Where to Spend Your Money First
In past “Carburetor Classes” we discussed individual carburetor components and how they work. But of all the components which are the most critical to going fast or being consistent? All of the lessons about how a carburetor works in theory are useless without practice. Now we will address where on your carburetor you should spend money first.
Carburetors by design are a piece of mechanical equipment that should (in theory) repeat the same task under the same conditions every time. One thing to consider is the fact that there are many parts and pieces of a carburetor that are not metallic and are being constantly subjected to fuel and its corrosive behavior. First things first, get a quality rebuild kit and ensure all of the gaskets, seals and other serviceable items are fresh for the racing season. A good rebuild is the foundation for further modification, and will also give you a chance to clean and familiarize yourself with the carburetor.
When upgrading, you must consider the intended application and the carburetor’s present condition. Since we are all drag racers, it is safe to believe that we want to go fast, not have any surprises during the burnout/staging process, and most importantly, need a certain amount of repeatability. Is your carburetor fairly new, does the throttle work seamlessly, are there any leaks or broken components? These are initial issues that should be addressed before any “performance modifications” are done.
Racing Main Body
Once you have determined your carburetor is acceptable to modify, the next thing that you want to ask yourself is what does the carburetor lack? Does it have certain things about it that are not adjustable? Perhaps it was originally set up for a different type of racing or fuel. There are several companies in the market that make individual components that can address virtually every inch of a carburetor. Our advice to customers who want to start the upgrade process is to purchase components that provide a broader range to work in, making your carburetor more versatile and tuneable. Our fully adjustable metering blocks are a big seller due in part to the fact that they allow customers to address several areas of operating range simply by changing bleeds.
Another starting point is the main body itself. Here at QFT we offer several different main bodies with different booster configurations that allow racers to make their carburetor more specific to the application. A new racing-style main body will also yield more airflow and provide tuneablity in the form of screw-in adjustable air bleeds.
Adjustable Metering Block
There are several ways to make your carburetor function like a purpose-built race carburetor and the aforementioned are just a few examples. Racing is all about efficiency, and your carburetor should be no different: Always keep an eye on the big picture of the carburetor and move slowly. Never discard old parts until you are completely satisfied with your results, and document all of your changes in case you have to step back. Installing parts that are versatile and easy to tune will make life easier; it is one less thing to deal with at the track and allows you to focus on tearing the tree down when the light goes green.