If a vehicle doesn't have an electrical system to power the WEGO™ system, an easy solution is to use a small 12 volt sealed lead acid battery and battery charger.
In addition, you can use a Patco® Model #3202P Charger will recharge the battery in about 2 hours. Also required is a Patco® Model #4010P Hookup Cable. These items are readily available from Digi-Key® online (www.digikey.com)
LASCAR® Electronics (www.lascarelectronics.com) offers a wide variety of inexpensive programmable displays with analog inputs. These displays can be powered from +12 volts and are compatible with standard zero to +5 volt TPS sensors.
The customer can easily program an almost infinite combination of styles, legends, colors, and ranges using their free PanelPilot® software. Prices start at under $125.00. The Model SGD 28-M display is shown on the right. This version is also available in an IP67 rated waterproof housing.
For easy hookup to the TPS sensor signal wire, you can use a Pomona insulation Piercing Test Clips as shown on our Diagnostic Tools and Recommended Suppliers page and Alligator Clips for +12 volt power and ground connections. NOTE: Always make the ground connection to the same point where the engine control module is grounded, never to the battery.
WEGO™ Fuel Type - Air/Fuel Ratio (AFR) Value Chart
For any given AFR, the concentrations of the various exhaust gas constituents can be measured under experimental conditions or calculated using computer programs based on chemical kinetics.
→ 'DYNO' WEGO™ USERS ←SPECIAL Tech Notes Click Here
If the vehicle you are working on does not have a factory ECM that provides +5 volt power for a standard automotive type MAP sensor, you can use an industrial sensor, such as the SSI Technologies® P51 series. These can be powered directly from +12 volt and provide a 1-5 volt output. Model #P51-15-A-UB-I36-5V-000-000has a 0-15 PSI a range and is suitable for normally aspirated engines. Other versions with higher pressure ratings are available for boosted applications. These sensors are available from Digi-Key® (www.digikey.com).
The comprehensive test that we perform in our lab requires reference gases and a small test chamber for the Bosch® sensor. The test is performed at three points: free air, stoichiometric, and 0.80 lambda (11.75 AFR for gasoline). Ambient air is used to test the free air point. Lab grade nitrogen gas is used for the stoichiometric point (no oxygen or hydrocarbons remaining after a theoretically complete combustion). For details on the Bosch® recommended reference gas used for the 0.80 lambda point, you can refer to page 9 of the Bosch® LSU 4.2 Specifications Factory Document. The Bosch® recommended reference gas is available from Scott Specialty Gases (www.scottgas.com), but is very expensive at about $1,000 for a C size cylinder.
Please Note That All Values Are Based On A +5.0 Volt Reference Supply To The MAP Sensor
MOTORCYCLE TUNERS! - If you are using the ScreaminEagle® Pro Super Tuner®, Screamin Eagle® Race Tuner® (SERT) or Dynojet® Power Commander®, check out the features of the Daytona Twin Tec™ TwinScan Plus™ for motorcycles.
WEGO™ Optimum Air/Fuel Ratio (AFR) Tuning Value Chart
LASCAR® Electronics PanelPilot® Model SGD 28-M Display with Combo Analog/Digital Program Reading in TPS% Units
Using 'Sniffers' in the Automotive segment, the BIG disadvantage is that you won't have AFR data on the Dynojet® chart or be able to directly link to a Power Commander®.
If you do decide to follow this method, please be sure to refer to the WEGO Automotive Exhaust 'Sniffer' Technical Bulletin shown on the right.
The first generation WEGO™ (originally sold by our sister company Daytona Twin Tec™) used a Honda®/NTK® L2H2 wide-band sensor and did not have any built-in data logging capability.
The WEGO™ II series was a Second Generation product. The WEGO™ II used the new Bosch® LSU 4.2 wide-band sensor and included built-in data logging. The Bosch® LSU 4.2 wide-band sensor was available at a much lower cost than the earlier Honda®/NTK® part. The result was that we were able to offer the WEGO™ II for substantially less than the price of the original unit.
The Third Generation WEGO™ III series is packaged in an improved low profile housing. WEGO™ III units with display and data logging use an ultra-bright daylight readable blue LED display that is water-proof and include a built-in USB interface. The older WEGO™ II units had a red LCD display that was prone to moisture intrusion and used an RS-232 serial data interface.
The Fourth Generation WEGO™ IV series is packaged in an aluminum housing intended for under dash or dyno lab environments. WEGO™ IV units are not sealed and susceptible to the elements
The Fifth and Latest Generation is the WEGO™ 5 - A dual channel unit with internal data logging. It features both CAN data bus and analog air/fuel ratio outputs. It does not have a built-in display. From an operational standpoint, all of our WEGO™ II, WEGO™ III, WEGO™ IV and WEGO™ 5 units are similar.
SSI Technologies® P51 Series Pressure Sensor
(Click Here For Full Size Drawing)
Our Unique WEGO™ Three-Step Quality Control Testing Process
Simple Exhaust Modification to Reduce Exhaust Reversion
Bosch® LSU 4.2 sensors come with several styles of proprietary connectors. A common style is shown at the right. The Bosch® connector includes a calibration resistor that establishes the nominal free-air calibration. This approach is required for original equipment applications. Obviously it would not be feasible to manually adjust the free-air calibration for each sensor installed on a vehicle assembly line.
Since all WEGO™ units have a free-air calibration adjustment and the Bosch® connector with its built-in calibration resistor is not required. There several reasons why we use a Deutsch® DT series connector in place of the Bosch connector:
Dual Digital Program
LASCAR® - PanelPilot®
Model SGD 28-M Display
MCC® 6 Amp Rectifier Diode
- The mating Bosch® connector that would be required on the WEGO™ wire harness is bulky and expensive.
- The Bosch® connector requires a special crimping tool whereas the Deutsch® DT series are widely used in automotive racing and most professional mechanics already have the proper crimping tool. Race car and dyno room installations that require routing custom length cables through small firewall openings and then installing the connector are considerably easier with the Deutsch® connectors.
- Using the Deutsch® connectors facilitates installation of our prefabricated extension harnesses. Simply plug the extension harness between the WEGO™ and the sensor. This would not be possible with the Bosch® connector.
- The customer can easily replace a failed sensor with any available Bosch® LSU 4.2 series part. The Deutsch® connector housings can be reused many times, only new terminals are required as explained in the next section below.
Performance Cycles™ Oxygen Sensor Installation Kit
For Info Visit Their Website At:
Dual Bargraph Program
LASCAR® - PanelPilot®
Model SGD 28-M Display
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It is important to understand that the wide-band sensor is measuring the apparent AFR based on the composition of the exhaust gas. The actual AFR is the mass of air divided by the mass of fuel inducted into the engine.
Special Gas Is Used For WEGO™ Testing
All WEGO™ Systems Can Be Used To Tune Most Four-Stroke Gasoline Powered Internal Combustion Engines As Shown Below:
LASCAR® - PanelPilot®
Model SGD 28-M Display
WEGO™ units have a 0-5V output that can be interfaced to Data Acquisition or Dynamometer systems. The scaling is the same for all WEGO™ models. Scale factors are listed below for common fuels. Our WEGO™ 'DYNO' Tech Info & Tips Page Fully Explains These Scale Factors. Click button below to view this web page:
Exhaust Reversion Modification Example
Dash Mount Displays - Looking for a single or dual channel dash mount display to use with your WEGO™ system? VEI Systems® sells Single and Dual Channel displays that are compatible with the 0-5 volt output of our WEGO™ systems.
These displays will read out directly in AFR units. Prices start at around $79 for Single Channel V1™ Series and $99 for Dual Channel D1™ Series displays. For full details and product information, visit
VEI Systems® at www.veisystems.com.
NOTE: When ordering from VEI Systems®, ask them to preset the display to read 10.0 AFR at zero volts and 20.0 AFR at 5.0 volts.
LASCAR® - PanelPilot®
Model SGD 28-M Display
Daytona Sensors™ WEGO™ Systems Are Each Tested Using A PC Based Automated Test System. All Systems Are Tested Using A Known Good WEGO™ Unit Incorporating Our Unique Three-Step Quality Control Process
Extra Connectors and Connector Housings Can Be Ordered From
Under rich conditions, excess hydrocarbons and carbon monoxide remain in the exhaust gas. Under lean conditions, excess oxygen remains in the exhaust gas. Earlier generations of exhaust gas analyzers were based on measuring the carbon monoxide level using infrared absorption techniques. Click the link below for in-depth information, images and graphs.
Easily identify the type of sensor your vehicle is equipped with by clicking, opening, downloading and referencing the Delphi® MAP Sensor Brochure links shown on the right.
WEGO™ LSU 4.2
Dual Channel Display
VEI Systems® D1™ Series
Dual Channel Wideband
Air-Fuel Ratio Monitor
Need Technical Help?
Call Us At 386-322-7390
- - - - - - - - - -
Email Us At:
They are intended to be used with 3-way catalytic converters that require operation near the stoichiometric point (14.7 air/fuel ratio).
The range of narrow-band sensors is inadequate for performance tuning. While originally developed for lab and specialized automotive, wide-band sensors are ideal for tuning. The 5-wire Bosch® LSU 4.2 sensor used with the WEGO™ operates over a range of 10.3 to infinite air/fuel ratio.
Common Conversions: Ppsi = .145038 x PkPa | Pin-Hg = .2953 x PkPa | Pin-Hg = 2.03602 x Ppsi
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The solution is to install some rectifier diodes in-line with the red WEGO™ power wire to reduce the supply voltage as shown in the figure below. Suitable 6 amp 400-1000 volt rated diodes are available from Mouser Electronics®. Here are links to recommended Micro Commercial Components® (MCC) Part Numbers 833-6A4-TP,833-6A6-TP, and 833-6A6-TP. If you are using multiple WEGO™ systems, each unit will require a separate diode string. When soldering the diodes together in series, leave about 1 inch lead length between diodes for best heat dissipation.
You Can Reduce Reversion Effects In Open Drag Pipes and Mufflers Without Restrictive Baffles With The Modification Shown Below
General Tech Info, Tips & More
Click A Subject Below To 'JUMP-DOWN' To The Tech Note Section
For the SSI Technologies® P51 Series Pressure Sensor, use the scaling listed below for this 15 PSI sensor:
If you can insert a broomstick through the mufflers, you have the equivalent of
open drag pipes and the WEGO™ sensors will not read accurate AFR values!
This technical note provides information WEGO™ for users connecting WEGO units with data logging to capacitive discharge (CD) ignitions found on many Japanese motorcycles and small engines with flywheel triggered systems.
In some cases, Daytona Sensors™ Tach Adapter Part #115005 and an alternate tach adapter, Daytona Sensors Part #115014 may be required with some inductive ignition systems.
Please refer to the Technical Note document shown on the right and call us if you require technical assistance.
The sensor will be quickly degraded if leaded racing gasoline is used. Under these conditions, expected sensor life will be less than 10 hours. As the sensor degrades, free air calibration will become impossible.
Oil or other hydrocarbon residues in the exhaust will affect the sensor readings. Likewise, gasoline containing ethanol will result is slight air/fuel reading errors.
The sensor responds to the partial pressure of oxygen. Excessive exhaust back pressure will affect sensor readings. This should not be a problem with any performance exhaust system. When used with a turbo, make sure the sensor is located downstream of the turbo.
Make sure that power is on to the WEGO™ whenever the engine is run. Without power to the internal heating element, the sensor will clog with hydrocarbon residues and may be permanently degraded. If you want to remove the sensor, we sell an 18 x 1.5mm hex plug.
There's MORE! For 'DYNO' WEGO™
Tech Notes & Tips - Click Here →
Three Units Are Commonly Used For Pressure Values. These Are As Follows:
Conventional (narrow-band) exhaust gas oxygen sensors have been widely used in automotive applications since 1981.
Conventional sensors have one to four wires and can only sense air/fuel ratio over a relatively narrow 14.5 to 15.0 range.
Use washers with an OD that is 2/3 to 3/4 the ID of the pipe (for example, 1-1/2” OD washers are suitable for pipes with an ID of 2” to 2.25”). Weld ¼-20 socket head cap screws to the washers as shown on the right. Drill holes at the bottom of the pipes about 2” from the end and use decorative acorn nuts to secure the washer assemblies. We highly suggest that you use stainless steel hardware.
The washers will reflect positive pressure waves that will cancel out the negative pressure waves reflecting from the end of the pipes. You can turn the washers just like throttle blades to provide more or less restriction. Dyno tests will show a significant increase in midrange torque and a small drop in top end horsepower as the restriction is increased.
WEGO™ Systems - Displaying Program Data Using VEI Systems® Products
EXCESSIVE EXHAUST BACK PRESSURE - Wide-band sensors are affected by back pressure. Excessive back pressure causes exaggerated AFR indications under rich and lean conditions, but has little effect at 14.7 AFR (stoichiometric). The WEGO™ is intended to be used with a free flowing performance exhaust. Overly restrictive stock mufflers may cause excessive back pressure under wide open throttle. When used with a turbo system, the sensor must be mounted downstream of the turbo. Motorcycle exhaust systems are relatively free flowing and problems with exhaust back pressure are not likely.
EXHAUST REVERSION - Reversion is the term for a negative pressure wave that can suck ambient air back into the exhaust and cause an erroneous lean AFR indication. Exhausts without mufflers, such as open headers or "drag pipes" on motorcycles, usually suffer from reversion effects and may not be suitable for use with the WEGO™. Reversion effects will also occur with certain exhausts used on "bagger" style motorcycles, where two pipes split off near the rear cylinder. At part throttle, air is actually sucked into the left tailpipe. Reversion effects will be most noticeable at idle, part throttle low RPM cruise, and deceleration.
Deutsch® Connector (DT Series)
Our Original WEGO™ I & WEGO™ II Systems
WEGO™ units manufactured before 2012 shut down if the battery voltage exceeded 16.5 volts. All new WEGO™ units operate up to 19.0 volts. If you have an older WEGO™ unit and your race vehicle has a 16 volt system with an alternator or any 18 volt system, the voltage will exceed the 16.5 volt maximum allowed by the WEGO™.
The Twin Scan II™ software analyzes logged data and displays AFR and the required volumetric efficiency (VE) correction (in percent) with the same RPM rows and throttle position sensor (TPS) columns used in SERT and PowerCommander® tables. Please visit our sister company's website at: www.daytona-twintec.com.
The Bosch® LSU 4.2 wide-band sensor integrates a conventional (narrow-band) heated oxygen sensing Nernst cell with an oxygen pump cell. With an appropriate electronic interface such as the WEGO™, this integrated sensor element is capable of measuring the air/fuel ratio (AFR) of hydrocarbon fuels over a very wide range. For more detailed information, you can click to read here the Bosch® LSU 4.2 Oxygen Sensor Specifications.
WEGO™ Automotive Exhaust 'Sniffer' Tech Bulletin →
This tech note provides WEGO™ hookup and setup information for Suzuki® Hayabusa® applications. Customers using WEGO™ II units in Hayabusa® applications will require firmware revision 4.0 or higher and WEGO™ Log software version 6.0 or higher. Older revisions do not support the tach signal de-bounce feature required to obtain a noise-free tach signal in Hayabusa® applications. The WEGO™ firmware revision is reported as part of the firmware ID whenever you upload to the WEGO™. If you have an older WEGO™ II unit, it can be upgraded to the latest firmware revision. Please contact our Technical Support department for details.
Single Channel Display
VEI Systems® V1™ Series
Single Channel Wideband
Air-Fuel Ratio Monitor
Need Tech Help To I.D.
Your MAP Sensor?
Call Us At 386-322-7390
Email Us At:
To begin, please refer to our Motorcycle Exhaust 'Sniffer' Tech Bulletin and Motorcycle Exhaust Sniffer Tech Bulletin shown below for full details.
- Pounds Per Square Inch (PSI)
- Inches Of Mercury (In-Hg)
- Kilopascals (kPA)
WEGO™Motorcycle Exhaust 'Sniffer' Tech Bulletin
(Click Here To View Full Size)
All WEGO™ Systems - Scaling For
Interface To Data Acquisition or Dynamometer
WEGO™ units can be used with exhaust 'Sniffers' that allow temporary installation on most motorcycles for tuning and diagnostic purposes. Jims® (www.jimsusa.com) offers an exhaust sniffer, P/N 777, suitable for use with the WEGO™. For additional information on do-it-yourself sniffers, refer to our Motorcycle Exhaust Sniffer Tech Note.
WEGO™ systems will work with most hydrocarbon fuels including Ethanol, E85, and Methanol. Newer WEGO™ units with display and data logging allow uploading a fuel type selection with the WEGO™ Log software including user defined fuels. WEGO™ III and IV units operate over the 0.70-1.33 Lambda range. WEGO™ 5 units operate over the 0.50-1.33 Lambda range. Corresponding Air/Fuel Ratio (AFR) values are:
1. One or two (for dual channel systems) sensors are mounted on a test manifold. The sensors are allowed to reach normal operating temperature and a free air calibration is performed at the WEGO™ to establish the free air operating point. Sensors with gross defects will fail during this test step.
2. Lab grade nitrogen gas is used to simulate the stoichiometric operating point (zero oxygen and zero hydrocarbon level corresponding to 1.00 Lambda).
3. A Bosch® specified reference gas (3.15% hydrogen, 3.15% carbon dioxide, and 4.05% carbon monoxide with balance nitrogen) is used to simulate the 0.8 Lambda (11.74 gasoline AFR) operating point. This reference gas is supplied by AirGas® Air Liquide® Specialty Gases Division. Outside of the major automotive companies and institutions such as Southwest Research Institute, Daytona Sensors™ is the only company in North America currently purchasing this reference gas.
As you can see, we take 'Quality Control' very serious. But then again, we'll let you draw your own conclusions about the thoroughness of our Quality Control Program .
Bosch® Connector (Common Style)
Our Pressure Conversion Calculator
TECH NOTE: 2010 and later H-D® touring models are equipped with miniature 12mm oxygen sensors.
The Bosch® LSU 4.2 wide-band oxygen sensors used with the WEGO series are 18mm and will not fit. Smaller wide-band sensors are not available.
However, there is a solution. Bay Area Performance Cycles™ sells an oxygen sensor manifold kit that allows easy installation of Bosch® LSU 4.2 wide-band sensors on any exhaust system for testing purposes.
The process involves drilling small holes and using a special tool to install threaded fittings for the sensor manifolds.
After testing, button head stainless steel screws are installed in place of the sensor manifolds and the heat shields are reinstalled.
Jims® Model #777 Exhaust 'Sniffer'
WEGO™ Systems Are Very Simply Once You Understand The Basics
Here's Some Helpful Info & Tips To Help Get You Started!
Motorcycle Applications - WEGO™ Systems and The DIY Exhaust 'Sniffer'
WEGO™ III & WEGO™ IV Systems
(WEGO™ 5 Not Shown)
Rectifier Diode Placement For High-Volt Race Batteries
All Items Available At: www.digikey.com
Exhaust Back Pressure Example
WEGO™ Sensor Test Manifold
Above 3.3 MAP Sensors Also Cross-Reference To Wells #SU1480 and #SU1514
For a basic quick test, you will require a 12 volt power source, digital voltmeter (DVM), and a small disposable butane cigarette lighter. If the WEGO™ has been removed from the vehicle, you can use a 12V battery as a power source. Do NOT use a battery charger as a power source.
Connect the black WEGO™ signal and power ground wires to the battery minus terminal. Connect the red WEGO™ power wire to the battery positive terminal (for WEGO™ IV series, make connections to the terminal block). Connect the black DVM lead to the WEGO™ signal ground and the red DVM lead to the WEGO™ AFR output (white wire on single channel units, white and blue wires on dual channel units, or appropriate terminal on WEGO™ IV series). Test each channel separately on dual channel units.
With the Bosch® sensor in free air, let the WEGO™ warm up and then perform the free air calibration procedure (refer to instructions). The status LED should be blinking rapidly (WEGO™ IIID) or the display should indicate FA (WEGO™ III and IV series units with display) and the DVM should read +4.95 to +5.05 volts. Use a butane lighter as a hydrocarbon vapor source. Torch type cigar lighters may not work properly, use the cheap disposable variety. Do not light the flame. Just hold the lighter at the tip of the Bosch sensor and spray butane at the sensor. The voltage should drop below 0.3 volts for WEGO™ IIID units and 0.25 volts for WEGO™ III and IV series with display. If your system passes this test, you can be 90% confident that it is functioning correctly.
DIY 'Homemade' WEGO™ Auto Exhaust 'Sniffer'
New WEGO™ units use a Bosch® LSU 4.2 sensor that is readily available from your local VW® dealer or Bosch® parts distributor.
To use one of these VW® dealer or Bosch® sensors, you must replace the Bosch® connector with a six terminal Deutsch® connector. You can reuse the connector housing. You can order terminals and extra connector housings from Ladd Distribution®(www.laddinc.com).
You can also make your own extension harness. Click on the links on the top right for the appropriate drawings. You should use a proper Deutsch® crimping tool. NOTE: If you do use a generic "Open Barrel" crimping tool, you must also solder all the terminals.
Higher AFR values correspond to a leaner (less fuel) condition. The practical operating range for most engines using gasoline fuel is from approximately 11.5 to 14.7 AFR. Combustion of a stoichiometric mixture (exactly enough air to burn all the fuel) results in 14.7 AFR indication.
Automotive engines with catalytic converters operate near 14.7 AFR during cruise and idle.
Race engines require a richer mixture to limit cylinder head temperature and prevent detonation. The table below lists recommended AFR values for race engines without emission controls.
Automotive Applications - WEGO™ Systems and The DIY Exhaust 'Sniffer'
NOTES: EXCESSIVE SCAVENGING - Turbo systems or tuned exhausts in combination with a high overlap camshaft profile can force unburned air and fuel mixture through the cylinder into the exhaust and cause an erroneous rich AFR indication. For motorcycles, some aftermarket 2-into-1 systems such as the Thunderheader® appear to suffer from this problem, whereas others such as the Vance & Hines Pro Pipe® and White Brothers® E-Series seem less affected.
MISFIRING - If the AFR is so rich that the engine misfires, high levels of oxygen will remain in the exhaust gas and result in an erroneous lean indication.
WEGO™ units can be used with exhaust sniffers that allow temporary installation on most automobiles and motorcycles for tuning and diagnostic purposes.
However, regardless of what some people may claim, it is impossible to properly tune a fuel injection system or carburetor on a modified engine without some means of exhaust gas analysis. WEGO™ units can be used with exhaust sniffers that allow temporary installation on most automobiles and motorcycles for tuning and diagnostic purposes.
Shops can use the WEGO™ as a low cost alternative to expensive systems such as those sold by Dynojet®. They can easily fabricate your own exhaust sniffer to use with the WEGO™, eliminating the need to install weld nuts in the exhaust. Please refer to our Automotive Exhaust Sniffer Tech Bulletin and Motorcycle Exhaust Sniffer Tech Bulletin shown in the sections below for full details.
WEGO™ Systems - Displaying Program Data Using LASCAR®/PanelPilot® Products
For Tech Notes & Tips From 'OTHER'
Product Categories - Click Here →
Modified Exhaust Example
Be Aware That WEGO™ Wide-Band Systems Will Give Inaccurate AFR Readings In Certain Situations:
Most original equipment data sheets and service manuals now use kPa as the unit of measurement. A standard atmosphere (atm) is the mean sea level pressure at 60° F. The unit bar (1 bar = 100 kpa) is also encountered in descriptions of manifold absolute pressure sensors and is just under one atmosphere.
Standard Atmosphere (atm) = 14.696 PSI = 29.92 In-Hg = 101.325 kPa
SSI Technologies® P51 Series Pressure Sensor Available At: www.digikey.com
3202P Battery Charger
4010P Charger Hook-Up Cable
All WEGO™ systems provide quick and easy at-a-glance verification and adjustment of the sensor free-air calibration. This allows the WEGO™ to maintain accuracy as the sensor ages and maximizes sensor life in racing applications where the sensor may be exposed to leaded fuels.
For applications using unleaded fuels, free-air calibration should be performed on initial installation and whenever a sensor is replaced. Periodic free-air calibration is generally not required. When used with leaded racing fuels, free-air calibration should be performed at the beginning of each race event or dyno tuning session. When free-air calibration is no longer possible, the sensor has reached end-of-life and must be replaced.