Sway bar question, need some help!

[DRACO A5OG]

Hewh! Glad that's over.


So what year are those "stabilizers" from?

[winders]

Originally Posted by DRACO A5OG

Hewh! Glad that's over.


So what year are those "stabilizers" from?

You're so funny.....

These are all names for the same device:

anti-roll bar
roll bar
sway bar
anti-sway bar
stabilizer bar
stabilizer

The term "anti-roll bar" is generally preferred by chassis/suspension engineers. Note that they are never called "torsion bars".

Scott

[DRACO A5OG]

Let's hope we will see his issue posted tonight.

[Tidybuoy]

Here is a picture of an early Porsche 911 Front Through-Body Sway Bar. I have no idea what size it is because I sold it ten years ago. I'm posting the picture just for reference.

[Tidybuoy]

Here is a picture of Porsche 911 Front & Rear Torsion Bars. I would not call these thru body because they don't actually go thru the body - they do however go thru the suspension.

[Tidybuoy]

Here's a picture of three girls "Planking". This has nothing to do with sway bars or torsion bars however, there is a car in the parking lot that uses sway bars.



The point is: Original Poster, you need to post photos when talking about something that is confusing like this: swar bars marked 15 but measure 23 but factory never made these but front and rear are mis-marked and somehow ended up on my car by the factory?

[Wrrnj]

Wow! I feel so stupid right now that I really did not want to even post this, but since so many of you tried to help me, I am going to admit fault. So my caliper was set at 32nd's, 19/32 = 15mm and 23/32 = 18mm. So the bars are correct based on what is stamped on them. Now I need to contact the person I bought them from and discuss that I was sold a 19mm bar and ended up with a 15mm.

Just out of curiosity, anyone running larger rear sway bar than front?

[DRACO A5OG]

I upped my OEM 85 stabilizers to 87's, both front and rears, larger id bushings had to be installed as well.

Don't sweat it brother we all done similar, ;-)

[winders]

Originally Posted by Wrrnj

Wow! I feel so stupid right now that I really did not want to even post this, but since so many of you tried to help me, I am going to admit fault. So my caliper was set at 32nd's, 19/32 = 15mm and 23/32 = 18mm. So the bars are correct based on what is stamped on them. Now I need to contact the person I bought them from and discuss that I was sold a 19mm bar and ended up with a 15mm.

Just out of curiosity, anyone running larger rear sway bar than front?

No worries. We all make stupid little mistakes like that...even if we don't admit to them in public!!

It is not at all uncommon to use a larger anti-roll bar at the rear. But, it all depends on your setup. I prefer to use adjustable anti-roll bars of the same size front and rear. I don't even know where to start using Factory anti-roll bars. Anyone would need to know what size torsion bars you are running front and rear.

Scott

[911pcars]

Originally Posted by winders

" ...... Calling an anti-roll bar a torsion bar because both are torsion springs is like calling a Doberman a German Shepard Dog because both are dogs.

Scott

Yes. Same species, both examples. They work on the same principle, both examples.

Sherwood

[Flieger]

Originally Posted by winders

Let's get technical and very clear. No one calls an anti-roll bar a torsion bar because it is not one. Yes, the anti-roll bar is a torsion spring, but that does not make it a torsion bar.

Calling an anti-roll bar a torsion bar because both are torsion springs is like calling a Doberman a German Shepard Dog because both are dogs.

Scott

Actually, torsion springs are coil springs that work in bending but act in a rotary manner. Torsion bars work in torsion and a torsion bar mounted in a certain way can be used to resist roll and one-wheel bump but not heave. An anti-roll torsion bar with the levers reversed is called a Z-bar and works in heave and one-wheel bump but not in roll.

You can add roll resistance independent of heave in many ways. Bellville washers, coil springs, bending of blades, etc.

[winders]

Originally Posted by Flieger

Actually, torsion springs are coil springs that work in bending but act in a rotary manner. Torsion bars work in torsion and a torsion bar mounted in a certain way can be used to resist roll and one-wheel bump but not heave. An anti-roll torsion bar with the levers reversed is called a Z-bar and works in heave and one-wheel bump but not in roll.

You can add roll resistance independent of heave in many ways. Bellville washers, coil springs, bending of blades, etc.

Torsion bars are also torsion springs. Look here:

Torsion Springs

Or here:

http://www.wisegeek.com/what-is-a-torsion-spring.htm

Scott

[Wrrnj]

Thanks for understanding. I want to share my set up with you guys and see if you can point me in the right direction. The car is a 1967 912, the car was not original by any means, so dont get upset when I explain the mods. I swapped the motor with a EJ2.5 Subaru, Stinger ECM, making around 200hp. The car has been flared in the back. Running 16x7 with 205/50 in the front and 16x8 with 225/50 in the rear. Stock torsion bars but I lowered it, added a strut brace. It has RS bumpers and has been lightened throughout. It has a 4 point roll bar. It was not equipped with sway bars so I thought I would run a 19mm up front and a 18mm in the rear. I bought the bars used online and the seller sent me a 15mm for the front by mistake. I notice that everyone seems to run a larger bar upfront, but I am curious if anyone runs larger bars in the rear. I am guessing with the light Subaru motor in the rear and SWB a larger bar might end up with excessive oversteer. Any thoughts?

[DRACO A5OG]

Will you be tracking or street only? DO you know your front and rear weights?

[Flieger]

Originally Posted by winders

Torsion bars are also torsion springs. Look here:

Torsion Springs

Or here:

What Is a Torsion Spring?

Scott

Originally Posted by the website

Torsion Spring

A typical torsion helical spring is shown below. There are a wide variety of coil end configurations to suit different applications and a torsion spring is usually positioned on a shaft. The coils are usually close wound as are tension springs but they generally do not have any initial tension unlike tension springs.

The primary stress induced in torsion spring is a bending stress in the wire . This is not the case for the tension and compression helical springs for which the primary stress is a torsional (shear) stress. During forming residual stresses are built up in the winding process. These residual stresses are in the same direction but of opposite sign to the working stresses resulting when the spring is loaded causing the coils to tighten. Torsion springs are stronger as a result and they are often designed to work at, or above the yield strength.

This was my point.

It also brings up the point that coil springs are actually torsion bars!!

[DRACO A5OG]

OP I think you've been hi-jacked :-o

[Wrrnj]

Originally Posted by DRACO A5OG

Will you be tracking or street only?

Its a weekend street car but I want to take it to track days at Thunder Hill

[DRACO A5OG]

Okay parttime AX/DE er, okay do you happen to know front and rear weights or at least total weight?

After suspension upgrades, you should consider corner balancing to optimize the mods.

[winders]

Originally Posted by Flieger

This was my point.

What was your point??

Scott

[winders]

Originally Posted by Wrrnj

Stock torsion bars....

What size?

Scott