Dellorto DHLA 40 universal performance

П’ятниця, 29 Лютого, 2008, 16:54
Розділ: Тюнінг Автор: vovka

Горизонтальні карбюратори Dellorto серії DHLA з розміром заслонки 40mm діляться на два типи:

  1. emission control type. Моделі DHLA 40 F-G-H-N-R-S
  2. universal performance type. Моделі DHLA 40, 40E, 40C

Як правило карбюратори universal performance без проблем настроюються на любому моторі і дають більше потужність на високих оборотах.

Так склалося що в мене є в наявності один карбюратор універсального типу DHLA 40.
Тому я вирішив розмістити фото карбюратора і деяких його комплектуючих, а також викласти деяку інформацію знайдену в буржунеті.
dhla 40 universal performance

dhla serial number 5233P, 105120401102

Дещо про карбюратори universal performance і зокрема DHLA 40 і про його відмінність від emission control карбюраторів.

Type 1 the first DHLA40 (no letter after) if you like the DCOE of the DHLA family, but boasts superior atomisation and tuning ability to the extra research at Dellorto…This carb has an idle jet (which also runs the progression and adds mixture at cruising) that is not connected to the main jet stack, the idle jet operates on its own from the float bowl. Also the idle jet air feed for the emulsion tube is ot fixed at a set size like later models…The main jets run on their own from the float bowl like the idle’s…This gives two seperate circuits that must be tuned for perfect overlap to get good cruise and pickup….This has the benefit on small engines and racing engines and hard tuned engines of giving the ability to make the idle jet progress long or short, you can bring the mains in early and cut back the progression on the idle jet air feed with differing jet holders with differing sized air holes, more air, bigger hole less progression….So you can tune this carb a million ways for million application, Fewsters just got a pair of these. They are the ulimate in tuneablity, they are also as a downside extremely hard to tune without a massive jet box or rolling road, cause they need to be bang on the money. This type of carb uses a .1 venturi which has a bigger pilot hole that the .2 and .3 (ill cover later), this means a bigger signal is generated in the venturi tube which gives a bigger signal (pulsing) to the main jet stack – the venturi feeds the main power circuit into the engine, the big jets. So the .1 vent can tuned to get on the mains right away from very low rpm and are super responsive to tuning, you can delay the vent by adjusting the tubes and air correctors on the main jet stack, so it needs more signal to start the stack feeding the vent or less setup the opposite way, so they can be tuned many ways also.

Type 2 DHLA40E – These are the same as the DHLA40 with seperate circuits and use either 1 or 2 venturi, they have extra progression holes for the idle jet, so the progression phase can be increased in length (over more plate angle) to suit production cars, and aid economy, real smooth runners when setup with lengthy progression. The 2 vent is just like a 1 with tiny bit smaller bore size to the signal tube, so they have fitted .2 often in the E model as they have extended the progression phase and using the .2 vent means they don’t have to delay the mains as much as fitting the .1 vent, so making jetting easier and more responsive. The Elan +2 used these with the 1 vent as its punchy sports car, the Alfa’s used 2 vent and fitted the E model to flagship models with lazyier owners, who like crisp but relaxed power delivery. Power is equal on both types and they can both delivery the same results.

Type 3 DHLA40F-G-H-N-R-S models. These are called emission completely different to the DCOE science, but noone really understands them and tries always to tune them like the early models. These differ because they have more progression holes and use the idle jet to feed most of the cruise phase and low rpm/low TP area of the engine AT ALL TIMES when the main jet isn’t in operation completely automatically no jetting needed. The idle jet has a very large fixed 2.2mm air feed, you cannot tune this phase of the carburetor for length like the others, but here lays the secrets….

The idle jet doesn’t feed from the float bowl, it feeds directly from the main jet stack, what happens after this is what gives these Dell’Ortos the sweetest road behaviour (what 25years of research came up with and not just for emissions) and dead easy tuning, you see when the main jet starts to emulsify fuel in the tube, the idle jet is feeding from it, so the gassy airy fuel shuts down the idle jet and sucks backwards yes BACKWARDS through the idle!! using every drip of fuel efficiently without ANY waste in circuit cross over where one is going after the other…this happens the moment the main jet fires, so there is NO need at all to tune the length of the progression and idle phase. This is pure magic they are automatically calibrated, you simply keep the idle jet above 59 up to 62 and not make the mistake of fitting numbers suited to the early DHLA or DCOE – with this simple technique you can tune anything from a 1300 to a 2000cc without really doing anything. The emulsion tubes in these carbs are always 8-10-11 and have to stay that way – which are really rich and have a hole straight down with loads of air holes, these atomise the fuel to an massive degree, also they have to be used cause the idle jet will not run correctly using the DHLA40-E type tubes (1-6-7-5) as the idle jet needs these airy tubes to function and cut out as designed…Usually people ram the DHLA40 idle holders with air holes in these carbs add the 1-6-5-7 style tubes and wonder why its a massive lean spot off idle, cause they missed the point completely!…These carbs use a .3 vent which has a very small signal tube to the main jet stack, this is because the holey tubes are basically ready to go from about 1250rpm (on my car using an 8tube 1 vent it was on the mains at 1250rpm!) so the holey tubes need holding back with a signal killing venturi…These carbs are wicked if you want bolt on power, they tune themselves!

The early types are better in respect of punch and tuneability on odd applications but dont’ really do anything these late types won’t on all but the best engines…I have run em all! These carbs will give the maximum power available on any engine if you take time to tune them right, but they are a bit more suited to standard motors over 1500cc, motors with mild cams or standard cams and they operate best if you are using 30-33 chokes, they hate race engines, mad cams and mad chokes cause they they are designed mainly for hot production engines with a clear pulse strength to suit the retarded venturi and tubes – great where silk town driving and alike is paramount and you do commuting or just sunday driving, they also give superior economy to the early types.

So the DCOE is the same as the DHLA40, but the DHLA40E and F-G-H-N-L-R-S are all evolutions of a principle and provided the application is matched to the carbs best qualities you have the ability to cater for everyones tastes and requirements using Dellorto…

Ще декілька фото.
Емульсійні трубки
В карбюраторах Dellorto є 16 видів емульсійних трубок 7772.1-7772.16

Ось фото емульсійних трубок 7772.7:
emulsion tube 7772.7
emulsion tube 7772.7

Idle jet holder
В карбюраторах універсального типу буває 10 видів idle jet holder. Від 7850.1 до 7850.10.
От порядок трубок від бідної до багатої:
7850.10, 7850.5, 7850.9,7850.4,7850.1,7850.3,7850.6,7850.7,7850.2,7850.8

Фото idle jet holder 7850.3:
idle jet holder 7850.3

Терміни до статті:

  • dellorto dhla 40
  • dellorto dhla
  • delloorto dhla 40 performance
  • dellorto DHLA40
  • dellorto dhla 40 f
  • Dellorto DHLA 40F
  • adjusting blow through dellorto dhla 40
  • dhla 40 tuning
  • Tuning Dellorto Carbs dlha 40
  • DHLA 40 f

10 коментарів

  1. Do you understand English. my name is brian and i was wondering if you can help me. i have DHLA40N what Idle jet do you recommend for 459cc cylinder 32mm choke i have .57 right now please email me at if you can help me. thank you.

    Коментар by Brian — 7 Квітня, 2008 @ 13:01

  2. hi i have a problem with dellorto dhla40.engine fiat uno1.5 twin dellorto,main jet 148,air correction 210,emulsion7772.11.pump jets40.idle jets 50.chokes 36.aux is for is a problem from idle to full throtle.engine gets a lot of fuel.and in the cocpit i feel a smell of live-gasoline.please help me with this problem i dont know whwt is a problem with it.

    Коментар by emir — 12 Травня, 2008 @ 23:58

  3. […] Придбав на ebay пару карбюраторів Dellorto DHLA 40 universal performance. […]

    Сповіщення by Dellorto DHLA 40 3 progression holes — 17 Серпня, 2008 @ 12:45

  4. Hi there im having problem with my DHLA 40..
    Im currently running the twin DHLA40 in my datsun A15(1500cc 8v) which i install a 270 cam with 1mm extra lift with external fuel pump.

    33 Pump jet
    200 main air bleed
    7727.7 Emulasion Tube
    135 Main Jet
    7850.3 Idle air corrector
    50 Idle jet

    My problem is when i rev above 4000rpm,the engine sound like misfire or flooded??
    But when i deaccelerate n accelerate few times,i will be fine for a very shot period.
    What seems to be the problem?

    Коментар by Ronald — 5 Березня, 2009 @ 15:48

  5. Hi, Do you have any quick info about the dellorto dhla “c” type. Might be right for an alfa romeo Berlina 2000 (giulia type) year 74? many thanks

    Коментар by van — 17 Березня, 2010 @ 16:34

  6. I am Chris from Malta owning an Escort Mk1 with 1700 xflow engine and semi race camshaft. Recently I bought a pair of Dellorto DHLA40H and need to jet them up to suit my engine. Is it possible to help me jetting the right way please?
    At the moment they have:
    34mm chokes
    .3 venturi
    145 main jets
    200 air correcters
    7772.6 emul tubes
    .9 idle holders
    60idle jets
    45 pump jets

    I experienced a flat spot at 4000revs. After that, it flies!
    I appreciate if you can help me please.
    Hope to hear bacj from you soon.

    Коментар by christopher Calleja — 26 Березня, 2010 @ 19:13

  7. У меня проблема с Dellorto dhla40H основной струи 148, 210 воздушных коррекции, emulsion7772.11.pump jets40.idle струй 50.chokes 32.aux vents7848.3
    ЯК гадаэш, диффузор змінити на 36 та які ще кроки потрібно зробити, для кращої роботи на високих 4500-6000об/хв Авто Alfa Alfetta 2.0 Twi Cam вали сток, на розрызних зырочках.

    Коментар by Володимир — 14 Липня, 2010 @ 16:19

  8. hey just wanna say thanks for writing the article it helped me alot on dellorto’s setting up and tuneing cheers mate

    Коментар by matt gr. — 17 Липня, 2010 @ 18:00

  9. Думаю неварто міняти на 36 дифузор – ці карби H не дуже добре з ними працюють. Вважаю краще змінити воздух з 210 на 180-185.
    Також підозріло малі idle jets 50. Там в стандарті під 2.0 альфу помоєму 57-58. а зазвичай під нестандартні мотори требується 60-62 в таких емісіонних карбах.
    Трубка холостого ходу без номера ?

    Коментар by vovka — 7 Серпня, 2010 @ 20:42

  10. Прoшу кого небудь допомогти знайти комплект прокладок и резинок для ТО карбюратора Dellorto 40N

    Коментар by Роман — 16 Лютого, 2011 @ 00:01

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