Does a front tower brace make a difference?

[Jennshark]

I'm sure this has been asked before, but my search function isn't working well.

I'm a track amateur and will graduate to "rookie" this summer. I'm wondering if a tower brace really makes a positive difference in a 330ci.

If so, is there an appreciable difference between an expensive one like Dinan and a cheaper brace? Thanks.

[Oli77]

I am not even a track amateur and felt a difference. Make sure bar is solid with no articulation.

[Reasoned1]

It's minor, but I notice a difference--I have a favorite, tight on-ramp that I can better handle--less body roll--with the strut bar installed (ECS/Turner carbon-fiber). I put one on each of my cars.

[cornercarver]

It has been debated many times on various forums.

I saw an article (linked on ZHPMafia I think) in which they measured the distance between the strut towers and concluded the displacement was only a millimeter or two. IIRC, it was also done on a track, where stresses are usually higher than street-driven cars.

Conversely; Those German engineers are pretty damn smart, and if BMW added it to the M3, it must do something.

I would have added one but haven't because;

1) I can't find a good one which is reasonably priced and meets all of my needs
2) Most are fixed and therefore cannot accommodate camber adjustments without modification.
3) Most are bent, and as any structural engineer will tell you, if it is bent it provides less rigidity than something straight.

-Just my two cents.

(Edit) Found the link (http://news.bimmerworld.com/is-a-strut-brace-worth-it/), and correction; the delta was actually only 0.7mm at the highest stress point.

http://www.zhpmafia.com/forums/attachment.php?attachmentid=32370&stc=1

[slater]

Make sure bar is solid with no articulation.

agreed.



3) Most are bent, and as any structural engineer will tell you, if it is bent it provides less rigidity than something straight.

yep.

i am running a $90 ebay bar that is straight, rigid and fits OK.

[Oli77]

Graphs above are really interesting thanks for posting empirical data.

I think the greatest deflection is actually > 1 mm in all. Should consider the deflections towards each other and away from each other (towers), so that's -0.55 to + 0.65 ~= 1.2 mm. Might not be that much when you think of the forces involved and the rigidity of the chassis, but it is nevertheless impactful.

[ZHPizza]

It has been debated many times on various forums.

I saw an article (linked on ZHPMafia I think) in which they measured the distance between the strut towers and concluded the displacement was only a millimeter or two. IIRC, it was also done on a track, where stresses are usually higher than street-driven cars.

Conversely; Those German engineers are pretty damn smart, and if BMW added it to the M3, it must do something.

I would have added one but haven't because;

1) I can't find a good one which is reasonably priced and meets all of my needs
2) Most are fixed and therefore cannot accommodate camber adjustments without modification.
3) Most are bent, and as any structural engineer will tell you, if it is bent it provides less rigidity than something straight.

-Just my two cents.

(Edit) Found the link (http://news.bimmerworld.com/is-a-strut-brace-worth-it/), and correction; the delta was actually only 0.7mm at the highest stress point.

http://www.zhpmafia.com/forums/attachment.php?attachmentid=32370&stc=1

I think I remember reading through that report just fascinated by the results....and then someone pointed out that the car had a welded in roll cage...so uhh it's a lil stiff already.

[Oli77]

^ that would be a real important piece of information to know indeed!

[cornercarver]

I think I remember reading through that report just fascinated by the results....and then someone pointed out that the car had a welded in roll cage...so uhh it's a lil stiff already.
Good point. I hadn't noticed that, but even a fully welded cage doesn't help the front clip much unless some component of it goes through the firewall to connect the frame and strut towers.

I've been looking for a STB which ties the strut towers to the firewall. I had one on my Mustang. It was reportedly the best design because it triangulated the strut towers with the firewall which acts like a shear plane. I think it's harder to do on the E46 because the cabin air filter is in the way, at a minimum.

[Vas]

$1k BMW performance strut bar is the best.... I kid I kid

[John in VA]

$1.6k BMW performance strut bar is the best.... I kid I kid
Fixed that for you!

[joeybananaz18]

So is there a verdict out on which strut tower bar offers the most stiffness?

[ELCID86]

So is there a verdict out on which strut tower bar offers the most stiffness?
Think that would be hard to say and doubt there is much difference in them (based on design and material).

[slater]

So is there a verdict out on which strut tower bar offers the most stiffness?

straight, unhinged bars.

also, CF is the best choice as it's rate of thermal expansion is crazy low... however, CF is expensive, so steel is the next best choice. aluminum expands a lot when hot, and in the engine bay... that ain't good. so CF or steel. i bought a straight, unhinged steel bar for $80 on ebay.

[cornercarver]

I would have bought the ECS CF bar, because it’s pretty cheap for a CF bar, but it doesn’t allow access to the top of the strut when installed. I have Koni Yellows, for which I wanted to maintain access. If you don’t need access to the strut, it is probably the most cost effective option on the market.

[joeybananaz18]

I would have bought the ECS CF bar, because it’s pretty cheap for a CF bar, but it doesn’t allow access to the top of the strut when installed. I have Koni Yellows, for which I wanted to maintain access. If you don’t need access to the strut, it is probably the most cost effective option on the market.

I’m actually considering that, or the M3 bar to keep things oem.


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[slater]

I would have bought the ECS CF bar, because it’s pretty cheap for a CF bar, but it doesn’t allow access to the top of the strut when installed. I have Koni Yellows, for which I wanted to maintain access.

that's precisely why i removed my CF ECS bar and installed the steel one. :)

i actually have been meaning to list the ECS CF bar for sale, just keep forgetting. :)

[eimkeith]

I think it's important to consider cycles/repetition - .7mm during that track event; probably more seasons later (like racecars - they get flexy/wobbly with age.)

[Reasoned1]

I would have bought the ECS CF bar, because it’s pretty cheap for a CF bar, but it doesn’t allow access to the top of the strut when installed. I have Koni Yellows, for which I wanted to maintain access. If you don’t need access to the strut, it is probably the most cost effective option on the market.

That's interesting... I just bought Koni yellows. However, I don't plan to have to adjust them frequently, and the strut bar is extremely to easy to remove--either in part or entirely (which is part of what I like about it).

I didn't want to spend a fortune on a strut bar and, even though it may not be the stiffest solution possible, it makes a noticeable difference which I considered worth the cost.

[Jennshark]

You guys rock, I appreciate the discussion. I think I'll order the ECS bar I've had an eye on.

The vids I've watched make installation look relatively easy - any advice on this?

[Reasoned1]

If it's tight going on, loosen the large screw(s) connecting the bar to it's mounts.

[danewilson77]

So is there a verdict out on which strut tower bar offers the most stiffness?Most likely something from Mason Engineering or the like is stiffest.

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[Sockethead]

I've been looking for a STB which ties the strut towers to the firewall. I had one on my Mustang. It was reportedly the best design because it triangulated the strut towers with the firewall which acts like a shear plane. I think it's harder to do on the E46 because the cabin air filter is in the way, at a minimum.

The 135 is designed like this. We added a Dinan strut bar to triangulate it...