What are used 930 rear control arms worth?

[doozer]

What are used 930 rear control arms worth?

Are they much different from 911 units? Bigger bearings?

Thanks
Todd

[arrivederci]

Dunno...but they are not a direct swap-in for 911s. I believe they have different pickup points and also account for the wider track of 930s. They are entirely different animals.

But if you have a line on a pair (or one), I'd like another set for my 930.

[doozer]

I was just wondering if it was worth the effort to upgrade and the cost...

Is there any real benefit to the upgrade?

I know that Juan (?) the guy who drags with his 911 uses the stock rear control arms.

[arrivederci]

Along those lines, I have heard that 930s do have better anti-squat geometry than the 911 rear suspesion, which I assume is attributable to the trailing arms.

My 930 squats like a pi$$ing female dog when I'm on boost in 1st gear. I need stiffer t-bars.

[doozer]

What bars are you using?

I am running hollow 31's on the rear of my 911

[82SC]

look up the build of jack olsen's BB2

you need to weld control boxes because the pick up points are different from non-930 chassis

I think they have more adjustablilty with the control boxes welded in vs a stock SC control arms. But I believe they are both lighter then the pre-SC 911 steel arms...thus you are not gaining anything in weight

unless you are building a hardcore racer...930 aren't gonna shange much to your car

but to answer your question I've seen pairs go in the 1000+ range...

[doozer]

Thank you!

I have later aluminum units with new bearings that I just rebuilt and powdercoated red. I just did not know if I made a mistake in not getting 930 units.

Thanks for the info!!!

Todd

[doozer]

Here is a set for sale:

Used 930 rear controls

[project935]

930 control arms have 2 bearings/wheel (bigger too) as opposed to a 911 having 1 bearing/wheel. They can support more HP and wheel loading. Require 930 stubs and hubs as well - 911s won't work.

930 arms w/bearings sell between $1000-1500/pr. Stubs and hubs can add another $500-750 to that price.

They are shorter and wider as well - mimic the RSR geometry that was developed. If you're doing custom bodywork/flares I wouldn't worry about wheel fitment - might be close on standard 911 bodywork with non-modified pick-up points.

EDIT: 930 arms are shorter and not longer than 911

[john walker's workshop]

smart racing sells these brackets to install 930 arms in a normal car. these have been modified to use on a G-50 car. they key onto the original bolt hole, then are welded in. there's a bracket that attaches from above, accessable thru the rear seat area, that positions the pivot point where you want it for alignment purposes.

[doozer]

Thanks Guys,

When you say "They can support more HP and wheel loading " is there a problem with 911 control arms under heavy load?? I have never heard of this failure..

Thanks for all the good info and the photograph!
Todd

[MichiganMat]

From what I've heard (and I could be wrong), the 930 arms are set up to handle wider wheels without putting loads of stress on the wheel bearings.

If thats the case, and I think it is, you might want to consider running them doozer, especially considering those crazy rears you're running.

[project935]

I've never heard of a failure, per se, either but there's no doubt the 930s and racing variants used them for a reason - wider wheels and higher cornering forces.

I do have a chunk of a 911 Al arm that was broken in half - not sure how it happened (probably one hell of a hit).

Check out these ancient threads for some more info/pics (my login used to be matt_d ... long since forgot that password);

930 axles and my local dealer...
bummer...@@!!#!... i need some serious reassurance now :-(

[doozer]

Well Foo, you guys are killing me... I wish I had known that from the beginning but I guess I know it now and that is what counts..

Does this adjustable box kill the back jump seats? Where will I store my super models??

Ok Juan is running stock 911 rear control arms (but with narrow wheels/tires) - I think I will risk it for now because I can always get in there and weld on some 930's

Thanks for all the info guys!
Todd

[project935]

Here's another pic of the camber boxes welded onto the stock pick-up points (from a radical Timmens project). The adjustment bolt on top is to raise/lower the pick-up point for more camber change.



Some people cut a access panel into the floor of the tub to access the bolts. Sitting on them under the jump seats might be uncomfortable for the supermodels ... but ya never know what they might be into

Worst comes to worst they'll need to sit on your lap

[doozer]

Are those top pick up points for coil overs??

I am starting to twitch and I think I hear my welder calling Bzzzzzz Bzzzzzz

Looks like there is a lot of excess on those adjuster bolts. I could figure out where they needed to go then make some shorter bolts to fit under the seats.

Are adjustable mounts required??
Can it just be a solid mount?
Are the 930 control arms wider at that mounting point?

Thanks
Todd

[project935]

Yes - those top points are for eye-mount coilovers ... just part of his roll cage. They're similar on my chassis.

The bolts are long because the adjustment slot is long ... probably doesn't need to be that much.
I'm not sure if adjustable mounts are really required - esp if you're using the factory adjustable swing plates. The mounts on my chassis (all tube ... not a tub) are solid as shown in this pic along with an upper shock mounts (upper LH corner)

I haven't decided yet if I'm going to make the lower pick-ups adjustable.

The 930 arms are the same width as 911 arms at the pick-up point - they use the same bushings or monoball cartridges.

[doozer]

So can you plug a 930 arm into a 911 mount or is the geo. off...

I cant lower my car anymore due to the V8.

I am wondering if I upgrade to 930 arms in the future should I do any welding now.

Thanks for the info!

[project935]

You can plug them in, but things will change a bit.
According to the BA "Porsche 911 Performance Handbook" ...
"The Turbo arms were shorter, and the pick-up points were moved to relocate the suspension's fulcrum points, similar to what had been done on the RSR. In addition to being moved away from the center by 22 to 25mm and rearward 47.5mm to compensate for the shorter arm, they were also moved up 10mm to give the suspension anti-squat characteristics. The Porsche 930 used a new rear torsion bar tube with different suspension pick-up points made as part of the tube."

So, if I'm figuring this correctly ... 930 arms can be used in a 911 pick-up point location, but the wheelbase will be roughly 47.5mm shorter and the ride height 10mm higher. The overall track will be the same because the 930 arms have the double wheel-bearing/hub face mounting that is moved futher outboard (the 22-25mm).

The 930 had a wider track than the 911 using the 930 pick-up points. '75-80 930 rear arms also used a 1" spacer on the hub ... '81-up 930 rear arms used a hub with a face that was 1" further outboard and no spacer.

930 rear arms also moved the brake caliper to the rear of the wheel ... 911s had the caliper in the front of the wheel.

[doozer]

I think I have just gone crosseyed...

Ok so If I did plug them in my rer wheels would be almost 2" off in the wheel wells..

Well thats no good, I may have to get the adjustable boxes...

but... the boxes in the photograph look like they are directly above the 911 arm mount because they index in the old bolt hole???