Solving High Idle Problems: Quad Flow Torque Wing Solving High Idle Problems: Quad Flow Torque Wing
Some of our carbureted snowmobiles have a problem sometimes called the “high idle syndrome”. It’s not predictable, and it can increase or decrease on... Solving High Idle Problems: Quad Flow Torque Wing

Some of our carbureted snowmobiles have a problem sometimes called the “high idle syndrome”. It’s not predictable, and it can increase or decrease on its own. Some riders have gotten off of their sleds and watched in despair as the sled took off on its own without them.

What Causes this? It’s a combination of things. First, the air enters the carburetors in big bursts or chunks. It is not a smooth steady flow like we might believe. With the pistons moving up and down and reed valves opening and closing, the airflow into the engine is all but smooth and fluid. Smaller carbs such as what Yamaha preferred to use have a higher air speed, therefore do a better job of delivering and atomizing the fuel. Larger carbs flow more air at wide open, but at partial throttle settings have lower air speeds, compromising low end performance. The carb design also contributes to the problem. The pilot jet is just a small hole in the bottom of the carb bore that delivers fuel. A portion of this fuel stays on the floor due to capillary action. This fuel puddles and eventually works its way to the reed valve and then slobbers its way into the crankcase. Now the pumping action in the crankcase sends the poorly atomized fuel charge up the transfers and speeds up the engine. Far from ideal, but what can we do about this problem?

You can install a “Quad Flow Torque Wing” into your carburetor. The QFTW has a vertical and a horizontal divider to kill turbulence and speed up the air. The horizontal divider cuts the carb bore in half, only allowing the air to enter the lower half of the carb bore until the carb slide is past half throttle. This keeps the air speed much higher. For example, a 40mm carb now acts much like a 20mm carb with a very high air speed. Now it can do a much better job of atomizing the fuel and eliminating fuel puddling. The high air speed also produces a very noticeable low-end power increase for great holeshots. The QFTW also has a vertical wing because turbulence is multi-directional, not just horizontal. The wings reduce this turbulence, including the reversionary back pulse that takes place in the intake system. You now have the best of both worlds, a high air speed down low to make the engine run clean and a large volume air flow up high to make maximum horsepower.

High Idle problems: Quad Flow Torque Wing

The Quad Flow Torque Wing is a patented performance device for carbureted engines. Mounted on the engine side of the carburetor slide, it increases throttle response and power by accelerating air speed and killing turbulence. Makes big carburetors act like smaller ones at partial throttle settings, giving you the best of both worlds. It is the only flow stabilizer with horizontal and vertical air stabilizers to increase fuel atomization and increase performance. Often imitated and copied, never duplicated. Thirty-one different patent pending models are available.

High Idle Problems : Quad Flow Torque Wing

The Torque Wing is designed to protrude from the end of the carb so you don’t lose control of the 4 air columns in the intake manifold. This takes the flow very close to the reed valve. You will notice that your reed valve is divided in half horizontally and vertically matching your QFTW. Remember air speed and control is your friend, turbulence is not. The QFTW usually wipes out the high idle problem completely; however, if there is any remaining trace, adjusting your fuel screw usually takes care of it. Fuel screws are always on the engine side of the carb slide. Air screws are always on the airbox side of the slide.

The QFTW is now used on motorcycles, snowmobiles, and ATV carburetors as well as EFI throttle bodies. There are now 31 different models available, all protected under U.S. Patent # 9,464,605. $99.95 per carburetor. Contact Thunder Products at 320-597-2700 or visit

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