Stewart Warner Performance Catalog - Auto Electric Service, Inc.

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Technical Information Tachometer Interfacing Air/Fuel Ratio TACHOMETERS—HOW THEY WORK: Until recently, tachometers were calibrated based on the number of cylinders in the engine. Now, there are all types of engine control modules (ECMs)(on-board computers) and distributor-less ignitions, and the old standard rule— ”half the number of cylinders equals the pulses per revolution (PPR)”—no longer applies. “Pulses per revolution” relates to how many times the ignition fires per crankshaft revolution. The tachometer outputs from the ECMs can range from 1-PPR to 4-PPR for a V-8 engine. So, the new standard is to refer to PPR instead of the number of cylinders. Stewart Warner Performance Tachometers work with most 2-, 3-, 4-, 5-, and 6-PPR, and our memory tachometers with shift-lights work with 1-PPR as well. This range of pulses per revolution will cover most 1-, 2-, 4-, 6-, 8-, 10-, and 12cylinder engines. Stewart Warner Performance Tachometers are designed to work with a wide variety of ignition types, including standard inductive [coil (-) connection] and any ignition system with a clean tachometer output signal. The input level can range from TTL 5V (outputs from newer engine control modules) and 300-400 volt pulses from coil (-) on most inductive ignition systems. Tachometers will operate on most traditional capacitive discharge (CD) ignitions when connected to the ignition primary circuit. However, for high-output CDs (such as MSD) only connect to the tach output terminal, never the coil primary. It’s best to consult our tech support team if you’re unsure, rather than risk damage to the tach or ignition system. Our Stewart Warner Performance Team is prepared to help you with tachometer installations! Call us a call 1-866-SWP- RACE. Be prepared to provide information about your ignition system. 36 The Air/Fuel Ratio Gauge is essentially a voltmeter that displays the voltage output of an oxygen sensor in order to determine the richness or leanness of the exhaust mixture. Our gauge features four red LEDs (for lean status), 10 yellow LEDs (stoichiometric), and six green LEDs (rich). The first LED comes on at .05V, the second at .10V and so on, in increments of .05V. The gauge is wired to an oxygen sensor (a device that measures the pres- ence of oxygen in the exhaust). More oxygen in the exhaust is a result of a lean air/fuel mixture and less 114902 oxygen is the result of a rich mixture. The “perfect” ratio (not rich or lean) of air and fuel is called the Stoichiometric (STOICH) ratio. Once the STOICH air/fuel ratio is achieved, the oxygen sensor will be very sensitive (i.e. accurate). Although it can’t measure exact richness or leanness, an Air/ Fuel Ratio Gauge provides a good indication of potentially dangerous conditions. For example, a vacuum leak or a drop in fuel pressure could damage your engine (assuming that the air/fuel ratio is too lean). The gauge will reveal this condition before damage occurs. When used in a fuel injected application, the PCM (Powertrain Control Module) uses the oxygen sensor to keep the engine running at the STOICH ratio. It does this by continually crossing the rich/lean point, leaning the mixture until the sensor shows lean, then richening the mixture until is shows rich (and it continues to loop rich and lean). Under heavy acceleration the PCM will keep the mixture rich for optimum power and under de-acceleration the PCM will lean the mixture for optimum economy. The Air/Fuel Ratio Gauge helps determine whether the PCM is functioning properly, and it can also be used with a tuning aid for carburetted engines. Start with rich-jetting, then gradually lean-out the mixture until the gauge shows lean, then richen the air/fuel ratio slightly until there is a rich reading. This should produce the most power, but as always, the final jetting should be verified by inspecting the spark plugs for proper jetting rings. 1-866-797-7223
Voltmeter vs. Ammeter Fuel Gauge Selection A voltmeter measures electrical potential (pressure) in units called volts that is necessary for current measured in amps (a quantity) to flow through your electrical system. If there is NO pressure (volts), there can be NO current flow (amps). This is analogous to having no oil pressure and, therefore, no oil flow. You must have one to get the other! Ammeters were popular when generators and alternators typically 114200 averaged 35-40 amps of output, and vehicle electrical systems were much less complex. Today, alternators commonly have output capacities of 100-110 amps with more complex wiring and higher accessory loads. This makes it more difficult to install an ammeter. Just as we measure oil pressure rather than oil flow, we prefer to measure volts rather than amps, so, the overwhelming choice for performance applications today is the voltmeter. In fact, ammeters are not available as a Stewart Warner Performance product, but they are available in our regular Stewart Warner line should you need one. Contact our tech support team if you have additional questions about ammeters or voltmeters. The bottom-line...an ammeter is NOT an effective solution for racing applications! www.SW-Performance.com WHICH FUEL-LEVEL GAUGE DO I USE FOR MY APPLICA- TION? Stewart Warner Performance can help you figure out which gauge to use. Fuel-level gauges, like electric gauges, are designed to work with specific fuel-level senders. Each sender is designed with a specific resistive input range so you must first measure the resistance of your existing sender. On the top of your sender, you’ll find a couple of wires. Since there are thousands of combinations for different vehicles, refer to your Owner’s Manual or Shop Manual to determine which wire is linked from the sender directly to the gauge. To measure the resistance, disconnect the plug at the sender and use a digital multimeter set for Ohms. Connect one lead of the multimeter to the sender wire and the other lead to the body of the sender (if the sender is grounded through the fuel tank), or to the ground wire of the sender (when the sender is not grounded through the fuel tank). Measure the resistance when the tank is full, and then again when the tank is empty. Once you know the resistance range of your sender, refer to the fuel gauge section of our catalog to find the proper gauge. Then you can “spec” out the right fuel gauge! OHMS/RESISTANCE POPULAR MODELS (EMPTY/FULL) 0-90 Ohms Works on most GM cars, 1965 to present. 73-10 Ohms Works on Fords prior to 1989 & most Chryslers. 240-33.5 Ohms Industry standard, works on many popular cars. 0-30 Ohms Works on most GM cars prior to 1965. 16-158 Ohms Works on most Fords, 1989 & newer. 37
Page 2 and 3: Our Commitment to Performance WHO W
Page 4 and 5: Featured Products NO PLUG-IN MODULE
Page 6 and 7: Featured Products 20 LEDS FOR HIGH-
Page 8 and 9: Featured Products Ultra-Alert Light
Page 10 and 11: Silver Dials Memory Tachs w/Shift-L
Page 12 and 13: Silver Dials Electric Gauges 114255
Page 14 and 15: 114519 Silver Dials Mechanical Gaug
Page 16 and 17: White Dials Memory Tachs w/Shift-Li
Page 18 and 19: White Dials Electric Gauges 114256
Page 20 and 21: White Dials Mechanical Gauges 11452
Page 22 and 23: Black Dials Memory Tachs w/Shift-Li
Page 24 and 25: Black Dials Electric Gauges 114254
Page 26 and 27: 114518 Black Dials Mechanical Gauge
Page 28 and 29: Trucks Ford Gauge Pods 114818 92-97
Page 30 and 31: Accessories Mounting Cup Kits 2-1/1
Page 32 and 33: Accessories Tubing/Adapters/Bushing
Page 34 and 35: Dimensions, Wiring Note: All dimens
Page 36 and 37: Technical Information Electrical Ga
Page 40 and 41: Gauge Family Cross-Reference SILVER
Page 42 and 43: Gauge Pod Cross-Reference SW-Perfor

Stewart Warner Performance Catalog - Auto Electric Service, Inc.

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