Elephant Chuck

This is part 3 of three threads that covers spring plate and torsion bar replacement. Part 1 covered removal. Part 2 covered bushing replacement. Part 3 will be replacement. See part 1 here and See part 2 here

Click any image for a larger view

Start by assembling the spring plates. The large eccentric bolt provides a height adjustment capability. Position it in the center of its range. This will give you +- .75 inches of range to make final adjustments.



Next install the spring plates.

Apply a good quality grease to the bearing surfaces. Try to fill the grease grooves.

I recommend doing a dry run, installing the spring plates without torsion bars to ensure the plates are moving freely. Pull the trailing arm back so it does not interfere with the spring plate. Slip the spring plate into place, install the spring plate cover and torque it down.

The spring plates should move freely without binding or friction. If they are tight, inspect the bearings to be sure they are full seated. With the plates moving freely, remove the spring plates covers and plates.

Grease up the torsion bars. It's a good idea to grease the entire bar for corrosion protection and the splines for easy installation. Slip the bar into the torsion bar tube.

Slip the spring plate over the torsion bar. Carefully compare the scribed line to the edge of the spring plate. You will note that indexing the torsion bar one spline makes a large change in the angle of the spring plate. Not to worry.

The torsion bar has a different spline count on each end. This makes it possible to make very fine adjustments in spring plate angle by rotating both splined ends simultaneously. I'll leave it as a homework assignment for anyone who wants to compute the affect of rotating each end. I find it easier to simply pull the torsion bar out, rotate the inside a spline or two, then do another test fit. Repeat until you get the desired angle. It usually only takes a few attempts to dial it in.



If you are re-installing the same torsion bars and want to maintain the same ride height your job is relatively easy; make the lines parallel.

If you are installing stiffer torsion bars and / or are adjusting ride height, you need to install the spring plate at an angle different than scribed line. Stiffer torsion bars will droop less under the weight of the car. The stiffer the torsion bar, the less droop. You will need to take a guess at how much to compensate for the new torsion bar stiffness and / or ride height. Fortunately the spring plates offer some adjustment for ride height, so you just need to get close. Careful here, too far off and you will be pulling this apart again to re-index the torsion bars.

Install the spring plate cover. Attach spring plate to trailing arm using two bolts.



You may need to lift the trailing arm with a jack to get the rearmost lower spring plate cover bolt and spacer into place.



Install the inner trailing arm link. The fit is tight, tap it into place using a mallet.



Next attach the front bushings to the tub. Use a jack to raise entire torsion tube assembly up into position. It is helpful to have two jacks, one on each side.



Once the bushing lines up, slip the bolt in. It probably wont go through the backside yet, you'll come back to this.

While you are raising the assembly up, make sure it aligns properly with the little hooks on the torque tube. A little pushing and prodding should be all it takes.



Attach the rear mounting bolts.



With the rear mounting bolts in place, the front bushing bolt hole should now line up better and the bolts should be fully installed.

Now it's just cleanup. Reinstall the sway bar, lower shock bolts, driver side axle, and spring clips for the brake lines. Go through and check all bolts for proper torque. Give a couple squirts of grease to each of the grease nipples for good measure.

All put back together, it looks like this:



To finish off the job you'll need to fine-tune ride height using the spring plate height adjusters. This is a straight forward process of loosening the bolts and turning the big eccentric nut. You will need the special 36mm wrench made for this job. Then get a good four wheel alignment and corner balance.

Now go out and drive. Appreciate your car's new-found handling precision.

See part 1 here and See part 2 here

PorscheG96

I was surprised when reading that torsion bar removal appears easier than others have described.

In the coming months I'll be converting to late offset and doing suspension upgrades, it seems like a great opportunity to replace bushings at the same time so I have a few questions:

1. How compliant are these bushings for a street car? Should I consider polybronze or stick with Porsche rubber bushings?
2. You described how deformed the factory rubber bushings get over time...what life expectancy do you have for the polybronze bushings? How about service intervals [lube, etc]?
3. What kinds of polybronze bushings do you plan to develop? You mentioned doing some for the a-arms...what else?

Looks like a great project, thanks for taking the time to post all of this information!

macnewma

That is awesome. I am very interested in your bushings. I was about to order some delrins but these look much better.

I have similar concerns as PorscheG96 about durability, etc. Also, do you need another beta tester???

BTW, you are the first person I have ever heard of that can pull the torsions without dropping the axle. I have heard the only way to pull them without dropping the axle is to cut a hole in the body. Have you done this on more than one 944?

Thanks for helping out the 944 community!
Max

Skip Wolfe

Nice write-up Chuck. I wish I would have seen this with dropping down one side at a time before I did mine. I dropped down the whole thing as a unit which looks to be fairly more involved than this procedure.

On a side note, anyone who is planning on putting in stiffer bars should use the indexing procedure/Excel spreadsheet at the following link. It enabled me to get the ride height the first time after putting in 29 mm bars.

http://az.pca.org/tech/articles/upgr...orsion_bar.htm

Let me know if you are looking for anymore Beta testers - I'm always looking to help out.

Elephant Chuck

G96

1 - PolyBronze bearings work very well on the street and deliver a smooth ride, much smoother than regular polyurethane or delrin bushings. Existing users consistantly report this to be the case. Ride harshness is actually caused by bushing friction, not bushing hardness. Check this article for an explanation of why this is so. PolyBronze is extremely low friction.

Rubber bushings are a good choice for street cars when performance is not the primary objective. It lasts a long time, is maintenance free and quiet. The problem with rubber is compressibility. Under load the rubber compresses and alignment settings wander around. Handling becomes vague and unpredictable.

2 - I recommend re-lubing PolyBronze every 10k miles. The bearings are substantially over-sized for the loads they see, yielding a long service life.

3 - I am developing bearings for the control arms (both front and rear bushing replacements) and the trailing arm inner link. PolyBronze works great for single-axis pivots like the spring plates, but those other applications require freedom on multiple axis. I'm developing spherical bearing monoballs for these points. Incidentally, polyurethane is similarly ill suited to these applications and causes binding. These monoballs will have weather seals to keep dirt and water out of the bearing, similar to my existing 911 products.

I'm also developing mounts for the front and rear of the spring plate cover.

Mac

Tilting the torsion bar tube worked well. The whole job really wasn't that difficult. I would recommend it as suitable for experienced DIYers.

Skip

I didn't dig too deep into the spreadsheet, but it looks like someone did the homework assignment I mentioned above. That will be a useful addition to anyone changing tbar sizes, helping to get the indexing right the first time. It's very frustrating to put it back together only to find the height is too far off and you need to re-index.

Sami951

This is excellent stuff. Thanks for the write-up Chuck!

hoffman912

question..

with the early 901 series cars (911/912), elephant racing bushings are the best choice.

do they make em for the 944 series? if so has anyone tried them? http://elephantracing.com/index.html

edit.. chuck talks about similer types.. polybronze bushings..

Elephant Chuck

Hoffman

I can see how my post above may have been confusing. I am developing the following items for the 944/series:

- PolyBronze Spring Plate bearings
- Control arm front spherical monoballs, weathersealed
- Control arm rear spherical monoballs, weathersealed
- Trailing arm spherical monoballs, weathersealed
- Spring plate cover rear mount
- Spring plate cover front mount

All these items are planned for September availability.

Part 2 has pictures of the 944 PolyBronze prototypes

Bill

I have been looking into upgrading my suspension for sometime now, and to be honest I have been very unhappy with the options available for the 944 series car.

The factory does not offer replacement bushings, ball joints, etc. If you want to refresh (stock) or upgrade (M030) you have to buy complete suspension components, ie. control arms, trailing arms, etc. This is not cheap. And you end up with new, 20 year old technology, that again can not be serviced.

I looked into the hard bushings, delrin, etc. and was again unhappy with what is available. I heard about harsh rides, squeeks, lack of seals to the environment and grease fittings.

Then I read an article in Excellence about a 911 guy that was upgrading his suspension. The tech writer Bruce Anderson sugested to the 911 owner, that the bushings be replaced with cutting edge pieces from Elephant Racing (poly bronze, sealed monoball, etc.). The write up went on to install the Elephant Racing pieces with the end result of a compliant, quiet, servicable and great handling 911. Everything I was looking for. I immediatly went to the ER website to check out their product line. I was impressed with the design and quality. Unfortunately what I also found, was that ER only manufactured their great products for the 911 series vehicle. Bummer. But I did note that ER was located near me, so I made made a mental note to someday visit ER and inquire into the possibility of ER making suspension pieces for the 944. As luck would have it I met Chuck (Elephant Racing) at the Parts Heaven swap meet. He said he had been considering the 944 series car, but was doing a brisk buisness suppling 911 owners and had not yet gone to the effort of procuring a 944 for a test mule. I was so impressed with Chucks knowledge and commitment to quality, I brought my 951 to Chuck the next day.

Chuck now has poly bronze bushings for the rear spring plate. These have been installed on my 951. As you can see from Chucks write up, everything is first class. I drove my 951 home last night and could not be happier. I need to do an alignment but the ride was Firm with NO harshness. Quiet with NO squeeks. Since this is only the first piece of many, it is too soon for me to tell everyone as to the amount of improvement Elephant Racings pieces will have, but I can not wait for the next installments.

Chuck intends to make sealed monoballs for the front control arm and the rear swing arm (Chuck correct me if I miss quote). Chuck explained to me, the short comings that the hard bushings have in this application. In order to set castor, Porsche via ecentrics, moves the control arm/trailing arm forward and backward to achieve the setting. Since rubber is compliant, the factory bushings deform to allow this movement. Hard bushings are not compliant. This is their strength and their limitation. They only allow a very small amount of compression. So they limit the amount of adjustment that can be made, then they just bind, squeek, etc. The sealed monoballs will not have these issues.

I am very happy that the 944 series owners, will soon have access to well designed, high quality, reasonably priced and serviceable suspension pieces. Thanks Elephant Racing and Thanks Chuck!

When my car is complete, I will allow other local Rennlisters (Danno, PorscheG96, Karl, Crazy Eddie, Efren, etc.) the opportunity to drive my 951 and give you all their oppinions.

macnewma

That's awesome Bill! I had thought about emailing ER after seeing some 911 pieces. You are one lucky dog being his test car.

How would you describe the difference in feel between your old stock setup and the new spring plate bushings?

Chuck-

Keep the products coming...and make sure you keep the Rennlist guys informed!

Max

Bill

Opportunity is there for those that seek it. But I could not agree more, thanks to Chuck (Elephant Racing).

Max,

If I were to describe the difference the poly bronze bushings made, it was like a stiffer rear sway bar was added. The car rides flatter (less lean), and has quicker responce to steering input. My first lane change at freeway speed, actually caught me off guard with the quickness in the steering. I thought....cool.

I also payed close attention to noise and smoothness. I purposfully did not turn on the radio and listened the entire way home. ABSOLUTLY no additional road noise. And less road noise is one on the main reasons I bought the Michelin Pilot Sports over the Bridgstones. As for harshness, on our bumpy Hwy 101, it actually rode smoother.

Again keep in mind, this is only one piece to a complete system. I also did not push it, because I need an alignment and do not want to tear up a new set of Michelin Pilot Sports.

Bill

G96,

If you decide to do the bushings, bring you car over to my garage. We could have a wrenching session with all the NorCal guys. With enough beer and pizza, we might even get everything installed correctly.

Elephant Chuck

Thanks for the kind words Bill. If there's going to be beer, you can count me in for the wrenching session

Bill

Hey, maybe we have something here! How about a group buy AND group install. I am sure we could get 10 to 20 - 944's in my garage and driveway. Then have Chuck guide us through the surgery, classroom style.

KuHL 951

What do have there Bill, an aircraft hangar? With two teenage boys into cars it's musical cars around here whenever it's wrench time. Hope this works out, a Tech Day like that would be worth the drive for sure.

Steve