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Front Sway Bar

Posted: Wed Mar 20, 2019 10:12 am
by 8bit-ash
Mine hasn't got one. Is it a worthwhile addition? I'm assuming it is so wondering if for road use the standard through the body bar is the best one to try and get.

Re: Front Sway Bar

Posted: Wed Mar 20, 2019 9:07 pm
by stretch
Yep. 15mm bar is standard. Still available from Porsche for reasonable money last time i checked.

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 9:48 am
by Ashley James
Anti-roll or sway bars do reduce sway and roll and improve steering response, but will introduce understeer if they’re too thick. This is overcome by fitting another on the rear. Most older cars improve with either one fitted or a slightly thicker one than they have because modern tyres are a tad more grippy.

Anyone who saw the Testa Rossa being hurled round a test track on the World Rour the other night will know what one that’s too thin does do the handling. An ugly old Ferrari actually rolling and wallowing round corners.

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 10:24 am
by 210bhp
I was under the assumption that you shouldn’t fit the one at the front without one on the rear.

Regards
Mike

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 10:32 am
by Gary71
210bhp wrote:I was under the assumption that you shouldn’t fit the one at the front without one on the rear.

Regards
Mike
Agreed. As Ashley mentioned it will just understeer more.

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 11:31 am
by stretch
Looks like your shell doesn't have the mounting points for a rear factory bar.

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 12:05 pm
by 8bit-ash
stretch wrote:Looks like your shell doesn't have the mounting points for a rear factory bar.
Correct, Front is a doddle to fit but back would be harder. There seems to be people out there that run front only and the '101 things to do' book suggest fitting a front only as an upgrade. I got all the bits needed other than the bar itself for not too much money so I can always experiment when the time finally comes.

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 12:22 pm
by Ashley James
I’d fit one and see how you get on. I fitted a Turbo R anti-roll bar to my Shadow many years ago when the R-R kit didn’t improve the appalling handling enough. It was a huge improvement but understeered excessively at the limit. Easy to reach with 2.5 tons, but still better than without and I’d have fitted a rear if I hadn’t got fed up with the old tank. Still have a soft spot for them, but.........

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 6:02 pm
by 911hillclimber
If your rear suspension and shell are not prepped for a rear bar then I would question doing either.
I'm sure you need to fit both Fr and Rr for good results.

Mine are RS 2.7 spec and I added all the mounting points on the rear, not too hard, the arms are the hard bit.
You can get a clamp on system from the States, or at least you could.

spelt wrong:

Weiltmeister did a whole range. Do not go for the largest bars, I did this and the car was awful.

Maybe your shell is not prepped for the 'through the body' bar?

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 7:02 pm
by brembo
brembo wrote:Front anti roll bar. will try 16mm bar to start with.

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Mikes drawing sent to manufacturer to make up brackets, to weld to inner wing.

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Arb fitted.


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Mike Bainbridge fitted front arb to my rep.He manufactured the strengthening brackets for the inner wing.Handy source if you need some made up

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 8:24 pm
by 8bit-ash
brembo wrote:
brembo wrote:Front anti roll bar. will try 16mm bar to start with.

Image

Mikes drawing sent to manufacturer to make up brackets, to weld to inner wing.

Image
Image
Image
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Arb fitted.


Image
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Mike Bainbridge fitted front arb to my rep.He manufactured the strengthening brackets for the inner wing.Handy source if you need some made up

Mines got all I need to fit fronts including the tabs on the A arms. Did you fit backs?

Re: Front Sway Bar

Posted: Thu Mar 21, 2019 8:31 pm
by fetuhoe
it's quite likely that a 1970 911 could have originally with fitted Boge 'Oleodynamic' Struts which were listed on the PET as 'Spring Struts'.

Cars with these struts didn't have torsion bars on the front of the car and hardly ever had sway bars.

The bodyshell, however, was always fitted with the inner captive nuts to allow a sway bar to be fitted so the inner wing shouldn't need strengthening. Later cars using the underbody swaybars do need this modification.

Fitting a factory through body sway bar is quite costly as the levers, drop links, guide plates, mounting plates and all the bushes cost about £780 if you buy them new from Porsche. This doesn't include the swaybar.

It is also possible that you may need to weld tabs to the front control arms.

If you fit a rear bar you will not only need to weld brackets to the bodyshell, you will also need to weld ball pins into the trailing arms and these pins ideally need to be jigged.

It is possible to make an initial attempt to see how the car behaves by fitting a small diameter bar to the front and not fitting a bar on the rear.

Early cars, which often only had front bars used a 13mm diameter part which improved steering response witout dialling in too much understeer. It will also tend to help with oversteer.

If you want to also improve rear roll stiffness without welding on brackets you could try using 24mm diameter Torsion bars from an SC which will be a good compromise with a 13mm front bar.

Re: Front Sway Bar

Posted: Mon Mar 25, 2019 11:59 am
by 8bit-ash
Thanks for all the useful input, I sourced all of the bits needed minus a couple of bolts and the bar for not a lot of money so I'll try the 13mm bar as suggested first and go from there.