Rear Sway Bar Mounted Upside Down?
 

Hey all! Phoning in the brain trust on this one.

I installed a Whiteline 16mm Rear Sway Bar and Whiteline Endlinks (maybe 1 mile of driving since install, was chasing a clunking front at the same time). After going back and looking at my reference picture of the stock one, I realized that I installed the damn thing upside down! I have searched and there is no topics about this, and Googling “BRZ Rear Sway Bar” shows about equal proportions of them in either direction, so I am at a total loss.

Is there any functional difference or concerns having the sway bar this way (endlink pickup point, collision with suspension parts during rotation, weird force loading, etc)? And if I do decide to flip it, are the bushings symmetrical top-to-bottom as well?

Thank you for your time!

It looks like there is contact between the sway bar and the subframe. Could this be the clunk?

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Top pic is the Whiteline, bottom pic is stock. The clunk existed before I installed this rear bar. It wound up being the front endlinks - sway bar bolt was loose. Point is, I’ve only driven with the rear bar in this orientation for about a mile, and haven’t noticed anything weird from the rear specifically so far.

I was able to move the bar through its full range of motion without any contact to subframe or other components, in this orientation.

If both rear tires move in compression the bar rotates, if one side only moves it twists. I don't really see an issue if it is in a slightly different orientation. It should still be able to function the same.

In the pic, both wheels are unloaded. When you drop the car, with the bent part down, it will rotate in closer to the subframe/diff mounts. Mounted correctly, it rotates away. Does it matter? :iono:

It's just a clearance thing.

Like others have stated the orientation is just a clearance thing, but imo you have it mounted upside down. I had the same exact question as you years ago and was also comparing the orientation of the stock bar via online pictures. However if you lay the stock bar on the ground, you’ll notice that the stock bar has its “bend” going directly backwards I.e it’ll lay perfectly flat on the ground. Most aftermarket bars I’ve noticed have that “bend” angled upwards towards the floor of the car for exhaust/diff clearance, similar to the front sway bars for our cars. I found that because of this, aftermarket bars don’t lay perfectly flat on the ground. I could be very wrong here, but just my personal observation.

I would personally make it so the bend is pointing up, but it probably won’t change how the car handles.

Hey all - thanks for the responses! Updates on my end: I have decided to retain the sway bar in the upside-down orientation. Here is my reasoning:

1. Per @norcalpb's post, I have a Whiteline 18mm bar as well, so I was able to examine that closely outside of the car. Sure enough, the centerline of the bar's mounting points (where bushing clamps) are completely in-plane with the centerline of the endlink holes. This rules out any possibility of geometric effect between mounting point and endlink hole if the bar is mounted upside down/right side up.
2. By disconnecting endlinks, I was able to run the bar fully through its range of motion. The endlink prongs hit subframe before the center (flipped) section did. Additionally, I believe that the level of rotational articulation required to make the endlink prongs find something solid is far beyond what would be possible during actual driving, given the shock travel.
3. I noticed that mounting it this way actually allows access to the diff bolts. The stock mounting orientation required the bar be removed, or at least bent out of the way, to access these three large bolts.
NOTE: I am running a stock exhaust, front to back. Additionally, I have no rear subframe bracing, just the Whiteline diff bushings shown in the prior post. This change may very well cause interference with aftermarket catback systems or aftermarket bracing packages (ex: Cusco, Carbing), depending on routing. So, if you have any of those items, ymmv!

I hope to take the car to several autocrosses over the next year, as well as canyon runs and the occasional drives to work. If any negative side effects happen as a result of this mounting configuration, I will report back & update this thread.

Remind me, are the mounting locations for the end link parallel, or slightly tilted?
On ND Miatas, the rear bar has slanted mounting locations, so if you put it upside down, the end links will have issues at some angles.