OK, I just read this on an English VW forum from some genius who calls himself MATT67 on there
http://www.volkszone.com/VZi/showthr...1&page=1&pp=10
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News update on this 911 suspension conversion.
If anyone is still interested I have done some more research for you..
It turns out that the 911 rear torsion bar is a direct fit into any Beetle
The length is 628mm (also known as 24+11/16 inches)
And as I said before, the number of splines is the same as a Beetle (40 inner, 44 outer)
So you have 2 options: use an 24+11/16 beetle torsion bar and bolt on the 911 spring plate
or use the stiffer 24+11/16 TB from the 911 and bolt the 911 spring plate onto that.
AFAIK the 911 spring plate cover fits straight onto the Beetle.
[Additionally, this could be a nice way of increasing spring rate on the rear of your Beetle
even if you keep the rest of your suspension as stock.
Cost of a new Porsche 911 OEM torsion bar starts from $143 from Pelican parts
http://www.pelicanparts.com/catalog..._pg3.htm#item11
(I think new rear VW OEM TBs for the Beetle are more expensive)
Fitting the 911 TB's may even work out cheaper than fitting some coil-overs.]
With the 57mm extra length on the trailing arms, it means the camber and toe-in variation
is reduced by 14% over the bog standard 1303/944, which probably won't be noticeable,
but in theory would just add a little understeer characteristics and probably help straight-line stability
Position of the brake caliper is better than on the 1303 or 944 trailing arms because it sits
closer to the suspension pivot (ie closer to the torsion bar)
And so it should help the car to ride over bumps and potholes more smoothly.
Rear track remains unaltered as far as I can tell.
You have 57 mm more room for fitting large diameter wheels on the back of you Beetle
ie 4 inches diameter bigger is not a problem.
Last but not least, due to the increased trailing arm length your weight distribution becomes 46/54,
and the car should handle more like a mid-engined 914, and less like a Beetle(42/58) or a 911(40/60)
Cost of used parts from a Porsche breakers (inluding the 911 calipers and disks) can work out less
than just fitting a Beetle rear disk brake kit ...
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