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  1. #21
    RallyRobin
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    Re: Carb Upgrade - S3 Fulvia

    I've been reading through this thread with great interest.

    Can someone enlighten me: were the Dell' DHLB a factory option on Fulvias? Just wondering if they fit the standard manifold. I recently acquired a NOS pair of DHLB 32s (waiting for them to arrive) and I'm wondering if the spacing is the same as the Solex's.

    Thanks!

  2. #22
    Master Lancista fulviafiend's Avatar
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by RallyRobin View Post
    I've been reading through this thread with great interest.

    Can someone enlighten me: were the Dell' DHLB a factory option on Fulvias? Just wondering if they fit the standard manifold. I recently acquired a NOS pair of DHLB 32s (waiting for them to arrive) and I'm wondering if the spacing is the same as the Solex's.

    Thanks!
    I don't think the Dell'Ortos were ever fitted as standard they may have been an option, but my DHLB 35's fit on a standard manifold rubber bracket, with no modifications needed (not including cables etc). Also note that there is no return feed to the fuel tank on DHLB's.

    I'm sure someone will correct me if I'm wrong…

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  3. #23
    Legendary Lancista 1,6 HF's Avatar
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by RallyRobin View Post
    Can someone enlighten me: were the Dell' DHLB a factory option on Fulvias?
    Never fitted as standard or as a factory option--at least not if you believe the factory documents and brochures.

    But I don't doubt that Dell'ortos and Webers were used for aftermarket conversions in period. If Mark is right that the DHLB fits the standard manifold, it must have been a tempting conversion at the time, and it's certainly worth considering now.

    Both Dell'orto DHLAs and Weber DCOEs were homologated for competition on the 1.6HF (and possibly the 1.3HF--I don't have the 1.3HF homologation documents). But DHLAs and DCOEs have a wider spacing between barrels than the standard Solex PHH, so they require a different manifold, which was also homologated.
    Last edited by 1,6 HF; 28th April 2009 at 10:56 AM.
    Ed Levin
    Fulvia 1,6 HF

  4. #24
    RallyRobin
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    Re: Carb Upgrade - S3 Fulvia

    I received my DHLB 32s. I'm not sure how they're jetted yet, but they have 22mm chokes in them. (I'm new to this, so forgive me if this is obvious). Given that:

    a) I read on Viva Lancia that a 31mm choke is recommended for DHLB 35s on a 1.3S engine and,
    b) I can't find either venturis or chokes for DHLB 32s anywhere (including Dellorto UK) and,
    c) it seems impossible to create a 31mm choke for a 32mm barrel anyway and,
    d) I pulled the venturi/choke out of one of the barrels and when I reinstall the venturi, there is no restriction or disruption in the barrel

    Can I just run the 32mm carbs with no chokes installed? This increases each inlet barrel cross section by about 6% - I'm guessing the recommended jetting will change?

    Thanks in advance!

  5. #25
    Site Founder DJ's Avatar
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by RallyRobin View Post
    Can I just run the 32mm carbs with no chokes installed?
    As long as you don't mind NOT having any torque.

    But I don't really know anything (yet) about Fulvias so pay more attention to the responses you get from the Fulvia gurus here.
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  6. #26
    Legendary Lancista 1,6 HF's Avatar
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    Re: Carb Upgrade - S3 Fulvia

    22mm chokes won't give you any power. As all jetting is done relative to the chokes, I think you need to assume that the current jetting reflects the 22mm chokes and won't work very well for anything else.

    31mm chokes sound about right for a 1.3, though you could easily go down to 30mm and possibly 28mm. Within a generally-acceptable range, the larger the chokes the greater the high-end power and the worse the low-end response, while the smaller the chokes the greater the low-end response and torque and the more it tends to run out of high-end revs. Personally, I'd say that 22mm chokes are outside the acceptable range.

    I'm not surprised you can't find any ready retail sources for DHLB chokes. I did a quick search on every source I know of, and I can't find any chokes of any size for DHLBs; as you probably know, they've been discontinued. I'd guess that eBay would be the only real hope.

    As you correctly suspect, 32mm barrels are too small for 31mm chokes; 31mm chokes probably require 35mm barrels, minimum.

    DJ's right; if you try to run open barrels, without chokes, you'll likely have lousy power, lousy torque, and lousy throttle response. "Chokes" are another word for venturis, and carbs depend on the venturi effect to accelerate air through the barrel. WIthout that accelerated air, you won't get proper fuel emulsion--in other words, the fuel and air won't mix well enough.

    I hate to say it, and I hope I'm just being too pessimistic, but I don't think you're going to be able to get DHLB 32s to work well--if at all.
    Last edited by 1,6 HF; 29th April 2009 at 09:10 PM.
    Ed Levin
    Fulvia 1,6 HF

  7. #27
    RallyRobin
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    Re: Carb Upgrade - S3 Fulvia

    Thank you for the response. I think I bought the carbs a bit too quickly - and asked the question a bit too quickly as well. When they arrived, the first thing I did is look down the barrel and saw the shape of the choke and also the cut-out - learning curve.

    Matt at Dellorto UK is having a look for the biggest choke they have for a 32 - I'm guessing it'll be no larger than 25mm - just to give enough wall material to create a smooth transition to the restriction.

  8. #28
    RallyRobin
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    Re: Carb Upgrade - S3 Fulvia

    It seems Dellorto UK has done this setup successfully before (DHLB32 on a 1.3S engine) and Matt was able to set me up with 28mm chokes and recommended jets to get started with. Very quick response from them - very helpful.

  9. #29
    Legendary Lancista 1,6 HF's Avatar
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    Re: Carb Upgrade - S3 Fulvia

    I'm glad to hear you're going to be able to get it sorted; I'm very glad to learn that I was too pessimistic about sourcing chokes for DHLB 32s. I'm not very surprised, however, that 28mm chokes are workable. They won't give you a lot of top-end power, but they should give you great throttle response and excellent low-end torque. As a street set-up it's likely to work fine.
    Ed Levin
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  10. #30
    rossocorsa
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    Re: Carb Upgrade - S3 Fulvia

    to clarify the 35's were a special upgrade that dellorto did specifically for the fulvia it was after market and they are very desirable much better made than the solex and give much better running and performance they fitted straight on the standard manifold and did have the option of fuel return etc as per second series cars I bought a pair new years ago when I ran a fulvia as my daily drive

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