In
Frank's Suspension, Part 1 we covered the fitting of
new Whiteline springs and dampers to our EF six cylinder Falcon. The result was
exceptional: a major improvement in handling and rear-end grip under power,
together with a good ride quality. We did the springs and dampers first, because
that’s the approach taken by the vast majority of people when upgrading
suspension. And, following the same perspective, we fitted the Whiteline
adjustable sway bars next.
Whiteline Adjustable Sway Bars
The front adjustable Whiteline sway bar (anti-roll
bar – same thing) has part number BFF35AZ and is 30mm in diameter. The rear
adjustable sway bar is 22mm in diameter and has part number BFR35Z. In each case
adjustment is made by moving the sway bar links, which comprise S-shaped designs
bent from steel bar, so that the effective lever arm length of the sway bar is
changed. To accommodate this variation, new brackets are supplied for the car
body that allow the links to be moved without unduly increasing their
angularity. The sway bar themselves are equipped with flattened ends drilled
with multiple holes. The D-bushes, on which the sway bars pivot, and the bushes
within the sway bar links, are made from polyurethane.
Here is the hardware for the front sway bar
mounting. From left to right: the new body mount brackets (note the three
adjustment holes), the S-links, nyloc nuts, washers, bolts and the D-brackets.
The polyurethane D-bushes and also shown, as is the grease to lubricate the
bushes.
The rear hardware follows the same approach.
Note: as with all the suspension products provided
by Whiteline for the Falcon, these components were made available free of
charge. Retail cost for the front and rear adjustable sway bars is AUD$266 each.
So how does the stiffness of the new sway bars
compare with the old? (Note that the Falcon was fitted as standard with the
raised Country Pack suspension; AFAIK, this alters only the springs but it may
provide different sway bar thicknesses as well.) Clearly, the actual stiffness
of the new sway bars depends on where the links are positioned in their
adjustment holes, but an immediate feel for the change can be given by looking
at the relative diameters of the old and new.
|
Standard |
Whiteline |
Stiffness Change* |
|
Front Diameter (mm) |
27 |
30 |
+52% |
|
Rear Diameter (mm) |
22 |
22 |
0 |
*calculated only from diameter change
We chose to leave the rear bar in its softest
position and set the front bar to +1 step-up in stiffness. The reason for doing
this was that with the new springs and dampers, the Falcon has a tendency to
transition to oversteer at higher speeds; we’d prefer it to start pushing into
understeer in the same conditions.
Handling
and Sway Bars
It’s
certainly not always the case, but in general, uprating the stiffness of the
sway bar at one end causes the biggest change in handling at the opposite end.
So for example, a much stiffer front sway bar will tend to reduce oversteer; a
much stiffer rear sway bar will tend to reduce understeer. This is also a
function of the fact that the grip of the end of the car with the upsized sway
bar is likely to be reduced: the sway bar works by trying to pick up the inner
wheel, so the downwards pressure of the rubber on the road at that end of the
car is lessened, leading to decreased grip.
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Installation
We had Simon of Simon’s Car Clinic install the
springs and dampers. This was a straightforward 2-hour job.
Rear Sway Bar
The standard rear sway bar is heavily curved to
clear the diff. It is connected to the rear axle by means of D-brackets and to
the car body by short sway bar links, rubber-mounted at each end to allow
angularity of movement as the axle moves up and down.
Removing the rear sway bar was just a case of
undoing the D-bracket and sway bar link bolts and nuts...
...until the old bar could be manoeuvred out past
the axle.
The body brackets for the sway bar links comprise
right-angled brackets. These are bolted to the original body mounts.
With the link brackets in place, the new sway bar
could be fed over the rear axle and tailshaft.
The D-bushes were thoroughly greased and then
slipped over the sway bar....
... before the original D-shackles were bolted back
into place.
The sway bar links were then installed, with the
previously chosen stiffness setting being used.
The finished job.
Front Sway Bar
The front sway bar has a less complex shape.
The first step was to undo the links. These use
polyurethane bushes as standard.
The D shackles could then be undone...
...and the standard sway bar removed.
Again, right-angled brackets with multiple
adjustment holes bolt to the body mounts.
The process was much the same as for the rear bar,
but because of the bar’s bigger diameter, new D-shackles were used in addition
to new bushes.
With the sway bar positioned beneath the
bell-housing, installation was easier than for the rear bar.
The S-shaped links were then fitted.
A final step was to wipe over the front and rear
bushes to remove surplus grease that might attract dirt that can then work its
way into the bushes.
On-Road Results
One characteristic of upsized sway bars that few
consider is the trade-off in ride comfort.
With two-wheel bumps, like those met when you
cross a bitumen filler strip, stiffer sway bars have no affect on ride quality.
The sway bar simply pivots in its mounts as the wheels rise together. But in
one-wheel bumps, the story is different. In those cases, the sway bar stiffness
has the affect of aiding that wheel’s spring, resulting in increased bump
stiffness.
And with the Falcon’s increased sway bar
stiffness, this change in one-wheel bump stiffness is quite clear. Whereas
previously you never went ‘ouch!’ when a front wheel hit a pothole, with the
increased sway bar stiffness, in these conditions a jar can now be felt through
the car. The quality of the ride with the combination of Whiteline springs,
dampers and sway bars is still quite good, but a similar drop in ride quality to
that which occurred with the fitting of the sway bars would start to make it
borderline. To put this another way: I wouldn’t have wanted to start off with
stiffer springs and dampers and have then fitted the sway bars...
However, the reasons you fit stiffer say bars are
to improve handling, and tweak the handling balance. And are the ‘bars
successful at this? Well, yes and no.
Even with the rear bar at its softest setting and
the front ‘bar at +1 stiffness, the propensity for oversteer is little changed.
The car sits flatter in corners (more on this in a moment) but the balance
feels, if anything, more inclined to oversteer than it did before. So why not
increase the front bar stiffness even further? The answer to that is that I now
think trying to tweak the balance is, at this stage of the suspension
modification process, not the approach that should be taken. There are still
plenty more suspension parts to be fitted and these will further change the
handling behaviour.
So, finally, how hard does the Falcon now corner?
The answer to that is: considerably better than before. As expected, the car
sits flatter. It also has less weight transfer in S-bends and turns-in more
sharply. But this also has a downside – in wet conditions the car is more
sudden. In wet, slippery urban conditions, the stiffer roll resistance and lack
of a rear limited slip diff makes it a bit of a lucky dip at to whether the car
will power oversteer or simply spin an inner wheel. This inconsistency is more
of a problem than either handling trait - what you want is to know is what to
expect!
(Incidentally, we didn’t mention it before but the
lowered springs have given the Falcon noticeable front negative camber. That’s
probably why we concentrate so much here on oversteer: the front-end grip is
very good.)
So would we recommend the Whiteline sway bars?
Sure! Their ability to be adjusted for stiffness is extremely useful – although
more so at the end of the handling set-up process than part way through. They
look well made and are easy to fit. But if this is as far as you’re going with
the handling upgrades, we’d suggest buying just the front sway bar, and then
seeing whether you can get the results you want by tweaking its adjustment.
Much more so than with the fitting of the
Whiteline springs and dampers, there are also trade-offs to consider when
fitting stiffer sway bars. Perhaps in retrospect we should have fitted the
upgrade sway bars right at the end of the handling upgrade...
Next: more work on the rear suspension
Contacts:
Whiteline
Suspension – www.whiteline.com.au
Simon’s
Car Clinic – Tamborine (Queensland) – 07 55436155
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The
Whiteline suspension components were supplied courtesy of Whiteline
Simon’s
Car Clinic was paid at normal commercial rates
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