Thanks - yes - I have made a few really stupid mistakes - but hopefully nothing expensive! The main mistake i made was to not redo a rod bearing - and have it burn out on engine break in - I will NEVER do that again.
Ok - update - I replaced the 1.55 main jets with 1.44, and still got under 9 AF ratio. So I went down to 1.35 and am getting more normal values. But I also had to lower my Idle Speed screws because the cycling on idle was because I think I was not totally on the idle circuit - and it was making the vacuum on the 1-2 side not open the blow off valve properly on idle...
D3Sshooter youtube channel. He breaks down a few types of weber carburetors. And goes through the characteristics of progression thoroughly. Could help with getting the air mix you're looking for.
Very interesting that it ran without the jets! I learned a lot last summer swapping jet sizes and carb tuning on my son’s car last year. How did you realize that you forgot to install those jets?
I was googling “jetting for blow through supercharger” and other similar things, and it kept referring to the air jet and main jet combo - like 2.00 with 1.45, etc…. Then one evening late at night I was like - holy crap - I didn’t switch over the air jets - are they still on the F11 tubes??? And they sure were! But the thing is, that makes the air hole the size of that top hole where the screwdriver slot is at the very top. So it isn’t that big, but probably like having a 3.50 air jet or something. This process of tuning a home grown supercharger setup has been a roller coaster ride…. Seems like I am close to getting it to work…
so once I lowered the idle speed screw on the 1-2 side, the idle evened out. I think the vacuum line from the manifold, and not being 100% on the idle jet on the 1-2 side was causing the cycling up and down in a mysterious way. It made the blow off valve get vacuum, and then less, and then more and so on. I am down to 1.35 main jets now and still a tad rich when revving. Interesting - the turbo emulsion tubes really do richen it up while revving. so much so, that I went from 1.55 to 1.45 to 1.35 and still not lean.... I only have 2.00 airs (and 1.75) - but would be curious to try 2.10 airs...
Well don’t feel that bad Mike! We all make mistakes sometimes! But we can always learn from them and correct them! Nicely done!👌😎👍
Thanks - yes - I have made a few really stupid mistakes - but hopefully nothing expensive! The main mistake i made was to not redo a rod bearing - and have it burn out on engine break in - I will NEVER do that again.
Ok - update - I replaced the 1.55 main jets with 1.44, and still got under 9 AF ratio. So I went down to 1.35 and am getting more normal values. But I also had to lower my Idle Speed screws because the cycling on idle was because I think I was not totally on the idle circuit - and it was making the vacuum on the 1-2 side not open the blow off valve properly on idle...
D3Sshooter youtube channel. He breaks down a few types of weber carburetors. And goes through the characteristics of progression thoroughly.
Could help with getting the air mix you're looking for.
Very interesting that it ran without the jets! I learned a lot last summer swapping jet sizes and carb tuning on my son’s car last year. How did you realize that you forgot to install those jets?
I was googling “jetting for blow through supercharger” and other similar things, and it kept referring to the air jet and main jet combo - like 2.00 with 1.45, etc…. Then one evening late at night I was like - holy crap - I didn’t switch over the air jets - are they still on the F11 tubes??? And they sure were! But the thing is, that makes the air hole the size of that top hole where the screwdriver slot is at the very top. So it isn’t that big, but probably like having a 3.50 air jet or something. This process of tuning a home grown supercharger setup has been a roller coaster ride…. Seems like I am close to getting it to work…
IDF carbs will idle and run up to 2000 rpm or more, without the emulsion in place. It how you you fine tune the idle jets. Look up videos about.
so once I lowered the idle speed screw on the 1-2 side, the idle evened out. I think the vacuum line from the manifold, and not being 100% on the idle jet on the 1-2 side was causing the cycling up and down in a mysterious way. It made the blow off valve get vacuum, and then less, and then more and so on. I am down to 1.35 main jets now and still a tad rich when revving. Interesting - the turbo emulsion tubes really do richen it up while revving. so much so, that I went from 1.55 to 1.45 to 1.35 and still not lean.... I only have 2.00 airs (and 1.75) - but would be curious to try 2.10 airs...