ALFAGTV6.COM

Sway Bars

I have seen lots of postings about the use of different sized sway bars and some of the European configurations use some big numbers like 33mm diameter. I do know that these would be hollow bars.

What I don't know is the correlation between the solid bars and hollow bars and the wall thickness.

How can you work out their equivalents? Are there charts around or what?

daily material.
Only not that simple to type the formula within the limited functions of the forum.
Will see if I can upload a pciture of it later today.

D=outer diameter [mm]
d=inner diameter [mm]

Iv=(D^4-d^4)*pi/32

There you go...

Mats is always quicker..

you are looking for Ip

Thanks Guys, I can work with that.

OK, so the formulas are out.

Then my opinion about anti roll (AR) bars.

For street cars huge AR bars may be a good idea sinse they add comfort when spring rates can be kept moderate.

However, for a race Alfa, this is not the way I'd choose. I would propose to keep the AR bars decent and use rather stiff springs. Front as well as rear.

You guys belong on Geeksdotcom......

This one maybe for you Baz but anyone who knows the score, please chime in.

I believe the rear "A"frame can be cut to set the rear wheel geometry up better for racing applications.

Questions:

How is this done
What size cuts are made? Where? Illustration ?
How much camber are we aiming for?
Toe in/out?

What are the benefits and what sort of circuits are the modifications useful for?

Thanks a bunch.

Fellow geeks,

many possibilities
- just heat & power
- cut the ends and weld together. Requires GOOD precision
- cut in the middle. About half way. Bend. Check Toe in. Weld together. Recheck toe. Can't go wrong.

Different opinions on camber. I'd say about -1 to -2 per side.

Slight toe in. When bending you easily end up with toe out. Really bad for high speed stability.

Benefit: Better grip, higher cornering speed, better lap times. Valid for most circuits.

Hey Micke (Reminds me of a song I heard once)

This work, is it done with the unit in the car or off the car?

ooh MD, not in the anti-rollbar thread, and you just created all those other threads...

Cut and weld is the way it's done here, near the middle. Not likely to mess with your toe values either which is nice.

It can be done on the car.

Easier to measure accurately and do a good job off the car of course.

If you put the DeDion standing on a set of old rims you can do the measurements without any special equipment. When you cut the axle in the middle you automatically get same camber left and right.

Here excactly done as Micke said on the car.

Cut at the sides and welded with a set rim to measure from.
Goal was from memory 2.5 deg camber and 2 mm toe in.

But would now cut in the middle and bend (also lowers your watt pickup point a little).
And use Mats trick (tack welds on one side) for some toe-in.

Thanks Mats & Micke,

The placement of this topic should be under the subheading of suspension which seems appropriate to me as for the other subheadings, they were intended to go under the main one ie Race Cars and Track Preparation. If that's not how its panning out, Mr Administrator ,help !!

However, for a race Alfa, this is not the way I'd choose. I would propose to keep the AR bars decent and use rather stiff springs. Front as well as rear.

Micke, I think in theory you are right; an AR bar just takes away grip from one (the inside of the corner) wheel...

My theory ( I know thin ice but will give it a try)
In real life you can’t stiffen a suspension unlimited. There is a point where your tires become the dominating factor in suspension stiffness. And that is something really undesirable because I think a tire is like an undampened spring.
So it is nice to use the other side’s stiffness to reduce roll.
The stiffness of the roll bar rises with the stiffness of the springs to limit the roll with the same factor.