Author Topic: Weber tuning  (Read 275 times)

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Offline dakazman

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Weber tuning
« on: Saturday,November 12, 2022, 04:06:12 PM »
  I found this Weber article interesting. However it has a link into Pinterest. Once there it has a link to
Poustusa.com which is hard to find this article.  https://pin.it/2nH5yos.
So I did the next best thing and took screenshots of the article. About 32 shots . Does anyone have a way to consolidate this.
Dakazman
« Last Edit: Saturday,November 12, 2022, 04:10:56 PM by dakazman »

Offline Richard48Y

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Re: Weber tuning
« Reply #1 on: Saturday,November 12, 2022, 04:48:12 PM »
Meh, they lost me at the first paragraph.
Claiming that you may have HP, Torque, or mileage but not all three.
Tell it to Ferrari, Alfa Romeo, or maybe Europa TC owners.

I think I have at least four different Weber books if I include chapters from factory manuals.
Much easier than dealing with PC's and screen-shots.

Correct idle jet, fuel pressure, and float level are key items.
Wrong idle jets will not let the engine run on the Idle circuit.
Too high fuel pressure messes everything up, Carol Shelby had to learn that to get Cobra's to run decently. You want about 3 PSI, no more than 4 PSI as I recall.
Float level is always important even with SU's or a Holly.

If I recall correctly you have a Wedge engine with single DCOE?
So you are not tuning for Individual Runners.
What is your displacement?
I may be able to look up approximate jetting in my books.
Has the Weber been jetted to this engine in the past or are you starting from scratch?
Do you know the numbers of your current jets?

Like a lot of tuning the first step is to know where you are starting from.

Offline BDA

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Re: Weber tuning
« Reply #2 on: Saturday,November 12, 2022, 04:55:31 PM »
You lost me too, D’man but going to the Pinterest link there were pictures that imply they are talking about this article: https://240260280.com/Tech/Carbs/Weber/DCOE%20Theory%20Operation%20and%20Tuning.html

If not, it’s a good description of how DCOEs work anyway and anyone interested in the inner workings of the DCOE would benefit from it.

Offline BDA

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Re: Weber tuning
« Reply #3 on: Saturday,November 12, 2022, 05:56:17 PM »
In a previous post, I mentioned that I use a ColorTune to set the idle mixture on my car. The attached white paper discusses issues around setting the idle mixture.

Richard is correct about all the things that are important. As a data point, my fuel pressure (regulated by the Facet cube pump I use) is 4 psi (IIRC from the last time I tested it) and it seems to work well. I've heard horror stories of fuel pressure regulators leaking so I'd prefer not to use one. I wouldn't go over 4 psi.

I found this video helpful for measuring the fuel height in the float bowl. You're aiming for 25mm from the top surface where the emulsion tube screws in to the surface of the fuel preferable when you have fuel pressure. It can be tough to see the depth probe of the dial caliper first touch the fuel but when you do, you know you have an accurate measurement. https://www.youtube.com/watch?v=meaGMoH4Pmw

I also found this video very helpful (maybe I mentioned it before): https://www.youtube.com/watch?v=FoUOcPYqDmU

Offline dakazman

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Re: Weber tuning
« Reply #4 on: Saturday,November 12, 2022, 07:24:40 PM »
Bda, scroll up and pick the single top picture. See pic. It took me to the poustusa.com. So I thought I could copy and paste the entire article.

 That looks very close.  I like to read more than one source on things. It’s just for reference only.

 Richard, correct on my build . Stock wedge 1565 with a slightly modded cam.  I also have the stock fuel pump that I do not know the pressures.  I purchased the Weber /Dellorto tuning manual.  The carb was setup previously from another Europa owner.  It’s a 40 and I did go through it and documented what was in it .
  Thanks for more information and will watch the videos, hopefully without interruption.

  Dakazman


« Last Edit: Saturday,November 12, 2022, 07:27:16 PM by dakazman »

Offline Richard48Y

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Re: Weber tuning
« Reply #5 on: Saturday,November 12, 2022, 08:22:02 PM »
If previously used on a similar Europa and well tuned your jetting should be pretty good.
How close is your home altitude?

Offline dakazman

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Re: Weber tuning
« Reply #6 on: Sunday,November 13, 2022, 08:20:07 AM »
   Thanks for all the videos. They will get me off to a good start.
Dakazman