Horses in your mailbox!
Bobit Publishing Co. Truck & SUV Performance
In the early 1960's, the federal government
began putting pressure on automakers to reduce tailpipe emissions. The
automakers immediately bolted on "smog devices" as a Band-Aid in an attempt to
clean up the air.
These devices included air pumps with all kinds of hoses, mysterious switching
and diverting valves, and lots of detuning. At one point, there were passenger
car and light truck engines with 400 cubic inch displacements, and less than 200
These first attachments did little more than create numerous driveability
problems and send fuel economy into the basement. Then the "OEM's" began
redesigning engines by installing anemic camshafts, retarding the ignition spark
timing, lowering compression ratios, and leaning out air fuel mixtures.
The harmful emissions coming out of the tailpipe were byproducts of the
combustion process. Poorly atomized fuel / air mixtures and inaccurate spark
timing offered very incomplete combustion, allowing gobs of carbon monoxide and
unburned hydrocarbons to make their way from the engine to the atmosphere.
As emission control regulations were strengthened, and early emission devices
were added, combustion chamber temperatures rose dramatically. In these high
chamber temperatures, more harmful and different pollutants were formed.
In 1975 unleaded fuel and catalytic converters were required on all cars
manufactured for sale in the United States in an effort to further clean up that
nasty exhaust. The catalytic converter was designed to function well at the
perfect air fuel mixture of 14.7 :1.
With carburetors, ignition distributors with contact points, mechanical and
vacuum controls, (all antiquated technology), keeping vehicles in an acceptable
state of tune was all but impossible. Even harder was maintaining the 14.7 :1
air fuel mixture. With ignition misfires, overly rich or overly lean fuel
mixtures, improper spark timing or even a stuck open cooling system thermostat,
catalytic converters suffered numerous failures.
The automakers soon figured out that the only way to cure these problems was to
introduce microprocessor controlled fuel and spark systems. These systems would
not only control the fuel / air mixture and spark timing much more closely; they
would also have "Adaptive Strategy". This "Adaptive Strategy" would enable the
management system to compensate for minor changes in component integrity,
thereby keeping the "State of Tune" as close to correct as possible.
The whole purpose of these electronic engine control management systems is to
keep the air / fuel ratio as close to 14.7 :1 as possible so the catalytic
converter would operate at maximum efficiency and survive for the life of the
vehicle. Combine the proper air / fuel ratio and optimum spark timing, and the
result is much cleaner combustion, better performance, and extremely low
Now you know why these systems exist in the first place!
First there were crude adaptations to electronically controlled carburetors, and
then on to electronically managed spark timing. The next generation moved us
into the gasoline engine fuel injection which more precisely metered fuel, and
allowed the use of feedback sensors, as well as the engine load, temperature,
and exhaust sensors.
This sent shock waves through the automotive service industry. I know, because I
was there. The screams for training, reference materials, and diagnostic aids
were plentiful from the field. Many mechanics left the trade, some switched to
transmission work, brake and suspension work, and anything else that would keep
them from being burdened with this horrible new technology.
Many analysts predicted that these newly employed electronics would not be
around very long. Many auto mechanics wished they would go away, and not many
good things were thought or spoken about this technology. Several people
believed that microprocessors should be reserved for scientific computers.
Remember, back then no one had a PC or notebook. Computers were something found
in a lab or a very large corporation.
Well, here we about 25 years later, and those "flash in the pan" electronics are
not only still here, but bigger, better, and smarter than ever. Evolution is a
Now those pesky microprocessors can be modified to unleash hidden horsepower and
torque. Engines are better than ever, and we can now go to our mailbox and get
tons of performance in a box! Now that we understand these systems, we realize
how easy they have made our lives when it comes to making vehicles run clean and
perform well. Microprocessors have also opened up a whole new world of "Instant
I'd like to share with you the modifications that have turned my 2002 Silverado
3500 DuraMax powered dually into a very respectable powerhouse. My truck has the
5 speed Allison automatic transmission.
One of the first things I did was to install this cold air system with a cotton
gauze air filter. You all know these reusable filters. They come in all
different colors, and my favorite is The Green Filter. Yes, (I know I need to
clean the one in the picture!)
Diesels need lots of air, which is why they are all equipped with an air filter
minder. This little pressure differential device warns of a restricted air flow.
Be sure that you select a cold air intake that utilizes this neat little device.
Bringing in cooler, denser air means better cylinder filling, then add more
fuel, and you have the recipe for better performance. With electronic fuel
injection, and now the latest generation of "Common Rail" fuel systems,
modifying fuel injection timing and duration is as easy as plugging in a
Thanks to the once dreaded electronic engine management systems, and the
brilliant guys and gals who research and develop advanced electronics, we can
easily increase horsepower and torque without breaking a sweat. Some don't even
require getting our hands dirty.
I chose the Edge Products Juice Module with Attitude for several reasons. This
unit has so many great features that they are too numerous to list here. I'll
attempt to give you the highlights and important things here.
First, it was easy to install. Mount the module under the hood and using two
sided tape, stick it on the electrical distribution center.
Next hook it up to the engine harness. This is simple. The module's harness
connectors just click right into the OEM harness connectors. Now the unit is in
series, and is ready to work. It can be programmed for 5 different levels of
power using the gear selector and throttle pedal (TPS).
If you add the Attitude display, you can program right from the display, and
even dial in the desired power level on the fly. You can also program and
monitor the Allison automatic transmission functions. Edge works with the
transmission also, and that is a very important feature.
The Attitude mounts on the dash or "A" pillar with adhesive or small screws.
(Your choice). Then the cable is snaked through the firewall of through the door
jamb and plugs right into the "Juice Module".
Another simple operation is to remove the right side front inner fender skirt,
and drill a tap hole for 1/8th inch NPT in the right bank's exhaust manifold.
This is where you will install the temp probe or thermocouple that reads EGT.
When you increase power by adding air and fuel to a diesel, you really need to
watch the exhaust gas temperatures to prevent internal engine damage.
A great feature included in the Edge product, is that it can monitor the EGT,
and de-fuel if they exceed the maximum setting. You can easily program this and
several other alerts right from the Attitude display. You can dial in tire
sizes, de-fuel on shifts to reduce transmission wear, and you can monitor up to
4 engine parameters at one time. You can even choose digital display or bar
graph, as well as what you personally want to monitor.
If you look at my display pictured here, you will se what I like to look at
while driving. I have it set to monitor EGT, boost, engine coolant temp, and
percent of engine load. I sometimes modify the display to monitor percentage of
transmission slip, a key feature if you are really hauling a load or going for
The five levels of programmable
power are as follows:
||150 Lb Ft
||180 Lb Ft
||220 Lb Ft
||250 Lb Ft
||325 Lb Ft
My truck came from the factory with a flywheel
horsepower rating of 300 HP. When I ran it on the chassis dyno, it developed a
consistent 245 rear wheel horsepower. When I first installed the Edge module, I
didn't have the Attitude Display. (What was I thinking?)
programmed it for an additional 60 HP, obviously level 2. Then I pulled
another dyno run. The results amazed me. Rear wheel horsepower was 300 to 305
averaged over five dyno pulls.
Since I installed the newer module with the Attitude display, I have
experimented with all the power levels, and have had a blast giving five liter
Mustangs ands Camaros a god run for their money.
I am planning a four inch exhaust, and maybe even that great new turbo setup
from BD Diesel Power in Canada. I may even have to upgrade to a stronger /
better torque converter and some transmission modifications.
Think about a quick installation of some simple wiring and a temperature probe
allowing you to add an additional 125 horse, and up to 325 additional foot
pounds of torque. Over 800 foot pounds of torque at the rear wheels is nothing
to sneeze at!
Like I said, it's fun to tell folks that you can fit 125 horses in your mailbox.
Check out an "Edge Product" for your diesel powered rig. It's just the ticket
for towing large trailers, hauling heavy loads, or just feeding your ego.