Sway Bars vs. Torsion Bars vs. Both

[dReAdLoK]

I have VWR Springs installed on my GTI and am getting ready to purchase some sway bars. I understand that sway bars help with the body roll in cornering. In searching for sway bars, I have found that Neuspeed has a Torsion Bar for sale, as well as all their sway bars. That is where my questions began...

What exactly does a Torsion Bar do for my car? I have read that it has something to do with the weight of the car, but wasn't able to find out how. Depending on what it does, would it be worth it to have a Rear Sway with the Torsion Bar?

My main concern is my rear wheels. Back in the day, when I had my Si, I had Coil Overs, but nothing else for the suspension. Every time I took a turn on an incline or dip, my rear wheels would come up off the ground. I have read, now, that when lowering the car, adding a Sway Bar to the rear and installing Rear End Links will completely prevent any wheels from coming off of the ground. I did read one post that said a Torsion Bar stops the wheels from coming off the ground.

So, would it be overkill to have both Sway & Torsion, or would front & rear Sways, with End Links be the best way to go? Or, would a UniBrace be a good substitution for the Torsion Bar? Thanks for any information regarding this.

 

[spelk3]

The torsion bar is for a twist beam rear axle, not the independent rear suspension of the GTI.

 

[dReAdLoK]

Ok, but what does it do for the car? What is the purpose? Will it help keep my wheels off the ground like some people say? Or do the End Links with a Sway Bar prevent the wheels from coming off the ground? You say it's for the rear axle but, you don't give the purpose for it.

 

[flipflp]

Ok, but what does it do for the car? What is the purpose? Will it help keep my wheels off the ground like some people say? Or do the End Links with a Sway Bar prevent the wheels from coming off the ground? You say it's for the rear axle but, you don't give the purpose for it.

Well, since you have a GTI, the torsion bar does nothing for your car because it's only designed for solid axle rear suspension vehicles.

What it does for solid axle cars is reduce the flex of the rear axle to reduce body roll, which is the same function a sway bar has in independent rear suspension cars (like your GTI).

I'm not sure what you mean by preventing the wheels from coming off of the ground, but sway bars reduce body roll in corners (how much the car leans in corners). They don't affect suspension travel though.

 

[golfdave]

If you have a GTI you have multilink rear suspension therefore you get a rear anti roll bar...USA speak sway bar.

You should have one fitted to car from factory, just if you want less body roll & are fitting stiffer springs dampers then a stiffer ARB can also help.

However suspension design is very complex & making everything stiff can ruin the ride totally. so thread with care.

An ARB works my linking the left & right wheels on the same axle up to a certain degree, & is felt when driving around a corner. The inside wheel lifts as the outside wheel is compressed due to weight/force transfer of the car to the outside of the corner. The ARB by linking these wheels force them to act more in a "together" way when the forces acting on them want them to do totally opposite actions to each other. So outside wheel is compressed which twists the ARB against the inside wheel force which wants to lift which resists this force transfer. So this "levels" out the body roll through the corner.

 

[donp]

I've got the ST 25mm rear sway bar with the VWR springs. I like it so far as the balance is a little better. I haven't done any track days yet, but the ride is nearly identical to stock.

 

[Rod Paine]

What exactly does a Torsion Bar do for my car? I have read that it has something to do with the weight of the car, but wasn't able to find out how. Depending on what it does, would it be worth it to have a Rear Sway with the Torsion Bar?

You may find this article helpful...
http://www.turnfast.com/tech_handling/handling
-Rod

 

[Geomets]

You should have one fitted to car from factory, just if you want less body roll & are fitting stiffer springs dampers then a stiffer ARB can also help.

Agreed. But keep in mind that stiffening the chassis too much can eventually ruin the handling of the car (the ride will be ruined first!)
The ani-roll bars add a certain amount of spring force. Therefore it is not recommended to stiffen the springs too. If you do though, you should install rather strong aftermarket dampers (with increased bumping and damping force) to work with the new increased spring rate (combined force of springs/anti-roll bars).

 

[golfdave]

Agreed. But keep in mind that stiffening the chassis too much can eventually ruin the handling of the car (the ride will be ruined first!)
The ani-roll bars add a certain amount of spring force. Therefore it is not recommended to stiffen the springs too. If you do though, you should install rather strong aftermarket dampers (with increased bumping and damping force) to work with the new increased spring rate (combined force of springs/anti-roll bars).

You forgot to quote my sentence below the one you quoted...

Anyway early Lotus cars had no ARBs & neither does the McLaren F1 road car, good suspension design sees to that's!

 

[donp]

The VWR springs aren't very stiff, the ride feels like stock even with a larger rear sway bar and 1.25" lower ride height. IMO, there's no need to touch the front sway bar.

 

[Geomets]

You forgot to quote my sentence below the one you quoted...

Anyway early Lotus cars had no ARBs & neither does the McLaren F1 road car, good suspension design sees to that's!

I forgot that, indeed
I'm a believer of the Great Britain's suspension architecture:
Select the best combination of springs/dampers, use exact same length driveshafts, don't add anything else (because you won't have pure steering feel), have fun!

 

[GIACUser]

I have VWR Springs installed on my GTI and am getting ready to purchase some sway bars. I understand that sway bars help with the body roll in cornering. In searching for sway bars, I have found that Neuspeed has a Torsion Bar for sale, as well as all their sway bars. That is where my questions began...

What exactly does a Torsion Bar do for my car? I have read that it has something to do with the weight of the car, but wasn't able to find out how. Depending on what it does, would it be worth it to have a Rear Sway with the Torsion Bar?

My main concern is my rear wheels. Back in the day, when I had my Si, I had Coil Overs, but nothing else for the suspension. Every time I took a turn on an incline or dip, my rear wheels would come up off the ground. I have read, now, that when lowering the car, adding a Sway Bar to the rear and installing Rear End Links will completely prevent any wheels from coming off of the ground. I did read one post that said a Torsion Bar stops the wheels from coming off the ground.

So, would it be overkill to have both Sway & Torsion, or would front & rear Sways, with End Links be the best way to go? Or, would a UniBrace be a good substitution for the Torsion Bar? Thanks for any information regarding this.

Torsion bar not for your car. The one you see on Neuspeed is for cars that have torsion beam rear axles, your car does not have this. You have full independent suspension so your car would use a sway bar in rear, not a torsion bar.

GTI comes from factory with sway bars front and rear. Aftermarket sway bars are typically going to be more aggressive than stock (thicker, stiffer, less flex) and adjustable. The more aggressive (generally) the less body roll. Also you will begin to feel bumps more with more aggressive bars.

Properly designed suspension will do a good job keeping your tire in contact with the road. If you lose contact you can lose ability to brake, steer or accelerate. In the case of your Honda it sounds like spring rate was way to high for the shocks. Springs bounce, the shock is supposed to control that bounce so your car does not lose traction.

The factory suspension is pretty darn good and really doesn't need much for street driving. A lot of improved handling can be had by spending money on really good tires as the ones from the factory are so-so.

I have an older GTI 2008 and have done a lot of suspension mods from shocks, springs, sway bars and bushings etc. Handling is way up but ride quality suffers. Fine on good roads but when the road gets rough you feel it much more than you would with stock suspension.

 

[Prairie Pete]

You shouldn't make a goal of keeping the inside wheels on the ground. That is irrelevant.

During hard cornering, the inside tires don't provide much cornering force. I have photos from the 60's showing Porsches at LeMans going through a corner with one inside wheel hanging several inches above the pavement. The engineers could have taken that out, but the car's performance would have suffered because that would changed how the car's weight transfers during corning.

Putting a stiffer sway bar changes the balance. A stiffer sway bar in the front increases understeer, while adding one in the rear, or making it stiffer, increases oversteer (or decreases understeer depending on the car).

As someone else already wrote, messing with suspension can ruin your car's handling. Don't think you can just start slapping on parts and end up with something great.

Pete