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Picked up some brass rod..

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comment_533856

I don't want to go on the cart!

Seriously though...  I'm just a guy with a latte.  :beer:

Those diagonal holes aren't gonna be the easiest thing in the world to do. You'll soon be in the market for a milling machine. Slippery slope I tell ya!!

    • Haha 1
    • Author
    comment_533879

    CO I am a coward and will go the Dellorto Mikuni/Solex route at first.  No angled holes at first.

    s-l1000.jpg            image.png

     

    These will be true "E-Tubes" for "empirical" testing. 

    Quick and dirty to understand the relation ships between hole locations and tube size.  Once this is mapped then angled holes will be tested.

    I plan to make a drilling block that will have guide holes to consistently drill holes in the same location on all tubes.

    I may even try to make a Mikuni solution that fits in a Weber's jet well as a second phase.  Some O rings may be all that is needed to keep the fuel in the tube. Have a look above at the tube on the right.

     

     

     

    comment_533882

    Haha! So the "E" stands for "empirical"! That's awesome! I never knew that!

    Drilling that hole through the center isn't going to be a huge amount of fun either. Sounds simple, but probably won't be as simple as it sounds on paper. They use a special cutting edge geometry for brass that isn't as grabby. You'll know what I'm talking about the first time the bit grabs and spins your chuck in the tailstock.  :D 

    You have a set of collets for the lathe? They lend themselves well to this kind of small, high accuracy work. It's nice to be able to work on one end, cut-off, and then spin the part around to work on the other end with pretty good accuracy using just a collet.

    And your idea of making a block to help locate the holes is a good one. I do that kind of stuff all the time. I've got so many little special purposed fixtures around here that I've forgotten what some of the old ones were for!

    I'm certainly no machinist, but you know how to reach me if you need a sympathetic ear!  :)

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    • Like 1
    • 11 months later...
    • Author
    comment_559408

    Bad pun.

    Back burnered for now.  We just tested F2,F11,F16,and F19 eTubes on the same car and the differences are not significant on 45DCOE carbs.

     

    @blodi The predominant parameter is the tube diameter and it acts like the main jet by making the carb richer or leaner. F19 gave the best results but a non-tunable part of the a/f curve at the start of the main coming in seems to be due to exhaust tuning. It can probably be tuned with a "torque tuner" (A reflecting point added to the exhaust system). Here is how the same problem occurred on a bike and how it was resolved:

     

    Look at how the torquetuner fixed the rich dip between 2500 and 4000 rpm.  It raised it from 12 to 13.

     

    http://www.drdyno.com/AIM_2006-06.html

     

    AIM_06-06_2.jpg

     

    Here is the device: https://www.tabperformance.com/Reduce-Back-Pressure-Exhaust-s/203.htm

     

    It would be needed in the header.

     

     

    • Like 1
    • 3 weeks later...
    comment_560566

    Well, the weather has gotten a lot cooler here and I haven't been able to get into the dyno due to scheduling or weather issues.  Might have to wait til spring on it. 

    The car is about a full point leaner under WOT with the cooler temps due to the air density. 

     

    • Like 1

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