vizard video on emulsion tube tuning

vector1 · #1 (**permalink**) 12-27-2011, 07:20 AM

thought this would interest a few

Weber Vizard.wmv - YouTube

jhirasak · #2 (**permalink**) 02-07-2012, 06:15 PM

Thanks for the tip on the Vizard discussion on Weber emulsion tubes. Anyone that has a wideband O2 sensor (LM-1 in my case) in their exhaust can use that information to dial in their emulsion tube to account for lean or rich spots during the RPM range instead of going to a dyno.

In my case, the 48 IDA Webers that I purchased came with F7 emulsion tubes. When I drove it during the first jetting test run, it showed that the carbs went pig rich between 2400 to 3400 in each gear during acceleration. Also, the car would not cruise without running rough during this range. To correct for this condition, I selected a set of F11 emulsion tubes, which has high holes at the C and D levels as well as having a diameter of 8mm instead of 7.5mm. This cleared up most of the midrange richness but I am now a bit lean at WOT (approx 13 to 1, would prefer to be closer to 12 to 1). If I had selected the F3 emulsion tube instead of the F11, perhaps I would not have the WOT lean problem. Now, I am trying to decide if I should fatten up the top end with a main jet and air correction jet change or leave well enough alone for street use.

In any case, the Vizard audio on YouTube is worth your time if any of you are trying to correct for midrange fuel ratio or driveability problems and are confused about how to select another emulsion tube.

Comments?

John

big deuce · #3 (**permalink**) 02-07-2012, 07:08 PM

What are your air correctors now? Three steps in the air corrector is like one main jet change. One jet change may be too much, the air corrector might sneak up on the problem.

jhirasak · #4 (**permalink**) 02-07-2012, 07:27 PM

I am now running 110 air correctors. Right now, I do not have any smaller air correctors but I do have several sets of main jets (140, 150, and 155) on hand. I think that I would prefer to try smaller air correctors rather than larger mains since I am still marginally rich in the mid-range.

To get everying dialed in correctly, a person needs to have a large number of different sized jet sets and air correctors on hand. However, an extensive collection of jets and air corrector sets can be a bit expensive, so I am sneaking up to what I think is the preferred combination for my engine by making one small change at a time.

vector1 · #5 (**permalink**) 02-07-2012, 07:33 PM

from my understanding reading what a lot of what i think is knowledgeable information in general and relatively speaking a little richer at peak torque and leaner at max hp is going to give the best results. your 13-1 if at peak hp i wouldn't worry about, that will probably make best power. this is all general as i do not know your engine specs. if it runs good through the rpm range and a/f is not too far off i would say good job! a/f ratio is a tool, not a bible.

big deuce · #6 (**permalink**) 02-07-2012, 08:13 PM

I would feel safe with 12.5 to 13:1 at cruise and obviously less under acceleration.

vector1 · #7 (**permalink**) 02-08-2012, 05:17 AM

i would want cruise at 14 or even 15-1 easily. but everyone to their own.

jhirasak · #8 (**permalink**) 02-08-2012, 06:04 AM

During steady state or cruise conditions at 70 mph, I am now seeing about 13.5 or 14 to 1 A/F ratios. As far as the emulsion tube is concerned, I am happy to stay with the F11 tube.

It has occurred to me that anyone who has gone through the process of dialing in their 48 IDA Webers to their particular car probably has a few extra set of jets that they have determined to be outside of their tuning range for normal changes due to temperature, altitude, and possible additional modifications to their setup. In addition, they also probably would like to have additional jet sets to fill in the sizes that bracket their current settings. This is true in my case where I have two sets of idle jets (50 and 55) that I would like to trade for a set of 60 or 65 idle jets, as well as a set of 155 main jets that I would like to trade for a set of 145 main jets.

What do you think of the idea of setting up a thread to exchange of a set of 48 IDA jets that you no longer need for some to fill in those you would like to have? I think that it would be to the advantage of everyone that runs 48 IDAs to list their excess jet set availability and desires and arrange for a swap using a PM where a match is available. If someone wanted to dispose of a set of jets outright, they could offer them up at half retail price which would still benefit both parties. There would have to be an understanding that any jet set offered by any party must not be altered in any way (i.e. re-drilled to another size). By using Priority Mail with delivery confimation, tracks of exchanges could be assured. Do any of you think that this is workable?

John