EDIT: I fixed the issue, and I'm incredibly embarrassed to admit it but the reason it was knocking is because my dumb ass installed the bar BACKWARDS. Yeah. It suddenly hit me when I was rewatching some tutorials on the installation, no clue how I managed to fuck up like that. I took an hour to get tools and I just broke and loosened the bolts, rotated the bar, reinstalled bolts, and torqued. It sounds perfectly fine now. Whoopsies.

Original Post:
Apologies for my annoying posts on here, but I'm worried right now because I installed the Progress Rear Sway Bar on my '09 that everyone seems to love, and performance-wise it's been AWESOME!
However, I noticed that whenever I go over a bump or pothole or a large crack or anything (which there are a lot of where I live) I've been hearing a brand new knocking sound come from the rear.
Originally I thought it was because I torqued the nuts incorrectly (I followed every other step exactly), and I borrowed a digital torque wrench from my boss to torque perfectly to spec. Knocking still persists...
I've checked back there, and the bar feels and looks perfectly sturdy, and I know for sure it ain't hitting the ground. I have factory suspension as well.
If this noise is normal, then fair enough. But so far what people have told me on the Honda Fit subreddit seems to suggest that it isn't...
I'm just scared I might break something. A part of me will die if I ruin anything on my little fit

 

The bar shouldn't move, so only thing to check is that all the bolts are tighten.

Other than that, my car also made a little more sound over some bumps with the bar. But it is not knocking or clunking. Just a bit more noisy then stock. At least that is what I remember as the bar had been on the car for several years now...

 

The rear suspension is pretty simple so there aren't many culprits for noise.

Did you mess with the rear shocks at all? I would confirm that your upper and lower shock bolts are correctly torqued.

You didn't mention how many miles you have, but it's also possible that you have a bad rear shock or a worn rear suspension beam bushing. Both will wear out eventually, and could lead to a clunking/knocking noise.

 

Post a picture of the rear beam and your install. I don't think you can install it backwards or anything. When I did mine I broke all the rubber spring bumper things. Though, the ride has actually been quieter since.

 

I checked all of the bolts earlier, they're all at 40+ ft/lb, as per the specification. The one grey are is the one bolt that had the rubber blocking it, which feels not as tight than the others but not particularly loose. The bar itself does not budge when I push and pull on it.

 

I didn't really touch the shocks at all apart from messing with this small rubber part that was covering up one of the holes where the bolt needed to go. My car sounded completely fine prior to installing the bar, am currently at 188k miles. I think there has been suspension work done before but I'm not 100%. Currently the 4th owner lol

 

Do you see or feel any scuffing and scrapes on the bar?

 

Are you sure you have the right bar? At one point in time, there was some odd mix up with CR-Z and GE8 bars from Progress.

Depending on the bar, it would contact the chassis during suspension compression. In addition to that, be mindful of the supplied fasteners to install the bar. Some bars come with traditional hex headed bolts that bump/scrape against the rear spring during suspension oscillation and others come with button headed bolts which need a hex socket to hold/fasten them. The button headed fasteners are lower profile and don't hit the spring and/or tuck under the rubber isolator/grommet for the spring.

 

I fixed the issue, and I'm incredibly embarrassed to admit it but the reason it was knocking is because my dumb ass installed the bar BACKWARDS. Yeah. It suddenly hit me when I was rewatching some tutorials on the installation, no clue how I managed to fuck up like that. I took an hour to get tools and I just broke and loosened the bolts, rotated the bar, reinstalled bolts, and torqued. It sounds perfectly fine now. Whoopsies.