Schnell Rear Strut Brace problem

[eslai]

Originally Posted by JackG

Overall the brace kit looks fairly well made, but the brackets that bolt to the struts seem a little wimpy. They are flat plates with welded-in studs for the spherical joints to bolt on. The joints fit over the threaded portion, then just wedges onto the unthreaded portion. It then sits about 1/2 - 3/4 inch above the plate, which seems to give the stud a chance to exert a good bit of force on the plate, possibly flexing or ultimately cracking/breaking the weld. Maybe not, but time will tell.

Unfortunately I've seen this sort of problem on many strut tower bars out there. Many of them are not engineered properly and will do nothing to prevent flex.

I've also kind of fallen off the strut tower brace bandwagon. There really doesn't seem to be that much bang-for-the-buck in most of the cars that I've played with this on, but perhaps the boxster is different.

Take for instance my eclipse. We removed the strut tower bar and then did some flex comparisons. We jacked up each corner of the car and measured deflection of the rear hatch area, front engine compartment and cabin. In stock form there was very little flex at all. Adding bars in did little to alleviate what little flex we had measured.

The only real way to strengthen a car's structure is to brace the chassis with a roll cage which of course, is a little invasive. Reedy little bars tacked to the strut towers just don't do as much as they're touted to do, no matter what the butt tries to tell you when you're driving.

Strut tower bars will tie the two sides together but they'll still deflect and since the bar isn't braced in a plane (in most cases--sometimes you'll see the ones that also connect to the firewall) it'll still shift front to back.

Again, I don't know--perhaps the Boxster is different, but then the age old argument for this sort of statement is the following:

If all it took to radically transform the handling of your car for the better was to connect a bar across the top of the strut towers, why didn't Porsche do it themselves?

If the improvements are repeatable and demonstrable, you'd think Porsche would take heed. At the very least I'd expect to see it as an option.

[MNBoxster]

@ESLAI,

Hi, while I don't necessarily disagree with you out-of-hand on all points, I'm not really certain what your Ad Hoc test really proved. It's probably safe to assume that one would expect the Car's chassis to accept it's own weight, whereas in Real-World application the added inertia from maneuvering can increase the weight greatly, possibly in Factors of the Vehicle's actual weight. This is where a Car's Rigidity is challenged.

Preventing the Strut Towers to oppose, or move independently of, each other does have an effect toward stiffening the Chassis because the Strut Towers will move Mostly laterally and the Bar will prevent this. Admittedly there is also some Fore and Aft movement, but there are additional braces on the Car's underside to help minimize this. Assuming some still remains, at least you've eliminated some part of the equation and that is worthwhile.

Also, tying the two Towers together effectively completes a circle with the Floor (chassis for all intents and purposes on a Uni-Body Car) which can then absorb (oppose actually) the forces imposed on it by the maneuvering suspension. And the suspension on that axel acts much more in unison while still preserving independent action.

I agree there are some Cars out there which do not benefit from such bracing, but for the Boxster I consider it most complimentary. I also agree that a Full RollCage adds even further Rigidity.

My own Ad Hoc test with the Braces showed positive results. I live on a twisty road and there is a very tight HairPin turn .5 mi. from my house. I have lived here many years and know this turn like the proverbial Back of My Hand. Over that time, this HairPin has served as sort of an Acid Test for all my Cars. Prior to adding the Front Brace alone, I could take this turn at 38MPH before the Rear got skittish, Tires squealing, etc. After the Front Brace, I raised the Bar to 43MPH. After the Rear was added, I could go through this turn at 52MPH before teetering on the edge. And, virtually all the annoying creaks, groans, and rattles are gone - something good is going on here...

Happy Motoring!... Jim'99

[eslai]

Well, perhaps i didn't describe our (admittedly off-the-cuff) testing very well. We jacked up the extreme corner of each car--not at the jacking points on the sides. We jacked them three feet in the air in fact. Certainly the car can support its own weight, but the amount of torsional force we were applying certainly went outside of the realm of what the car was designed for.

However, this was on a coupe, and so I'll defer to you on this one. I agree that putting strut tower bars on the boxster would help give a bit of a "lid" to the "shoebox", so to speak, but i'm still hesitant to say how much it would help. Again, why no option for this sort of thing from Porsche themselves?

I've seen it time and time again where people want to believe a modification helped them when in reality it just gave them confidence to exceed their personal limits. I'm not saying that you're full of it or anything, just that without formal testing I am always very hesitant to accept any sort of car modifications.

In spite of all of this talk, I DO have front and rear strut tower bars on my Eclipse. I just don't put much faith in them. The fact that they cost me less than $200 together and are about as solid as they can possibly be makes me not worry about it too much. Of course, next to the $4000 or so I spent on suspension tuning and R&D, one could say that the benefits of the strut tower bars could be masked--hard to say. I haven't been all that scientific in my testing either, I suppose.

I've been considering a front stut tower bar for the 987 and that racing dynamics one seems like a valid candidate, but geez, it's $300!

I have just the right turn to test it out on too, much like you do...

[threpwood]

I'm convinced so I'm getting the Racing Dynamic front strut and Weltmeister rear strut. Hopefully can install it next week. Will post how the car handles after installation.

[BobMarley1]

Toolpants - do these work?

[MNBoxster]

Originally Posted by BobMarley1

Toolpants - do these work?

For the greatest benefit from both Braces, you really need them both. But, I would start with the Front Brace and you'll be convinced to add the Rear. Hope this helps...

Happy Motoring!... Jim'99

[threpwood]

Installed the front brace today. Got me 30 minutes installing the stuff because I ended up wiping the dust off of the plastics, etc

Absolutely an improvement in handling. Not only that , it also eliminate the squeeky sounds coming from the front. Can't wait to put the rear one

[cs9314]

I've read this entire thread and so far, I've installed the front RD brace, no problem (it came with instructions). I won the rear Schnell bar in an auction at Porsche Palooza but like others have stated here, it came with zero written instructions.
An e-mail to Schnell has turned up zip as well. Can anyone supply at minimum a picture of one installed? At best, some written instructions for some one of "smarter than the average bear"intelligence? I had the engine cover of mine yesterday, as well as pulled up/down most of the liner in the rear storage area as I was doing my routine oil change and spark plug change. I couldn't see or find the mounting bolts to attach the darn thing to. Did I not go far enough in removing items?

Thanks for any guidance from others who have walked this path ahead of me.

Carl

Originally Posted by cs9314

I've read this entire thread and so far, I've installed the front RD brace, no problem (it came with instructions). I won the rear Schnell bar in an auction at Porsche Palooza but like others have stated here, it came with zero written instructions.
An e-mail to Schnell has turned up zip as well. Can anyone supply at minimum a picture of one installed? At best, some written instructions for some one of "smarter than the average bear"intelligence? I had the engine cover of mine yesterday, as well as pulled up/down most of the liner in the rear storage area as I was doing my routine oil change and spark plug change. I couldn't see or find the mounting bolts to attach the darn thing to. Did I not go far enough in removing items?

Thanks for any guidance from others who have walked this path ahead of me.

Carl

Hi Cs9314, maybe this old thread, with pictures, will assist your effort:

http://www.986forum.com/forums/showthread.php?t=4912&highlight=strut+brace

[cs9314]

Man do I feel stupid! As soon as I saw the 1st picture, I realized how close I was and how easy it should have been.
Thanks, that thread solves the mystery for me.

Carl