Carburetors versus Electronic Fuel Injection, are there similar traits that should be considered? This concept does appear quite often on-line, and because of this, I am in the pro category. Whatever I post here is not slamming the die-hard carburetor fans and the different mods that are done. It’s just my opinion and I will try to put forth a case supporting this. It is also about the Gold Wing.
Carburetors have been around since the advent of the internal combustion engine (ICE). A tried and true engine component.
The 1000/1100/1200 carbureted models all have four carburetors, and for good reason.
There is limited real estate available for a single large bore carburetor that will be as efficient and provide the same engine performance and fuel economy.
A carburetor is dependent on the engine vacuum to draw the required air and fuel into the cylinder. Having a single large bore carburetor before the air plenum is relying on the air plenum vacuum to draw the required air-fuel mixture into the plenum and be distributed to the various cylinders as required. Possible, yes, probable, no.
The engine vacuum in the plenum will be a mixture of the 4-cylinder vacuums, and be an average of the four cylinders. The engine vacuum is dependent on the health of the engine. Is there any piston ring blowby, is the cylinder compression equal in. all cylinders.
The best engine vacuum for a carburetor is as close as possible to the cylinder intake valve, and after the carburetor throttle plate.
The length of the air-fuel ratio travel to an individual cylinder be it a single or multiple carburetor can be problematic. The further the carburetor is from the engine cylinder; the more wall wetting/puddling will be happening even at normal engine operating temperatures. Getting the correct amount of fuel will be very challenging. The amount of fuel must be increased to compensate for the air-fuel mixture travel.
Changing the carburetor orientation, or converting to a single carburetor will upset the stoichiometric (air-fuel) ratio. Exhaust emissions go out the window.
There are issues with multiple carburetors such as spark plug fouling, mostly because the carburetors are not synchronized. Carburetor jetting is also a culprit.
Any change in the carburetor orientation/placement will require you to account for the changed air flow.
Engine backfiring can be an issue. This is caused by incorrect timing, not much can be done about this unless you are able to adjust the timing and on the carbureted God Wings – not possible. It will primarily be because of excess fuel being drawn into the engine cylinder and not combusted in the cylinder. This unburnt fuel enters the hot exhaust an is ignited. Time to synchronize the carburetors and do some maintenance.
A dirty carburetor is an issue. Over time, the carburetor parts get clogged, become less responsive, and result in decreased engine performance and fuel economy. You can tell when an automobile is carbureted or fuel injected. Drive behind this type of vehicle and inhale the smell of efficiency. This is not to say that a fuel injected vehicle is immune to this.
The next consideration is the single carb club (SCC). This is a conversion from the OEM 4-carburetor setup to a single automotive carburetor normally installed before the air plenum. There are many forum threads regarding this conversion and the installation methods are very ingenious. This modification is for the hobbyist, and IMO, not for the daily or touring rider. There are so many unknowns.
The distribution of the air-fuel mixture is never discussed in these forum threads, but the design of the air plenum is. There are quite a few air plenum design options available, but none are based on empirical data.
The preferred SC is a Solex carburetor, normally associated with a Volkswagen. This carburetor is designed to provide rich air-fuel mixtures when the engine is started, and good driving performance once at normal engine operating temperatures. It is used on other European vehicles such as Porsche, Rolls-Royce and Mercedes Benz.
As mentioned, this is a pig in the poke so to speak as to what is happening to the engine. Is it operating in a lean or rich fuel condition, installation of a wide band O2 (WBO2) sensor would provide a wealth of data. Has the engine performance been improved, most of us would not notice a difference.
Carburetors versus throttle bodies is apparently misunderstood, myself included.
A carburetor mixes the air and fuel in the correct ratio before the air-fuel mixture enters the engine cylinders. A carburetor mixes the air and fuel in the carburetor throat using Bernoulli’s principle.
A throttle body controls the amount of air entering into the engine and does not mix air with fuel. This is done separately after the throttle body using separate fuel injectors. The throttle body is an air flow opening that has the same diameter throughout the air flow passage and does not use Bernoulli’s principle to mis the air with the fuel.
This information is available on-line, but it dovetails nicely with my ECU project from an information perspective. My general disclaimer is that I am paraphrasing what I have found on-line and I'm not the author, but more similar to a news media correspondent, reporting on an issue.
Next post I will relate carburetors to fuel injection.
Carburetors have been around since the advent of the internal combustion engine (ICE). A tried and true engine component.
The 1000/1100/1200 carbureted models all have four carburetors, and for good reason.
There is limited real estate available for a single large bore carburetor that will be as efficient and provide the same engine performance and fuel economy.
A carburetor is dependent on the engine vacuum to draw the required air and fuel into the cylinder. Having a single large bore carburetor before the air plenum is relying on the air plenum vacuum to draw the required air-fuel mixture into the plenum and be distributed to the various cylinders as required. Possible, yes, probable, no.
The engine vacuum in the plenum will be a mixture of the 4-cylinder vacuums, and be an average of the four cylinders. The engine vacuum is dependent on the health of the engine. Is there any piston ring blowby, is the cylinder compression equal in. all cylinders.
The best engine vacuum for a carburetor is as close as possible to the cylinder intake valve, and after the carburetor throttle plate.
The length of the air-fuel ratio travel to an individual cylinder be it a single or multiple carburetor can be problematic. The further the carburetor is from the engine cylinder; the more wall wetting/puddling will be happening even at normal engine operating temperatures. Getting the correct amount of fuel will be very challenging. The amount of fuel must be increased to compensate for the air-fuel mixture travel.
Changing the carburetor orientation, or converting to a single carburetor will upset the stoichiometric (air-fuel) ratio. Exhaust emissions go out the window.
There are issues with multiple carburetors such as spark plug fouling, mostly because the carburetors are not synchronized. Carburetor jetting is also a culprit.
Any change in the carburetor orientation/placement will require you to account for the changed air flow.
Engine backfiring can be an issue. This is caused by incorrect timing, not much can be done about this unless you are able to adjust the timing and on the carbureted God Wings – not possible. It will primarily be because of excess fuel being drawn into the engine cylinder and not combusted in the cylinder. This unburnt fuel enters the hot exhaust an is ignited. Time to synchronize the carburetors and do some maintenance.
A dirty carburetor is an issue. Over time, the carburetor parts get clogged, become less responsive, and result in decreased engine performance and fuel economy. You can tell when an automobile is carbureted or fuel injected. Drive behind this type of vehicle and inhale the smell of efficiency. This is not to say that a fuel injected vehicle is immune to this.
The next consideration is the single carb club (SCC). This is a conversion from the OEM 4-carburetor setup to a single automotive carburetor normally installed before the air plenum. There are many forum threads regarding this conversion and the installation methods are very ingenious. This modification is for the hobbyist, and IMO, not for the daily or touring rider. There are so many unknowns.
The distribution of the air-fuel mixture is never discussed in these forum threads, but the design of the air plenum is. There are quite a few air plenum design options available, but none are based on empirical data.
The preferred SC is a Solex carburetor, normally associated with a Volkswagen. This carburetor is designed to provide rich air-fuel mixtures when the engine is started, and good driving performance once at normal engine operating temperatures. It is used on other European vehicles such as Porsche, Rolls-Royce and Mercedes Benz.
As mentioned, this is a pig in the poke so to speak as to what is happening to the engine. Is it operating in a lean or rich fuel condition, installation of a wide band O2 (WBO2) sensor would provide a wealth of data. Has the engine performance been improved, most of us would not notice a difference.
Carburetors versus throttle bodies is apparently misunderstood, myself included.
A carburetor mixes the air and fuel in the correct ratio before the air-fuel mixture enters the engine cylinders. A carburetor mixes the air and fuel in the carburetor throat using Bernoulli’s principle.
A throttle body controls the amount of air entering into the engine and does not mix air with fuel. This is done separately after the throttle body using separate fuel injectors. The throttle body is an air flow opening that has the same diameter throughout the air flow passage and does not use Bernoulli’s principle to mis the air with the fuel.
This information is available on-line, but it dovetails nicely with my ECU project from an information perspective. My general disclaimer is that I am paraphrasing what I have found on-line and I'm not the author, but more similar to a news media correspondent, reporting on an issue.
Next post I will relate carburetors to fuel injection.
