Carburetor Operation

Carburetors, contrary to popular opinion, are a very basic device similar in relative design since Henry Ford and his Model T. The same basic things make them tick no matter who designed it. People over the years have heard horror stories about carburetors or maybe even had a bad experience firsthand (who hasn’t been at the race track and witnessed a carburetor fire in their lifetime?) but that should not keep you from learning how one works. So without further ado, it’s time to dispel the myths, lies, and black magic.
The first thing required for a carburetor to function properly is atmospheric pressure. Pressure is the most important variable tied to a carburetor’s performance, and without it one simply will not run! Most carburetors will have a vent tube that acts as a “port” to the fuel bowl; this “port” provides the carburetor with pressure from it’s ambient surroundings and forces the fuel to move through the metering passages as required based on engine demand. Manipulation or changing the length of the fuel bowl port can have dramatic affects on the fuel curve of a carburetor and should only be done with the assistance of a professional engine dyno. Many people think that fuel pressure is what moves fuel through a carburetor and they are which is incorrect. Fuel pressure simply pushes the fuel to the carburetor, atmospheric pressure takes over from there.
Another phenomenon a carburetor requires is something we refer to as draw. Draw is essentially what the engine wants from the carburetor in terms of air and fuel. When an engine starts going through the RPM range, draw will increase (naturally as engine speed increases air and fuel demand will as well). As draw increases a carburetor must react to properly mix the air and fuel together. Air and fuel mixture is very important and varies depending on the type of fuel you use as well the elevation you are racing at. The word carburetor gurus use for the process of mixing air with fuel is “atomization”. Atomization is where things get tricky and some black magic comes to play; carburetor manufacturers, modifiers and other fuel system related companies are always searching for more efficient ways to atomize fuel and air.
So how does the atomized fuel get to where it needs to be? This is a question that many might know the answer to - the Venturi effect - named after the Italian physicist Giovanni Venturi, the Venturi effect is a phenomenon where pressure is reduced after air flows through a constricted area. The constricted area in questions is easy to spot as it is the skinniest part of the “barrel” on a carburetor. To explain a little further, air rushes past the area with the smallest circumference causing it to speed up and form an area of low pressure right below the venturi, this low pressure will in turn pull (remember our term draw) atomized fuel from the booster venturi and send it along to the intake runners. One thing nearly all carburetors have in common no matter how many barrels is the venturi.
To sum it up; a carburetor will not run without atmospheric pressure, something to mix the fuel and a means of getting the fuel to combustion chamber - these are the basics and the details are where performance is found. Carburetor development has come a long way since Henry Ford’s Model T and each new season of racing brings some innovation giving racers an edge. Still foggy on the principals or want to know more? Give us a call, we love talking about these contraptions and helping people make the most of their race car.

knocking of engine

When engine knocking is detected the knock sensor sends electrical signal to the ECU. Directionally as the compression ratio of the engine increases so does the required octane number of the gasoline if engine knocking is to be avoided. Engine knocking is in fact a pulse detonation and we all known what that can do an engine. Thus, the likelihood to engine knocking is reduced and the engine runs more smoothly. Engine knocking is the premature fuel combustion that can result in power loss of the engine. Engine knocking is compression detonation or pre-ignition of fuel in the power stroke of the engine. Engine knocking is normal for 4-stroke bike.

If you have an older car or a high performance car, you may need a higher octane gasoline to help prevent engine knocking and improve engine performance. In order to prevent engine knocking at high rpm's, NGK's high-spark #7 platinums are used. Before leaded gasolines were removed from the market, bromine was used in an additive to help prevent engine "knocking". Motor mount also help prevent or at least minimize engine knocking. There was a need for improvement in the refining process for fuels that would prevent engine knocking and increase engine efficiency. This prevent engine knocking which is very common at the time of a transmission kick down. MMT is a fuel additive, which is mixed with petrol in order to prevent engine knocking. Has been used in gasoline to prevent engine knocking. Lead was originally added to prevent engine knocking. The lead compound TETRAETHEL LEAD was added to gasoline to prevent engine "knocking".

If anything, high octane gas will help reduce engine knocking in most cars (assuming your car's manual says it's okay to use such a gas). Replace Air Filter - Dirty filter can reduce fuel economy by 10% or more. Ethanol in unleaded gasoline helps reduce carbon monoxide emissions by as much as 30 percent. It is oxygen-bearing additive used to reduce engine knocking and assist gasoline burn more cleanly. An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating. Thereafter, the engine performance will peak and emission will reduce. Lead has also been added to gasoline to reduce engine knocking. Standard Oil began adding ethanol to gasoline to increase octane and reduce engine knocking. Lead, in the form of tetra-methyl lead or tetra-ethyl lead, is added to petrol to increase its octane rating to reduce engine knocking. Some manganese compounds have been added to gasoline to boost octane rating and reduce engine knocking.

When engine knocking is detected the knock sensor sends electrical signal to the ECU. Engine knocking is in fact a pulse detonation and we all known what that can do an engine. Thus, the likelihood to engine knocking is reduced and the engine runs more smoothly. Directionally as the compression ratio of the engine increases so does the required octane number of the gasoline if engine knocking is to be avoided.