Great, Decent, and MEH modifications for an 8th gen

In my never-ending quest to make this car into something it’s not, I decided to add three more modifications that would only further prove how dumb I am. Considering how easy all three of the modifications are, rather than make individual posts for each part I figured I would lump three of them into one big post.

Preface: Below you will read about three different modifications I have done to my 8th generation Civic. I will go through the installation process and give you my unbiased review and opinion of each one. Enjoy!

It’s a well-established fact that by upgrading to a larger rear sway bar, you’ll inject a new level of liveliness and excitement into a FWD vehicle, courtesy of some controlled oversteer. Given that FWD cars lack the means to swing their rear with the drivetrain, a significantly up-sized rear sway bar is the secret weapon for shaving seconds off your lap times. This strategic modification combats the typical understeer, pivots it towards beneficial oversteer – ensuring you’re not only maintaining greater speed through the bends but also getting on the throttle earlier and powering through much more of the corner. It’s a straightforward upgrade with a substantial impact on performance.

You’re probably wondering why a guy with an R18 Civic is so eager to increase its oversteer. Let me make it clear – it’s my relentless passion for upgrades and my inability to settle for the stock. Now, you might be curious as to why I didn’t opt for an aftermarket rear sway bar, like a Progress or Eibach. The answer is straightforward. I went with an OEM rear sway bar for several compelling reasons.

1. Getting a Progress or Eibach would mean that I would be getting a 22mm or larger bar and for me, I just felt that such a large RSB was going to create too much oversteer for driving under normal conditions.
2. I didn’t want “all” the oversteer, I wanted just the right amount of it. You know, enough to let the car get a little tail happy, yet not totally spin me into a wall. (and to be honest, if you don’t have VSA turned off you can’t get the tail out at all, no matter how large the RSB. Most of the time I forget to turn off the VSA)
3. Getting even a 22mm RSB would potentially cause the end links to tear out the mount on the LCA and this concerned me because I knew I would be driving the car pretty aggressively and I definitely didn’t want to encounter any tearing of brackets. Plus, it’s not like I would need to be shaving milliseconds of my lap times… or would I? Sure, the progress does include an additional bracket to strengthen the LCA but again, for what I’m doing with the car it’s just not necessary.
4. A larger RSB is essentially just increasing the spring rate in the rear. This means that the rear will become much stiffer/bouncier and this is not ideal for making a comfortable daily car.
5. TOO much of something is never good and since having a larger rear sway translates to more oversteer, while this is fun and does help you get around the track quicker, I’m not running sticky enough tires to truly benefit from a super large RSB. Usually my tires aren’t even warmed up enough before I’m jamming through my first on ramp of the day.
6. Lastly, I think it’s neat how you can incorporate OEM parts from other chassis in the modification of your car, it’s more unique and is surprisingly a cheaper route than an aftermarket RSB. Plus, since it is all OEM it is designed to fit perfectly, will not cause any sort of noise or vibrations, and will last forever.

Let the record state that if I were building this car for the track (which I’m clearly not), I would have opted for the largest sway bar possible.

Remember that the 9th gen 2012-13 sway bar is smaller… make sure you get parts for a 2014-15 9th gen Si. (this will make sense the further on you read)

Lets get into it!

OEM GOODNESS! Below is the complete parts list you’ll need to do the 9th gen RSB upgrade. Click the P/N to go to the part on the Honda site.

This will work for all 8th gen civic platforms, ALL OF THEM!

• 9th gen RSB. P/N 52300-TR7-A51
• 9th gen rear stabilizer bracket left and right. P/N 52318-TR7-A01, 52317-TR7-A01
• 9th gen bolt-washer (10×30). P/N 93404-10030-08 you’ll need 4
• 9th gen rear stabilizer busing. P/N 52306-TR7-A51 you’ll need 2
• 9th gen rear stabilizer bushing holder. P/N 52308-TR7-A00 you’ll need 2

Below you can see the parts unpackaged.

one for fun

Make sure this is the part number you order. This is the 20mm one; the 2012/2013 is not 20mm.

Jack up the car, place it on jack stands, remove the wheels. Now, you can scoot under and start to remove the rear sway bar. I just disconnect the RSB from the end link, leaving the end link connected to the lower control arm. The end links will be the same for any of the models of 8th/9th gen models, so if yours are in good condition (like mine), you can just reuse yours. Or, for 18 bucks each, you can replace them if you wish to do so. Here are the part numbers, 52320-SNA-A01, 52321-SNA-A01.

Now instead of removing the RSB from the bracket, just remove the whole bracket with RSB still connected.

Keep in mind that I had already installed the 8th gen SI rear sway bar on my car, so the comparison below is between the 8th gen SI RSB and the 2013/2014 4-door RSB.

below you can see what I mean about remove the whole bracket leaving the RSB connected still.

Below are some good size comparison shots between the 8th gen SI RSB (that I just removed) and the new 9th gen RSB.

Below you can see why you need to order new brackets. See how the new 9th gen bracket is reinforced for the larger 20mm 9th gen RSB compared to the 8th gen SI bracket which is for a 17mm RSB.

Here’s the definitive reason you should opt for the X4 longer bolts: Take a close look at the bolt on the left, which secures the 8th gen bracket to the chassis, versus the bolt on the right, designed for the 9th gen bracket. The 9th gen bracket comes equipped with robust, thicker bracing, necessitating the use of a longer bolt. This ensures ample threading into the chassis, offering a stronghold that’s guaranteed not to fail. Don’t compromise on security – choose the right bolt for the job.

Now loosely assemble all the new parts together, and install the new RSB the same way you removed the old one.

Bonus extra… Since I was going to be under the car anyway, I decided to order new front sway bar bushings, since the ones I had gotten from the Si parts car were beat. So, when I ordered all the RSB stuff, I just added two of these bad boys to the order P/N 51306-SNX-A01

Notice the “27” on the bushing. This indicates that it is in fact for a 27mm sway bar. Remember that the SI Sedan comes with a 27mm front sway bar, and the SI Coupe comes with a 28mm front sway bar. I got my front sway bar from an SI sedan, so mine is a 27mm.

These are super easy to change out. Just leave the sway bar connected at the end links and unbolt the bushing brackets. The sway bar will hang, allowing you to slide off the old bushing and pop on the new bushings.

Make sure you take note of the arrows on the brackets when you reinstall them. They should be pointing forward (towards the front of the car).

That takes care of the first of the three modifications that I’ll be writing about in this post.

Next, we are moving on to K-Tuned Roll Center Adjusters… Now, I’m going to be completely honest; the motive to buy these was strictly for appearance reasons only. I know, I know… Crazy, right? Basically, on the Swift springs, the car sat a smidge higher in the front, and this drove me bonkers. (This is what ultimately led me to purchase coilovers for the car, which you will be able to read about in an upcoming blog post). Admittedly, this is somewhat of a “NOOB” moment on my part. But this is how we learn.

Roll center adjusters, often integrated with adjustable ball joints or tie rod ends, are designed to correct the suspension geometry of a lowered vehicle. The benefits of roll center adjusters include:

1. Improved Handling: By keeping the suspension arms closer to their original angles, roll center adjusters help maintain the intended suspension geometry. This can lead to better handling characteristics, as the car will behave more predictably under cornering and maneuvering.
2. Reduced Body Roll: A corrected suspension geometry helps minimize body roll during cornering. With a lowered center of gravity but aligned suspension, the vehicle can maintain better stability when turning.
3. Optimized Tire Contact: Adjusters help keep the tires flat on the road as the suspension moves, optimizing the contact patch of the tire and improving grip and traction.
4. Enhanced Steering Response: When the suspension geometry is corrected, the vehicle typically has better steering response. This means the car can turn in more crisply and accurately to steering inputs.
5. Decreased Suspension Stress: Lowered vehicles without corrected geometry are prone to increased stress on the suspension components. Roll center adjusters help alleviate this issue, potentially leading to longer component life.
6. Maintained Ride Quality: While lowering a vehicle can often lead to a harsher ride due to increased suspension stiffness, roll center adjusters can help maintain the original ride quality by preserving the intended suspension angles and minimizing jarring movements.
7. Reduced Bump Steer: By correcting the geometry, roll center adjusters can reduce bump steer, which is the tendency of the wheel to steer itself as it moves up and down. Less bump steer contributes to a smoother and more controlled ride.

Even though roll center adjusters can provide these advantages, they are often used by enthusiasts who prioritize performance driving, as the benefits may be more noticeable during aggressive driving or on the racetrack than during everyday street use.

Remembering when I installed the Buddy Club roll center adjusters on my EK sedan, it substantially lowered the front, and I had to raise the ride height of the car after installation.

You can read about that by clicking the link below.

https://functiontheory.com/2019/05/everything-you-need-to-know-about-extended-balljoints-including-how-to-install-them/

Since the ride height on my 8th gen was killing me and I just needed the car to sit about a half inch lower in the front to be satisfied, I decided to order some Roll Center Adjusters for the car. At this point, I was grasping at straws by hoping that installing Roll Center Adjusters would lower the car enough to satisfy me, but I figured it would be substantially cheaper than ordering coilovers and it would surely improve the ride quality and handling of the car.

So let’s go through the install process and then talk about the results at the end.

Honestly, I didn’t want to go with the K-Tuned, but since the Hardrace ones were out of stock everywhere and I couldn’t find any other quality branded ones to order, these are what I ended up going with. There are other brands out there that are quality, but they just offer replacement ball joints and don’t do anything for adjusting the roll center.

Not to say that I don’t like K-Tuned stuff… In fact, I have quite a few of their parts on my K-swapped EG, but I just know that some of their stuff is just rebranded Chinese stuff. Either way, these are what I went with, and they have been working great for more than 6 months with over 8k miles on them.

Below is the ride height measurement before installing them.

Start by jacking up the car and placing it on jackstands.

Next, remove the two nuts and one bolt that secure the ball joint to the lower control arm. Then pull the cotter pin from the ball joint castle nut and remove the castle nut from the ball joint. Now use a ball joint separator to separate the ball joint from the spindle. Note that the ball joint separator will normally destroy the rubber boot of the ball joint, but in my case, I’m putting new ball joints on, so I’m not worried about destroying the boot.

Below you can see the ball joint is separated from the spindle.

Now take a jack and jack up from under the brake rotor. This will allow you to remove the ball joint from the lower arm.

Now we can compare the difference between the OEM ball joint and the K-Tuned Roll Center Adjuster ball joint. See the 10mm spacer; that is what realigns the suspension to more OEM geometry when the car is lowered.

And what it looks like installed.

These are actually a very simple install, and unlike most cars, on the 8th gens, you don’t need to press out/in old and new ones. They simply bolt off and back on!

Here is what the ride height looks like after the car is back on the ground and driven out of, and back into, the garage.

It turns out that RCA’s on MacPherson strut style suspension don’t actually lower the car any further. This was a surprising revelation, but it’s always good to understand the mechanics in depth.

Roll center adjusters (RCAs) are suspension components that are mainly used to correct suspension geometry, particularly on lowered vehicles. The impact of RCAs on ride height varies with the type of suspension system—MacPherson strut or double wishbone.

In MacPherson strut systems, the strut itself essentially forms one side of a triangle, with the wheel and tire assembly at the lower point and the top mount fixed to the vehicle body. When RCAs are installed on a MacPherson strut system, they usually affect the position of the lower control arm and thus influence the suspension’s pivot points. However, because the MacPherson strut’s spring and damper unit is a single assembly, adjusting the geometry of the lower part of the suspension doesn’t change the position where the strut meets the body of the car. Therefore, RCAs don’t typically change the ride height of the vehicle; instead, they adjust the angles of the suspension arms to improve handling and maintain a proper tire contact patch.

On the other hand, double wishbone suspension systems have upper and lower arms (or wishbones) that allow for independent movement of each component. When RCAs are installed on a double wishbone suspension, they alter the height relationship between the upper and lower arms which can effectively lower the vehicle. Since the spring perch is typically mounted on one of the arms, adjusting this suspension can indeed change the ride height.

In summary, while RCAs can affect the suspension geometry of vehicles with MacPherson strut systems, they do not typically influence ride height because the ride height in such systems is controlled primarily by the fixed points where the strut assembly is attached to the vehicle. Contrast this with double wishbone suspension systems, where the relationship between the arms can directly affect ride height when RCAs are used.

I have just learned that Roll Center Adjusters on a MacPherson strut do not have the same impact on ride height of the car as much as roll center adjusters do on a double wishbone style suspension. I’m also aware that my car is only lowered on springs that drop the car about an inch, which is not enough to throw the stock suspension geometry out of whack, and this is also probably why I didn’t notice that much performance gain from installing them.

Below are the best comparison pictures I have since honestly, I thought there would be a much more noticeable difference. Left (daylight) is the OEM, and right (night) is the K-Tuned Roll Center Adjusters installed.

After that disappointing modification, let’s jump into the third and final modification for this post. The final modification is probably the best mod I’ve done to the car so far. It was such an impactful modification that I ordered one for Angie’s Fit too.

Manufacturers expertly tune stock cars to provide the ultimate in comfort, skillfully damping unnecessary harshness without sacrificing performance. Under the hood, a potent engine pulses with energy, yet advanced engineering mitigates any intrusive noises and vibrations. This meticulous design ensures a serene cabin environment, ideal for drivers who seek a pure transportation solution devoid of any extraneous driving sensations.

I know that on 8th gens and really any Honda that was made after 2001, a rear motor mount is quite a common modification. I do also know that when you install three or more, even 62a urethane mounts on a car it becomes quite noticeable, and the vibrations of the engine are easily transferred to the chassis and steering wheel of the car. This can take a lot of comfort out of the car and take it from “daily driver” to more of a “weekend” car.

You should know by now that this car is my daily driver, and I’m trying my hardest to keep it very comfortable. The comfort goal is… would it pass the girlfriend test? You know, is it comfortable enough that when you say “Let’s take my car” she doesn’t shrug or sigh deeply? I knew I was taking a risk by adding even one stiffer motor mount to the car, but I was willing to take the risk to improve the driving sensation of such a dull car. Usually, rear motor mounts help aid in stopping wheel hop and assisting in putting power down smoother and more evenly. In my case, the R18 doesn’t have any power, so I wouldn’t be installing it to help me with anything like that. No, I was going to be installing it strictly for research purposes only. I never had a car that had only a rear motor mount as an upgradable option, so I figured for 160 bucks, I could find out what all the hype was about. All I have to say is… I’m glad I took the chance and bought it.

When it comes to purchasing engine mounts, for me, Hasport stands unrivaled. There’s a reason other brands don’t even enter the equation. I’ve had a flawless track record with every Hasport mount I’ve ever fitted—on my own vehicles and those of others. Hasport has mastered this product, and it’s inconceivable to gamble on any alternative. It’s not just about the premium quality or the unmatched no-questions-asked warranty; it’s about the peace of mind that comes with choosing the best—period. You get what you pay for, and with Hasport, every penny is a steadfast investment in excellence.

Here is what you get in the box… For the R18 model, it actually comes with a whole new bracket that bolts to the car.

Installing this on an 8th gen is a breeze. Simply hoist the car, secure it on jack stands, and effortlessly remove the OEM rear motor mount along with the bracket. You’ll find no splash guards or extraneous panels to wrestle with just to reach it. Rest assured, the engine is firmly supported by two additional mounts—or three if you’re working with an SI model—so there’s no risk of it dropping. Though the engine will have increased mobility, it’s designed to stay put, giving you hassle-free access to complete the task.

Below you can see the complete OEM mount setup.

Below is the comparison between the OEM mount and the Hasport kit.

Transfer over the X4 OEM bolts from the OEM bracket to the Hasport bracket. Please note that I failed to document that the Hasport kit comes with a spacer that needs to be used on the longest bolt located on the upper left of the bracket. (It’s the longest bolt in the picture below)

It’s also a good idea to use Loctite on all bolts securing both the bracket and the motor mount.

First, bolt the black bracket to the engine, then slide the motor mount in. You might need to move the engine back and forth since there isn’t much play in the new 62a urethane mount. Pro tip… use some lube, grease, or WD-40 on the rubber part of the mount to help it slide into the subframe easier.

In the image below, you can see the spacer used on the upper left of the mount bracket (it’s just below the exhaust).

Absolutely thrilled to discuss this enhancement! Hands down, it’s the pinnacle of the modifications I’ve done to my car, even including the ones I’ve yet to unveil. The throttle response has been revolutionized. We’re talking about pure, unadulterated power delivery here—with no energy squandered due to the engine’s own inertia.

What this mod achieves is a masterclass in efficiency; it’s not about adding horsepower, but rather optimizing the existing muscle of the engine. This means the power heads straight to the wheels, unimpeded by the engine’s kinetic dance. The result? Acceleration that snaps to your command.

But the benefits don’t stop there. The art of shifting gears becomes a symphony of smoothness, directly tied to the reduction in engine movement. Downshifting turns into a breeze, with throttle input that’s sharp and instant. And the braking—prepare to be astounded. The brakes now have an opportunity to truly shine, even the stock setup, because the engine’s reduced tendency to shift upon braking maximizes the initial brake force.

It might sound like a deep dive into automotive theory, and, sure, my terminology might not be straight out of an engineering textbook. But what’s clear is this: Limiting the engine’s unnecessary motion unlocks a depth of driving pleasure you didn’t know you were missing. If you haven’t yet considered what a solid-mounted engine could do for your ride, it’s time to start.

Like I said earlier, this modification was so amazing… I ordered one for Angie’s Fit. Sure, under initial startup, right when you turn the key, there is a slightly more noticeable engine vibration, but when idling at a stoplight, or driving down the road, a normal person wouldn’t be able to tell that you have a stiffer rear motor mount in the car. Like me, Angie daily drives her car, and we are not talking about a few miles a day… no, she drives a round trip of 32 miles a day to work across the Las Vegas valley and she has zero complaints about comfort or noise.

As always, thanks for finding some time to sit back and read my long-winded ramblings about pointless car modifications. I can only hope that what you take from my journeys helps you along the path to modifying your own car, or helps you gain the courage to even try to modify your own car. If you have any questions about this post or any other posts on the blog, please don’t hesitate to reach out.

• BIlly@functiontheory.com
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• Or just comment below

I love hearing from everyone; it helps keep me motivated to continue making mini-documentaries of my install process.