These
guides, covering the Q45 from 1990-2005, will assist you in servicing or upgrading your
vehicle. No
guarantees are made on the results, and anything you do yourself
is at your own risk.
All about Sway bars
and sway bar bushings
By Wes Stinson
One of the good
things you can do to your Q45 to make the handling better is
upgrade sway bars. Outlined
below is what the G50 Q45 got as far as sway bars from the
factory
Std. Q45- 29mm front
bar, no rear bar
Q45t- 28mm front,
15.9mm rear bar
Q45a- 28mm front,
20mm rear bar
Stillen made a 24mm
rear bar as well and it is no longer made
The bar on the Q45t
really does not do very much.
However if you add urethane bushings you can certainly
take full advantage of what benefits it does have.
Any rear sway bar is better than none!!
So what does all this
mean with sway bars? Here
is a quote from NICO by Q45tech.
The safe [dry] rule of thumb is
never install a rear sway bar equal to or > the rear spring
stiffness: and a 20 mm bar is only 34% of spring if perfectly
coupled with solid metal bushings...the more typical rubber
oem bushings slack will reduce the 1st inch [of wheel/body
travel] to almost no added stiffness.....then the bar will
kick in progressively. So under a fully side to side swing [-3
to zero to +3] the 20 mm might get close to 85/366 or 23%
total stiffness increase. {ON A GOOD DAY}
I use urethane rear bushings and
rigid metal inserts to try to get the full 34% usually
bend/deform the end links as they are not designed to take the
full load [rubber bushings remember -sideslip].
The severe problem is no shock
absorber design takes into account the extra springiness of a
sway bar even the Tokico blues are only 10-15% stiffer not the
34% extra rebound one needs in auto cross or a 70 mph
emergency lane change.
We have about 7 Q customers with the solid 24 mm rear bar,
many for over 5 years guess they just learned to drive better
no accidents I am aware of!
I had the 24 mm for 4.5 years before
down grading to the 20 mm to make my bottom and hernia feel
better on railroad tracks! Miss it on some ocassions but I've
learned to adapt to another 0.9" of sway.
Oh! I started out with urethane till
I bent two sets of end links [the heavy duty ones supplied
with bar]. Then I tried various combinations of
rubber/urethane finally all rubber.
The problem is the 4:1 reduction 1" of wheel movement is
only 1/4" of movement at the end link......very very hard
to make a fine adjustment that stays the way you want
it.....what happens is nothing then wham a sudden stiffening
which will cause a lack of smoothness and snap oversteer with
rubber bushings. Severe oscillations when you whipsaw the
steering again due to the imability of shocks to provide
adequate control over something twice as stiff as they were
designed for!!!!!!!!!
By the way some of my driving bent
the bar an 3/4" permanently part of the reason why the
rear subframe needed replacement.
So
lets cut to the chase here, what is best overall for the Q?
Really ideally would be a 22mm rear bar with the 28mm
front bar, but such a rear bar does not exist.
Its hard to make the 20mm stiff enough or the 24mm soft
enough. The best
and readily available mix is the 20mm rear Q45a bar and 28mm
front bar from a Q45t. If
you don’t have access to it easily, its not worth the
upgrade to the 28mm bar. Making the front bar smaller is in essence making the rear
bar stiffer.
You
can get a Q45a rear sway bar from Joe at infiniti of
Scottsdale. He
sells it for about $300 and that includes the bar, brackets,
and bushings. The
good news is if you have a Q45t you don’t need the brackets,
end links and so forth. You
will just need new bushings and the bar itself.
You
can make the most of the rear Q45a bar by installing
polyurethane bushings. These
will however make the ride somewhat harsh.
I recommend to people with a Q45t to try and upgrade
the bushings first before switching to the Q45a bar.
Energy
suspension makes universal end link kits that you can get
about anywhere. Here
are the part numbers.
7.8120
rear endlink set
7.8122 front endlink set
9.5163 front swaybar bushing for 28mm
(5164 is 28.5 mm)
9.5157 rear swaybar bushing for 20mm
(5157 is 20.5mm) there is no 20mm ....except 9.5124 (non-greaseable)
Using
the poly bushings will make the car ride harsher but will
really tighten it up. I have talked to people that use all poly bushings and it
does ride firm, but they really like it because it makes the Q
feel like a sports car!
Supplimental
links
http://forums.nicoclub.com/zerothread?id=1137
http://forums.nicoclub.com/zerothread?id=4856
http://forums.nicoclub.com/zerothread?id=2256&highlight=urethane
http://forums.nicoclub.com/zerothread?id=5248
