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Performance
Improvements For Tow Vehicles
Many RVers that we meet ask how to improve the power and
torque of their tow vehicles to get up the hills easier
and feel better about towing a heavy load. Race car teams
have always tried to get the maximum output from their engines
so that they can leave all the other cars behind and grab
the checkered flag at the finish. It is not uncommon to
see racers blow an engine that has been stroked to the limits
and driven hard in competition.
An RVer can get better power and performance from his engine
without blowing it up on the way up a hill or while towing
a heavy load. Power comes from being able to burn more fuel,
and this requires more air to allow the combustion to take
place. When we burn this extra fuel, we also need to be
able to get rid of the waste gases so that the engine is
not strangled by exhaust.
Diesel engines often respond well to increasing horsepower
by changes in fuel pumps, better injectors, adjustments
to injector timing, turbo charging, and better exhaust systems.
But, whenever power is increased, we have to be sure that
this power is not too great for the other elements of the
drive train, such as the transmission, or the braking system.
When we increase the power to go faster or pull more load,
we have to remember that sometimes we still need to be able
to stop that load in a safe distance.
The first thing that most drivers try is to change the
standard settings of the computer that determines fuel delivery
to the engine. This is normally done by reprogramming the
chip in the computer, or replacing it with one that can
be programmed externally. Some of these commercial chips
can be programmed at installation time with a laptop computer,
and others allow you to choose from several different characteristics
as you drive with controls mounted on the dash. The new
computer chip uses the original air intake, engine temperature,
exhaust gas temperature, oil temperature, and other sensors
plus a pyrometer, to sense when the timing needs to be backed
down to keep the engine operating within safe limits. This
increase in the ability to burn the fuel more efficiently
can result in an average gain of 55 to 65 horsepower and
an additional 125 to 185 pounds-feet of torque.
What does this do to fuel economy when towing? Since we
are burning fuel more efficiently, it is possible to keep
the transmission in a higher gear thanks to increased torque.
The engine operates at a lower RPM, so fuel economy often
increases by two to five mpg. If you are running solo without
a trailer, the truck does not need the extra torque to maintain
the speed and fuel economy may drop. Mileage will depend
on the rear gear selection, the terrain, and the size of
your right foot. If you drive the truck like you stole it,
your fuel economy will reflect that.
Since factory code readers used in dealerships are programmed
to recognize factory fault codes, the chip manufacturers
recommend unplugging the chip when you take your truck in
for service or for a clean air test. This also points out
whether the problem you have is related to the stock engine
or to your aftermarket installation.
There is a law in the USA protecting vehicle owners from
fraudulent behavior practiced by some automotive dealers,
called the Magnusson-Moss Warranty - Federal Trade Commission
Improvement Act of 1975.
Under the Magnusson-Moss Act, aftermarket equipment that
improves vehicle performance does not void a manufacturer's
original warranty, unless the warranty clearly states the
addition of such aftermarket device is the direct cause
of the failure. Since many of the trucks sold in Canada
are built in the USA, you would wonder why Canada does not
have a similar law to protect vehicle owners.
GM Duramax 6.6 Engines
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Ford PowerStroke Engines
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Cummins 24 Valve Engines
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(Read full article in the magazine.) (Top)
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