Weber Jetting Survey

[priobe]

Just out of curiousity, not that it makes a difference, but how many of you have successfully tuned a Weber setup on a BB Ford on multiple motors. I have not but it obvious to me that they are not all the same from these post.

How many of you have tuned Weber carbs successfully? Meaning with no more needed adjustments or if adjustment is needed you know exactly why the adjustment is needed.

The reason for these questions is because unless you understand from the begining that this is going to be a learned process of tuning these carbs, then just put a 4 bbl.

I have seen suggested setups with people constantly complaining that it does not work!

Well I am convenience that either no 2 motors are tuned with the same setup or no two tuners are doing the same thing, i.e. mixture screw idle sync of carbs and so forth. I will favor both of these options.

I agree you can get it in ball park but many are having trouble seeing the game.

Personally, I think (1) get your tuning at idle correct. dont worry about wide open throttle right now. Get you car to run right. This is where you will spend 98 % of your time.

Play with Etubes, idle jets , idle holders and main jet
Hint: The larger the idle jet, the richer the mixture the longer the circuit will be engaged.

I personally would not run anything smaller than a 40 mm choke (period)

Pump jet jets are 4.5

Exhaust (at the bottom of the bowl), start off with a 50/ 55. The the ultimate goal here is to not rely on this circuit so the higher the exhaust number the better the tune is becoming. You can use this circuit to mask alot of your problems, however everytime you touch the throttle there is added fuel being delievered.

Idle jet, if you have 55 try it, then move up to a 60 or 65. This will depend on (1) your eTube (2) your main jet. Keep this in mind.

Select your idle jet and you idle jet holder.

Idle jet holder (air) start off with a 70 and open it slightly in .05 increments. Rich to lean

When doing this make sure you remove your main stack so that your car dies around 2200 - 2800 depending on the size of idle jet. The larger the idle jet the longer the rpm range. Remeber you want your main jet to slightly overlap you idle jet

now that you feel you got the feel for how and when the circuit behaves move to your main circuit. Here is a simple BASE formula for main jet choke size x 4 (round up to nearest value of jet). This is pretty much all teh books

Then play with all the Etubes you have. I personaly like the F11 Tube, then F16.

Concentrate on the Etube this will help you dramatically. Many books say that you need a dyno for changing Etubes. I think you can clearly see the difference from tube to tube.

Air jet, put the biggest one you can find on hand. Dont worry about this one right now. But dont step on it either. What you want to do is take you time when tuning these carbs. You are not going to find the magic setup and floor it and be happy.

After you get drivablility and idling good / very good. You should have a grip as to how the system works.

Air corrector you can then use a LM 1 or some other analyzer to to see your fuel ratio.

Again your floats have to be correct, linkage has to be correct and mixture screw has be tune correctly.

Again what I am saying may not work for you but it works for me and I am nolonger complaining about these carbs, nor am I afraid of them. I have invested a ton of money and time teaching myself these cars to my motor to my car resulting in my satisfaction.

I am simply passing on approximatly 3-4 years of my experience with the hope of help others.

Finally most important, I can not stress this enough. warm up the motor!!! My motor runs great but when it reaches optimal temperature what a different motor, different sound, and now its time to let those Webers sing!

Also remeber, temperature, altitude, gearing, cam, ported heads and many many more may play a role in the jetting. So you may not get a direct dial in from 1 motor to another.