Gopher pretty much nailed it.

However:

1. The strut bar weighs 3.95lbs

2. The mounts are slotted to allow for a little movement during install because the studs are not straight up and down relative to the plane of the bar, and when measuring the distance between towers for the initial design we always used the cars on the ground. Leaving the car on the ground to install is the same as pre-loading the bar. And as Gopher said, we designed it solid for a reason, because it is extremely effective. So much so that it has a noticeable decrease in low speed NVH, which is attributed to it's stiffness:

https://www.grimmspeed.com/product_i...ace_14_635.jpg

This shows the cyclic nature of the movement between strut towers. They move both towards each other, and away from each other. So being able to adjust preload to push the towers against each other starts to make less sense compared to simply locking them together.

Chase
Engineering

I see - makes sense thanks!

8lbs, 3lbs, whatever lol.

I know nothing.

Just got my GrimmSpeed strut bar today, is there a specific torque setting for this or just until tight? Want to make sure I do it right

Yes, it's the same torque as the factory value, 12 ftlbs. It's also right there in the installation guide for this product: http://www.grimmspeed.com/content/in...ne_version.pdf

Most large torque wrenches won't be very sensitive/accurate at 12ftlbs, so you need to be very careful, as you do not want to break those studs.

Chase
Engineering

I am curious why the Grimmspeed bar is so different from all others. Other bars hold the top three studs on top of the struts. The one is attached by the studs for the diagonal bars. This will make the bar lighter for sure, but grabbing the three studs might provide more rigidity. Does it make sense?

Quote:

Originally Posted by qqzj (Post 3283125) I am curious why the Grimmspeed bar is so different from all others. Other bars hold the top three studs on top of the struts. The one is attached by the studs for the diagonal bars. This will make the bar lighter for sure, but grabbing the three studs might provide more rigidity. Does it make sense?

No.
The clamping force exerted by the two diagonal bar bolts is enough to tie the two towers* together. That is, using the three bolts you've suggested is superfluous.
See this thread for development.



*No relation to Tolkien

With that being said, how would you rate the STI tower brace? It uses more bolts + has the damper in the center of it.

Or is it just for +JDM points?

Disclosure: I am not an engineer and maybe STI has done the analysis but that strut bar offends my sensibilities. Why would you want a flexible strut bar? Yeah, it is "longitudinally mobile while helping laterally stiffen the body of the car." but it sounds like 100% marketing wank to me.
And yes, my position is totally unsupported by testing.

The same could be said for the flexible v-Braces that come in the tS, yes?