FODDER AIR/FUEL. Introducing the latest tools for datalogging your air/fuel ratio and what to do with that valuable information.

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1 AIR/FUEL FODDER Introducing the latest tools for datalogging your air/fuel ratio and what to do with that valuable information. BY EVAN J. SMITH n the current era of performance, one of the toughest challenges for enthusiasts and racers is tuning a modified engine. Tuning refers to the process of dialing in or calibrating the fuel and ignition timing curves (or maps), which allows the engine to run with the proper air/fuel ratio under all driving conditions. Finding the proper air/fuel ratio is necessary in order for the engine to have the best power, reliability, and driveability. If your beast is experiencing lean or rich conditions, I 196 There are quite a few manufacturers selling systems to monitor and record air/fuel ratios. The three we ve included are the O2 Alert from Altronics, Dynojet s Wide Band Commander, and Innovate Motorsport s LM-1. Each kit uses a Bosch wide-band oxygen sensor that can accurately monitor air/fuel ratio from 9:1 to 20:1.

2 chances are it won t be much fun to drive. New-car manufacturers achieve proper calibration only after spending millions of dollars and thousands of man-hours testing vehicles. They sometimes spend months or years driving and dyno testing in various weather conditions. And they do so for every vehicle that rolls down the line. Manufacturers use sophisticated and often expensive equipment to get the best driveability during cold start, cold and warm idle, part-throttle cruise, and wide-open throttle. Most vehicles are also tuned to handle extreme circumstances such as towing, extended periods of idling, running in the desert, and at high altitude. Equally important to the manufacturers is fuel consumption, so efficiency is a big part of any calibration. And, after it s all said and done, we car nuts take these perfectly calibrated engines and alter them, throwing on bigger intakes, headers, different cams, forced induction, and more. So the question then becomes, Dynojet s Wide Band Commander allows you to datalog air/fuel ratio, engine rpm, and throttle position. This kit installs easily and retails for $530. It includes the WBC control module, a 270-degree full-sweep electric air/fuel gauge, a Bosch five-wire LSU4 wideband O 2 sensor, an O 2 harness, a multifunction cable, a power cable, a USB cable, a sensor bung and plug, mounting hardware, and WBC software. The LM-1 has many options, but the basic unit retails for about $349. Altronics O 2 Alert can be equipped with two oxygen sensors and includes a warning output that helps protect against lean-out. The basic kit includes one sensor, a USB cable, the control box, and system software. This kit can log engine rpm and battery voltage. It can be upgraded with EGT thermocouplers and two analog outputs for pressure, flow, and position sensors. Altronics O 2 Alert features this relatively small aluminum readout box with a backlit display. A personal computer is not needed as the playback can be viewed on the screen, however, the kit includes software so graphs can be seen on your personal computer. The warning system can activate a light, enable fuel enrichment, shut down nitrous, or retard the timing. Innovate Motorsports LM-1 is one of the hottest units on the market. It has a sampling rate of 12 samples per second and can record up to 44 minutes. Installation is easy, as you can be up and running in a matter of minutes. 198

3 how can you ensure your engine stays in proper tune once it has been modified? The solution lies in one of today s technologically advanced wide-band air/fuel monitors such as Altronics O 2 Alert, Dynojet s Wide Band Commander, or Innovate Motorsport s LM-1. With one of these kits the average car guy or gal can gather the information needed to dial-in almost any highperformance engine. And while tuning your engine properly takes some experience, with an understanding of fueling, ignition timing, and ECU (or carburetor) function, you can affordably do your own tuning. NEED TO FEED(BACK) About 20 years ago, auto manufacturers began to employ oxygen-feedback systems on new cars. These early systems were used to help engines run cleaner with less emissions resulting from combustion. As time passed, the systems and the equipment, namely the computers and oxygen sensors, became better and better. Today s cars run very clean, and even the typical racer or hot rodder has realized the benefits that can be had from such a system. Early aftermarket systems used narrowband O 2 sensors that could tell only if the engine was running right at 14.7:1 air/fuel ratio. Therefore, it drew only a vague picture of rich and lean. But things have changed, as almost all the aftermarket kits now use a wide-band O 2 sensor that can chart the air/fuel ratio between roughly 9:1 and 20:1. Along with this, these systems use advanced, yet affordable, logging computers so the end user gets easy-to-use information that is easily digested. This is important because tuning with air/fuel data is far more accurate than using EGT readings, or even reading spark plugs. Best of all, the systems listed install easily, so you can tune at the track or on the road, as well as on the dyno. When beginning to dial in any engine, the tuner will want to extract the most available horsepower and torque. He will also want to make sure the engine remains in good running order in other words, he doesn t want it to blow up. This generally means The Wide Band Commander uses this module that is mounted in the vehicle. It is necessary to use a PC to download and view the information with this system. Knowing the exact air/fuel ratio makes it much easier to dial in the jetting on your carburetor. Without some type of air/fuel monitoring system, it is extremely difficult to tune forcedinduction or nitrous-equipped engines. OCTOBER

4 avoiding detonation, which is a serious killer of high-performance engines. Before any tuning session, be it at the track, on the dyno, or on the street, the tuner should also be certain the vehicle is in good running order. This will limit any potential problems. Next, you will need some datagathering equipment, such as one of the air/fuel meters listed previously. Other common tools used are exhaust gas temperature (EGT) meters, which measure the temperature of the exhaust gasses in the header(s), as well as vacuum gauges and fuel-flow meters. Fortunately, you can do almost 100 percent of the tuning using a quality air/fuel meter. But how do you know what the proper actual air/fuel ratio should be? As mentioned earlier, manufacturers began using oxygenfeedback systems on new cars some years ago. These systems monitor the oxygen content in the exhaust with the use of oxygen sensors, which relay the running conditions of the engine (rich or lean) to the engine management computer. The programs can add or trim the fueling of the engine to maintain the most efficient mixture for the given driving conditions. This may be 15.0:1 during cruise or 12.5:1 at WOT. At light cruise the mixture will be lean to help achieve good fuel economy, whereas more fuel will be added when the throttle is depressed for acceleration. And with modern EFI, we can fine-tune for the wide variety of driving conditions and loads that the engine sees. Holley offers this jet kit with a complete range of jets. In order to tune your fuel-injected engine, you will need to get one of the handheld tuners or have a chip burned for your applications. Where carbureted engines use jets, EFI uses fuel injectors with different flow rates. Fuel flow can also be adjusted with fuel pressure and/or by altering the pulse width, which is the amount of time the injectors stay open. 200 Another way to tune your fuel injection is with a stand-alone EFI system such as this one from ACCEL/DFI. With a system like this you can custom tailor all aspects of fuel and ignition timing for all driving situation.

5 IN COMMAND While the electronics on each of the systems is impressive, none of this would be possible without the five-wire LSU4 Bosch wide-band oxygen sensors. These sensors have the ability to precisely indicate the oxygen content in the exhaust flow. By measuring the level of oxygen in the exhaust flow, the sensor can relay the information and the computer can determine how rich or lean the mixture is. A typical production vehicle, along with many of the aftermarket systems, uses sensors that have a very narrow resolution, says Dan Hourigan of Dynojet. They are inexpensive and can tell you only if the engine is richer or leaner than 14.7:1, but they can t accurately monitor and datalog the air/fuel ratio like our system can. The Wide Band Commander gives you everything you need to accurately monitor your air/fuel ratio. In most cases, the target air/fuel ratio for naturally aspirated engines will be between 12.8:1 and 13.2:1, whereas supercharged, turbocharged, and nitrousinjected engines will like a richer mixture between 11.5:1 and 12.5:1. Each vehicle is different, but we give you the ability to datalog and tune based on the actual amount of air and fuel that your engine is consuming. I ve found that using this equipment in conjunction with chassis or engine dyno testing can bring some fantastic results, but using it at the track works well, too. In fact, most tuners who use a chassis dyno rely on air/fuel datalogging to accurately build a fuel curve for each vehicle. Road and track testing is still a big part of it, but dialing in the proper air/fuel ratio is what most tuners look for when tuning for power and economy, Most wide-band air/fuel systems rely on the Bosch LSU 4.2 wide-band oxygen sensor. Unlike earlier narrow-band sensors, which knew only if the air/fuel ratio was at or near 14.7:1, the newer sensors remain accurate from about 9:1 up to 20:1. In order to prevent the sensor from contamination, it should be located in the top half of the pipe. This will prevent condensation from getting in the sensor. 202 At the heart of any air/fuel measuring system is the oxygen sensor. Most modern kits use a Bosch wide-band sensor that is capable of monitoring the exact air/fuel ratio across a wide range. The oxygen sensor will sit directly in the path of the exhaust gasses normally in the header collector or downpipe after the exhaust manifold.

6 and the chassis dyno is a great tool for that. In addition to measuring and recording air/fuel, rpm, and throttle position, the Wide Band Commander also has three programmable relay outputs that can be used to control a circuit based on one, two, or three of the WBC inputs, Hourigan says. This means that before the system will activate the circuit (like a nitrous solenoid), it will look at up to three parameters, and if they are not met, the switch will not turn on. THE MODERN TUNE As many of you know, there are a host of hand-held tuners, highly advanced chips, and many specialty speed/performance shops capable of dialing in even the most serious high-horsepower machines. And while most of the dyno shops have some type of wideband oxygen sensor to record air/fuel ratio, the systems are connected to the dyno and are used in-house only. These are great if you keep the car on the dyno, but once the car leaves there is no way to keep track of the air/fuel ratio in most vehicles. But this isn t a problem with the listed systems because they are installed in the vehicle. These days, tuning with air/fuel has surpassed many of the older, tried-and-true techniques. While measuring EGT and reading spark plugs works on race cars that can be run wide open and then safely shut off, this just isn t a feasible way to tune on the street. According to Hourigan, Racers or street enthusiasts looking for maximum performance Many engine builders use oxygen feedback when dyno testing. You can even dyno test with one of the listed kits and then transfer the kit to the vehicle to make sure the tune doesn t change from the dyno to the street or track. 204 Each of the kits comes with software so the information can be downloaded and viewed on the computer.

7 should be concerned with knowing the air/fuel ratio of their engines. This is one of the most insightful tuning tools because it can allow you to end up with a powerful yet safe engine tune-up. For every type of fuel (gasoline, methanol, nitromethane, and so on) there s a perfect air-to-fuel ratio that will result in complete combustion of the fuel during the combustion cycle. When this occurs, all the heat energy of the fuel is released and the engine is said to be running efficiently. When gasoline is used, this perfect ratio is 14.7:1 (but this changes under heavy throttle load). This 14.7:1 ratio is termed the stoichiometric ratio. Therefore, when an internal combustion engine is running at 14.7:1, all the fuel will theoretically be burned and optimum fuel efficiency will be achieved. But 14.7:1 is not the perfect ratio for all driving conditions. For instance, idle and partthrottle cruise can withstand a leaner air/fuel ratio upward of 15:1, but stick your foot in it and a richer mixture such as 12.5:1 is required. Under heavy load, such as in racing, lean conditions can lead to misfire, a stumble, and at the worst detonation. An overly rich mixture often leads to increased emissions and a reduction in power. You ll also notice fouled plugs as well as stumble and misfire. In the future, we plan to put these units to the test and do some tuning. They are the perfect tool for the self-tuner or even for someone who just wants some extra information. Dynojet s kit comes with an easy-to-read gauge that the driver can see while on the street or track. S O U R C E S ALTRONICS Dept. MMFF 1411 S. Roselle Rd. Schaumburg, IL / DYNOJET RESEARCH Dept. MMFF 2191 Mendenhall Dr. N. Las Vegas, NV / INNOVATE MOTORSPORTS Dept. MMFF 5 Jenner, Ste. 100 Irvine, CA / Innovate s LM-1 kit (top to bottom) can be optioned with this LC-1 Lamda cable. According to Innovate, The LC-1 cable is a complete wide-band controller built into a sealed cable. It features the same awardwinning, patented digital measurement principal found in the LM-1, and includes digital input, output, and two programmable analog outputs. 206