E30 Zone

Just wanted to know who does a larger anti roll bar set up for a 325i. I use the car for road rallying it already has bilstein dampers but i would like to sturdy it up a bit when it is sideways.

H&R, whiteline and eibach all do them AFAIK.

alternatively, you could make sure you have the thickest BMW ARB's available. sport rear and 325i cab front.

you can drill the front ones and increase the pre load on them

I use Whiteline, 24mm front, 16mm adjustable rear. Get a set of Ireland Engineering Rear Bar Mounts, and make up your own solid adjustable end links with rod ends.

We offer the Eibach kits:

http://www.raceperformancemodified.com/ ... B_Kits.asp

Let me know if you need anymore info on them

jimmy@raceperformancemodified.com

I would look at springs 1st..

Question on the ARB issue.

Is the thickness the be all and end all of them, or do some of the manufacturers use materials that perform better than thicker standard items?

NOOb, I reckon the biggest issue would be the differences between manufacturers who produce hollow bars and those who do solid ones.

Cheers guys, i forgot that im using 325 sport springs, as i dont want to lower the car as such. I am basically trying to get the car to stop leaning quite so much when pushing it hard. Thinking of converting the front legs to coilovers, any suggestions on any uprated rear springs?

We can offer the GAZ golds for track use, available with rear coilover or inboard rear springs. Spring rates can be whatever you like or we can advise:

http://www.raceperformancemodified.com/ ... r_Kits.asp

I have a 19mm rear on mine, For drifting it's grate, but for rally I would have thought softer would be better.

AdamGardner wrote:Cheers guys, i forgot that im using 325 sport springs, as i dont want to lower the car as such. I am basically trying to get the car to stop leaning quite so much when pushing it hard. Thinking of converting the front legs to coilovers, any suggestions on any uprated rear springs?

Custom springs as I said.. Fatter ARB's will compromise other areas, such as traction

Jhonno wrote:

AdamGardner wrote:Cheers guys, i forgot that im using 325 sport springs, as i dont want to lower the car as such. I am basically trying to get the car to stop leaning quite so much when pushing it hard. Thinking of converting the front legs to coilovers, any suggestions on any uprated rear springs?

Custom springs as I said.. Fatter ARB's will compromise other areas, such as traction

As in the car will pick up an inside rear more easily, or are there other effects?

Pick up either inside wheel.. It will unload the inside wheel more, over bumps, it makes the suspension almost less independent..

Thicker (or stiffer) ARBs only compromise traction IF the suspension is too soft AND there is no LSD fitted...

You wouldn't really want to put stiffer ARBs on a car with standard suspension, really...It will stop it rolling more and help in the initial turn-in, but it also will make the car feel very oversteer biased on exit, especially under power...

However, if you have uprated your springs (and dampers) and the car is lower than standard, then stiffer roll bars will help in reducing the roll without compromising the ride too much. Of course you could just stiffen the suspension even more, but the ride tyhen does get compromised and you may still have issue with a rear wheel lifting and, therefore, reducing traction.

On RWD cars, it is generally accepted that the rear roll stiffness should be less than at the front. ie: You want a stiffer/thicker front bar to a rear one...

You also can acheive the same result in a better way by lowering the centre of gravity of the car...that means getting rid of as much weight as possible and the higher up that weight comes from, the better...So removing the sunroof, fro example, has more benefit than fitting alloy control arms (for controlling the roll centre).

Fushion_Julz wrote:Thicker (or stiffer) ARBs only compromise traction IF the suspension is too soft AND there is no LSD fitted...

No.. The effect is more noticeable, but it still reduces traction. An LSD has very little to do with it, especially front end grip...

You wouldn't really want to put stiffer ARBs on a car with standard suspension, really...It will stop it rolling more and help in the initial turn-in, but it also will make the car feel very oversteer biased on exit, especially under power...

Compromised traction.. The balance of the car will remain the same unless you change the ratio of arb effect front and rear

However, if you have uprated your springs (and dampers) and the car is lower than standard, then stiffer roll bars will help in reducing the roll without compromising the ride too much. Of course you could just stiffen the suspension even more, but the ride tyhen does get compromised and you may still have issue with a rear wheel lifting and, therefore, reducing traction.

Stiffer springs will NOT encourage the inside rear wheel to lift

On RWD cars, it is generally accepted that the rear roll stiffness should be less than at the front. ie: You want a stiffer/thicker front bar to a rear one...

Correct

You also can acheive the same result in a better way by lowering the centre of gravity of the car...that means getting rid of as much weight as possible and the higher up that weight comes from, the better...So removing the sunroof, fro example, has more benefit than fitting alloy control arms (for controlling the roll centre).

Aluminium control arms benefit the car's unsprung mass..

Removing weight from the car will require lower springs to be fitted or else the centre of gravity will raise with the suspension and will end up rolling over in corners like you are trying to avoid

djs325 wrote:I use Whiteline, 24mm front, 16mm adjustable rear. Get a set of Ireland Engineering Rear Bar Mounts, and make up your own solid adjustable end links with rod ends.

Oh i like the sound of making my own adjustable arb with trackrod ends. I there a post on this anywhere?

N00b wrote:Question on the ARB issue.

Is the thickness the be all and end all of them, or do some of the manufacturers use materials that perform better than thicker standard items?

Yeah thickness is massively more important.

Torsional stiffness is proportional to the Shear Modulus of the material but also Diameter to the power of four. Shear Modulus doesn't vary much for different grades of steel either.

Stiffer ARBs can only reduce the grip an axle produces compared to the to the other axle. The front to rear balance. They don't really alter weight transfer a noticeable amount. They do improve driver confidence though as the body doesn't wobble around all over the place.

not really read the thread but has anyone else mentioned thicker bars can crack the mounts?

djs325 touched on the problem with the mounts when he mentioned the IE mounts.

The trailing arms have a tendancy to bend where the ARB mounts to it when you stick a thicker one on and the mount on the cross member can break/crack/bend etc.

Have a look at this thread for a fantastic detailed look at the bits that can be a problem.

Clicky Clicky

Cheers
Chris

My H&R roll bars bent the mounting tabs.. I have plated my new arms to stop this happening again

It doesn't take much to reinforce the mounting tabs if your handy with a mig, drill and grinder, and as we work on e30's that love to rust, you should be already

it will be more save

Jhonno wrote:My H&R roll bars bent the mounting tabs.. I have plated my new arms to stop this happening again

So far I haven't had any problems with my H&R Arbs bending tabs.
Maybe the stiff springs help by reducing body roll in the first place so the ARB hasn't to work too hard?

I think that is the case.. Mine were working harder due to more roll!

AdamGardner wrote:Just wanted to know who does a larger anti roll bar set up for a 325i. I use the car for road rallying it already has bilstein dampers but i would like to sturdy it up a bit when it is sideways.

Harder durometer Bushes for the suspension and subframe.
This will make the car more stable by removing unwanted steering.
Higher rate springs (Non lowering) to control roll and landings.
These will provide more roll resistance and keep the desired independent suspension.


Larger sway bars...those advising against, have it.

Pick up some reading on competition car suspension.

m