One of the most oft asked questions I receive is what exactly are you going to do to my carburetor. I spend quite a bit of my time on the phone describing double step boosters, notched floats or shear stepped banjos just to name a few. So I thought a photo essay might explain things a little better to kind of give you some in-site into what it is we do at Pro-Systems and what to look for in a good carburetor.
Photo 1: Take a look at the booster on the left, notice the thicker base area as compared to the booster on the right. Also notice the booster on the right is equipped with an extra ledge below the radial fuel feed holes. These are all trimming options based on what you need to see happen in the venturi. The thick base is an excellent directive, and the ledge is an excellent additional shear edge to fan the fuel out for greater impact and atomization. But forget about combining them all in one package..these options tend to hate each other as a combination.
Photo 2: 8, 12, 18 or 24 hole emulsion. Some holes are radiused some are not. These are excellent little tweaks that’lll really sharpen up a carburetor.
Photo 3: Notice the drop holes located in the booster. These in some applications offer excellent 330 times, cylinder to cylinder tuneability and throttle response. In other applications they create an uncorrectable forward and rearward fuel bias. When to use them is also based on experience.
Photo 4: The booster banjo on the left has a semi circle cut into the bottom of it. This is an anti-reversion device. It also creates a vortex swirl and really aids in acceleration on some applications. But once again, you can’t use this option all the time.
Photo 5: Notched floats are a necessity. You’ll be real surprised to see how much fuel is evacuated out of your bowl in two seconds at WOT. These notches allow the float to be stabile, drop properly and allow fuel to refill the bowl to keep the engine from going lean.
Photo 6: Aaaah, when to plug an emulsion and when to enlarge them. That choice varies with the power-plant and HP level in relation to signal created and fuel consumed. A simple brass plug in the right spot can realize 10-15 lbs of torque at peak.
Photo 7: This is where carburetors are at in the year 2001. It doesn’t matter what they look like on the shelf (decals and shiny finishes don’t help them out on our fully computerized wet-flow system) , the numbers they show us on this screen are all that matter.
Photo 8: This is our newest design venturi for tunnel ram applications in the 1200-1600 hp range. The venturi alone has shown a 7 hp increase on a top running NHRA Pro-Stock teams dyno. The past peak numbers were the really impressive part. This particular one is for R and D on a Pro-Mod car. We’ll keep you posted on how this turns out.
Photo 9: This was the development piece that we fitted with pitot tubes to allow us to get where we are with the new venturi.
Photo 10: This is a true 1000 HP. Notice the very large bore and extra tubes for trimming throttle response and low end acceleration. Our Trans Am design uses a similar layout. These are a bear to build, but they sure do work.
Photo 11: Tapered reamers. These are a few of my favorites. We have over 70 different tapers to alter the wells in metering blocks. Each one offers different characteristics in fuel pickup and acceleration.
Photo 12: These are our World Record Holding Marine carburetors. At over 182 mph on the water it takes well over 1200 lbs. of fuel and hour to make a boat move that fast. These boats use two engines and four carburetors that have to be synchronized together. So these carburetors are built, wet-flowed and live tested as a balanced set. We try to build all four of them in one day. We’re superstitious like that.
Photo 13: Finally, its the details that make the difference. When you’re scratching for .02 of a mph or so to get a national record. Don’t forget the details. Something as simple as an incorrect inlet tube radius or too light a float will impair your “on track” fuel curve and ruin any chance at a record.
Well I hope this photo essay helped shed some light on what goes on at Pro-Systems. I hope you learned something and if you have any questions feel free to E or call.
Thanks for reading.