Adding rear sway bar to an early 911

[joetiii]

So my 69 911 E was upgraded in early life from the hydropneumatic struts to bilsteins. At that time, a 20 mm through body sway bar was added. I am currently having the car rebushed, lowered & cornerbalanced and am thinking about adding a rear sway bar.

The car has a nice & torquey 3.0 transplanted in it so I figure theres more weight hanging over the back axle and am considering adding a rear sway bar. A 20 mm rear sway bar was included with my deal on this car and it came in the front trunk. I think it fits a later car so I suggested to the shop that's doing the suspension update that we could use this bar. He suggested that the car would tend to oversteer with a rear sway bar and recommended that upgrading front and rear torsion bars would give better handling with the 3.0 than a rear sway bar.

When I ordered Street kit 1 from Elephant racing, Chuck asked whether the car tended to understeer with only a front bar on it. Since I havn't driven the car in the twisties that much yet, I havn't really noticed.

The shop doing the upgrade is Musante Motorsport in Windsor, Ct. He deals exclusively in Porsche. I'm dealing with the owner himself Chris who is a race driver himself. (He's up at the track in Canada this weekend). I trust his judgement from his years of track experience but wonder what the technical reasons for his suggestion are?

I realize that the early cars came w/o rwar sway, but the factory added them as years went on. Was that because later cars are heavier than long hoods?

I know that 911s have an oversteer characteristic which is certainly desireable on the track and a little less so on the street. What am I missing?

[stlrj]

He suggested that the car would tend to oversteer with a rear sway bar and recommended that upgrading front and rear torsion bars would give better handling with the 3.0 than a rear sway bar.

He is absolutley correct.

I know that 911s have an oversteer characteristic which is certainly desireable on the track and a little less so on the street. What am I missing?

On some tracks the rear sway bar is deleted to reduce oversteer which is not always a desirable characteristic.

I have a 3.2 in my 74 and have run it with and without the rear sway bar only to find it handles so much better without.

Joe

[joetiii]

So am I correct in assuming that the rear bars were added as the 911 took on more weight and her arse got wider??

[70SATMan]

The rear sway was standard on the early 911S from 67-0n IIRC. Optional on Ts. You will need the trailing arms that have the ball mount to add the rear sway.

[Oldporsche]

My 911E came delivered with hydropneumatic struts and no bars. I converted them to hold inserts, used T torsion bars and added factory sway bars to both ends. Overall for street use I like the bars on both ends.

When I was autox-ing it depended on the course as to wheather I left the rear sway bar as is or un-hooked one end.

Good luck,
David Duffield