n The Terminal Velocity II Alpha-N Closed-Loop unit gets readings from the built-in exhaust sensor and makes necessary air/fuel adjustments in milliseconds.

he reason the automotive, and now motorcycle industry, are advancing to fuel injection is to comply with the new E.P.A. regulations and emissions controls that become more strict each year. The motorcycle industry understands that fuel injection is the most accurate way of controlling fuel delivery and producing a reduction in emission deposits.
     Just a few years ago there were more new Harley-Davidson motorcycles purchased with carburetors than with fuel-injection systems. Times have changed and it's now the other way around. The one thing that has not changed, though, is the typical Harley owner's desire to personalize their motorcycle to look, sound and perform the way they anticipate. One of the most common changes made to the motorcycle is the choice of exhaust and air induction systems. Some new Harley-Davidson owners, before taking delivery of their new motorcycle, will even increase the motor size to a 95- or a 103-cubic inch displacement.
     Whether the changes are major or minor, any performance upgrades made to a fuel-injected motorcycle will be a disturbance to the factory-installed air/fuel calibration settings in the engine's ECU computer. To run properly, adjustments must be made to give the ECU the necessary "instructions" of how much air and fuel is needed.
     Making the necessary corrections to the factory ECU computer, however, is not as easy as changing the jets in a carburetor. Rather than changing jets mechanically, adjustments in a fuel-injection system are done by the computer as it obtains readings from various sensors on the machine. Monitored are such conditions as ambient temperature, engine temperature, throttle position and others.
     It is important to understand that there are two types of Fuel Injection systems to monitor these many different readings: Open-Loop and Closed-Loop. Harley-Davidson, through 2005, along with most aftermarket companies that manufacture fuel management systems, chose an Open-Loop system to control fuel delivery. This style of fuel control has pre-set fuel calibration tables in either aftermarket or factory ECUs which are very limited to operational changes; it simply cannot adjust on its own. When any changes are made to the motor (exhaust system, air induction or internal motor components) the factory calibration tables are no longer correct, the air/fuel ratio will be incorrect and possibly harmful to the motor.
     This Open-Loop system can be corrected by rewriting new calibration tables to the factory ECU, or by the method of installing aftermarket product, which doesn't change the factory calibration, but changes the output of the factory calibration. It requires lengthy dynamometer testing to chart the countless possibilities of changes from the stock setup. The consumer then selects a revised setting based on what modifications have been made to his motorcycle at that point. That's all good and fine until another modification is made to the bike, and the process starts all over.
     The alternative is the Closed-Loop system which allows for an additional measurement reading in the exhaust. This is the type that was chosen 25 years ago in the automotive industry.

     Keith Terry of Terry Components, a one-time professional baseball player, has been involved in fuel systems since 1967 and with automotive fuel-injection systems since the mid-1980s. A company he once owned was later sold to Magneti-Marelli, one of the world's largest auto parts suppliers.
     "I believe in the Closed-Loop system," said Terry. "I worked in the auto business with it for years and I've always believed that the motorcycle industry would eventually go to it. Apparently that time has come. In addition to what we are doing, Harley-Davidson has introduced a Closed-Loop operational fuel control on their 2006 Dyna Glide."
     Why? He added, "A Closed-Loop operation introduces an oxygen sensor (O2 sensor) into the exhaust stream so that it can monitor the oxygen content while you ride. With the sensor in place, the fuel delivery can be corrected to the factory calibration tables. This method will result in achieving the correct air/fuel ratio."
     Most aftermarket exhaust companies understand the need to properly correct the air/fuel ratios when the aftermarket exhaust systems are being installed. Denis Manning, owner of Bub Enterprises, the manufacturer of both Bub and Rinehart exhaust systems is one that agrees with Terry's preference of the Closed-Loop system.
     At their emissions dyno lab, BUB has had the opportunity to test all the current fuel management systems that are available to correct the fuel delivery as an aftermarket fuel controller. Based on an extensive analysis the results were clear...Terry Components' Terminal Velocity IIª Alpha-N Closed Loop Fuel Management System delivered the best results. Because of this, Manning has decided to install a threaded opening known as a "bung" on all exhaust systems he produces to allow for an easy installation of an O2 sensor. Keith Terry expects other pipe makers to follow.
     Terry Components' Terminal Velocity IIª Alpha-N Closed Loop system constantly tunes the motorcycle as it is ridden. Their computer recalibrates to over 500 times per second to adjust to any load the rider may frequently put on the motorcycle such as going up hills, a passenger or any additional weight that may be introduced that would change load conditions.
     The Terminal Velocity IIª will also automatically compensate when any new component is added to the motorcycle, like exhaust and air induction systems, cams, big bore kits and performance heads. The Terminal Velocity IIª doesn't care! It reads the exhaust stream, analyzes the parts per million and delivers that information in milliseconds to the computer so that it can determine how much fuel is necessary instantly. The same thing happens with changes in altitude. As the air becomes thinner, less air goes out the exhaust. The Terminal Velocity IIª recognizes less air and automatically reduces the amount of fuel delivered.
     The Terminal Velocity IIª will automatically adjust to any component change, altitude and loads without turning a single wrench on the motorcycle or subjecting it to expensive and punishing dynamometer runs. It is a technology used in Formula One racing; by companies such as Toyota, Honda, BMW, Mercedes, General Motors, Ford, Chrysler and Harley-Davidson.
The Terry Components' Terminal Velocity IIª Alpha-N Closed Loop Fuel Management System works with Magneti-Marelli, Delphi and V-Rods, along with many metric motorcycles. Talk to your Drag Specialties sales rep today for more details. 

Terry Components includes the parts for an O2 sensor "bung" with location instructions for exhaust pipes that do not yet come with one as original equipment.