Rogue Engineering Racebrace

[Hermes]

Anybody have this/opinions? I'm thinking of this strut brace for my car. Looks nice and sturdy/well built. $319 for E46



http://www.rogueengineering.com/rogue/StrutB/RE_RB.html

[M0nk3y]

Anybody have this/opinions? I'm thinking of this strut brace for my car. Looks nice and sturdy/well built. $319 for E46



http://www.rogueengineering.com/rogue/StrutB/RE_RB.html

If you don't have stiffer sway bars I'd suggest throwing the money towards that first. Strut Bars offer little to no gain

[Hermes]

I was gonna do that at the same time, just trying to get some ideas so I can come up with a list of what I want to get. I have some slight mushrooming on the right tower, only reason I'm starting to look

[blablac]

The brace I would get if I didn't get my hands on the performance brace. That thing is bound to stiffen up the front end quite a bit. Nothing fancy but solid design for sure.

[zj96sc]

Ahh rogue engineering....not telling the whole story.

I like their little bit on coefficients of thermal expansion...

Since the heat of an engine compartment can exceed 200ºF, this would cause an aluminum or magnesium center bar to start expanding. Simply switching the center bar to steel would cut the variation by nearly 50%. Of course, switching to carbon fiber would make the expansion virtually immeasurable.

Probably would be more professional of them to actually run the numbers instead of using some fancy words and leaving the analysis incomplete.

If you actually go get the equations for linear thermal expansion, you'll find this:

(delta)L = alpha * L(naught) * (delta)T

Where alpha is your coefficient of linear expansion and L(naught) is the length of the (cold) strut bar.

so...assuming ambient of 70F and a strut bar length of 36" for the sake of analysis, substituting our values, you get:

(delta)L = (12.3x10^-6) * (36) * (130)

Gives a total expansion of .06" whereas steel still would expand about .03". There's vastly more flexibility than this even in just the control arm bushings, let alone the remainder of components in the system plus the chassis flexibility itself.

Anyway.....just didn't want their engineering quick tricks to fool anyone into thinking they've built a superior product.

Paul

[danewilson77]

Looks great Hermes. Buy it.

[Hermes]

Ahh rogue engineering....not telling the whole story.

I like their little bit on coefficients of thermal expansion...



Probably would be more professional of them to actually run the numbers instead of using some fancy words and leaving the analysis incomplete.

If you actually go get the equations for linear thermal expansion, you'll find this:

(delta)L = alpha * L(naught) * (delta)T

Where alpha is your coefficient of linear expansion and L(naught) is the length of the (cold) strut bar.

so...assuming ambient of 70F and a strut bar length of 36" for the sake of analysis, substituting our values, you get:

(delta)L = (12.3x10^-6) * (36) * (130)

Gives a total expansion of .06" whereas steel still would expand about .03". There's vastly more flexibility than this even in just the control arm bushings, let alone the remainder of components in the system plus the chassis flexibility itself.

Anyway.....just didn't want their engineering quick tricks to fool anyone into thinking they've built a superior product.

Paul

Interesting, i was hoping to get some sort of answer like this didn't know how soon it would be. So then you're voting no?

[zj96sc]

Not at all...I just didn't want you to feel like they're engineering their products harder than someone else. It gave me a smoke and mirrors feeling to the point that I just wanted to prove that particular design choice isn't such a big deal.

I'd find the cheapest steel non-hinged bar that picks up all 3 bolts and call it a day. If that's RE, then that's RE.

Good luck!

[Hermes]

Cool, good to know and thanks again Paul. I wasnt looking at it as if RE's are significantly better than anybody else's product, i just was looking at it from the standpoint (non-engineer) of it having a beefier setup than say a straight bar. Price (as long as its reasonable and similar to the others) isn't really an issue, but then again I'm not gonna go spend $1k or more for the BMW Performance CF bar. The OEM M3 bar is about the same price, I think maybe $40 more. Just trying to get some ideas.

[zj96sc]

As another engineering tidbit, the best resistance to pure compression (tower tops moving towards each other) you're going to get will actually come from a single straight tube in the center of the applied load. This is why racing roll cages are usually a lot of straight tube (within design constraints, anyway). In this application the single straight tube will work well in compression too, better than a fancy truss or bent bar anyway.

All of this is easily lost within the noise for this application - like I said above, pick one that suits your price range while picking up all 3 strut bolts to protect from shrooming and go for it.