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  1. #1
    lanciatomcat
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    Smile Carb Upgrade - S3 Fulvia

    Hi there
    Any advise please on suitable upgrades for my existing solex carbs appreciated. Have pair Dellorto DHLA40's and also some Weber 40 DCOE's that I can get reconditioned if suitable.
    Many thanks
    Tom

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    Re: Carb Upgrade - S3 Fulvia

    I think that you will find 40mm carbs are too big for an unmodified 1.3 engine. You will not see any benefit - and probably a drop in low and mid-range torque with no appreciable top end gain.

    I would look for either a set of good standard Solex 35's (non-emission) or if you can get hold of some (they are hard to come by) a set of Dellorto 35's and maybe a better inlet manifold.

    You can do quite a bit of improvement to the standard set up by matching the ports of the manifold - rubber support joint. Often there are large mismatches at the joint that can be smoothed and the same goes for the manifold - head joint. Nothing too difficult.

    Solex's are not that good, a complete rebuild will make a difference with particular attention paid to the throttle spindle holes in the body. These wear (as do the spindles) and the resultant air leaks make it impossible to set the idel speed. Re-bushing the holes and new spindles make alot of difference. But Dellorto 35's are the way to go - and fit an air filter - those without will suffer from accelerated wear at the TDC point of the bore.

    My 5 pen'eth worth anyway

    Neil

  3. #3
    lanciatomcat
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    Thumbs up Re: Carb Upgrade - S3 Fulvia

    Hi
    Thanks for that. Very informative.
    Have Dellortos & Webers in my 'aladdin's cave' for the Monte and wondered if....!!
    Have a good carb restore man at Leighton Buzzard so will go have a chat with him about costs.
    Tom

  4. #4
    shaun pond
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by lanciatomcat View Post
    Hi
    Thanks for that. Very informative.
    Have Dellortos & Webers in my 'aladdin's cave' for the Monte and wondered if....!!
    Have a good carb restore man at Leighton Buzzard so will go have a chat with him about costs.
    Tom
    Tom, what's your planned use for the car?

    Neil's absolutely right that carbs too large for the induction/combusion/exhaust system of the motor won't provide much gain for normal use.

    You may be able to live with the drawbacks, however, if you are planning/hoping to spend most of your time at the upper end of the RPM range and not intending to use it for grocery getting.. And your carb expert should be able to suggest changes to the internals (e.g. smaller venturis) that at least partially mitigate the low end drive-ability issues and still provide some upside.

    There's another option, which I'm hoping someone will try on a 1.3 Fulvia and report back about: the fuel injection system based on Weber DCOE bodies:
    http://69.0.202.131/html/Fuel_Inject..._Contents1.htm

    Regards

  5. #5
    lanciatomcat
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    Smile Re: Carb Upgrade - S3 Fulvia

    Shaun
    Planned use is really touring not track, or equivalent, use.
    Will discuss rebuild on my existing carbs and see what my man has to suggest.
    The option you gave certainly does look interesting.
    Best regards
    Tom

  6. #6
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by ncundy View Post
    I think that you will find 40mm carbs are too big for an unmodified 1.3 engine. You will not see any benefit - and probably a drop in low and mid-range torque with no appreciable top end gain.
    I hate to quibble with either Neil or Shaun, but in the context of 40DCOEs or 40 Dell'ortos, "40mm carbs" just refers to the size of the barrel; the power/torque characteristics are a function of the main venturi (or 'choke') size. 40DCOEs will accept a wide range of main venturis, from 24mm to 36mm. According to the Weber tech manual, for a 1.3L engine with max hp @ 6000rpm, you'd want 28mm or 30mm main venturis.

    So you could easily use Dell'orto 40s for the street, providing you select the proper venturis. But the real question is 'is it worth the effort'? Dell'ortos and Webers have a wider barrel spacing than Solexes, which means you'd need to change the intake manifold to a replica of those used by the works rally cars; they're available, but not cheap. You'd end up with a far more tunable carb than the Solex, and you'd get to make your own choices about torque versus top-end power, but at a cost.

    But speaking of 'not cheap', Shaun's suggestion of fuel injection using DCOE throttle bodies is an intriguing one--particularly if you combine them with coil-on-piug ignition, all fully software-programmable. Serious overkill of the best possible kind, but not the bargain solution...
    Ed Levin
    Fulvia 1,6 HF

  7. #7
    lanciatomcat
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    Smile Re: Carb Upgrade - S3 Fulvia

    Ed
    Was planning to discuss costs for a Grp 4 manifold with Omicron.
    Appreciate your comments regarding size of chokes etc.,
    Again will investigate costs and use and see which way I go.
    Many thanks
    Tom

  8. #8
    alfaromeo
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    Re: Carb Upgrade - S3 Fulvia

    The chapter president, Harlan Hadley, of the Capital chapter of the Alfa Romeo owners club, has two S1 Fulvia Zagatos and had problems with his Solexes. And, he could not find a pair of 35 mm Dell'Ortos either, but then learned of a source in Italy who specializes and rebuilds the major brands of carbs, including Solex. Harlan has sent this guy a pair and claims that they have been rebuilt very well, supposedly (don't hold me to this) with ball bearings and seals for the throttle shafts..... anyway, Harlan is very pleased with the results and the carbs are performing well.

    On my cars, two have the 35 mm Dells and two have the still original 35 mm Solexes. Certainly, the Dells are superior, yet for the time being, the Solexes are adjustable and both engines run very well with them. I would also say the Solexes seem to tolerate a greater amount of dirty gasoline than the far more sensitive Dells.

    In searching for the elusive Dell'Ortos, I came across leads where they were sometimes fitted as a aftermarket carb for very early Honda Civic engines, I think 1200 cc.... I am referring to the 35 mm Dells, so some Ebay auctions or other listings might be a source for these hard to get carbs. Also, the Japanese firm Mikuni made a copy of the Solex (again, don't ask me about why...) but actually ended up being a much improved copy of the original. Yet, I haven't been able to locate any 35 mm Mikunis for sale yet. I do believe Mikuni had a 44 mm carb that might be a possible fit onto Fulvia 1.6 engines, perhaps Ed knows of this.

    Jay

  9. #9
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    Re: Carb Upgrade - S3 Fulvia

    Mikuni bought the design from Solex when they went bust - IIRC the Mikuni versions were fitted to Celicas. I don't know anyone who has used them, but a quick look on the web shows a variety of sizes. Don't know what the body dimensions are though.

    The details of the chap in Italy are somewhere on Viva-Lancia - Huib has recommended him before.

  10. #10
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    Re: Carb Upgrade - S3 Fulvia

    Quote Originally Posted by alfaromeo View Post
    ...In searching for the elusive Dell'Ortos, I came across leads where they were sometimes fitted as a aftermarket carb for very early Honda Civic engines, I think 1200 cc.... I am referring to the 35 mm Dells, so some Ebay auctions or other listings might be a source for these hard to get carbs. Also, the Japanese firm Mikuni made a copy of the Solex (again, don't ask me about why...) but actually ended up being a much improved copy of the original. Yet, I haven't been able to locate any 35 mm Mikunis for sale yet. I do believe Mikuni had a 44 mm carb that might be a possible fit onto Fulvia 1.6 engines, perhaps Ed knows of this.
    Sorry, I really don't know the Mikunis. Tom's problem isn't sourcing the Dell'ortos--his first post makes it clear that he already has a pair of DHLA 40s--it's really the manifold. Coincidentally, one version just turned up (for maybe cheap) on eBay.it: http://cgi.ebay.com/LANCIA-FULVIA-ZAGATO-INLET-MANIFOLD-WEBER-DELLORTO_W0QQitemZ220391438249QQcmdZViewItemQQptZR icambi_automobili?hash=item220391438249&_trksid=p3 286.c0.m14&_trkparms=66%3A2%7C65%3A10%7C39%3A1%7C2 40%3A1318

    Assuming that they're improved copies of the Solex, 44 Mikunis might well work for a 1.6. The 'normal' S1 1.6 came with 42 Solexes; the variante 1016 version came with 45s, which were really bored-out and restamped 42s. Apparently, these proved temperamental, which is why the works team homologated the wider manifold to allow the use of DCOE/DHLA 45s (and ultimately 48s).
    Ed Levin
    Fulvia 1,6 HF

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