Opinions on strut tower brace? 1 link vs 3 link?
 

Finally getting to a point in my life where I can irresponsibly buy some car parts.

I've enjoyed buying and installing novel trinkets and knick-knacks. A dash cam, radar detector, UEL header, etc.

I'm curious about the effectiveness of a strut tower brace?
From an engineering standpoint, I love it.

I found a DC sports 1 link (only from tower to tower) for $85 shipped! Wow.
Then I found a local JDL 3 link (triangular brace) for $200.
$200 is likely more than I want to spend on this, but it looks like a much more impressive piece, and certainly more effective in stiffness, combining 3 links into 1 single link.

Question: Is it possible for a strut brace to be too stiff?

Anyone with experience on DC 1-link brace vs a JDL (or other) triangular brace?


Thrashed my car around pretty good going through some mountain twisties last week. 100% stock as far as suspension.
Definitely a very capable car, but always room for improvement.

Get the JDL. Heck I wish the still made that thing. AEM, Hotchkiss etc... makes $200+ braces a well. Don't always cheap out. If want a good one piece bar get GrimmSpeed!

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there is already some bracing to tie the strut towers into the main chassis. a single link tieing the 2 sides together would realistically be the only thing that would need to be added.

though i'm of the opinion that perceived additional stiffness is of the butt dyno variety.

I'm an aerospace structural engineer, and I compete with my car in time trials. I doubt that an aftermarket strut tower brace is going to do much for me in terms of measurable performance gains (i.e. quicker lap times), while taking $$$ out of my budget and adding weight (albeit a small amount) to the wrong end of the car. Only way I'd consider one is if I had *reliable* measurements of chassis stiffness before and after installation, and I had a really stiff track-only suspension (which I don't at the moment).

I say save yer $$$...

i believe the only way to measure it would be to buy a single bar brace, cut it up, and put a load cell in the middle of it to measure side-to-side force...

Grimmspeed did some deflection testing between the strut towers under load:

https://cdn11.bigcommerce.com/s-8fmm...ace_14_635.jpg

https://www.grimmspeed.com/strut-tow...ce-brz-frs-86/

The JDL bar looks cool. Seems like it was $400 brand new so $200 is a steal and you’d be able to sell it for the same amount if you didn’t like it.

I think you’ll notice an increase in stiffness, but maybe also the sluggishness from the additional weight.

Unless you are running serious g's in the corners (i.e. race slicks, firm susp., etc.) there is effectively zero "performance" gains to beefing up the OEM tower braces. That said, you might feel a change in how the front of the car feels under certain conditions, and that might be worth it to you.

I bought the AEM brace because it's triangulated, is a solid piece so there are no real flex points in the design (unlike many options on the market) and most importantly, it serves two functions at once - it has an incorporated brake master cylinder brace, which I did notice a difference with. Was $200 I think.

I got the cusco front w/ mc brace and rear strut braces. My butt dyno is not very sensitive, but definitely noticed a difference in feel. At first I didn’t really like it, but got used to it and now enjoy it. But it is more of a final mod then a first mod.

I did notice it was surprisingly hard to find the original product listing. I saw JDL discontinued it. Not sure how I feel on JDL as a company as their info is a bit sparse, and it takes a lot nowadays to decipher between the legit pro companies using engineering approaches vs some fly-by-night jokesters hocking imitation products.
Not sure why you're telling me "don't always cheap out". As far as I'm concerned, I purchased a quality 1-link bar. I'm not intimately familiar with the dozens of 'go-fast' brands, but I know DC sports has been around for quite a while, and the bar looks stellar upon close inspection.

I've browsed GrimmSpeed's website a bit. Their products seem just about as good as any other, but I do appreciate their in-depth engineering principle explanations coupled with real graphs/data, which seems to be a rarity...

Yes, my car has the 2 stock links going from the center of the firewall to the stock towers. Better than nothing, but certainly not a substitute to a direct tower-to-tower bar. I've also noticed that some vendors sell adjustable diagonal bars. Just gives an option for pre-load adjust, I guess.
Additionally, a one-piece 3-link bar would be structurally and effectively different than adding a 1-link to the 2 existing bars. Maybe slightly, but don't think they're 100% the same thing.


As far as 'butt dyno' dismissals go, I don't really buy into it anymore. First of all, the driving experience [for the driver] is really all that matters. To me, at least.
Second, there's an immense amount of feeling an experienced driver can pick up on that a novice is completely oblivious to. This is true with anything - diagnosing issues, by ear for example.
I've run a landscaping company for 10 years now, and spent wayyyy too many hours diagnosing small engine equipment. Last week, my employee was mowing a lawn 400 feet away while I was inside doing paperwork. I heard the mower stuttering slightly. I immediately knew what sound meant. I walk outside, get a gas can out of the truck, walk over and hand it to him before he even knows there's a problem. He stops, gives me a funny look and then the mower dies.
"How did you know?"
What do you mean? I heard it clear as day. When you would bank the mower left on a hill, it sputters.
"You heard it... from across the street, 3 houses away, in your living room?"

Not saying this to brag, but to say that I couldn't do that 8 years ago. Back then, I would freak out, thinking the engine was broken, and then remember 'oh right, gas'.

Same with driving. To a novice, it's just noise. An experienced driver can distinguish the signal from the noise.
Not claiming to be any sort of expert driver, but these are the things you have to do to get a feel for what's going on.
Oh pretty cool.
I'll be graduating in ~5 weeks from WVU's Mechanical & Aerospace engineering school. It's been totally different 'on the other side', after having learned proper engineering principles, mechanics of materials, machine design, etc.
You're probably right. In terms of lap time or time trials, it probably wouldn't do much. But I do have faith in the concept of adding a solid link between the strut towers, for multiple reasons.
The most obvious reason is the chassis rigidity. "The front end folding like a taco" through a turn. An exaggeration, obviously, but that's the simple description.
I think it would also make the car feel more planted/solid. Which improves driver confidence.
I also like the secondary effect of reduced NHV, since I drive this car on the highway a lot (for a few more months at least), and over some rough roads, and it's a pretty brutal car in terms of NHV. Hopefully, it will shift up the first mode of resonance.
Very minor improvements across the board, I'm sure, but I'm excited to see for myself.

Good point as well about this being less of an issue on soft suspensions. As the suspension firms up, more of that loading gets transferred to the chassis, and the chassis must respond (aka flex).

Not sure why you would cut the brace up.

There's actually a few ways to measure it. Basically just use a strain gauge measured across the strut towers.
In this thread, they don't explain exactly what's being done, but it looks like a wire under tension that's linked to a strain gauge.
http://news.bimmerworld.com/wp-conte...p-1024x768.jpg
http://news.bimmerworld.com/is-a-strut-brace-worth-it/

I suppose you could use a sort of string like they do, which I assume doesn't add any structural support.
Or you could add a strain gauge along the axis of a strut bar and see how it changed.
Yeah, I did see that. Thanks.
I appreciate them actually gathering data and organizing it in a plot.
IIRC correctly, their analysis still left a bit to be desired. Also, what produces skepticism is the Y-axis, which is measured in "thousands of an inch". The problem is, I just don't know how significant 0.002" deflection is :iono:
http://news.bimmerworld.com/wp-conte...on_VIRFull.jpg
Good point about re-selling.
'Sluggishness from the additional weight'?
Lol, I think I'm willing to risk 6lbs.

Yes.

If you are looking for a feel of rigidity, you might consider stiffer sway bars. If you already have that a strut bar might be a good add on. Or stiffer struts.

I have a fairly stiff suspension and still wouldn't add more than the factory has.

I'd recommended changing suspension bushings long before I added an aftermarket strut tower brace. The stock bushings are deflecting way more then .02 of an inch, and over a much shorter area.

^^this^^