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Q45 Sway Bars 

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 donít 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 donít 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!



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This web site is the intellectual property of Jesda Gulati and Wes Stinson.