strut braces
 

got some questions on struct braces. i know that there are differing opinions on these, some say they help, some say they don't. some say they help if on sticky tires, some say only after your car gets tired and loose, etc. i ask as, anytime my car spends any time on jack stands, it gets all out of whack. top won't close, trunk won't close, etc. cleans up when back on it's feet, but it speaks to rigidity of frame (or lack thereof).

so, looking at options. there are carbon products and hollow aluminum products, but nothing solid and nothing steel. would carbon or hollow aluminum do any good, as i could see carbon and hollow aluminum being ok for tension but no good at compression? seems steel or solid aluminum would be best ...

IMO, only the addition of a front strut brace is a worthwhile upgrade . Worthwhile meaning it does a great job of tightening up the cowl and soft top to the extent that it reduces some squeaks and creaks . Does nothing for handling however. A light weight one piece aluminum is my recommendation.

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I doubt it would help your issue, since convertibles obviously flex across the driver's compartment, with no stiffening from a roof structure.

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RK my 2000 S with 102K miles doesn't flex anything like yours & I assume yours didn't when new so maybe the great white north & the roads there you have mentioned have caused unusual wear &/or damage. Sounds like a through 30min + underbody inspection is in order. I don't see how a strut brace could hurt. Aluminum tube is probably safest bet.I do have a Technobrace from Pedro that seemed to help lateral rigidity.

I have light weight aluminum front (only) strut braces in both cars (987S and 993 Turbo). Both cars exhibit very sharp and crisp turn in. No creaks and squeaks. I've always had the strut braces, so I can't really compare to a car without.

Cost is less than $200. Easy to install (remember....24-25 ft. lbs. torque on the strut bolts) and takes less than an hour.

I'd say the front strut brace helped in every respect you mentioned. I have aluminum material and love it.
Have/had braces in my other cars over the years as well and results were practically the same, nothing negative to report.

OK I'll be the voice of reason. The Boxster already has a strut brace built in AND the towers are pretty much braced by the bulkheads at front and rear. Anybody who thinks that adding a flimsy piece of carbon fibre or hollow aluminum is improving their car is just kidding themselves. If you want to stop the scuttle shake then install a full roll cage that picks up the A pillars and reinforces across the knee bar.

i'd agree with you except that, from what i've read, a proper bracing design is actually a triangle; each strut tied back to the firewall on a diagonal such that they meet at a common point, and then a third member tying the two struts together. the boxster has the tiebacks to the firewall, but doesn't have the member tying them together and relies on the integrity of the frame. i agree than a thin bar isn't going to do much on compression, but will work on tension and perhaps provide some benefit. regarding the rear bar, uncertain if any benefit at all, as there appears to be a lot of structure there already.

Stiffer is not necessary better.... If that's the case we'd all go for the thickest sway bars and coilovers and turn them to the stiffest setting for better turn-in, etc.

From what I understand, in a hard turn the force causes the strut towers to move away from each other, leading to loss of negative camber. This is particularly strong on the outside tire, which needs all the negative camber it can get to prevent rolling onto the side wall. The brace keeps the towers from spreading, preserving the negative camber.
On my car, before I had the brace, I noticed that the "caulking" around the strut towers was beginning to crack. Since I've had the brace, the cracking has not worsened.

I'm lost as to what you think this tensional improvement a brace is going to make that the reinforced bulkhead in front of the battery that ties both strut towers together is not already. THis is particularly true if you imagine it as a massive U section made by the front bulkhead, the horizontal plane over the tank and the secondary bulkhead in front of the dash. Even that U section has a braced top made by the substantial steel braces producing an effective box section. Interestingly I would have said that the front structure is considerably stronger than the rear and I would not concern myself about either. My SpecBox has neither front or rear ties (because we are not allowed too) and I do not consider it to lack any structural rigidity.

Having said that, if it would make you feel better it certainly can't make it worse. I simply see it as a waste.

Interesting anacdotal evidence but I just looked at my SpecBox and mine (which I'm sure takes a greater beating than any street car) has no cracked caulk. Nor does my GT3 or my 01 996. The 996 was a club racer for 2 years without a full cage (in the days when that legal).

i guess the strut tower brace spreading issue is supported by the tension vs compression idea - thin aftermarket braces would combat towers spreading much better than they could withstand towers trying to come together. also supported by what i've seen on my car - on jack stands the strut towers appear to be spreading - shoulders drooping - as the front fenders are sitting lower than the trunk; this goes away when on the ground. variation between cars may be due to age = metal fatigue, driving surface, suspension stiffness (ie., how much force transferred to the chassis) and the witches brew that results when you combine all these factors.

As I said a brace can't do any harm. Particularily if the car is really spreading by being jacked up!!!!!

Has your car ever been crashed? I have had my car on stands and on a lift and never had a problem opening and closing doors. I know of one 993 Carrera cabrio that had enough flex to prevent the doors from opening when it was on a lift. My Boxster is not like that.

not that i know of. doors will open and close, i just see the gaps change when wheels are not loaded for long periods of time (note that it has been on stands for almost two months, and that i drive on heinous northern roads that can deliver some big hits).

This thread is about body,tub,frame etc where you want to eliminate deflection so stiffer is better.

Lot's of folks in the BMW world swear by strut braces, and on a McStrut car like we have and the BMW's, it makes some sense.

However, it looks like Porsche already saw this need, and my 986S already has a brace from each front strut tower going back to the bulkhead.

Still, if I found one like this one on my M3, I might add it on: