914 front struts on super?

[simon_C]

I've got a 3 bolt super and I've been researching front suspension options.

Spurred by the current cost of a disc brake kit and front coilover setups (diy or aftermarket kits), I have been looking into alternatives for my super's front suspension and brake setup.

I noticed, 914 front struts and spindles look like they may be able to fit if I switched to 2 bolt control arms.

This is what I was thinking:
914 front struts and spindles are already set up for discs.
914 struts are narrow and look like they would be easy to add coilover sleeves to, as well as upgrade to better shocks.

I can get 914 front struts, shocks, and coilover sleeves (real ones, not ebay crap) for less money than buying a disc conversion kit and coilovers for my super.

Would 914 struts ever have a chance of fitting my super? Is there a ball joint that fits the 914 spindles and the 2 bolt super control arms?
would the geometry work at all?
Are there tie rods/rod ends that would work in this situation?


Has this even been done? I've been googling and so far have found nothing.


914 struts:

[Piledriver]

Interesting. That's one combination I have not tried.
It is entirely plausible, but there are a few issues to be overcome, that are avoided buying a pre-engineered solution like the Topline parts.

The first gotcha may be the spindle/strut angle and the track.
Does the spindle end up level or with a small negative camber when strut is installed?
Does the wheel offset end up way too far out or in? (likely not an issue, but is a concern)
The 914 is rear steer, the super is front steer...
What height vs stock does the tie rod end wind up w/strut swapped L<>R??

To swap to the 1303 setup involves simply bolting in the complete 1303 parts setup on the 1302:
the struts/spindles, stamped steel lower arms and a late sway bar as well.
(not sure if the upper strut mount is same, may be)

You may want to go rack and pinion at the same time, eliminates the poor//weak 1302 steering setup and will allow some bump steer geometry flexibility when you make the new mounts.

There is only one way to be absolutely certain: Try it.
...at least see where the wheel ends up and where the tie rod end ends up in relation to stock, no springs required, just strut mounts etc, cycle suspension with jack under center car to test bump steer.

914 struts might work used the same way with the 1302 strut mounts, the SB or 914 tie rod end may just fit or be adaptable, but 914s are "rear steer', note the height the tie rod end ... ends up at may be an issue flipped around, but you may be simply able to install a tie rod end flip kit and get what you need geometry wise.

I'm pretty sure neither the SB nor 914 struts have "trail" built in (axle is on center of strut) but I have not carefully measured specifically for it to be certain.

The 914 damping is likely going to be closer to what a Super needs than a Golf strut insert.
1303 lowered Superbeetle struts are simply aftermaket MK1 Golf/Rabbit struts, usually with adjustable smaller coilover setup attached.

The early forged steel lower arm might be able to be adapted to Mk1 golf lower ball joints and a 924/944 front spindle, making it sturdy and cheap, and provide big brakes and a 5x130 bolt pattern, also on the cheap.

The 1302 struts spindles may also be reamable to the Golf size.
(I have been threatening to do tha 944 spindle/golf strut and balljoint setup for ages but my son owns the 1302 and he has had other major projects in front of it)

[simon_C]

The idea here is to reduce parts count, reduce the number of retrofit parts needed, and make everything as simple as possible.

I had the idea of using the 914 struts with stock 914 discs and calipers, a 1303 2 bolt lower control arm (or a custom unit, i'm no stranger to metal fab) and use any ball joint that will fit the 914 struts/spindle assembly (they're one piece). The addition of some nicer shocks and some universal 100lb coilover sleeves to the struts would make it (in my opinion) a nice, compact, simple solution to the front suspension and brake retrofit.

As for the rear vs front steer, couldnt the struts just be swapped side to side to put the steer arm where it needs to be? if they are zero-trail like you say, i don't see an issue doing this. A tie rod flip wouldnt be an issue, i'm going lower than stock anyway. I'm going to swap to rack and pinion steering eventually anyway.

What i'm most worried about is the wheel placement and camber with this setup. Would it have too much positive or negative camber?

of course, the upper strut mounts would be easy, Ill retrofit anything i need to make em work.
.

[Piledriver]

Sorry, I was still editing, I may have added some more things to look out for in my previous post.
I like the idea and its worth mocking up at least, that (and some careful measurements) will tell you in a hurry if its doable.
Will require a quick and dirty adapter for the 1302 lower arm/ball joint to test for fit.

I have a set of 914 struts on the bench if you don't have any, can at least provide dimensions.

[simon_C]

Sorry, I was still editing, I may have added some more things to look out for in my previous post.

gotcha.

[Piledriver]

IIRC the spindle is ~7 degrees from perpendicular to the 914 strut.
You can probably do some magic if needed making up the early lower control arm to ball joint adapter as far as angle and track width using the SB strut mounts as-is, of course you could also box them out and relocate etc.
Let me know if you need other measurements.

I'd offer up some struts but you can probably source some locally for far less than shipping.

Note that you will lose your stock speedometer: The 914 drives the speedo off the transmission via an implausibly long (but surprisingly trouble free) cable. Being mounted to things that don't really move helps a lot.

One other thing that you might consider would be looking at the feasability of grafting in the 914 front suspension entirely.
The ride height is screw-adjustable, torsion bars about the right stiffness, and the geometry and reliability are well proven.
Also better tire clearance since there is no spring on the strut at all to hit.

One delightfully demented fellow here did it to his early T3 with great results, but with a super you already have strut mounts so you are way ahead of the game.

Not as bolt-in, or easily reversible, but probably quite doable if you have good fab skills.

The track width is identical to a T3, not sure about the early super off the top of my head, but definitely in the ballpark.

[Marc]

...couldnt the struts just be swapped side to side to put the steer arm where it needs to be? if they are zero-trail like you say, i don't see an issue doing this....

Swapping the steering knuckles would change the steering geometry to "anti-Ackermann" - the outboard wheel would steer tighter than the inboard. Not necessarily a bad thing at low steering angles and high speeds (i.e. track racing) but it would be absolutely horrid for a street machine.

https://en.wikipedia.org/wiki/Ackermann ... g_geometry

[Piledriver]

The rack location/tie rod angles on the SB would largely drive that, the tie rod vs the strut axis on a super is pretty similar.
The height when flipped around would concern me more, but that can be fixed.

A tape measure and a mockup will reveal most of the showstoppers.

Unfortunately I don't have a handy 1302 or I would be in the back yard trying it already. Really.

[Marc]

No, Ackerman has to do with the lateral location of the outer tierod attach points. On a front-steer car they have to be outboard of the steering axis, while on a rear-steer car they're inboard....basically, an imaginary line drawn through the center of the outer tierod end and the steering axis should intersect the midpoint of the rear axle (see the diagram at the Wikipedia link above). With reverse, or "anti" Ackermann that line diverges at the rear - the result is terrible mismatch of steering angles when negotiating tight turns, the tires will be squealing like piggies and the car will resist being turned. Not as bad as with a locked diff, but no fun to drive at low/moderate speeds - until the inboard tire unweights it'll make the front end push ahead.

[Piledriver]

I can measure that on the 914 struts, anyway.
EDIT: tie rod mounts ~1" inboard of strut CL.
This could also likely be "fixed" pretty easily, as well as height to some extent.
Strut spindle face offset 3" from strut centerline. (approximate)
Arm throw ~6" from centerline. Would get longer if arms bent out.

Fabricated steering arms are an option.

Going rear steer is also ~doable but requires steering column mods and rack relocation, and probably an extended tie rod heim joint double shear setup as Nate used.

Thinking about this, I looked at my sons car for this...It surprised me the 1302 struts tie rods were pretty close to strut centerline, eyeballing it, I figured they would be much further out (from center) for that reason.
(I don't have access to the 1302 right now)

It would be interesting...

[simon_C]

If I remember correctly (from my kart days) isnt ackerman determined by the relationship of the steering arm length and tie rod arm length? I thought it was a relationship between the radius of movement of the tie rod and the steering arm, etc

[Piledriver]

Hit the wikipedias reference links in the article Marc posted, i needed a refresher too.

[Piledriver]

Here's a frontal shot of 944 struts on a 1302 lateral setup. (similar to 1303)

sticks out ~2" further than stock due to the angles/spacing of the 944 spindle.
(would probably be a good setup paired with the late 944 alloy arms that are also 2" wider/side)
I'm curious if the 1303 spindle is similar or would stick out less: I don't have one handy.

The "adapter" is a simple plasma cut bit of 3/8" mild steel plate, and total overkill, the Mk1 ball joint is usually bolted to a bit of stamped sheetmetal. 1/8" would probably have been more than sufficient given the size/loads.

The bottom could probably go in another ~1/4" or more and still have a good adjustment range.

Plan is to drop a ~1/2" grade8 bolt in the existing ball joint hole and TIG or TIG braze the perimeter of the adapter to the arm, hopefully with some wicking if braze is used.

Its all sorta held together with Vice-Grips for the shot as I was sanity testing the idea.

I'll take some 914 struts up with me tomorrow as we continue to play.

[simon_C]

Oh cool. If the 914 stuff becomes an option, I may go with it. 944 stuff is not an option really. Not until i get new fenders to fit the wheels with the higher track width.

[Piledriver]

It has since registered that the Mk1 BJ needs to be mounted double shear, so will be making up a pair of 1/8" plates that wrap around the arm a bit it will sandwich in between. A notch will be needed in the center of the arm.

Unfortunately a bit wet to get much done this weekend.

The 914 struts steering arm will need bent out ~2". Cut off/reweld and gusset is likely a better way to put it in the right place/length.

We have a stash of old german fenders in various states of beat up, so will probably just make out own steel wide fenders.