heim joint rear suspension

[TsiMiata]

Because I have way too much time on my hands I decided to build a heim joint type rear suspension for my car. It probably won't make the car any better in any way but it's something I've always wanted to do. I've got all the parts I'll need on order, and they should be here tuesday.

Here is a 3d model I made of the forward control arm-

http://www.cardomain.com/memberpage/675896/2

I also modeled the other two arms but they are not real exciting to look at. Just straight tubes with some rod ends in them.

<small>[ December 18, 2004, 12:30 PM: Message edited by: TsiMiata ]</small>

[bubbaflaat]

hmmm interesting. Looks very trick, and even if it doesn't help it looks neat. Keep us posted.

[mxer4eva]

The suspension, under that kind of a setup will be benefical in two ways. The first way is that it will, depending on the type of materials you use and the welding technique, make the part much stronger than stock. Thus improving handling, while also if you use materials such as chrome-moly, aluminum, etc... The parts will be much lighter than the stock pieces as well, thus futhering in advancing weight reduction on the car.

[lstpier]

How's that?

<img src="http://sites.rapidus.net/stpierlu/temp/IM002052b.jpg" alt=" - " />

<img src="http://sites.rapidus.net/stpierlu/temp/IM002053.JPG" alt=" - " />


Setup is not really streetable - much too noisy, but does wonders on the track. Rear end is a lot more responsive than reactive (mushy OEM bushings slows suspension response noticeably).

[atlantamx3]

Damn Luc-- thats HOT!!

:::DROOL:::

[jaydog5678]

Any chance of the rest of the Mx-3 community getting some of these pieces?

Good work!

[MrMX3]

I've been toying with the heim joint rear suspension idea since I had to do my end links last year and followed a bit of help from luc and made some heim joint end-links.....

Now do you say it's not streetable just because of noise?? So if say you've got 2 solobaric's run off their own amp and don't hear anything anyways...... it'd be great??

[TsiMiata]

All the tubing I bought is 4130 steel. I did weigh the stock parts. I got some weights from the models I did and the heim joint setup should be a little lighter. Not a lot though, maybe 30%.

Good to see someone else has tackled it. Very nice looking setup. We'll see how streetable it is I guess. I have converted my front suspension to use delrin bushings. The only downside I found from that was a tiny increase in road noise. Almost not noticeable. The suspension moves so much more freely now also, I suppose that might actually help with the ride.

It's like xmas a few days early for me. UPS website says all the parts show up tomorrow afternoon

<small>[ December 20, 2004, 11:43 PM: Message edited by: TsiMiata ]</small>

[bubbaflaat]

very nice. About how much did all of it cost you. And you are going to make a complete writup afterwards correct?

[matt-gerrard]

Originally posted by Bubbaflaat:
hmmm interesting. Looks very trick, and even if it doesn't help it looks neat. Keep us posted.

[TsiMiata]

Originally posted by Bubbaflaat:
very nice. About how much did all of it cost you. And you are going to make a complete writup afterwards correct?

I think I'm at ~$300 right now. Some of that was tooling though. I had to buy metric taps right and left hand thread to do this. They ran around $70. Some of the stock I bought too I will only use a small fraction of the 6 lengths they come in. Theres going to be a lot of welding in the end. I figure that is going to run another $150. I will have everything professionally TIG welded.

[lstpier]

Complete setup shaved 7lbs (heim joints, arms and the 28 custom bushings/spacers) of semi-unsprung weight. Tricky part is to avoid any binding/preload in any suspension position with the end links. Needed to do CAD modeling of the complete rear suspension.

I knew you guys would like pictures of shinny parts like these:
<img src="http://sites.rapidus.net/stpierlu/temp/IM002050b.jpg" alt=" - " />

<img src="http://sites.rapidus.net/stpierlu/temp/IM002043b.jpg" alt=" - " />

If you notice on the right side of the bottom picture, part of the long bolt holding the stock arms to the hub is still there "rust-welded" to the sleeve of the rubber bushing. Car has only saw 3 canadian winters and all rear control arm bushings sleeves were stuck on the bolts. Not even a torch could free them. Rear arm movement required the bushings to twist around the sleeves.

Even if metric heim joints were used, there's still 0.001" to 0.003" of freeplay that converts to clunking noises once grease has spreaded out. Now imagine 12 small "clunking generators" at once...

On the plus side: suspension geometry stays the same on heavy cornering. The prybar test on the hub confirmed a good 1.5 deg of camber that can be lost at high cornering load because of bushing compliance. I run 1.6deg negative at the rear which means I used to reach almost zero on aggressive curves.

[TsiMiata]

They new pics are even better than the first ones. very trick all aluminum. I went with the 4130 tubing because i think it will be a little easier/cheaper.

All the joints showed up yesterday. Still waiting on the tubing and some hex stock.

Im going to run into the same rust problem. My inner bolts are free. At least the drivers side lower/outer bolt is siezed up solid. I haven't tried the passenger side one yet. My car was from florida too.

<small>[ December 22, 2004, 06:32 AM: Message edited by: TsiMiata ]</small>

[TsiMiata]

Here's an update of the suspension setup. I need to make the sway bar mounting plates and one more small tube. Then it's all off to the welders. With the holiday though it probably won't be until late next week before it hits the welders.

http://www.cardomain.com/memberpage/675896/3

[projectmx]

so did you finish these? and still no one mentioned buying these? yeah iknow this thread is old but now that my car is getting much farther along I would love more info on these