14.7 to 1
I am on a mission. I guess I have really been on this mission for a while. I am actually thinking of the whole human race when I say I would like to rid the world of the carburetor. I can hear the cries. Blasphemy!
The carburetor is SIMPLE and it WORKS and it COSTS LESS.
The carburetor has pretty much been around since the beginning of the automobile. It was invented to mix the fuel with the air entering the engine. It has always mostly been a mechanical device. An impressive one at that.
For a gasoline engine to run it requires a constant supply of air and fuel. The air to fuel ratio that produces the most perfect explosion to power your vehicle is 14.7 to 1. At this ratio all the fuel is burned and it is arguably the cleanest burn.
The carburetor was designed to provide this ratio of air to fuel. Unfortunately by design the carburetor is less than perfect at feeding every cylinder in your vehicle a continuous diet of 14.7 grams of air for every gram of fuel.
Most carburetors are centrally located on the engine. In that position they do not feed fuel evenly to all the cylinders. One cylinder’s 14.7 to 1 is another cylinder’s 13.0 to 1 where another’s might be 16 to 1. With this variation the 13.0 to 1 cylinder will actually produce a little more power than the 14.7 to 1 ideal at the expense of using a little more fuel and little more pollution for our atmosphere. The 16.0 to 1 cylinder will be short on power, efficient on fuel but it might result in some excess nitrous oxides for our environment.
Thus you cannot buy a vehicle equipped with a carburetor anymore. That kind of cylinder to cylinder variation just will not satisfy our current emission standards. We now use a electronically controlled fuel injector for each cylinder. The fuel is sprayed directly into the cylinder (direct injection) or into the air stream just before the cylinder. Each cylinder receives a precise amount of fuel. Each cylinder produces the same power and the same level of emissions.
An important side benefit of precise fuel control is the longevity factor. Have you ever wondered why you can now easily drive two hundred thousand kilometres without any major engine repairs? Even fuel distribution.
So if no vehicles are built with carburetors anymore my mission is complete, right? Not quite.
The performance industry still sells carburetors. Those of us (me included) who like to tinker with automobiles (old and new) are generally looking for increased performance. If the vehicle already had a carburetor the most cost effective fuel system is another carburetor.
A performance carburetor will be sized and set up to feed fuel at less than 14.7 to 1. Extra fuel means extra power and guarantees none of the cylinders will get short changed.
Some tinkerers will even change a fuel injected vehicle to carburetion. When the size of an engine is changed (ie bigger) the fuel injection system may not be up to providing the required amount of fuel. New larger fuel injectors, a larger fuel pump and new software for the computer that runs the fuel injection will cost significantly more than a bigger carburetor.
I am suggesting there are adjustable fuel injection systems that can provide the performance improvements us tinkerers are looking for. In the process of installing them we learn the new technology, we hopefully burn less fuel and our performance engine will last longer due to precise fuel distribution.
Spend a little extra money, save the planet a little, and learn something new. I have spoken.