DIY - Autotech Rear Swaybar Install - Part 1

[ünpimptheauto]

Some have complained (on VWVortex) about squeeky Autotech rear bars, after the install.

Having just purchased a rear bar from NA Motorsports, I was NOT interested in having a squeeky bar. So, after getting mine, it was time to do some quick investigation.

It would appear that the bushings provided are in fact, have an ID that is too small for the rear bar. This causes the bar to "bind", squeezing out any and all lubrication originally added during the install. After this, you will get miles and miles of squeeky operation. NOT my idea of an upgrade (plus, the wife would kill me!)

Autotech states on their website:

"Our legendary polyurethane bushings are specially formulated to be virtually squeak-free for years of trouble-free performance."

I'm all for some marketing lingo, but an interference fit on the bar and bushing is not my idea of spectaular quality control.

Time to mod the mod.

[ünpimptheauto]

Then...the results.

I've added a video clip, to show the how easy the bushing now pivots on the bar, without any lubrication at all.

http://www.benliaw.com/video/autotech_swaybar.wmv

[Faerus]

Nice job, I wonder how H&R's and Neuspeeds' diameters match up. The one that matches would definitely have me buying it.

[ünpimptheauto]

IF the H&R bushing diameters didn't match the bar, there would be a bigger issue.

H&R uses some sort of Teflon composite inside the bushing, which would mean reaming it larger would basically eliminate this coating.

http://www.hrsprings.com/site/products/images/swaybarbushings.jpg

[atomoverride]

so do you do this for other people? =)

[ünpimptheauto]

so do you do this for other people? =)

Come on! There's a sense of accomplishment when you do it yourself! Plus, it's not like its really that difficult to do.

Unless, of course, you're the kind of person that begins his day by waking up at 1pm...

[KaynE]

Wow... very interesting.
I like how you wrote it directly on the jpgs.

[loccusst]

Good job.....now you should send it to the manufacturer. Maybe they will compensate you......or not.

[ünpimptheauto]

I emailed Autotech with a link to this post. We'll see what they say.

[nomad]

this is perhaps the most comprehensive and easy to understand DIY ive ever seen. thank you!

[Wild Hare]

I still see a gap.

[ünpimptheauto]

I still see a gap.

Good...because if it closes, the bushing would be too loose.

Check the video I posted.

[atomoverride]

Come on! There's a sense of accomplishment when you do it yourself! Plus, it's not like its really that difficult to do.

Unless, of course, you're the kind of person that begins his day by waking up at 1pm...
No I get up hella early and work way too damn much. Plus I have issues with power tools.

[ünpimptheauto]

I got an email back from Autotech.

Basically, in a nutshell, they claim that their bushing/bar fit is designed to be in a "preload" state. The say that the allowable tolerance is 0.050" between the bar OD and bushing ID. If this is the case, I'm slightly outside of the tolerance at 0.062". Not a big deal, I tell them since the modification is easy.

My experience is that any bushing in "preload" or "tension" will generally mean that any and all lubrication will get squeezed out. I'll install the suspension when I return, and report back my results.

[Wantagti]

How would you rate that autotech bar vs the H&R? Sure is a lot less money, but I gotta wonder about the stiffness and design differences.

[DBCPerformance]

i don't know the Autotech, but i am all over H&R, used three different ones in the past. As a matter of fact, one had more than 40K miles without any problems, passing over 30 autoX and hard trackdays.

[ünpimptheauto]

How would you rate that autotech bar vs the H&R? Sure is a lot less money, but I gotta wonder about the stiffness and design differences.

UPDATED INFORMATION!

The Autotech bar is hollow, whereas the H&R is nost likely solid (ie. heavier). The important difference is actually the "working" diameter of the bar.

H&R advertise both a 22mm and 24mm bar. Out of curiosity, I called Autotech to get the wall thickness of their rear bar (I could cut my Autotech rear swaybar in half to find out, but that would make it useless). The tech guy is out, so I emailed him.

Depending on the wall thickness, it is difficult to tell the working spring rate of the Autotech hollow rear bar.

As an example, the H&R 22mm bar has a working rate of:

22^4 = 234256

The Autotech rear bar has a wall thickness of 0.095". This would make the ID of the bar 20.57mm. Since it has an OD of 1.0" (25.4mm), you have to subtract the ID from the OD:

(25.4^4) - (20.57^4) = 416231 - 179173 = 237058

Thus, the Autotech has a working rate of 22.0mm.

I did call Neuspeed about their "25mm" rear bar. After a few minutes on hold (the customer service rep didn't understand why I wanted the inside dimensions), they told me the wall thickness was .156 on their rear bar. With this info...

(25.4^4) - (17.4752^4) = 416231 - 93258 = 322973

So, the Neuspeed bar has a working rate of 23.839mm (the same as a solid 15/16" bar). Of course, this is assuming that Neuspeed makes the bar here, from commonly available material sources (metric tubing is VERY expensive and limited in sizes).

[hakgwai]

to post above...
what does this mean in english
=P

[ünpimptheauto]

to post above...
what does this mean in english
=P

UPDATED INFORMATION!

Well, I was trying to answer Wantagti's request about "wondering about the stiffness and design differences" with factual information about the bar itself from my observations.

In english, the TRUE rate of the Autotech bar is unknown, until they provide me a wall thickness to their tubular rear bar. Until then, this far is known:

STOCK Bar = 21mm
Neuspeed 25mm Rear Bar TRUE rate = 23.83mm (tubular)
H&R Rear Bar 22mm TRUE rate = 22mm (hey, it's solid)
H&R Rear Bar 24mm TRUE rate = 24mm (solid as well)
AutoTech 25mm Rear Bar TRUE rate = 22mm(tubular)

These relative rates (compared to stock) is only if the aftermarket bars have the same exact mounting point as the factory swaybar connection. If they have the adjustable points (points closer to the center of the bar), the rate changes (becomes stiffer).

Of course, generally speaking, the larger rear bar you have, it promotes more oversteer (rear end coming around). So, until I get Autotech info, I won't really know how it compares to others on the market.

[Wantagti]

Wow, way more engineering than I am, but very good answers. I doubt I could tell the difference. I wonder how much the weight diff is. I would imagine a hollow bar would have to possess a very strong tensile strength. I guess the only test that matters is lap times and or how it handles.

[rickerbr]

For what it's worth, I was the guy complaing about the squeaky autotech bar. The bushings are tight and I ran mine dry for about a week and a 1 sq inch piece of paint/powercoat flaked off on both sides (but not down to bare metal). I lubed mine up with lithium grease and it hasn't squeaked for the last 4 weeks or so, and with the endlinks disconnected, I can easily move the bar by hand. I can see where reaming the bushings would give more clearance, did you assemble it dry after modifying the bushings?

[Bad hare]

like some others here - a little lost. Great write up, btw. But after all is said and done, which bar would you recommend?

[ünpimptheauto]

For what it's worth, I was the guy complaing about the squeaky autotech bar. The bushings are tight and I ran mine dry for about a week and a 1 sq inch piece of paint/powercoat flaked off on both sides (but not down to bare metal). I lubed mine up with lithium grease and it hasn't squeaked for the last 4 weeks or so, and with the endlinks disconnected, I can easily move the bar by hand. I can see where reaming the bushings would give more clearance, did you assemble it dry after modifying the bushings?

Having the powdercoating wear off isn't a good thing, especially on a steel bar. I've seen factory bars rust, because of a crack in the factory coating and it looks like hell in as little as 4 years.

I haven't actually installed the bar, yet. This wednesday is the plan.

[DBCPerformance]

Pimp, one more time you comfirmed my thoughts on H&Rs, nice findings, nice write up

[rickerbr]

Having the powdercoating wear off isn't a good thing, especially on a steel bar. I've seen factory bars rust, because of a crack in the factory coating and it looks like hell in as little as 4 years.

I haven't actually installed the bar, yet. This wednesday is the plan.

I was under the car this weekend and I've got a bigger problem, the bar is shifting from side to side in the bushings and the bars that that endlinks attach to have bent at the stiffest mounting hole (this is with all season tires, less than 1000 miles (all street), and the bar on the softest setting). I'm going to call Autotech and see what they want to do, and I'll report back.

[ünpimptheauto]

I was under the car this weekend and I've got a bigger problem, the bar is shifting from side to side in the bushings and the bars that that endlinks attach to have bent at the stiffest mounting hole (this is with all season tires, less than 1000 miles (all street), and the bar on the softest setting). I'm going to call Autotech and see what they want to do, and I'll report back.

I'm a little confused.

Your endlinks are bent while installed in the stiffest mounting hole (which is the one furthest from the end of the bars)? If so, this is indeed not the softest setting, but the stiffest swaybar setting.

[rickerbr]

I'm a little confused.

Your endlinks are bent while installed in the stiffest mounting hole (which is the one furthest from the end of the bars)? If so, this is indeed not the softest setting, but the stiffest swaybar setting.

I guess I reversed it. The end links were in the furthest mounting hole, the bar is bending basically at the centerline of the nearest mounting hole. I've moved it to the middle and I'm going to see what happens. I've yet to call autotech, but I think there's a definite problem.

[ünpimptheauto]

I guess I reversed it. The end links were in the furthest mounting hole, the bar is bending basically at the centerline of the nearest mounting hole. I've moved it to the middle and I'm going to see what happens. I've yet to call autotech, but I think there's a definite problem.

Be sure to take pictures, that definitely helps when speaking to someone about a technical issue.

I've set the swaybar in the middle position as well, as as start. Then again, it's not that stiff, relative to stock, from the calculations I've made. I'll keep an eye on this.

I did also notice that the bushing "stops" were not optimally placed, like stock. I'll also watch to see if it shifts.

[rickerbr]

Be sure to take pictures, that definitely helps when speaking to someone about a technical issue.

...

I did also notice that the bushing "stops" were not optimally placed, like stock. I'll also watch to see if it shifts.

I think that is at least part of the issue, the stops on the bar are approximately 1/2-3/4" too far apart. I think this allows the bar to shift and that load is transfered to the end bars, ultimately deforming them (at least at the stiffest setting).

I hope to get unburied at work enough to spend some time on a phone call with them. I'd like to replace the bar, because as it is, I'm probably going to put the stock one back on as I don't want to deal with a broken bar.

[Moose]

The bushings you reamed out are actually designed for overclosure to the bar to prevent a klunking over time. I'm a chassis engineer for a bushing company. Typically what will happen is after a while the holes in the bushing will start to try and become egg shapped which can lead to the bar flopping around in the hole and making noise. To prevent this we put some pre-compression on the bushings to make them last longer.

I saw a picture somewhere in the thread of the teflon sock style rubber mounts. Personally if I were to change bars I would look for something along those lines as it should be a long time before those squeak, and rubber generally will hold up better over time vs. polyurathane.

Also what is this "rate" your calculating? looks more like area to me with mm units on it. If you mean spring rate it should have units of either N/mm or N-m/deg. Not trying to be an ass just trying to figure out what your calc'ing.

I'll have to see if I can dig out the papers we had around here for calculating bar spring rates, from what i remember it was kinda complex.

just my 2 cents.

[ünpimptheauto]

I spoke with the engineer at Autotech reponsible for the development of the swaybars. The bushing stops were intentially meant to be at least 1/8" away from the bushing itself.

Also, the bushing could have some preload as Moose mentioned, but he said there was no harm except decreased bushing longevity. I did order a set of replacement bushings just in case.

They are considering a set of greaseable bushings, as found in the aftermarket now. Would be pretty easy to retrofit, assuming the center hole-hole dimensions are close to the MKV.

http://static.summitracing.com/global/images/prod/large/ens-9-5161g_w.jpg

Energy Suspension Greaseable Swaybar Bushings (http://www.energysuspension.com/pages/swaybbct.html)

The only issue is making sure that the centerline of the bar remains close to the same place as the Autotech one. My measurements on the replacement Autotech bar bushings I received seem like they're 13/16" (0.8125) which is just about 9% of the 0.75 of the Energy Suspension version. I could easily shim the Energy Suspension bracket to make it perfect.

The modding continues.

[rickerbr]

Autotech took my bar back and they are sending me a new one. When I got it removed I noticed that there is a slight bend in the bar on the right side outside of the right side stop that happened while it was on the car. This may have been a cause or a symptom or the mounting bars bending.

[JonGrace959]

idk if i can do it myself.. can u do it for me.. lol

[Raven6t9]

I just got a Neuspeed sway bar and I noticed that on the poly bushings that its grooved on the inside, possibly to hold the lube in, I havent checked the ID diameter against the OD of the bar yet though.

[Dan GSR]

possibly to hold the lube in

thats exactly what its for

[JudgementDEY]

Ive heard nothing but good things from Neuspeed!

[Raven6t9]

Ive heard nothing but good things from Neuspeed!
I love Neuspeed, everything except their prices. lol. Some of their parts could be a little more extreme but at least theyre not overkill.:thumbup: