by Gerard Rivett
The vehicle weight, or the measure of heaviness, is the enemy of all
performance enthusiasts. However, as the Aussie dollar increases in
value, it is becoming easier and more economical to achieve a
significant performance boost to your car by substituting some of the
factory components with modern alloy units available from a host of
willing suppliers.
I will use George’s Dodge Challenger as an example to show how
approximately 200 kg can be shaved from the weight of your pride and
joy.
The best area to reduce weight in a vehicle is from forward of
the front windscreen. This will improve the road handling and lighten
the steering.
We will start with a lightweight Starter Motor. These are
usually high-powered units that give a higher cranking speed than a
conventional starter. They are also considerably smaller than the old
style units being approximately half the size. This also adds to the
visual appeal of a well-presented engine bay. At this stage you may
comment that this substitution will not make a hell of a lot of
difference but it will in due course as we are adding this increment to
the overall result.
Whilst we are considering the engine, an aluminium inlet
manifold for the 4 Barrel inclined owners, will give further weight
savings. The first time I picked up a boxed unit I thought it was empty
and overreacted on the lift nearly hitting myself in the face. Anyone
who has changed one over will appreciate how much lighter the alloy
unit is than a cast iron job. Apart from the weight benefit there is
also an improved power output and higher running economy. Once again it
will improve the finish in the engine bay.
Extractors are another area where many benefits may be
obtained. They provide higher power output, improve economy, are
lighter than the factory cast exhaust manifolds and add to the appeal
of the engine bay.
As we are still looking for improvements at the top of the
engine let us take a look at alloy cylinder heads. The most popular
units are undoubtably the Edelbrock heads. They are a smart investment
in this area and you can buy a bare unit, or a completely assembled
unit that is ready to go. In getting bangs for your bucks I don’t know
of a better deal. They reduce weight, improve the power output, through
better air intake and exhaust gas flow characteristics, and allow the
engine to operate at a higher compression ratio.
It is interesting to note that all of the lightweight
components mentioned to date not only save weight but also offer
improved performance and, perhaps best of all, improves the cars’ “wow
factor”.
The Radiator is another location where more weight can be
shed. George purchased his new radiator after his clutch fan “felt” the
power from the engine and it decided to escape the heat by sending the
fan into the radiator at high velocity. His engine bay now sports a
4-core alloy unit taking care of the cooling duties. This is backed up
with an electric thermostatic cooling fan. An aluminium water pump and
timing cover substituted for the original cast iron units.
Turning now to areas below the engine it was felt that a rack
and pinion steering system would improve things a little. This
eliminated two inner tie rods, the idler arm, the pitman arm, the drag
link and the heavy steering box. Over time that is a lot of parts that
won’t need greasing or replacing. This change can also improve road
feel although, for a well set up car equipped with the original factory
steering components, this effect is marginal. One factor that is a
definite improvement is the increased clearance around the exhaust that
makes it a lot easier to remove and replace. In the past I have come
across a steering box that had lost all lubrication due to excessive
heat from the exhaust melting the grease. If done properly a rack and
pinion conversion can also reduce the turns, lock to lock. I believe
the “Commondoor” non power steering rack is best used for this purpose.
These are all impressive benefits.
As George had a Challenger the choice of bonnet was easy:
factory T/A fibreglass. Of course I know that doesn’t apply to Aussie
Valiants and Chryslers but that’s not to say it can’t be done. This
substitution gives a smooth finish to the scoop – bonnet join line and
results in an intimidating presence for your car. Also you may like to
try the fibreglass bumper bars seen around recently.
Last but not least there are alloy wheels. Even the factory
knew about this one and offered alloy wheels on some models that are
still popular today. The world is your oyster and there is a large
aftermarket industry catering to your choice. Imagination and the size
of your wallet only limit you. This is the simplest way to personalise
your car but I won’t expound the benefits, as I am sure you are aware
of most of them.
In addition to the above there are still other areas where you
can save weight. These include the braking system (Alloy callipers and
4 Wheel disks), lightweight front seats, perspex windows, lightweight
fuel tank etc., etc.
Last but not least weight saving can be accomplished by limiting the add on’s and options.
Large Stereo’s and that extra weight from the items left in the
boot from the trip before last. What about the towbar that you last
used to tow a trailer ten years ago?
So there you have it with all of these improvements having one
common theme – “Light Weight”. Willingly or not these items have also
improved the performance of their intended function with the added
bonus of realising a heightened “wow factor” to your car. With all of
these changes George’s Challenger lost over 200kg.
And the good news is that nearly all of these items are
available in Australia and you can pay in good old Aussie dollars and
not worry about exchange rates!
If, after all of the above, you are still not happy give the nearest weight reduction service, such as Jenny Craig, a ring!
OLD SCHOOL
Factory Starter
Motor 6.86kg
LBD4 (cast iron
4bbl) 12.94kg
Factory Exhaust
Manifold 4.86kg
Factory Head 23.60kg
Factory Steering
Box 10.38kg
Factory Steel Wheel (5.5
by 14) 8.04kg
Factory Inlet
Manifold 9.00kg
NEW SCHOOL
Light Weight
Starter 3.98kg
Edelbrock Performer
RPM 7.90kg
Pacemaker Extractors (1
side) 4.12kg
Edelbrock Cylinder
Head 12.94kg
Rack & Pinion
Steering 6.34kg
5 Slot Kidney Mags
ea. 7.10kg
Cain Inlet Manifold
(6cyl) 5.02kg
The above charts give you some idea of the weight comparisons.
I would like to thank Tony Reynard for the use of the Scales and Paul
and the team, at Blue Star Spares, for their assistance in the
compilation of this article.
Gerard Rivett
September 2003
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