2g carbon fiber strut tower brace

[m_0ney_pit]

Does anyone make a carbon fiber front strut tower brace for the 2g?

 

[ViciousLord]

depends, do you want a functional piece or just for looks?

a proper strut brace is one solid piece... does anyone make solid CF brace, no.

Now I have seen CF braces with hinges around the mounting plates.

 

[gixrman]

Most braces I believe are made out of tubing. Tubing is strong enough. Here are some examples and some CF ones. $$$
Rogue Engineering Carbon Fiber Strut Tower Brace - Rogue Engineering specializes in high performance upgrades for BMWs.

 

[m_0ney_pit]

I was interested because of the possible weight savings wasn't really thinking about performance. I was thinking if I'm adding something something that could add 15-20lbs wanted to check if there was a lighter alternative.

 

[bryanwheat]

I was interested because of the possible weight savings wasn't really thinking about performance. I was thinking if I'm adding something something that could add 15-20lbs wanted to check if there was a lighter alternative.

That aluminum ones are probably 5-8 lbs total. A carbon fiber brace wouldn't really be that strong compared to a metal tube brace and would be kind of pointless.

 

[ViciousLord]

I was interested because of the possible weight savings wasn't really thinking about performance. I was thinking if I'm adding something something that could add 15-20lbs wanted to check if there was a lighter alternative.

15-20lbs?

 

[lowell]

Tower bar made from solid bar stock?

 

[m_0ney_pit]

Tower bar made from solid bar stock?

Thats a great idea, Unidirectional Carbon Fiber Tubing - Unidirectional Composites - Rock West Composites

I may buy a cheap adjustable rod-type bar on ebay for the links and mounts and then just swap one of these stock CF rods for the steel or aluminum to fit. Thanks for the idea!

 

[Pipnorcali]

Mine is about 5 lbs or less

 

[BadAss4Bangers]

Why don't you just get a real tower brace that's functional and wrap it in fake CF? There is no way that CF would hold all that tension if you actually wanted functionality.

 

[m_0ney_pit]

Why don't you just get a real tower brace that's functional and wrap it in fake CF? There is no way that CF would hold all that tension if you actually wanted functionality.

No thanks...

Anyway, some properties

Carbon steel
Tensile strength - 840 MPa
Density - 7.5 g/cc

Aluminum (T6, no most companies probably won't use this)
Tensile strength - 480 MPa
Density - 2.6 g/cc

Carbon Fiber
Tensile strength - 1600 MPa
Density - 1.7


Besides the fact that CF has twice the tensile strength of carbon steel, a hollow tube that is 1.5" Diameter with wall thickness of .12" and length of 3' will weigh about 5lbs in steel, 1.7lbs in Aluminum, and 1.1 lb Carbon fiber. Please check this to verify for yourself.

Now will the aluminum bar be hollow, no probably not it will most likely be solid so the weight would be closer to 6 lbs. Also the elastic modulus is very close to steel with the fiber direction.

 

[m_0ney_pit]

15-20lbs?

your right , I was way off .

I think my plan is going to be a 1" CF rod with adjustable stainless steel end pieces and either stainless rings or a donuts to tie it onto the towers.

 

[BadAss4Bangers]

No thanks...

Anyway, some properties

Carbon steel
Tensile strength - 840 MPa
Density - 7.5 g/cc

Aluminum (T6, no most companies probably won't use this)
Tensile strength - 480 MPa
Density - 2.6 g/cc

Carbon Fiber
Tensile strength - 1600 MPa
Density - 1.7


Besides the fact that CF has twice the tensile strength of carbon steel, a hollow tube that is 1.5" Diameter with wall thickness of .12" and length of 3' will weigh about 5lbs in steel, 1.7lbs in Aluminum, and 1.1 lb Carbon fiber. Please check this to verify for yourself.

Now will the aluminum bar be hollow, no probably not it will most likely be solid so the weight would be closer to 6 lbs. Also the elastic modulus is very close to steel with the fiber direction.

Facts are true. This is my view on it from my research, whether its true or not:

CF has a bunch of strength but CF is weak when it comes to compression\tension which is what a strut bar is fighting to do. Im sure it will work and perform better than stock but, not better than steel or aluminum, steel would be ideal for functionality. Your best bet would be to have an aluminum core with real CF wrapped around it if you really want the real CF look and it will be a tiny bit lighter.

 

[m_0ney_pit]

Facts are true. This is my view on it from my research, whether its true or not:

CF has a bunch of strength but CF is weak when it comes to compression\tension which is what a strut bar is fighting to do. Im sure it will work and perform better than stock but, not better than steel or aluminum, steel would be ideal for functionality. Your best bet would be to have an aluminum core with real CF wrapped around it if you really want the real CF look and it will be a tiny bit lighter.

I see what your saying, when the piece is in tension ( tensile strength) we want a low strain to make sure the towers are tied together and the camber stays the same. When the piece is in compression we want a high flexural strength to make sure there is no deflection right? ( so the bar stays where you have tension it to)

Why would steel be ideal? So it can have high strain probably on the order of 0.5mm under high load? Wrapping a metal bar with CF would only help flexural strength.

Can a suspension guru help me out, maybe I'm not understanding the priniciple of this bar right. Isn't a strut bar supposed to work in tension?

 

[ACM]

The weave and layup determines the loading capabilities of a CF part as much as anything else.

F1 suspension arms have been CF for ages - they are subjected to their fair share of compressive loads and survive quite happily (in the short term).

CF strut bars for DSMs would be a perfectly acceptable example of ridiculous overkill - at a bare minimum they would be at least as effective as the multiply-hinged examples found floating around, particularly the staple-shaped one sold by Neuspeed...

 

[jtmcinder]

When the piece is in compression ...

Remind me again as to when this actually happens, please.

 

[ACM]

When the outside wheel kisses the wall from running too high on the banking ?

 

[DirtyDSMDan]

a strut bar is in compression right after a corner under hard g's. think of the unibody of your car as a roll cage, when you turn to the left real sharp at speed, all your weight is trying to push onto your right front tire, however gravity is still working on the left rear to attempt to bring it back to the ground, while this may not seem like a whole lot, it will cause your car to flex, pulling the two towers apart, once you enter the straight, the car settles down and the towers come back together... this is compression. a strut bar has to deal with stretch and compression, but also twisting that occurs when the frame starts to bend under extreme loads. Carbon Fiber strut bars do exist, and work well, however when you are talking about a 3000lb awd car, the weight difference between a steel strut bar and a cf strut bar is miniscule, maybe a pound? but the price difference will be huge, mostly because a high qualiy strut bar is what would make a difference, and that would be extremely pricey.

 

[H@xtGSX]

Carbon fiber is strong parallel to the fiber, compression or tension. Unidirectional fiber takes advantage of this fact. For example, some garbage truck axles are made from unidirectional CF spun axially as the shaft would turn and load applied. Why? Not for weight. Those trucks were snapping solid steel axles. The CF spun correctly made the steel look like a toothpick being compared a 2x4 strength wise. CF is just plain stronger if oriented parallel to the direction of force... By a lot.

A unidirectional fiber CF tube, or possibly a long fiber chop rod, will be stronger than steel if designed for the load encountered. It will be lighter also. Even the ring tying the strut bar to the tower could be CF if the loads were taken into account. The problem would be that if you were to have someone such as myself custom make you something like this, between the structural analysis and load engineering for the fiber layout, and the layup with vacuum bagging, your CF strut tower bar would cost you more than you can probably sell your car for.

Every CF brace commercially sold I have seen marketed publically as "racing equipment" has been poorly designed at best. They are mostly cosmetic. A real brace like what you want would likely cost a minimum of 10x the BEST brace you can find. CF is EXPENSIVE. The raw material is extremely expensive! I know, I buy it, and it can easily cost $50+ a linear foot for good cloth and $1400 for a single unidirectional spindle of tow. On top of that, right now, there is a shortage of CF anyhow. Suppliers are charging a fortune for basic forms of CF. Things like real CF hoods are going up in price, and quick. The fiberglass hoods with a single layer of CF plastered of top to make it a "Carbon Fiber Hood" aren't getting much more expensive, because you aren't really buying pure CF. A real complete CF hood from a company with an existing vacuum mold of what you want could easily cost well over $1000, if it is kept thin.