Front strut Braces

[the baron]

Having just invested in a Hardtop it has made me realise just how much flex there is in the 986 chassis due to the creeks over bumps (Which i have now eleviated with some Gummi Pflege)

Any advice on what I  should get brace wise, is this an easy home install?

The good, bad and ugly would really help.

Thanks in advance guys

[Jason986S]

Ultra-racing make decent braces and I've not heard bad about them. They're white too

[the baron]

Ive just found this interesting article on Pelican parts that seems to suggest that they are a waste of time, makes for interesting reading:

The Porsche Boxsters are well known for their agility and superb performance in handling. However, because of the design of the chassis, there exists a weakness in the handling of the cars. The front shock towers are not well supported in the Boxster chassis: they are somewhat isolated and unsupported. As a result, the towers can bend and flex under heavy cornering. This flexing can cause detrimental changes in the handling of your car, because in general, the stiffer the chassis, the better the handling of the car. Camber strut braces are designed to maintain the distance between the shocks under heavy cornering. A bar linking the top of the shock towers insures that the towers do not bend when the chassis is flexing.

Well, that's what the marketers say when selling these bars. The strut bars are yet another controversial product that many people feel the need to install on their cars. On some cars, the early Porsche 911s for example, the installation of the strut bar is an important chassis stiffening device. Because of their rear engine design, the front chassis can be decidedly weak, particularly when rust has started to affect the chassis stiffness. But the Boxster mid-engined chassis is different: it's supported by a much more rigid frame, which includes a very strong sheet metal structure that runs the width of the car.

Which strut bars are most effective? First of all, I have little faith in the strut bars that are manufactured out of aluminum. Aluminum is not a very strong metal: you can often bend aluminum pipes with your hands. Add to that the fact that most of the strut bars must have some type of angle in them in order to fit neatly around the engine and under the hood: there's no straight shot across the engine bay. This combination creates a very weak support when you think of the forces you're trying to counteract. In my opinion, the aluminum strut braces are merely window dressing for the engine compartment.

I'm also not fond of bars with hinges built-in to the strut mounts. If they move at all, the shock towers are likely to see movement that would place the strut brace in both compression and tension. This means that a stiff connection between the strut towers is vital to proper operation of any strut bar. Any time you place a fastener in the assembly, you will introduce backlash and slop in at least one direction (compression or tension). This results in the bar becoming ineffective in at least one direction (compression or tension).

The best strut tower braces are the one-piece units manufactured out of thick steel pipe welded together. These will offer the best protection against any chassis flex when installed between the two strut towers. Unfortunately, I can't say that I've seen one installed in a Boxster that I actually thought would provide additional stiffness.

I also find it surprising that if you ask die hard racers who drive their Boxster cars on the track, most of them don't run with a strut brace, and can't even feel the difference even when pulling some significant side loads (1.4G) out of the corners. For dedicated track cars, the strut towers are often reinforced with steel pipe that is welded diagonally across the front trunk compartment. Another problem I see is that the Boxster already has reinforcement bars bolted from the shock towers to the chassis. These already provide a tremendous amount of structural support for the towers.

The bottom line? If you believe that a strut bar will do you some benefit, or you are looking to spruce up your engine compartment, then adding one to your car is a relatively simply task: simply bolt it on top of your strut towers. If your goal is increased performance, then I would probably spend your money elsewhere.

[spyderman8]

Not many of the race Boxsters have them but unless they're welded to the towers I can't see the point.

[edc]

I have a rear brace across the lower subframe. Back there it's only effectively 3 sides and no sheet metal. The point of these things is to help control the dynamic camber change. Give the suspension a solid base to work from. 

[Boxster Melbourne]

Just installed a carbon fibre strut bar on my 986 and a rear rennline chassis bar. Do not listen to the naysayers. They make a huge difference. No more convertible top moaning and squeaking. NVH is improved significantly. I think the front one made more of a difference. The front strut triangulates and complements the existing boxster 986 brace. 

[Boxster Melbourne]

Doesn't really matter what the hell you used as a strut bar as long as it's inert and strong enough post install. Shake the bar vigorously after install to ascertain if there is any movement in the strut bar components. If the vehicle moves around and the strut bar stays inert then the bar will do the job. 

[james_ly]

18 minutes ago, Boxster Melbourne said:

Just installed a carbon fibre strut bar on my 986 and a rear rennline chassis bar. Do not listen to the naysayers. They make a huge difference.

I guess the racers go on laptime only, so it might make a subjective difference but not make the car faster?

[Menoporsche]

37 minutes ago, Boxster Melbourne said:

Just installed a carbon fibre strut bar on my 986 and a rear rennline chassis bar. Do not listen to the naysayers. They make a huge difference. No more convertible top moaning and squeaking. NVH is improved significantly. I think the front one made more of a difference. The front strut triangulates and complements the existing boxster 986 brace. 

Interesting first post.

[½cwt]

This is a complex engineering problem as load directions and rotations are not easy to calculate even with a complete 3D model of the structure.  However there is a reason race and rally cars have strut brace when based on a production shell.  Open top cars have to be weaker than closed cars as there is no bracing of a whole open area at the top of the shell, hence scuttle shake etc.  You can add a lot of weight and stiffness lower down on the shell but something unsupported has to flex.  The strut brace with help to eliminate this movement.  Whilst a bend or link in a strut is not desirable (there are some adjustable ones out there to allow camber adjustment through the top struct positon) but this is often required particularly on front engine cars.  If the material is properly attached and stiffer in a given direction than the other bracing the car has is has to have an effect. In competition weight higher up, say at the top of the struts is undesirable so stiff alloy and carbon braces have been developed.  As said previously in the post a straight steel brace welded to the top of the struts is the strongest solution but other dynamic costs of this to ultimate speed and dynamic performance may not be worth the compromise when 1/10ths of seconds count or the engine is in the way.... 

Will a strut brace help, yes particularly at the front in a Boxster, but in isolation as a performance part it won't make a whole lot of difference; there are better ways to improve basic track performance before fitting a brace. Is it worth the cost to stop a creaking hardtop?  I'll leave that decision to you.

[Boxster Melbourne]

Yes. So far I can only assess the impacts to NVH levels. I was going to spend the $150 aud on nice meal until I thought about all the post that said it wouldn't make any difference were from people who hadn't installed one but conjectured about engineering theories. Those that did install a strut bar reported positive experiences from a perception of more solidity to the overall driving experience. It's my first post and last post as I just wanted to share my experience as the overwhelming opinion seems that a strut bar for the boxster is useless because it already has the same front end set up as a GT3 cup car. 

[Boxster Melbourne]

20 minutes ago, Lennym1984 said:

I'll be honest and say that I am not convinced on the need for a front one. The rear lower stress bar seems sensible (I have one installed - it cost me £10) but I cannot see much benefit at the front given that there is already a lot of reinforcement there.

In my opinion, the best way to spend £150 is to change the transmission mounts for stiffer (993 RS) versions. This made a noticeable difference to me on track and the car felt much more stable/planted.

That sounds like an interesting mod. 

[map]

On 10/2/2017 at 8:06 PM, spyderman8 said:

Not many of the race Boxsters have them but unless they're welded to the towers I can't see the point.

54 minutes ago, ½cwt said:

...open top cars have to be weaker than closed cars as there is no bracing of a whole open area at the top of the shell, hence scuttle shake etc.  You can add a lot of weight and stiffness lower down on the shell but something unsupported has to flex....

And of course the race Boxsters run a full cage  - this essentially closes the hole in our open topped cars which will in turn better support the front end. 

For me the jury's still out on a front brace.

[bally4563]

I had both years back, but still ending up having my wisdom teeth pulled! I'll get my coat !!!

,

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[toplad]

On 3/13/2019 at 10:24 AM, Boxster Melbourne said:

Just installed a carbon fibre strut bar on my 986 and a rear rennline chassis bar. Do not listen to the naysayers. They make a huge difference. No more convertible top moaning and squeaking. NVH is improved significantly. I think the front one made more of a difference. The front strut triangulates and complements the existing boxster 986 brace. 

Agreed, makes a noticeable difference. 

Sharpens up the steering and better control over rough ground are some of the instant benefits on the 986 and 987. 

For the money, it's a no brainer 

[thefunkygibbon]

any pointers to ones people have used please?

[Cheddar Bob]

relive dead thread. So i'm looking at a front strut bar. Does anyone have one fitted? 

for example, i don't remember seeing these on my 2.7: https://www.ebay.co.uk/itm/123902013851 Whilst this isn't a strut bar, are these parts only available on the 3.2?

 

this is what I'm looking at: https://www.design911.co.uk/fu/prod126484/Porsche-986-Boxster-Front-Strut-Brace-Ultra-Racing/?source=doofinder

[½cwt]

I hope they are there, between the top mounts and buried under the centre under of the windscreen scuttle, as they are part of the shell design structure.  If you go to that D911 link and zoom in you will see the black rods that are below the nice shiny strut brace.  Easier to see driver's side than the one that runs behind the battery.

As you focus on handling benefits, a strut brace can induce some under steer by stiffening the front end but probably only noticeable if done as a back-to-back test on track.  Could be balanced by a techno brace on the rear across the bottom of the two rear sub-frame castings.

[bally4563]

On 3/13/2019 at 11:29 AM, Boxster Melbourne said:

That sounds like an interesting mod. 

Fitting one on my old E36 M3 made a noticeable difference , saying that unless I could get one very cheap I would not bother for now , however I am going to make a rear brace, for£15 in material it’s a no brainer.

[Cheddar Bob]

38 minutes ago, ½cwt said:

I hope they are there, between the top mounts and buried under the centre under of the windscreen scuttle, as they are part of the shell design structure.  If you go to that D911 link and zoom in you will see the black rods that are below the nice shiny strut brace.  Easier to see driver's side than the one that runs behind the battery.

As you focus on handling benefits, a strut brace can induce some under steer by stiffening the front end but probably only noticeable if done as a back-to-back test on track.  Could be balanced by a techno brace on the rear across the bottom of the two rear sub-frame castings.

I'm sure they are, I've not really taken the porsche apart much. I spend less time dismantling cars like I used to, (bodging them back together was the norm) 

 

I used to find stiffening the rear in a front engine car made a huge difference, I'm thinking this might do the same in a mid engine car, strengthening the front, even if it is psychological 

[Ninesomething]

Saw a vid once someone had fitted a strut brace, sawed it in half, mounted a camera under the hood and taken it on the track. The two halves were moving apart all over the place. Can't remember the car.

I had one on my Soob. Took it off to fit an intake and drove it without putting it back on. Couldn't really notice any difference but that car had a lower brace, fender braces and hard engine mounts by then. 

I think the problem is (or isn't) that the shock towers are so close to the bulkhead on most cars that there's not a lot of flex at that point. Mind you the loads going through the suspension are high. Dunno....

Whenever a manufacturer releases a new version of a car they always bang on about how it's 30% or whatever stiffer than the old car yadda yadda. 

I guess it can't hurt. Only way is to try it.

I have the Pedro's brace on the rear of my car. I deffo felt an improvement when I fitted it.

[dunks]

I'm considering fitting one , On my old Peugeot Convertible I fitted an Upper and Lower Strut brace on the front, It turned the car into a go cart , it absolutely stuck to the road in the corners , giving complete confidence to push it to the boundaries and it reduced any kind of flex whatsoever 

[Cheddar Bob]

2 hours ago, dunks said:

I'm considering fitting one , On my old Peugeot Convertible I fitted an Upper and Lower Strut brace on the front, It turned the car into a go cart , it absolutely stuck to the road in the corners , giving complete confidence to push it to the boundaries and it reduced any kind of flex whatsoever 

Yes I got this confidence experience in the past too

[Pordave]

I had confidence until I got spat off on a gravelly bend. Going backwards into a wall with my wife sat next to me was a sobering experience..... after the car stopped moving!    WTF etc.....

[Cheddar Bob]

7 hours ago, Pordave said:

I had confidence until I got spat off on a gravelly bend. Going backwards into a wall with my wife sat next to me was a sobering experience..... after the car stopped moving!    WTF etc.....

You were driving a 205 I assume