Dellorto Dhla 40 skillnader mellan varianter

Dellorto, Weber, trycka eller suga?
crillevolvo
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Blev medlem: ons aug 04, 2010 10:30 pm
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Dellorto Dhla 40 skillnader mellan varianter

Inlägg av crillevolvo »

hej vill försöka få ihop en så komplett lista på skillnader mellan dom olika förgasarvarianterna på dhla40 serierna.samt lista på skillnader mellan dom olika emulsionsrören.

dhla förgasarna har ju en märkning på vänster sida efter dhla typ F G H R samt omärkta vilka sorter finns det mer? samt vad är skillnaderna mellan dessa??
H och G är emissionsförgasare för alfa.


samma fråga gäller emulsionsrören.
vad jag kommit fram till hittils så finns dessa

7772.1
2
3
4
5
6 race lämpig till sugtrimmad b230.
7 race
8 race.är restriktiv på högre varv?? lämplig till b20.
9
10
11
14 lämplig till turbo.
15
16
17

Dellorto Idle Jet Holders (Idle Air Corrector Jets) are not numbered sequentially, but totally randomly. Don't get caught making any assumptions about which one is the next size richer or leaner based upon the number. Go by the following chart:
Weaker ................ Normal .............. Richer
7850.5, .10, .9, .4, .1, .3, .6, .7, .2, .8


Each jet is paired with an air corrector.
Main Jet / Air Corrector Jet
Idle Jet / Idle Air Corrector (Idle Jet Holder)

The jet meters the amount of fuel and the air corrector meters the amount of air that is mixed in the emulsion tubes. The idle circuit feeds the engine up to 3500 rpm (maybe 4000 rpm depending upon how everything is set up) and the main circuit feeds if from there on up. In each range (idle and main), the jet has greater impact on mixture at the low end of the range, and the air corrector has more impact on mixture at the high end. It's not correct to just plug in richer/leaner idle jets without dealing with the air correctors at the same time. The overall capacity of each circuit is limited by the jet each size can only flow so much fuel before it max's out.


From idle, slowly open the throttle slow enough that the accelerator pump isn't much of a factor. If the engine hesitates just off idle, then the idle mixture is too lean.

Set the idle mixture screws all out equally at about 3 to 3.5 turns and adjust the idle speed to get the idle as smooth as possible. Then slooowly open the throttle to increase the speed without help from the accelerator pump. If the engine stumbles, the mixture is too lean. Go to about a two step richer IDLE AIR CORRECTOR (jet holder, not the idle jet) and repeat.

If you get all the way to a 7850.8 air corrector (richest) and it's still too lean, then go to a larger idle jet (like from 40 to 45 or 50 to 55), back down on the air corrector to something mid-range like a 7850.1 and repeat the process working back toward a 7850.8 again. It's putzy, repetitive work, but that's how you get it right.

All that assumes the mixture is lean. If it's too rich to begin with, proceed the other way through progressively leaner combinations. Air correctors first, then the idle jets.

After the best idle jet/ air bleed combination is found, adjust the mixture screws to optimize the idle mixture for the smoothest idle. It's best to use a 4-tube manometer and adjust the screws for the strongest manifold vacuum at idle.

If the jets and bleeds were set correctly, then it shouldn't take more then +/- 1/4 turn of the screws to fine tune the mixture. Be gentle and wait 5-10 seconds between adjustments for the engine to settle down.


That's the no load idle jetting. Under load that may turn out to be too lean. If the engine stumbles under slow acceleration (no accelerator pump), especially at around 3200-3700 rpm, then picks up and keeps going, the idle circuit is running out of fuel capacity before the main circuit kicks in.

If that is so, then go richer on the idle jet until there's no stumble on slow acceleration, but leave the air bleeds alone... you're done with them now. Then adjust the mixture screws to get the smooth idle back (peak manifold vacuum at idle), and adjust the idle speed to around 1000 rpm.

The accelerator pump's affect is felt when the throttle is opened quickly. After the idle jets and air correctors are set, any stumble on rapid acceleration probably involves the accelerator pump, and should be dealt with by adjusting the pump jet and pump stroke (volume). On the Dellortos, you can also adjust the preload of the spring in the accelerator pump linkage to determine if that volume of fuel is squirted in quickly, or over a longer period of time.


Jetting the main circuit is best done with a chassis dyno and Air/Fuel Ratio meter. I'll leave that alone for now.
Senast redigerad av crillevolvo den ons feb 27, 2013 11:52 pm, redigerad totalt 2 gång.
242 -84 stundande renoveringsobjekt. såld till txr performance ab.
944 -91 blivande voc. såld rullar som folkracebil nu.
945 Ltt -97.
DruTTeN
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Blev medlem: tor feb 08, 2007 3:54 pm
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Re: Dellorto Dhla 40 skillnader mellan varianter

Inlägg av DruTTeN »

7or i E rör finns.

6or , 7or och 8or är så kallade race rör och används främst vid sug trimning.
6or är väldigt lämpliga till b23/230 dvs 2,3 liter eller mer då dom ger mer soppa.
8or funkar väldigt bra i b20.
7orna är nånstans mitt emellan.

nr 14 är lämpliga att använda vid turbo bruk.
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