Congratulations! You have purchased the ACCEL TIMING COMPUTER. Your ACCEL TIMING COMPUTER allows you to pre-program timing curves, for engines at use distributors, from 0 to 16,000 RPM in 500 RPM increments. When reading manifold ressure with a MAP sensor it can adjust timing for vacuum advance and boost retard. It also as inputs for Nitrous Retard and two RPM-activated outputs. You must use your ACCEL TIMING COMPUTER with an ACCEL+ ignition module.
THE TIMING COMPUTER – AN OVERVIEW our new ACCEL TIMING COMPUTER controls the signals that tell your ignition when to fire. must be installed between your triggering device (distributor pickup, crank or magnetic igger, etc.) and your ignition module. our ACCEL TIMING COMPUTER also has two dditional inputs to further adjust timing alues (from a MAP Sensor and a Nitrous olenoid). It outputs timing values to your CCEL+ ignition.
CONNECTING THE ACCEL TIMING COMPUTER TO AN ACCEL IGNITION SYSTEM he ACCEL TIMING COMPUTER uses special signals to communicate with your ACCEL+ gnition, and DIP-Switch-4, inside your ACCEL+ ignition module, must be pushed UP. • Open the ACCEL+ ignition’s cover plate (the one with the wires coming through it). Unscrew the screws and swivel it out of the way to reveal the DIP-Switches. • Using a small tool (A pencil is good) gently push up DIP-Switch-4.
PROGRAMMING YOUR TRIGGER POSITION (Maximum Timing - 34°) good choice to program for trigger position is the maximum timing you’ll ever use plus 2°. 1. With the engine stopped, and the Timing Computer powered off, adjust the trigger Programming Dot (distributor position, crank or mag trigger, etc.) as close to 36° as possible. 2. Press and hold the SAVE and VAC ADV buttons, and apply power. The unit will display a value for Trigger Position. 3.
SETTING TIMING – A BASE CURVE he ACCEL TIMING COMPUTER has been designed to automatically Advance or Retard your gnition timing to meet changing conditions. You must program a Base Timing Curve efore it can make any adjustments. The Base Timing Curve is the timing that takes effect t specific RPM and atmospheric pressure (no Vacuum, no Boost, no N20, open throttle). he Base Curve, and all future adjustments, are done in 1° per 500 RPM increments. 1. Begin by pressing the RPM button.
SETTING VACUUM ADVANCE / BOOST RETARD The ACCEL Timing Computer can program Vacuum and Boost when Manifold Absolute ressure is read with a 2-Bar MAP Sensor. When Vacuum Advance or Boost Retard takes ffect, the whole Base Timing Curve either Advances or Retards. (MAP Sensor info Pg 4) When Retarding timing, the number displayed is subtracted from the Base Timing Curve. When Advancing timing, the number displayed is added to the Base Timing Curve. (Timing, however, can never exceed Maximum Timing.
CONFIGURING WITHOUT A MAP SENSOR lthough we do recommend a MAP Sensor, you can operate without one. For best results se Magnetic Triggering, or a Points Distributor with mechanical advance locked out. o not adjust or remove the Vacuum Advance mechanism on the distributor. 1. Program your Base Timing Curve as described on Pg 6. 2. Set VAC ADV and BOOST RETARD both to 0°. 3. Press SAVE to store all new values. ADJUSTING YOUR IGNITION TIMING TO PROPER SPECIFICATIONS 1.
ACTUATING N2O nstall all your N2O hardware according to the manufacturer’s instructions. If you are sing an ACCEL 3-STAGE REV-LIMITER to trigger N2O, follow the Rev-limiter’s instructions. using a third party’s actuator, follow that manufacturer’s instructions. our new ACCEL TIMING COMPUTER as two RPM-Activated switches connected to two 2-pin connectors. Use one of them to actuate N2O. or consistency use the connector Brown ith theandBROWN and PINK wires.
THE 4-PIN, FLAT, INPUT CONNECTOR he 4-pin, flat connector is your ACCEL TIMING COMPUTER’s main power input. It also inputs signals from the N2O actuator for Nitrous timing retard. RED Connects to +12 volts. BLACK Connects to Ground. GRAY Connects to the Black ground wire from the N2O actuator. YELLOW Connects to the Red +12 volt power wire from the N2O actuator.
THE SQUARE, 4-PIN, MALE INPUT CONNECTOR he ACCEL TIMING COMPUTER inputs from all kinds of trigger types, except distributor-less, nd its digital, micro-processor controlled, rev-limiter will be as sensitive as your trigger. We recommend an ACCEL Billetech Distributor or ACCEL Crank Trigger. Triggering inputs re read through the square male connector: WHITE wire, or the PURPLE and ORANGE wires. Your ACCEL+ ignition system should already have this connector in place.
QUICK REFERENCE When setting Timing this button will show a value for RPM. This button is also used, with other buttons, for other functions. Shows Timing at a selected RPM. It is also used with other buttons for other functions. These buttons increase or decrease the displayed values. Adjusts the entire Timing Curve up, for Vacuum Advance, in 1° increments. Can only be used with an ACCEL 2-Bar MAP Sensor (Part# 74776). Adjusts your entire Timing Curve down, for Boost Retard, in 1° increments.
TROUBLE SHOOTING THE ACCEL TIMING COMPUTER LED’s do The Timing Computer is not getting power. not display Check the 4-Pin connectors’s Red and Black wires. See Pg 10. Timing light does The engine was not retimed when the Timing Computer was not show the originally installed, or the wrong number of cylinders was selected programmed value Re-time the engine. Check the number of cylinders (4, 6, or 8). (Incorrect cylinder selection can also cause incorrect tach readings.
INSTALLATION CHECKLIST Disconnect the battery’s negative (ground) connections. If Nitrous has been installed, disconnect the Nitrous solenoid. (Pg 9) Install the your ACCEL ignition module and set its DIP-Switches. (Pg 4) Connect to the MAP sensor, and N2O Retard, Shift Light, Trigger Input. Connect your ACCEL Timing Computer to your ACCEL+ ignition module. Reconnect the battery. Set and save the number of Cylinders in the Timing Computer. (Pg 4) Program and Save the Trigger Position.
ACCEL TIMING COMPUTER COMPATIBILITY CHART ACCEL SUPER COIL PART # 140009 ACCEL DRAG RACE COIL PART # 140010 Any of the ACCEL+ family of ignition systems, in this case an ACCEL 300+. ACCEL 3-STAGE REV-LIMITER PART # 49345 BILLETECH DISTRIBUTOR Your ACCEL TIMING COMPUTER connects directly to any of the ACCEL Capacitive Discharge ignition systems. If it is connected through an ACCEL 3-STAGE REV-LIMITER, and it outputs to the ignition through the Rev-limiter.
