924Board.org

[Herr-Kuhn]

Great, thanks for the photo. Can you tell me...did you keep the stock rubber bushings on the torsion beam pieces from the 924S or were these cut off and replaced with a poly bushing set? You appear to have used the 77 cover caps.

I assume you also mounted the tabs for the rear sway bar? I plan to run the 25.5mm front and the 18mm rear with a 350-400 lb/in set front and a 30mm torsion bar set our back (330 lb/in effective). It looks like you just welded a pad onto the torsion bar tube. Hard to believe the factory installed a torsion bar without strapping it down...kinda makes pure torsion there quite difficult!

Additionally, are you just running the torsion bar tube with only the two mounting tabs on either side and no rubber bumpers on the top side to limit suspension travel?

[Andrew NZ]

[Herr-Kuhn]

No other mounting provisions for the torsion tube beam other than the 2 bolts as per factory on the 1977?

You did coil overs on this, correct? What spring rates are you running front and rear and how difficult was it to reinforce the frame in the upper rear to allow for good durability back there? I recall you saying you cracked the original frame member with the coil overs. The coil overs are only about +$100 over the big torsion bars, so it's still an option but I'd like to know how hard it is to modify the mount...I assume one just welds on extra metal on either side of the box.

I'm likely going to just stick with the 30mm bars and like a 350-400 lb/in spring up front. However, there is concern here based on the fact that there will be a much larger moment induced on the torsion bar tube with the larger bars installed. I had neglected to take this into consideration when I looked at the design. The tube has to effectively distribute the moment to the frame and with the 1977's smaller footprint, I may be pushing my luck. This also explains why the later cars had the swoopy bars on them which attach to the body above the wheels...this really spreads out the moment to the frame.

[RC]

[Andrew NZ]

[MikeJinCO]

On my '77 the torsion bar carrier appears to be straight off a Super Beetle. I got inner TB poly bushings for a SB and then used the standard 924/944 adjustable spring plates. I got sway bar brackets from the Portland Porsche dealer(forgot name) and welded them onto the carrier tube. An easy job with the carrier on the floor. I stayed with original steel trailing arms, but used SB trailing arm bushings with new inner sleeves machined for the 12mm bolts rather than the SB 17mm or some such.
_________________
Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[Rasta Monsta]

What's the weight of the alloy arms? I recall them being quite heavy, and I found myself wondering if they were heavier than the steel pieces
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Raceboy]

The weight is the same, they are not lighter than steel arms, but they are more rigid.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Andrew NZ]

For me it was more about width and reliability rather than weight. I was having so many hassles with wheel bearings with the steel arms, and have had none with the alloy ones.
_________________
Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[Herr-Kuhn]

So if I do fit the aluminium arms, will this be too wide for me to place an 8" rim under the back of the car? I was of the understanding that the arms were the same track width as the steel arms.

I'm likely going to make some braces to tie the torsion bar tube into the frame right at the wheel center, this pinning the torsion loads out on a wider point. From there I'd like to fit a 30mm torsion bar set.

Whatever I do, I need the 928S4 8" rims to fit under the back of the car, so I hope all of these bits can come together to make that happen.

[ideola]

If you're sticking with narrow body, you'll need to source the trailing arms from an 86 951 or 87-88 924S. These trailing arms have the same track width as the early steel trailing arms + spacers; i.e., you don't use spacers with the "early offset" alu trailing arms. The 87-onward 944/951 all had the "late offset" alu trailing arms. These will not work with any OEM wheels on a narrow body 924 because they push the hub face out by another 22mm or so, and would consequently require offsets in the 75-85mm range, which are non-existent in OEM wheels.

8" high offset rims like the 52.3mm offset D90s will fit with little issue on such a setup, although some have reported needing to roll the inner rear arches to avoid rubbing (probably somewhat dependent on rear camber settings). I've never had an issue with the 8" D90s on steel or alu arms.

When I test fit the 60mm offset 9" club sport rims on my Euro 931 (with alu trailing arms from 86 951), the inner edge of the wheel rubbed on the brake lines, and it appeared to me that if they had rubber on them, the tires would rub on both the front and rear faces. I've seen one report of these wheels on a narrow body car, but details were scant with respect to tires and camber settings. So it might be doable, but I opted not to pay for the rubber and stuck with 7" wheels (for balance) on all four corners. There aren't too many other 9" high offset OEM wheels.
_________________
erstwhile owner of just about every 924 variant ever made

[Raceboy]

To be correct, the rear aluminium trailing arms have all the same width, but the wheel hubs and rear brake rotors are different between 924S/'86 951 and later cars.

With my first rear alloy arm conversion, I bought '90 951 rear arms and found '85/9 944 NA wheel hubs. Made the conversion and bought brand new '86 951 rotors, worked like a charm.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Herr-Kuhn]

My rear suspension is directly off of an 87 924S, so then I should be fine. It is still sitting out in the storage shed. I just want to get a 225 in the back with some good compound rubber. Doing any crazyness to the rear quarters is completely out of the question...I want to retain the original lines and the paint in the car is pretty much show quality right now. I've been acquiring parts for many months now. 928S4 brakes, early sport seats, 928S4 wheels, etc., etc.

This bloody project gets deeper and deeper all the time, but upon completion, I'm certain it will be worth it. It sure does look good with the new paint job though...now I just have to make it able to get out of its own way!

[!tom]

[Raceboy]

The bearings are different on alloy arms, and better design.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche