Super Beetle single A arm front suspension.

[The Pirate]

Super Beetle single A arm front suspension.

Since I am putting on the 944 porsche brakes on my car I have decided that due to the heavier nature of the porsche set up that I would like a beefier controll arm. I had first considered fabricating one from scratch, but then thought some off the shelf technology would make finding replacement parts easier in the future. I found some Audi 4000 A arms that may work.

I may have some questions for the pros here as this is my first front suspension mod.

Here is what I know so far.

The frame head for a super looks like an Capital I just with larger lines on the top and bottom lol. The S beetle control arm attaches to the midded of the I shape in the middel of the I kind of like this I-. How ever to mount the A arm the arm will have to be mounted to the ends of the I like this I>. This puts the pivot points a good 4 to 5 inches farther from the center of the car than the original S bettle control arm. It will have the same amount of travel as the original S bettle control arm. How ever the A arm has no provisions for camber adjustment at the ends like the S bettle arm does. To get around this I will be either using the lower half of a porsche 944 strut assembly as the camber adjustment is built in there or adapting the S beetle strut to do the same.

Here is where the questions come in.

1- Will having the pivot points moved farther out from the center of the car cause problems I need to know about?

2- Has any one done this before? If so what parts did they use?

[The Pirate]

hello? Echo echo echo echo............

(puts beetle in gear and drives deeper into the freakish desolation of this thread)

[alt+f4]

I say for the benifits and strength v.s. the amount of time and work its not worth it. to change out the arms you would need to set it up to have proper roll centers, and a whole lot of other stuff. Now I am normally one of those guys that wants to convert or fab up stuff myself, but the super is a good design as it is. If you want to strengthen it just make some box ins like Racelook did.

[The Pirate]

What do you mean by "roll centers"? I will be able to better explain my idea and design when I get a chance to draw up a diagram and post it. Plus If the I shaped control arm was such a good design why didnt VW use it on the early rabbits? My main concern is that the A arms are shorter and have to be mounted farther from the center of the car. Yet once this is done they will have the same amount up and down travel as the original I arm and the same arc of travel as well. I guess the question I currently have now is.

Again what do you mean "roll centers"?

Will the same springs work on the struts or will I need some softer or harder springs?

Will having the pivot points farther from center cause the way the car rides or sits on the suspesion to affected in a negative way?

Thanks for any help .

[The Pirate]

Ok I know what roll centers are now. And my idea may work. The main thing is that the a arm has the same ball joint position and amount of travel as the original I arm. The length of the A arm and its mounting location are subodinate to the ball joint location and travel of the arm. I finaly found a nifty website for this conversion as well as a handy free program for working out suspension geometry. Thanks for the tip. :p

[yetibone]

I've modified my 1303's front end to include strut rods grafted into the original lower control arms. This seemed the lightest, easiest, and least compromising way to strengthen the front suspension, and turn the front swaybar into a non-structural component.

Still gotta finish the rest of the car to see how good it is...

[The Pirate]

Ok those are nice.:D But it looks like you took notches out of you frame head to channel those struts into? That and they look like they may interfear with the frame moving up as the body comes down. Dont they bottom out in that channel? I will use paint to draw up a general sketch to show what I have in mind. Plus a little more wight in the front is ok with me as the super is a little to light in the front. That And I want to be able to get parts with out having to fab them incase of breakage.

Gave me some ideas.....

[yetibone]

During mock-up the struts bottomed out with a full 7mm between the channels and strut-rods. I put a ~7 degree downward angle at the root of the strut-rods, and a 12 degree upward bend about 10" away from the rod-end to keep them from bottoming.

[The Pirate]

Also yetibone how do you plan to fit a sway bar?

here is a very basic idea of what i am planing. I will be using Audi A arms. This is just a rough draft and may be changed during design and application.

[yetibone]

Front sway bar fits in it's stock location. It no longer bolts directly through the control arms, but with drop-links.

[Jeza]

A freind of mine remade his lower arms, but turned them into really long A arms.

Have a look at this thread on the subject and the pics I posted then.

http://www.germanlook.com/Forums/showthread.php?t=5994&highlight=s1fter

Having said that, I don't have a problem with my setup -944 NA brakes on standard setup but urethane bushes and Topline swaybar. Another fellow I know has the same setup being pushed around by a 2.5 SOHC Subi motor, and he hasn't mentioned any problems either.

Cheers
Jeremy

[The Pirate]

Thanks guys this is great. I will document my mod carefully for all of you.

[The Pirate]

Ok here are some pictures.

A arms -1982 Audi 4000 A arms with mounting bolts.

Ball joints -are bolt in, same size and length of the Porsche 944 ball joints.
The ball joints are cheap even for quality ones. About $30.00 US each.

The beetel strut can easily be modified to have the camber adjustment on the top mounting bolt to the spindel like the 944 Porsche. all you need to modify it is a round file and some time and work.

Now all I have to do is figure where exactly to mount the arm and fab the mounts. The hardest part is the precise position. I am guessing I want to position the A arm so the camber adjustment is right in the middle. That way I will have adjustment either up or down. To find that I will need to keep the face of the spindel 90 degrees to the ground. I also will need to find a way to simulate the way the suspension will behave with the cars empty weight.

hmmm

The A arms are shown roughly where they will need to be to match where the beetle ball joint ends end. About 21 inches from the center of the mount on the frame to the center of the ball joint. I will be leaving the orignal mounts so If i ever want to change back I will be able to.

[The Pirate]

Ok so now here is the basic plan for the way to mount these. In the following picture the solid black bar represents a peice of heafty tubular steel that will be welded in place on this tubular steel there are mounting points welded on. I left those uncolored to show the joints. Finaly for a bit of added strength and just to give them something to do a third member bolts from the old mount point to the tubular steel. I may be able to make tha whole rig bolt on but I doubt it.

The arms them selves are remarkably light considering the front end weight of the car they came off of. The great thing about this approach is that it stays completely out of the way of the master cylinder. Hmm power brakes now maybe?

[alt+f4]

Since you have the same spindle mounting area but are moving the main pivot out wards that will effect you roll center. With the pivot being that much closer to where the strut is centered you might not get enough neg camber gain under compressiion durring high g cornering.


with your software you have try to set it up to get your roll center as close as or below the ground as possible. and just as a guid line try to get the virtual pivot to the opposite wheel on the outside of the center of the wheel.

[The Pirate]

Ok thanks for the tip. :)

[volkdent]

What sort of steering rack changes have you made to compensate for the change in lower pivot point for the control arms?

Jason

[The Pirate]

So far I have made none. As it stands the free program I got refuses to unzip so I trashed it. Going to purchase some new software.

I have been working it out on paper for now. Took a ton of measurements ect ect.

The pivot points aren't so much lower as they are farther out. From what I am seeing so far the roll centes will not move to much out of their original planes. The spindle and ball joint are still in the same locations and thus far see no conflict with the rack at all. Everthing looks like it will clear at full drop and at full compression along with all increments in between.

Will have some pics of the drawings up soon.

[volkdent]

The inner pivots on the tie rods will have to be moved out accordingly then. You will have bump steer issues otherwise.

Jason

[The Pirate]

Hmmm. A conflict has come up. I built the suspension in mock up with all the parts and the tie rods bump at one point. going to have to redesign a little. I will have revised plans up later this week or early next week. Plus I have found a way to make it a bolt on mod with just a little welding of reforcement plates and capture nuts ecet...

[The Pirate]

Still working on this should have a solution soon. Just need to finish the rebuild on my rack and wainting for a fresh set of tie rods to come in. If this works out I may want to market this sucker. :cool:

[volkdent]

Still working on this should have a solution soon. Just need to finish the rebuild on my rack and wainting for a fresh set of tie rods to come in. If this works out I may want to market this sucker. :cool:

You're going to have to have custom arms built if you want this thing to work out right. Because the lower pivot points have been moved outward so far, the pivots on the end of the steering rack have to be moved out accordingly. As your new lower control arms travels through its new, smaller than original arc, the longer arc of the original tie rod will cause toe-in as compression occurs. That is assuming the Super is rear steer, I've never looked at one. If it is front steer, you'll have toe-out.

Jason

[The Pirate]

I am looking into this but so far as I am seeing the ball joint end of the A arm has the same amount of travel and arc size as the original beetle arm. I value your input on this and take all you say seriously. other wise I may already be on the road with my death machine. :eek:

The super is front steer in this case as I am using Porsche 944 spindels and brakes.

[The Pirate]

Ok so by its very nature the McPhearson strut assembly will toe in or out as it travels up and down respectivly. This is part of its very design as the distance between where the tie rod joins the wheel and the steering rack gets longer or shorter through the arc. While this distance changes the tie rods cannot as their lengths are fixed. It is a matter of deciding how much toe in and toe out is acceptable.

Here is the math on the suspension mod so far as the travel arc. The original lower control arm is 21 inches from pivot point to the middel of the ball joint. The A arm is 13 inches from pivot points to middel of ball joint. This is a diffrence of 8 inches. The folowing diargam while basic shows what I am seeing for this mod.

The red arc shows the original control arm travel arc.

The black arc shows the A arms travel arc.

The red line shows both the long arm and the shorter A arm. The black dot is the point of demarkation.

The gray lines show the max travel and angel of the original control arm.

The blue lines show the max travel and angel of the A arm.

The two arcs over lap in the range of the suspension travel enough to keep the toe in and out within acceptable ranges.

So far the largest change is the amount negative camber the wheel will gain in hard cornering or when the suspension bottoms and the amount positive camber the wheel will gain when the suspesion reaches full drop. This is due to the sharper angels the A arm reaches.

I may need to add at least 4 inches to the A arm to minimize these effects.

I am not planning to use this car as a racer or a competition car. As long as it handels well I will be happy.

[The Pirate]

Still working folks. Here are the updates. Through good advice here and just plain observation it has become clear that the A arms have to be moved closer for various reasons. The A arms are being moved in 4 and 1/2 inches from my original plan. This means the arms are now to short and will need to be legthened by this much. I had sought to avoid this so as to keep most of the off the shelf parts stock and easy to find replacements. On the other hand though if a person manages to bust a lower control arm it is probably due to an accident or such. I havent seen a conrol arm wear out due to normal road use yet. I am currently wating on a set of fresh tie rods and for the paint to dry on my rebuilt rack. I am also experementing with some diffrent break MCs to see if I can get the A arms even closer to center. As soon as a few things are worked out I will post some pics and begin a step by step.

[The Pirate]

Ok so after a small break in work it is back to the A arms.

New developements:

1- The arms will be built from the ground up using either round tubing or square tubing. It depends on what grade steel tubing I can get my hands on around here. If any one has suggestions on what grade to use as well as where to get it, please chime in. Sizes are yet to be determined. I would like to use DOM tubing but cannot find it in square form. I would prefer a square solution. Trying to amalgimate 2 types of factory suspension peices has beed determined to be unweildy.

2- Decided to use a type 3 master cylinder as it will give better clearance for the arm as well as allow each brake to have a connection directly to the MC.

3-The A arms will use the bushings from the 1982 Audi 4000 A arms and the normal beetle sway bar bushing.

4-Total distance from original mount point of the beetel I arm is now about 2 inches to minimize adverse effects on the supension.

That is the plan for now.

[The Pirate]

I am currently building a jig to hold the struts and rack in place as if they were in the car. I am doing this for 2 reasons. One is that I am driving the car that will donate the body for this project. Two is that it allows me unobstructed visual acess to what is going on as well as easier hands on acess. To get the A arms just the right length the strut spindle assembly will be set at absolute neutral camber. This will alow me to get the length of the A arms just right. Once they are fabricated and attatched to the car the camber adjustment will be readded at the top spindel to strut bolt. This is the same set up that the 944 usses and can be adapted to the beetle. All one needs is the ecentric bolts off the 944 as well as ovaling out the top strut to spindel hole on the beetle strut. Will have some pictures soon.

[volkdent]

Is it going to look like this when you are done?

http://www.beetspeedengines.nl/voorwieloph.jpg

http://www.beetspeedengines.nl/voorvering_groot.jpg

Found these on this site, linked from http://www.beetspeedengines.nl/hoofd_frameset_1.htm posted by Jeza


Jason

[The Pirate]

Sort of but not exactly. I do like the soloution for the sway bar though. Iwill try to get a diagram up at some point. Thanks for the input!

[The Pirate]

So my current question is refering to the picture posted above: What is the part used to attatch the sway bar to the A arm? What is it called and where can one be obtained? Plus what type of ball joint is being used? Where can one get a ball joint like that? I am currently looking into refining a few things in my basic design and I want to explore some more options.

[ricola]

Alex has put 944 A arms on his strut converted ghia (the white French oe on here that is being converted to G50 and 993 flat 6). Maybe he can share some info on here too? I saw some pics on his build thread on german-spirit.
Rich

[Jeza]

Thats essentially the same setup S1fter (Mark) is using on his. I posted a couple of pics on the first page. Look him up here or check him out at http://themetricnut.co.nz/

[The Pirate]

Ok so I now know that the part between the sway bar and the A arm is a drop link. What I need to know now is where to get some. Next question that needs to be aswered is: What is the type of ball joints these A arms are using? I have not seen them before and do not know where to obtain them. Next is: What are these threaded A arm piviots these supensions are using and where to get them? Are these performance parts? This is my first BIG all out complete custom suspension rebuild so some of these parts are unknown to me but I want to learn and rapidly. My main idea here is to make a series of low cost high quality, modded super beetle suspension options that use common off the shelf bushings, ball joints and other parts for easy low cost rebuild.

[juse]

They are spherical bearings or rod ends that you mean. People call them rosejoints, uniballs etc. by the brand name. Try to search the web with words like those or manufacturers like Aurora, National, SKF,...
Easiest way to make a droplink or a "dogbone" is to use a male and a female rod end bolted together.
Good rod ends arent cheap. And you should study the load ratings of differend ends capable to handle the forces your front suspension creates. I am not he one to advice you here, maybe someone knows mats and physics better?
Use only bearings with a PTFE liner, or not liner at all (grease needed). The cheapest bearings have brass liner in them which breaks soon under heavy loads.
J.

[The Pirate]

thanks for the info. yeah these A arms are not going to be for racing. Just an upgrade for street use. I may later try to develope a set for races and roders but not just yet. The arms will be made of metal that is the same thickness as the original beetle I arms if not a little thicker, plus the metal will be of a bettter quality. For ease of replacement the ball joint is a 944 bolt on replacement. The pivot point bushings are out of a 1982 Audi 4000. The sway bar bushings will most likely be the beetle ones. I may have found an existing drop link on BMW that may fit the set up. After I have one arm properly welded up and ready to go, I am taking it to a local fab shop to have it bend and torque tested. They have a machine there that bends and twists fabricated items to see if and where they would fail. I have a freind that works there so he is sliping me in early morning to use tha machine.

[The Pirate]

So here is what is going on with my set up. I have had to battle my way through some family issues this year culminating in a trip to Germany around October or November to settle an estate. I have been working from a friend’s garage as I do not yet have one of my own so this has also limited my access. Currently most of my extra money is going toward the trip so it is slow going on the suspension front. However after getting back I will have my own workspace and more time and money to throw at the project.


I have a front jig finished that holds the front suspension on the super as if it were on the car. I finished one prototype A arm several months ago but it failed the off car stress tests. The new one was designed with the help of a local speed shop and is similar to one used on an extreme off-road buggy they race. So this time round I foresee it passing the off car stress tests and I can move on to fabricating its mate and get them on the car.

The overall goal of these arms is not for racing just a handling and ride upgrade. The A arms will be mirror to each other so they can be used left or right side. They use 1985 Audi 4000 control arm bushings and bolt on ball joints for use with Porsche or Beetle spindles. They are just a tad bit shorter than the standard control arms by like 2cm and are set up to put the wheels at absolute neutral camber by default. Camber adjustment is re added at the strut spindle interface. On the later super beetle struts the top spindle bolt holes can be ovaled out for the addition of a cam bolt. A set cam bolts from a 1985 944 struts work perfect. This set up mirrors the same amount of camber as the factory set up.