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Project S2000: Part 21 - Getting Rid of Squish

by Khiem Dinh

Khiem Dinh is an engineer for Honeywell Turbo Technologies at the time of this writing.  All statements and opinions expressed by Khiem Dinh are solely those of Khiem Dinh and not reflective of Honeywell Turbo Technologies.

I’m often of the philosophy of replacing things as they wear out. And when they wear out, I might as well upgrade! It all started with a slight banging noise while going over bumps. Over a bit of time, it got progressively worse. Eventually, going over any type of bump including creeping over speed bumps caused a loud banging noise. What was the source?

I took a few steps in diagnosing the issue. The banging noise while going over bumps would disappear if I held brake pressure. Therefore, the torque applied by the brakes was holding whatever that was loose in place while going over the bump. In researching possible issues, it seems bad tie-rods and sway bar end links were possible culprits. I checked the tie-rods and could not determine any free play in the joints. I disconnected the sway bar and drove around but the banging noise still remained. I checked everything in the brake system to make sure there was nothing loose. Yet the noise remained. So what was left that could cause the noise?

Control arm bushings were what I narrowed it down to. The noise only came from the left side of the car. With the wheels off, I banged on the brake caliper on each side of the car with my hand. Banging on the right side resulted in no noise. Banging on the left side did result in little bit of noise. Why bang on the brake caliper? The caliper is solidly mounted to the spindle which is connected to the control arm. So the force I applied to the caliper gets sent all the way through the control arm. In addition to the noise getting worse, the steering was getting progressively unstable during hard cornering. While cornering at relatively high lateral G’s mid-corner, the car was not tracking true. Instead, the front-end felt unstable and would not hold a clean line. So this issue also pointed to the control arm bushings being the issue. The handling malady did not noticeably manifest itself until the banging noise had gotten severe. It should not be a surprise the stock bushings have worn out after the hard use I’ve put them through along with the additional loading from the high grip Nitto NT01s.

 

Here’s the front lower control arm in its rusty cast iron glory.
This is the big bushing at the end of the front lower control arm. There are huge voids in the rubber between the control arm and the metal sleeve in the middle. Look closely at the 4 o’clock position, and you can see the white background peeping through indicating this bushing was torn and worn.
On the left are the upper wishbone control arms with the SPC adjustable ball joints. On the right is a rear upper arm. All of the arms are shown in their rusty used form.
A close-up of one of the bushings on the rear upper arm shows some of the wear on the components.
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Comments
Crousti
Croustilink
Monday, December 15, 2014 12:00 AM
The amazing thing about people telling this :
"Spherical bearings for a dual purpose street/track car? But the car will be loud and ride harsh !"
Is they never, ever installed and tried some. Or they installed crappy ebay ones that wore out in 30 miles.

I like to remind them that there already are some spherical bearings on the suspension, and that you get what you pay for. I got quality spherical everywhere i could on my s13 (except rear knuckles) and it feels so much better than urethane :) The alignment guys also stopped cursing me (because PU bushes have the habit of not working at all with joints that require more than 1 degree of freedom; they bind).



Ole-M
Ole-Mlink
Monday, December 15, 2014 2:20 AM
Crousti, where did you get your spherical bearings ?
I have some driftworks, got 30000 Km's on my s14 with a few trackdays and they are worn out (driftworks(Kinda like ebay) )

Thanks
Crousti
Croustilink
Monday, December 15, 2014 2:36 AM
NRR favors QA1 bearings, you can get some from summit racing .

Before changing yours, make sure your arms have not developped play at the length adjusters.
8695Beaters
8695Beaterslink
Monday, December 15, 2014 8:16 AM
Wow, the attention to detail Honda put into those arms is amazing! They are seriously optimized for weight reduction. Completely different than most stamped OE arms. One question though: Why did you choose to keep the OE arms, as opposed to using some kind of tubular arm?
theneil
theneillink
Monday, December 15, 2014 9:30 AM
im just guessing but the high cost and minimal weight benefits
GCMBob
GCMBoblink
Monday, December 15, 2014 10:32 AM
I have full pillow ball on my Altezza and found similar things to this. The ride feels super controlled and not jarring or overly noisy. If i still had any sound deadening it would be completely liveable on a daily basis.
jeffball610
jeffball610link
Monday, December 15, 2014 10:43 AM
Being a street car, should there be any dust protection on those bearings? I've also wondered why the two lower arm pick up points rotate on a different axis. Shouldn't both points use the same axis (x or y)? I'm sure there's a good reason, I'd just like to know why.
Very cool that they work so well and don't add any unwanted NVH. When the suspension is allowed do its work without distraction, amazing things happen.
Mike Kojima
Mike Kojimalink
Monday, December 15, 2014 7:37 PM
I find that typically ride gets better but noise gets worse.
spdracerut
spdracerutlink
Monday, December 15, 2014 11:31 PM
Yup, bearing quality is critical. That's why the bearings are from Aurora or New Hampshire Ball Bearing which are all made in the USA.

8695, I only know of one set of tubular arms for the S2k and those are made by Asura but they can be difficult to get a hold of... OEM arms are easy to get a hold of. Not to mention, proven durability.

Jeff, I unfortunately do not drive the car much anymore as it is no longer the DD. So it only gets taken out on good days and track days. But yes, I had thought about trying to make some type of dust boot, but as I only drive on nice days, I'm not worried about it.
rawkus
rawkuslink
Tuesday, December 16, 2014 9:56 AM
What year is your S2000?
spdracerut
spdracerutlink
Tuesday, December 16, 2014 11:54 AM
2005
DaveC
DaveClink
Wednesday, December 17, 2014 10:14 AM
Glad to see project S2000 back! I expected these bearings to be expensive, but WOW! Bit of a sticker shock. Or maybe I'm just cheap. Guess my AP2 will get more conventional bushings.
spdracerut
spdracerutlink
Thursday, December 18, 2014 6:57 AM
Mmmm...... Trust me, I thought about it long and hard. But consider this, if you're like me and most other people, you don't have a bushing press in your garage. So you're going to be paying someone to press out all the old ones for you anyway and probably the new ones in. That cost is built into this product from Blacktrax. Plus they do the very nice painting of them. I'm also keeping this car for freakin ever! No new car being built or in the future can match the relatively analog feel of this car. I still have a throttle cable! And the shifter feel... Yup, holding onto this one for a very long time.
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