

I have a very midly ported 12A with a 48mm DCOE Weber carb. At the moment, I am averaging just over 11MPG (21Litres / 100Klms) around town. On the highway I have managed to get around 24MPG (10L/100Klms).

Based on drivability, my jetting seems perfect, but I would like to compare what I am doing with what everyone else is doing.

My current jetting is :

Chokes : 38mm
Tube : F11
Main : 180
Air : 165
Idle : 76F9
Pump : 55
Pump rod : 10mm
Spring : Soft
Discharge : closed

I know there are a lot of other Weber threads (I have read them all about 10 times over) but noone seems to post back with the results of their jetting changes and what has worked. All the "good" threads have just died off with no outcomes.

If you have a Weber and have read this far, could you please spare a few more seconds of your life to reply to this thread.

Thanks!
--Scott.

 

put some f16 emulsion tubes in, these are leaner in the bottom/mid range area so you will loose some low end acceleration, but your mpg or for you kilometers per litre will improve alot!!
the rest of your jetting is right on the money!!

 

680RWHP12A is a genius !

After swapping etubes from F11 to F16, not only did my economy improve, but I got a MASSIVE increase in mid range power. It has the power curve of a turbo rotary now. Top end (7000rpm on) remained the same and I can't notice any difference in the low end. The midrange difference is so great, that the car would probably be quicker if I didnt rev it out as far, but shifted earlier to drop it back into the power.

Economy is better, I don't have a hangover from the exhaust fumes and I can now cruise at 30mph in 5th with no jurking or carry on.

Thank you very much mate!!!!!