Best resources for learning how to tune Webers? | FerrariChat

Best resources for learning how to tune Webers?

Discussion in 'Technical Q&A' started by nathandarby67, Jan 31, 2016.

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  1. nathandarby67

    nathandarby67 F1 Veteran
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    #1 nathandarby67, Jan 31, 2016
    Last edited by a moderator: Sep 7, 2017
    I just bought this little beauty, a 1974 Alfa Spider. The previous owner did a complete restoration including engine rebuild about 2000 miles ago, and the original SPICA injection was swapped to Weber DCOE's. The car runs good, but to my ear sounds and feels like it's perhaps a tad rich. Also just on general principal I go through and fully service and tune up any car when I first buy it, I want to make sure it's honed razor sharp!

    As a car guy, I am somewhat embarrassed to admit these are my first Webers. I can tune SU's with my eyes closed, but obviously that isn't going to help me much here. What are some good references for learning about Webers? I ordered the Braden book on Webers, but are there any other good resources you'd suggest for a Weber virgin like me?
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  2. nathandarby67

    nathandarby67 F1 Veteran
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  3. Steve Magnusson

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    #3 Steve Magnusson, Jan 31, 2016
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  4. miketuason

    miketuason F1 World Champ
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  5. Streetsurfer

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    Probably nothing new to you guys, but the Ducati Paso, Cagiva Elephant, and 750 Sport (I think all three, and maybe others) used the 44DCNF on it. Ducatipaso.org also has good resources listed for parts and tuning, if any will carry over.
    I checked this Braden book out a couple times from local library while my bike was in service. Never had to do much beside clean my carb after a few years of sitting. It came dialed in pretty good on the LTD Edition.
     
  6. Kevin Rev'n

    Kevin Rev'n Two Time F1 World Champ
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    Look at all those screws!!!!!! Sweet car.
     
  7. jmaienza

    jmaienza Formula Junior

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    Good explanation about how Webers work. Many additional tuning tips on subsequent pages from this site.

    Performance Oriented
     
  8. BJJ

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    #9 BJJ, Feb 1, 2016
    Last edited: Feb 1, 2016
    This is my "bible" and very valuable, since it also lists any and all jet sizes etc. for essentially all 60s and 70s cars, which had Webers fitted by the factory or aftermarket.

    Aside this, tuning really is simple. In almost all cases, where I had the carbs off and in parts (for cleaning and checking), the base settings (idle and mixture) were near perfect with just a minor need of adjustment (the main work being getting the levers for 6 cars well synchronized and free from backlash). Base settings as indicated in the Haynes book.

    Nice Alfa! Since they never were provided with Webers by the factory (as to my knowledge), the only things going wrong might be wrong jets, emulsion pipe, etc., or wrong lift of the accelerator pump. And do not forget to check the needle valve size, but it is presumably 1.50 (standard in the 151, I believe) and this should be sufficient for your car.

    By the way, in yours the choke cable seems to be missing ;).

    Cheers, Bernhard
     
  9. 2NA

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  11. Keith360

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  12. Keith360

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  13. staatsof

    staatsof Nine Time F1 World Champ
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    Count your blessings that there's only two of them and a relatively simple linkage.
    I'm convinced that Beelzebub himself designed the Lamborghini V12 linkage. :D
     
  14. BJJ

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    #15 BJJ, Feb 3, 2016
    Last edited: Feb 3, 2016
    Nope, it was Diavolo Satana himself :D.

    You just need to check that all joints are without backlash, very simple .... :p :D.

    If you have disassembled the carbs and reassembled them with new leather covers on the bearings, then you might be tricked, because the return spring of the carb alone might not be sufficient to close the throttle completely, due to the (initially) stiff fit of the leather on the throttle shaft . If you adjust the linkages without taking close care of that, then you for sure will have fun ... :D

    P.S.: I definitely prefer the 6 DCOEs over the IDL40s (Miura, 4 x triple choke), because in case of the latter it may be very advisable to have a fire extinguisher nearby, if the car suffers misfires for whatever reason .... :D
     
  15. Martin308GTB

    Martin308GTB F1 Rookie

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  16. nathandarby67

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  17. BJJ

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    Have fun! :D

    For checking that all the jets have the proper sizes for your car, according to the list in the left book, you must, however, dissassemble the carbs quite completely ...... :D

    Cheers, Bernhard
     
  18. Wade

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    #20 Wade, Feb 11, 2016
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