by FordMuscle Staff
Introduction
Bog, flat spot, hesitation, stumble, and surge. These vague
descriptors are examples of the challenges faced when tuning
your own carburetor. Something has always seemed odd about
deriving very quantitative decisions, such as choosing a 80
jet over a 76 jet or one metering rod size over another, from
such ambiguous terminology. And what the heck is the difference
between a stumble and a bog anyway? Before you email FordMuscle
the answer, be aware that we no longer need clarification.
Why? Because we are the latest disciples of the purely quantitative
and completely logical tuning method that is known as the
wideband tuning system.
Wideband refers to the use of a wideband oxygen sensor. Wideband
O2 sensors are nothing new and if you've had your car on a
chassis dyno that measured air-fuel ratio, it was likely using
a wideband O2 sensor mounted in your tailpipe. However, what
is new is the 'tuning system' in the hands of the everyday
enthusiast. Gone are the days of having to pay handsomely
for dyno tuning time just to get air-fuel ratios. With Innovate
Motorsports' LM1 Digital Wideband kit and RPM Converter you
can tune on your clock, under real road conditions, for under
what it would cost for three or four dyno sessions. The system
combines two very powerful tuning "inputs"; air-fuel
ratio and rpm. By measuring and logging these two variables,
you have the ability to tune absolutely anything for optimum
power, fuel economy, or the best of both. We'll show you how.
About
the Innovate Motorsports Wideband Tuning System
The Innovate
Motorsports LM-1 kit with RPM Converter is a complete
wideband tuning system. The single self-contained unit
combines a wideband air/fuel ratio sensor controller,
a 6-channel data logger, and an easy-to-read backlit LCD
display. This RPM Converter converts a normal tach signal
to an analog RPM signal that can be logged by the LM-1.
The system includes LogWorks software for powerful results
analysis and real-time data viewing. |
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Carburetor Tuning with the Wideband
Tuning System
Whether you consider yourself a beginner, an amateur, or a
professional at tuning carburetors the old-fashioned way,
don't be afraid to adopt the digital tuning technology found
in the LM-1. The satisfaction of making carburetor tuning
decisions based on quantifiable data logged by this wideband
air/fuel meter is not difficult to realize. We demonstrate
on FordMuscle's Project MX.
Setting up the Innovate LM1 begins
with installing the supplied oxygen sensor fitting into
your exhaust stream. Any exhaust
shop can weld this fitting in for you, just be sure it
is in a location where the installed sensor will not hit
the ground or interfere with the chassis. The fitting
is best placed in the header collector or just after it,
on either side. Place one in each side if you want to
tune each bank individually. |
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The unit has a 9V battery to power up for data transfer
purposes, however you need to supply it with 12V power
to preheat the Bosch wideband oxygen sensor. The kit comes
with a cigarette lighter power cable to achieve this.
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Plug the end of the oxygen sensor data cable into the
marked port on the LM1 unit.
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Before we place the wideband O2 sensor in the exhaust
we will perform the required calibration. Connect the
sensor to the data cable and hold or place the sensor
in the air. It will be heated so do not touch or place
anything in contact with the metal part of the sensor.
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Press and hold the "Calibrate" button until
the display indicates it is calibrating. This calibrates
the LM1 to the wideband O2 sensor and only needs to be
done the first time the sensor is used. |
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When the calibration is complete the unit will read
the O2 content of air, about 20.7%.
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The wideband O2 sensor can now be installed into the exhaust.
Unless you have a need or desire to monitor air-fuel ratio
constantly, our recommendation is to only use the wideband
sensor when you are tuning, then remove it and use the
supplied pipe plug to close the hole. This will maximize
the life-span of the sensor. Replacement Bosch sensors
are about $80 through Innovate. |
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With the wideband sensor installed in the Montego's exhaust,
we routed the wiring along side the door and secured it
with electrical tape. Clearly this is temporary install
since once the carburetor is tuned we would remove the
LM1 from the vehicle. For permanent mounting guys often
route the cable up through a hole drilled in the floor
pan. Innovate offers a variety of permanent
mount accessories, including the XD-16 digital gauge. |
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The next step is to hook-up the RPM module (also termed
the LMA-2). We cut some wire to run from inside the car
through to the engine compartment. One end goes to the
terminal marked RPM on the LMA-2 as shown. |
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The other end of the wire needs to tap into a tachometer
feed, such as the dedicated terminal on the D.U.I.
distributor shown, or the tach output on an MSD box.
On a stock ignition system you can use the negative side
of the coil or tap into the factory tach wiring if so
equipped. |
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Plug the RPM module into the LM1 port marked AUX IN. Before
we fire up the engine we need to set the RPM module to
reflect the number of cylinders in the engine. |
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Setting the RPM module is performed using the supplied
software and 3.5mm audio cable. You can take the RPM module
over to your desktop computer, or use a laptop as we have
done. Install the software and fire up the LM Programmer
utility. Follow the on-screen instructions for setting
your modue for a V8 four-stroke engine. |
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