123 vacuum Adv Distributor

Discussion in 'Product Reviews' started by Andyvan1, Aug 6, 2023.

  1. 77 Westy

    77 Westy Supporter

    Vacuum is the only way a distributor has of knowing how much load there is on the engine, so it can add advance not just with revs but also load. Don't go for the non-vacuum 123, you might as well stay with a 009.
    I've used the 123VW-4-R-V for several years on a Type 4 engine with IDFs, it works fine. I purchased it from Classic Auto Elec in France – not much use for you but it was the best deal I could find at the time.
    If you like fiddling the 123 tune gives you the opportunity to optimise the ignition map for a particular engine under particular conditions. And apparently it can tell you the time, how hot it is etc. just by looking at a mobile 'phone. I believe it can also immobilise the engine, and that feature alone would be enough to make me avoid it.
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  2. Ozziedog

    Ozziedog Supporter

    I’m being swayed bit by bit and I’m thinking mine runs pretty funky anyway with an old 009 . It’ll be interesting to see how much difference there is. As a rolling road type test, I run my van up a certain local hill and I make sure I’m doing forty on the flat before the hill when I hit the forty speed sign then just go as fast as I can until it eventually starts to drop after hitting fifty plus , then once it gets to thirty five, I change down to third and note where I am exactly and that’s how I work out how well everything is running.:)

    Ozziedog,,,,,,,,,,not exactly scientific ,, but I get an idea.:)
  3. Ozziedog

    Ozziedog Supporter

    Oh yeah, as I was saying before I was so rudely interrupted by my failing memory.
    I’m liking what was being said about the vac info to the carb under load. So who do I go to to get one ? In all the links I’ve followed, they’ve usually ended up with a
    123 VW -4-R-V-V is that the same as the one with only one V on the end?
    I’ve a 1641 Mexican / Brazilian with twin 34s and 009 currently.:)

    Ozziedog,,,,,,,,,,, Interesting indeed. :)
  4. When I fitted ICT's I found the vacuum signal really erratic from one even with the anti pulse valve. The signal was much smoother from teeing them both in and it seemed to pull better.



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  5. Cool air have started selling 123s.

    Think we may even get a forum discount from them?
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  6. DubCat

    DubCat Sponsor

    Thanks Geoff. So it's the same model for a type 1 and a type 4?
  7. When we first got the our van it had a 123 vacuum distributor fitted, but the vacuum port on the 123 and the carb were blanked off. I could never figure out why. Finally got around to connecting the two earlier this year. Can't say I've noticed a huge difference, although I'd like to think it accelerates a little smoother under load.

    Is there a good reason why you would not connect the vacuum advance?
  8. https://www.123ignitionshop.com/gb/volkswagen/243-139-123vwrv.html#/1-distributor_cap-straight_r

    "The 123/VW-R-V can be used in all type '1', '2' and '3' VW cars WITH vacuum advance."

    I posted the relevant page from the 123 manual on my build thread. Type 2 (ie bus) 1700 cc ie type 4, curve 9 is what you need:

    Last edited: Aug 10, 2023
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  9. 77 Westy

    77 Westy Supporter

    What Rob said^ :thumbsup:
  10. 77 Westy

    77 Westy Supporter

    I can't think of a reason why you shouldn't. VW never fitted a non-vacuum distributor to any engine.
  11. 77 Westy

    77 Westy Supporter

    If you mean you put your foot to the floor when you say you go as fast as you can you probably wouldn't notice a difference with a 123 with vacuum - the engine develops little vacuum with the throttle wide open. What a vacuum distributor will do is smooth the transition between idle and acceleration and improve fuel consumption because it can advance the ignition when the engine is under light load and the vacuum is high – cruising speed.
    rob.e and DubCat like this.
  12. scrooge95

    scrooge95 Moderator and piggy bank keeper

    Minor and possibly silly question, but has anyone got any top tips for purchasing a relevantly sized t-piece (assuming both of my Dells has the vacuum port drilled?)
  13. 77 Westy

    77 Westy Supporter

    Fairly sure I used a screen washer 'T', like this: https://www.eurocarparts.com/p/t-connector-3mm-barpc15
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  14. scrooge95

    scrooge95 Moderator and piggy bank keeper

    Perfect, thank you.
    Now to find out if my right hand carb is good for vacuum (the left hand is, but just weak apparently. Maybe the two of them, combined with 28 venturis instead of 30s will do the trick.....)
    DubCat likes this.
  15. 77 Westy

    77 Westy Supporter

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  16. mikedjames

    mikedjames Supporter

    If you have a weak vacuum from larger venturis then you need either the 123tune style or another system that allows you to steepen the vacuum advance curve so it takes less vacuum to get the extra 12 degrees timing advance the vacuum buys you..and the economy and mid range torque that goes with it.
    scrooge95 likes this.
  17. Belly

    Belly Button fluff

    RV is the basic one ... RVV the medium one and has usb for connection to laptop or whatever and tune+ the top end bluetooth one

    Also what type of hose are you guys using to link up stuff ?
  18. 77 Westy

    77 Westy Supporter

    Vacuum hose. :thumbsup:
  19. scrooge95

    scrooge95 Moderator and piggy bank keeper

    Surely not?
    Poor Henry.
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  20. Zed

    Zed Gradually getting grumpier

    The venturi doesn't effect the vacuum to the distributor, the throttle plate does that.
    77 Westy likes this.

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