The carburetor on the V8 ensures acceptable fuel consumption both in city mode and when traveling on the highway. Solex 21083 is one of the best and most reliable domestic devices of this kind. Making changes to its design can help improve dynamic performance or reduce gasoline consumption. The question arises, which jets should be replaced to achieve the desired effect?
To get the answer, you will need to understand the principle of operation of the device. The main task of the carburetor is to create a lean air-fuel mixture. To achieve this, the designers were forced to install fuel jets with a small flow area on the carburetor. The air channels have calibrated holes opposite the increased diameter. As operating practice shows, engine operation in this case remains stable even with sudden changes in modes.
Solex carburetor 21083 jets: types and selection
Solex 21083 carburetor jets are presented in two types: fuel and air.
Air and fuel jets have opposite effects on the composition and quality of the combustible mixture. In the process of increasing the cross-sectional area of the fuel nozzle, an enrichment of the combustible mixture will be observed, and in the case of an air nozzle, a depletion will occur.
It should be taken into account that the degree of their influence is not the same under different operating modes of the Solex 21083 carburetor. If you change the cross-section of the main jet, the composition of the fuel mixture will begin to change in direct proportion for all throttling modes from low loads to full throttle opening.
Also, the effect of the air jet is felt more in the process of increasing the opening angle of the throttle valve.
Thus, if it is necessary to change the composition of the fuel mixture over the entire range of characteristics, then it will be necessary to change the performance of the fuel main jet. To change the characteristics of the combustible mixture composition curve, it is necessary to use an air jet.
From the shown economic characteristics of a car with different performance of the air and fuel jets of the main carburetor system, it follows that if the performance of the fuel main jet increases, fuel consumption will correspondingly increase at all speed modes of the car.
Changing the performance of the air jet allows you to increase fuel consumption only at high speeds of the car. When selecting the most suitable performance of the air and fuel jets, it is important to select the optimal composition of the supplied fuel mixture for a certain operating mode of the car engine.
The correct choice of the necessary characteristics of the metering main system will further determine the smoothness and stability of the engine, this will be especially noticeable at partial loads. While driving around the city, 65% of the time the car operates with the throttle valve slightly closed at the moment the intake pipeline is discharged above 450 mmHg, and also consumes up to 35% of the total amount of fuel.
Results
Of course, it is clear that there is no limit to improvements. Sometimes they can even go to excess: drilling, for example, a throttle valve, polishing an MD, soldering epulsion tubes on a carburetor. But, as they say, what is in excess is unhealthy. But such a procedure, fascinating in its own way, like selecting the types of jets for a Solex 21073 carburetor, for example, is something quite necessary for the correct setup of the unit and its complete compatibility with the engine compartment. As a result, you get an economical car that responds well to gas.
Table of fuel jets for Solex carburetor 21083
During the process of carburetor throttling, one can observe an unstable composition of the fuel mixture over time in the working charges; there is no cycle identity. This has a significant impact on the composition of exhaust gases. Also, the heterogeneous composition of the combustible mixture over cycles can be affected by three factors:
The type of flow of the emulsion mixture from the channel of the main spray system can have a significant impact on the flow structure. Depending on the ratio of the productivity in the dosing jet system and the flow rate of the emulsion, the following types of flow can be obtained: laminar, plug, coarse emulsion, axisymmetric and wave.
Thus, depending on the change in the type of flow from the nozzle of the main emulsion system, the homogeneity of the composition of the fuel mixture in the operating cycles of the car engine will change significantly. The axisymmetric mode is the most optimal for stable operation of the car engine. This can be achieved thanks to a uniform fuel supply.
The air jets of the Solex 21083 carburetor allow you to adjust, together with the fuel jets, the optimal operation of the carburetor. It should be remembered that the location of the air jet of the main system inside the fuel-air main path is undesirable due to the possibility of clogging or tarring of the jet, which can lead to carburetor malfunctions.
This is often observed when engine crankcase gases pass through the carburetor. It is best to place the air jets in special pockets that will protect them from the effects of direct air flow.
In case of modification or tuning of the Solex 21083 carburetor, it is necessary to pay due attention to the selection of jets. This process should be carried out depending on the volume of the car’s engine. Thus, for large engine volumes, for example 1.5-1.7, it is best to use small jets.
Due to the large volume, a lot of air will pass through the diffuser per unit of time, and as a result, significantly more fuel will be consumed. Of course, if you are not going to pump up your car for fast driving, then this will not be so significant for you. Otherwise, it is better to install jets with a smaller cross-section.
It is best to start selecting a jet with a fuel jet, and then move on to choosing an air jet. It should also be noted that you first need to select jets for the first chamber, and after installing the jets on it, you should move on to the second chamber of the carburetor. This is the only way to consider the most correct installation or replacement of jets.
Qualified specialists advise that before starting work, find the original factory Solex 21083 carburetor, which is designed for the same engine size as that installed on your car, and try installing these jets on it. Below is a table of jets for the Solex 21083 carburetor.
Depending on your preferred driving style, you can choose the most optimal jet size for yourself. But keep in mind that when using sport series jets, the fuel consumption of your car can double.
Therefore, if you prefer optimal fuel consumption and a dynamic car, then it is better to choose the middle option, for example “normal power” or “moderate power”. For those who prefer a measured, calm driving style, “economical” jets are best suited. By the way, there is also another modification: Solex carburetor 21083 1107010, it has its advantages.
And the video shows how to choose the right jets for the Solex 21083 carburetor:
Source
Replacement in every detail
Having selected the Solex carburetor jets by numbers, you can begin to replace them; unlike boring, it is quite possible to carry out this operation yourself at home. By the way, the reason is not always an incorrectly selected element; very often during operation, these parts wear out and become clogged, which leads to a change in the diameter and composition of the mixture with all the ensuing consequences. In addition, car owners in this way increase the power of their “iron horse” or, conversely, reduce gasoline consumption. In general, replacing jets is quite suitable in the category of vehicle tuning.
Solex carburetor jets
Carburetors of the Solex family have almost the same design (body, cover). But they have different jets (with different performance), since they are used on engines of different sizes. Let's compare the performance of fuel and air jets of the main carburetor systems of the Solex family. This information can help when checking whether the markings of the jets installed on a particular carburetor correspond to the nominal value or when setting the carburetor to an economical operating mode by selecting jets or a more powerful mode.
Solex carburetor jets, applicability table
Fuel jets GDS carburetors Solex
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | 97,5 | 97,5 |
| 21081-1107010 | 95 | 97,5 |
| 21083-1107010 | 95 | 97,5 |
| 21073-1107010 | 107,5 | 117,5 |
| 21051-1107010 | 105 | 110 |
| 21083-1107010-31 | 95 | 100 |
| 21083-1107010-35 | 95 | 100 |
| 21083-1107010-62 | 80 | 100 |
| 21412 | 95 | 95 |
Location on carburetor
Fuel jet GDS of the first chamber of the Solex 21083 carburetor
Air jets GDS carburetors Solex
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | 165 | 125 |
| 21081-1107010 | 165 | 135 |
| 21083-1107010 | 155 | 125 |
| 21073-1107010 | 150 | 135 |
| 21051-1107010 | 150 | 135 |
| 21083-1107010-31 | 155 | 125 |
| 21083-1107010-35 | 150 | 125 |
| 21083-1107010-62 | 165 | 125 |
| 21412 | 160 | 100 |
Location on carburetor
Details of the MDS (main metering systems) of the Solex 21083 carburetor
Fuel jets for the idle system of Solex carburetors
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | 39-44 | — |
| 21081-1107010 | 39-44 | — |
| 21083-1107010 | 39-44 | — |
| 21073-1107010 | 39-44 | — |
| 21051-1107010 | 37-43 | — |
| 21083-1107010-31 | 38-44 | — |
| 21083-1107010-35 | 38-44 | — |
| 21083-1107010-62 | 50 | — |
| 21412 | 35-41 | — |
Location on carburetor
Electromagnetic valve EPHH of a Solex carburetor with fuel jet CXX
Air jets for the idle system of Solex carburetors
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | 170 | — |
| 21081-1107010 | 170 | — |
| 21083-1107010 | 170 | — |
| 21073-1107010 | 140 | — |
| 21051-1107010 | 140 | — |
| 21083-1107010-31 | 170 | — |
| 21083-1107010-35 | 170 | — |
| 21083-1107010-62 | 160 | — |
| 21412 | 150 | — |
Location on carburetor
Visible elements of the CXX carburetor 2108, 21081, 21083 Solex with the cover removed
Fuel jet of the transition system of the 2nd chamber of the Solex carburetor
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | — | 50 |
| 21081-1107010 | — | 50 |
| 21083-1107010 | — | 50 |
| 21073-1107010 | — | 70 |
| 21051-1107010 | — | 50 |
| 21083-1107010-31 | — | 50 |
| 21083-1107010-35 | — | 80 |
| 21083-1107010-62 | — | 50 |
| 21412 | — | 80 |
Location on carburetor
Fuel nozzle of the transition system of the second chamber of the Solex 2108, 21081, 21083 carburetor, installed in the fuel intake tube
Air jet of the transition system of the 2nd chamber of the Solex carburetor
| Carburetor models | 1st camera | 2nd camera |
| 2108-1107010 | — | 120 |
| 21081-1107010 | — | 120 |
| 21083-1107010 | — | 120 |
| 21073-1107010 | — | 140 |
| 21051-1107010 | — | 150 |
| 21083-1107010-31 | — | 120 |
| 21083-1107010-35 | — | 150 |
| 21083-1107010-62 | — | 120 |
| 21412 | — | 150 |
Location on carburetor
Air jet of the transition system of the second chamber of the Solex carburetor
Fuel jet for GDS carburetor actuator 21083-1107010-62 Solex
Notes and additions
— Solex carburetor jets are interchangeable. That is, you can install jets from another Solex carburetor on your carburetor without any problems, but, for example, with higher or lower performance.
— The transition system of the first chamber of the carburetor does not have its own jets; it is structurally combined with the carburetor idle system.
— The fuel and air jets of the gas pumping system, the fuel jet of the idle system can be unscrewed and replaced, the rest cannot.
More articles on the Solex carburetor
Tags: Solex, factory data, calibrations, 21041, 21073, 21053, 21051, 2108
Comments 39
For UZAM 2.0 in Solex-21041, what jets should I choose?
for starters (without knowing the engine compression, camshaft model) something like this: GTZh1=105-107.5 GVZh1=150ZD GTZh2=115-117.5-120 GVZh2=135ZC UN atomizer 40*40 (make it yourself from two 2108) or 45*40 (from 2108 and 21073) Cam UN No. 5, if not, then use No. 7. No. 4 as a last resort. TJ EMR=60 TJ XX 42.43 and further “to taste”
