Extended Front Control Arms ?

[EarlySport]

Hi All,

I've been searching for a picture or details on extending the front suspension control arms to improve the suspension geometry on a wide body car.

In short, I'd like the widebody IROC replica I'm building to steer like my narrow RS replica. To do this (amongst other things) I want to move the spindle closer to the centre of the front wheel, eliminating the 1" wheel spacer that I currently run, and improving the scrub radius.

I know Tyson did this with Jack's BB2. Hopefully he can help out here.

My Questions are;

1. How far to extend the control arm? I've bought a second set so I can 'cut and shut' the two to make one newer longer arm

2. What about tie-rods? There won't be enough adjustment to accomodate a 2" wider track - I think.

3. What about camber change? The extended arms will give me XX more negative camber. Anyone know how much XX will be? Another 1.5 degrees would be nice - much more and I'll have to do something about it, like...

4. I've heard of guys bending the spindle to get more negative camber. Anyone done this? With Oxy or cold? I may have to bend them to reduce negative camber.

Your responses are greatly appreciated.

[Shawn 357]

I haven't extended control arms on a 911 but for #3 and 4:
If you get to much negative camber with the extended control arms you can put on the aftermarket camber plates that are made to give you more negative camber but just put them on the wrong sides and the will give you more positive camber. I can't recall how much the aftermarket camber plates change your camber so call one of the people who make them before you bank on that idea.
Hope this helps,
Shawn

[Chuck Moreland]

An exact answer depends on your spindle height and ride height. But the following is in the ballpark and may be close enough for government work.

1) If your goal is to completely eliminate the 1 inch spacer, you'll need to extend the arm approximately 1.4 inches.

2) I have tie rods that are extra long and will solve this problem

3) If you extend the arms 1.4 inches the camber will become about 5 degrees more negative. You would need to add positive camber to the spindle.

4) don't bend the spindle, machine the spindle collar

[midnight911]

Rauh-welt does it.
I have a magazine with those pics. not sure if it's okay to scan and post the pic here.
The note by the side for the pic says the A-arm was extended by 2cm each side, inner and outer, total 4cm. The tie rod was also extended by 4cm to match.
The reason for Rauh-welt doing so is to get the negative camber...THE negative camber...at 6 degrees. Why THE negative camber? 'cuz it's cool...

[PcarPhil]

Subscribing.

I too have been researching this modification for my widebody car. This seems like a worthwhile mod to get the best suspension geometry for widebody cars.

[EarlySport]

Originally Posted by Chuck Moreland

An exact answer depends on your spindle height and ride height. But the following is in the ballpark and may be close enough for government work.

1) If your goal is to completely eliminate the 1 inch spacer, you'll need to extend the arm approximately 1.4 inches.

2) I have tie rods that are extra long and will solve this problem

3) If you extend the arms 1.4 inches the camber will become about 5 degrees more negative. You would need to add positive camber to the spindle.

4) don't bend the spindle, machine the spindle collar

Thanks for your information Chuck - much appreciated.

On point 2, I assume they are a turbo tie-rod style, but are available with a rod end so I can also run a bump steer kit? I'm going to need these from you.

And can you please elaborate a little on (4) the machining of the spindle collar to change camber?

[Chuck Moreland]

on 2, they are a turbo tie rod only longer. The tie rod end is as stock, not a rod end. Or you can have them with rod ends and a bump steer kit.

Remove the spindle collar. Machine the hole through the spindle collar at the desired angle, using a mill. Weld the spindle collar into place.