Tuning my webers part two....

[priobe]

Originally Posted by Eljaro

On the main, with 40 mm chokes I have now an F15 with some additional holes drilled up the tube, which has been running quite well, with no transition problems whatsoever with a 145 main jet and 100 air corrector. Yes, an .100 air corrector and the lambda sensor does not lie, the a/f ratio (still rich right now) stays the same up to 6000 rpm.

Eljaro,

Would you say that you have found that the formula that you should take the choke x 4 = Main , then main jet + 60 is not correct?


How is is it that you are using a 100 air corrector?

Also,

have you thought about running the weber with no choke at all ?

May people feel that the webers carbs do not flow enough for the FE engines and here we are running 40 mm chokes

thanks

[Eljaro]

I have used the lambda sensor to tune, and with the larger air corrector the mixture gets lean at the top end. The 100 worked best and the A/F ratio stays steady up to max rpm. I started with the 220 air corrector and went all the way down to 80, but I settled for the 100 which I have now. When I put the 115 on to double check that I am not going astray with the tuning I get a lean top end.
Webers were used on smaller engines when they were popular, and the formula may hold true for them.
I do not think running webers without the chokes will work. The chokes have a distinctive shape inside to create under-pressure for the aux venturis to work.
You con go larger with up to 45mm chokes for the 48IDA.
Top end will probably be some better but driveability will suffer.

[Gaz64]

Two variables swapped at the same time, both towards lean.
I run a F16 in a 1500cc 4 cylinder of mine (DCOEs).

Eljaro is on the money, the old rule of main jet + 60 is out the window.
The air corrector determines main system start point as well as top end.
Just imagine a 300 main and a 360 air, won't work.