[exE36M3]

Special thanks to Farkle for his help on this project and his expertise!


OK gentlemen and ladies:

So at 57k, my F32 driver thrust arm/control arm bushing was toast.
I bought the car with 49k miles and originally chalked it up to just a floaty suspension. However as the miles and months progressed, I was always a little caught-off guard when the car would oversteer a bit... but only on the driver side. I chalked it up to well it's a heavier, longer, and bigger car than either my old BRZ and E36 M3.

But then while in for service, the BMW tech suggested I replace the Thrust Arm Bushing for $800 (parts and labor, ONE side). I did some research online and decided to not get into this issue again with the stock ones and went with the Turner Monoball bushing. Basically instead of a metal pipe stuck into a fluid and rubber encased bushing, Turner uses a metal and rubber encased monoball. It's more durable and precise.

Here's what you are looking at...

The arm with the monoball is the "smaller" looking unit.





And once installed...


The monoball set-up uses two spacers (as seen above) to make it fit. Because the monoball is about 2-3 inches shorter in length than the OEM bushing. Also interesting, per Farkle, the monoball is dead center in the housing. The OEM bushing is slightly offset by maybe 1/2" off center. So your caster will change. It looks like the wheel is *slightly* more forward in the wheel well, don't don't quote me on that yet.

Installation can be done with common tools within about 3 hours. You will spend more time removing/replacing your bottom splash panels to get to everything than actually removing the arms. (Although you may want to WD-40 up the bolts. They will fight a bit).

HOW DO THEY FEEL?

1. Noise, Vibration, Harshness

STOCK - there is NO noise, no vibration, no harshness
MONOBALL - this is some road noise, some vibration, some harshness. On a scale of 10 being the worst... maybe a 3-4 tops. I'm a car guy (BRZ, E36M3, Miata) with all my previous cars with lowered suspensions and the such. With the monoball, the ride is still better than all those cars. In fact, it's comparable to the new G80 3 series I drove as a loaner.

2. Handling

STOCK - without SPORT mode, floaty and vague. Oversteers. In SPORT mode, good, but tad vague. Oversteers less.
MONOBALL - YEOW!, precise, more feedback, SPORT level steering feel in COMFORT MODE.

In short, I like it. I like it a lot. It makes my 435i *feel* more sportier.
Turner sells the entire arm with ball joint, monoball, spacers, and bolts for about $508 (+tax/shipping). Not cheap. But if the Norcal dealer wants $800 for parts and labor for ONE side, you can get both arms (complete with new ball joints, arms, monoball bushing) for $500, that leftover $300 should cover a chunk of the installation cost from a shop or an alignment.


100 MILE ROAD TRIP UPDATE
So far so good. But some things I've noticed. Around town, the car rides quietly enough but not quite near stock. If stock was a 10, this one is a 7 or 8. You do notice more potholes and broken cement as your wheel moves over them. If you have a bad patch of freeway, you WILL feel the rutting, thump, thump of things as well as hear them. It's not teeth jarring, but again, if stock is 10, then we are talking 7 or 8.

I'm still pretty happy with the monoball solution. The car just feels SOOOO much more planted and responsive.
If you test drive the new G80 3-series BMW and a 4 with the monoball, it's VERY similar. Makes me wonder a bit.

[FaRKle!]

One other thing noticed is that the bolt hole for the monoball is in the center of the arm hole, vs the OE bushing's slightly offset hole, so this will increase your caster.

[exE36M3]

Originally Posted by FaRKle!

One other thing noticed is that the bolt hole for the monoball is in the center of the arm hole, vs the OE bushing's slightly offset hole, so this will increase your caster.

Thanks Farkle! Updated post!

[M4_GTS]

Someone needs to try this out on a xdrive car if it works.

[FaRKle!]

Originally Posted by M4_GTS

Someone needs to try this out on a xdrive car if it works.

It should work as long as the appropriate spacers are supplied. The bushing/spacer length is longer on RWD compared to xDrive cars.

KMAC makes a caster adjustable monoball for xDrive (PN 193916-7J). I have them on my vehicle.

Originally Posted by percychow

100 MILE ROAD TRIP UPDATE
So far so good. But some things I've noticed. Around town, the car ride quietly enough but note quite near stock. If stock was a 10, this one is a 7 or 8. You do notice more potholes and broken cement as your wheel moves over them. If you have a bad patch of freeway, you WILL feel the rutting, thump, thump of things as well as hear them. It's not teeth jarring, but again, if stock is 10, then we are talking 7 or 8.

Would you say the increased noise that you hear/feel is more like a low frequency pressure wave rather than audible sound? That's how I felt the NVH increase was with KMACs. I wonder if Turner is the same.

[exE36M3]

"Would you say the increased noise that you hear/feel is more like a low frequency pressure wave rather than audible sound? That's how I felt the NVH increase was with KMACs. I wonder if Turner is the same."

[ laughing ]

Farkle-man, you seriously out-car-geek me!
But clearly in a good way! We should swap cars sometime and compare notes.

But I would say...
1. Over a pothole or rough pavement - I can hear the tire/radial ping, kind of like when you bounce a tire/rim on the ground. And if the road is bad enough, that body BANG!

2. Over normal/decent road surfaces - it's maybe with 1-2 points of stock comfort feel. (So stock a 10 - cushy, now an 8-9 - still decent)

3. I do feel some pressure waves on moderate road surfaces, mostly in my butt - nothing around my head/ears.

But if any of the above was considered annoying, it goes away as soon as I turn the car! In COMFORT mode the turn-in and road holding is amazing. Like 4-5 points better than stock. There's no dive, no oversteer... and going into SPORT feels like the car is 500lbs lighter response-wise. That missing 1+ inch of the stock rubber bushing is VERY noticeable.

I had the new 2019 330i loaner from BMW a few weeks back for a few days. Even with the monoball in my 435i, the ride was VERY comparable. Heck I'd even go so far as to say almost the same. Makes me wonder if BMW tweaked that bushing.

[andino]

Both of you getting the monoballs installed make me want to accelerate my plans to get the KMAC ones. My suspension has always been a tiny bit floaty with the stock tension strut bushing even after coils and stuff. Need to stop procrastinating and reach out to KMAC to get them ordered!

[eleven11]

Thanks for the insightful post.

I'm curious if this is the best component upgrade/swap to help reduce the play/delay I have when steering. I'd like to have a more direct steering feel when initiating a wheel turn. Now, there's a small gap of wheel non-movement when turning the steering wheel. I'm on dropped KW DDC coilovers.

Farkle, you have an F31. Has your K-MAC upgrade improved my complaint above?

[exE36M3]

Andino - Get them. Or heck, take a drive of either of our cars. It's dramatic enough for me to say, do the monoballs FIRST before even thinking of a spring swap, shocks, etc.

Eleven11 - like I said. I chalked up the disconnected/floaty feel to the f32/435i platform originally. With each new BMW platform, handling and steering feel is compromised a bit. But I think given the way the new G80/330i drives... I can't help but wonder if BMW ditched that thrust/control arm bushing design and did something else. I'm just on stock adaptive shocks and Eibach Pro-kits and I find myself NOT switching into SPORT mode as often because I get the steering and handling I want in COMFORT mode now.

[eleven11]

Originally Posted by percychow

Eleven11 - like I said. I chalked up the disconnected/floaty feel to the f32/435i platform originally. With each new BMW platform, handling and steering feel is compromised a bit. But I think given the way the new G80/330i drives... I can't help but wonder if BMW ditched that thrust/control arm bushing design and did something else. I'm just on stock adaptive shocks and Eibach Pro-kits and I find myself NOT switching into SPORT mode as often because I get the steering and handling I want in COMFORT mode now.

Got it. Thanks.

I might give these a try. My only hesitation is my current NVH is rather significant on any rough road (secondary to how low I'm dropped).

[andino]

Originally Posted by percychow

Andino - Get them. Or heck, take a drive of either of our cars. It's dramatic enough for me to say, do the monoballs FIRST before even thinking of a spring swap, shocks, etc.

Eleven11 - like I said. I chalked up the disconnected/floaty feel to the f32/435i platform originally. With each new BMW platform, handling and steering feel is compromised a bit. But I think given the way the new G80/330i drives... I can't help but wonder if BMW ditched that thrust/control arm bushing design and did something else. I'm just on stock adaptive shocks and Eibach Pro-kits and I find myself NOT switching into SPORT mode as often because I get the steering and handling I want in COMFORT mode now.

Farkie and I have done a bunch of back to back driving of each others cars while dialing in suspension. Night and day difference between how our cars handle inputs haha

[andino]

Originally Posted by eleven11

Thanks for the insightful post.

I'm curious if this is the best component upgrade/swap to help reduce the play/delay I have when steering. I'd like to have a more direct steering feel when initiating a wheel turn. Now, there's a small gap of wheel non-movement when turning the steering wheel. I'm on dropped KW DDC coilovers.

Farkle, you have an F31. Has your K-MAC upgrade improved my complaint above?

With monoballs, you'll def get rid of that "momentary delay to settle" feeling and I didn't think that Farkie's car was too loud on rough surfaces. Its certainly louder than stock but still within tolerances for me.

[FaRKle!]

Originally Posted by eleven11

Thanks for the insightful post.

I'm curious if this is the best component upgrade/swap to help reduce the play/delay I have when steering. I'd like to have a more direct steering feel when initiating a wheel turn. Now, there's a small gap of wheel non-movement when turning the steering wheel. I'm on dropped KW DDC coilovers.

Farkle, you have an F31. Has your K-MAC upgrade improved my complaint above?

Yup, monoballs definitely reduce the feeling of latency from steering wheel movement to actual wheel movement/front end response.

After I changed to monoballs I began to understand "slow hands" when turning in. Prior to that my steering inputs had been faster, but after the monoballs I found myself turning in too early because the front of the car responded more quickly.

As for steering feel, I don't really think people will complain about the F3x's steering feel after changing to monoballs.

[Jvac]

Anyone consider the Dinan monoballs as opposed to the turners? Price is a good bit higher, but they claim to offer the same performance with no additional noise. They also claim that they are the only ones which are properly sealed against water and mud for long term durability... But, those have to be pressed into the arms where Turner is selling new arms with their bushings pressed in so they should be cheaper to install than Dinan as well.

[exE36M3]

Jvac - yep. Turner sells the monoballs for $308 by themselves. You can pull your old arm out and press. But for $200+ more, you get the whole arm and ball joint so it makes installation go faster.

The Dinan one looks like it kept the design of the stock bushing - a machined giant housing, a monoball, and a sealed unit. It looks like it woul be the quietest of the group.

The Turner is "bare-bones" per se - monoball and surround.

The KMac - I'll let Farkle chime in, but if I recall right, it's built similar to the Turner one but offers caster adjustment.

[Jvac]

You guys rule. Have learned so much about the finer points of tuning this car. Now all I need is the $

[FaRKle!]

Originally Posted by percychow

The KMac - I'll let Farkle chime in, but if I recall right, it's built similar to the Turner one but offers caster adjustment.

Here's a pic of the KMAC tension strut monoball bushing. It's fully sealed. The bolt hole is offset to allow for caster adjustment (loosen the bolt holding the arm to the subframe and then put a wrench around the hex nut to spin it). These press in just like the OE bushings do (KMAC includes pressing cups for removal of the OE bushing and installation of the new one). You can add some loctite to the OD of the bushing that gets pressed into the arm hole if you think it needs a bit more securing.

[exE36M3]

Not to tempt you guys or anything BUT - Turner has them on sale for $50 off!!

https://www.turnermotorsport.com/p-3...nstalled-arms/

[BMW DIY Guy]

You need an alignment after changing these out I assume?

[BMW DIY Guy]

And also lots of folks swap in the M3/M4 control arms.. so what if you installed the F8X arm with the improved bushings?

https://www.turnermotorsport.com/p-4...nstalled-arms/

[JaredG_F30]

You can also save some coin and get just the bushings if your lower bushings are still in good shape.

https://www.turnermotorsport.com/p-3...oball-upgrade/

Originally Posted by percychow

Not to tempt you guys or anything BUT - Turner has them on sale for $50 off!!

https://www.turnermotorsport.com/p-3...nstalled-arms/

[andino]

Finally back from traveling and ordered my KMAC monoballs. Looking forward to getting them in along with my camber plates!