X-brace for Z4?

[phoenixbmwlife]

Hi all!
I installed an Xbrace for my e36 a few years ago and I loved the difference it gave in the turns. It felt so much sturdier.

My question is, has anyone heard of an X-brace for the Z4? I could not find any. If not what alternative have you used and what are your impressions on it?

Thanks in advance.
Cheers!

[Ron Stygar]

Originally Posted by K3N R3D

Hi all!
I installed an Xbrace for my e36 a few years ago and I loved the difference it gave in the turns. It felt so much sturdier.

My question is, has anyone heard of an X-brace for the Z4? I could not find any. If not what alternative have you used and what are your impressions on it?

Thanks in advance.
Cheers!

You have a reinforcement plate.

Number 1:
http://www.penskeparts.com/DiagramsR...iagram=51_4957

[blender]

Strong Strut makes really beefy replacements for the factory rear frame bracing bars (vendor picture):



Got 'em. Like 'em. Great build quality, extremely sturdy.

RC.

[Blind32]

That strong strut is pretty cool.

I saw some numbers that I think BeeDub posted stating that our (coupe) frame is already hella tough(technical term). My understanding is they originally built our car as a convertible and just added a roof. Where normally, convertible cars have more reinforcement added since they are missing the roof the original non-convertible car was designed with.

Adding more couldn't hurt tho. Stiffer is always better

[Beedub]

Originally Posted by Blind32

That strong strut is pretty cool.

I saw some numbers that I think BeeDub posted stating that our (coupe) frame is already hella tough(technical term). My understanding is they originally built our car as a convertible and just added a roof. Where normally, convertible cars have more reinforcement added since they are missing the roof the original non-convertible car was designed with.

Adding more couldn't hurt tho. Stiffer is always better

Roadster is stiffer than a lotus exige!!! Coupe is stiffer than 99% of the cars out their, ill dig out the figures.........
I promise those bars will make 0 different.......

[Pheonix]

Originally Posted by Beedub

Roadster is stiffer than a lotus exige!!! Coupe is stiffer than 99% of the cars out their, ill dig out the figures.........
I promise those bars will make 0 different.......

Exactly! I read that somewhere as well. I hope you will dig it out and post it up. I think it is a waste of time, money and added weight for nothing

[Beedub]

BAMMM

Alfa 159 - 31.400Nm/degree
Aston Martin DB9 Coupe 27,000 Nm/deg
Aston Martin DB9 Convertible 15,500 Nm/deg
Aston Martin Vanquish 28,500 Nm/deg
Audi TT Coupe 19,000 Nm/deg
Bugatti EB110 - 19,000 Nm/degree
BMW E36 Touring 10,900 Nm/deg
BMW E36 Z3 5,600 Nm/deg
BMW E46 Sedan (w/o folding seats) 18,000 Nm/deg
BMW E46 Sedan (w/folding seats) 13,000 Nm/deg
BMW E46 Wagon (w/folding seats) 14,000 Nm/deg
BMW E46 Coupe (w/folding seats) 12,500 Nm/deg
BMW E46 Convertible 10,500 Nm/deg
BMW X5 (2004) - 23,100 Nm/degree
BMW E90: 22,500 Nm/deg
BMW Z4 Coupe, 32,000Nm/degree
BMW Z4 Roadster: 14,500 Nm/deg
Bugatti Veyron - 60,000 Nm/degree
Chrysler Crossfire 20,140 Nm/deg
Chrysler Durango 6,800 Nm/deg
Chevrolet Corvette C5 9,100 Nm/deg
Dodge Viper Coupe 7,600 Nm/deg
Ferrari 360 Spider 8,500 Nm/deg
Ford GT: 27,100 Nm/deg
Ford GT40 MkI 17,000 Nm/deg
Ford Mustang 2003 16,000 Nm/deg
Ford Mustang 2005 21,000 Nm/deg
Ford Mustang Convertible (2003) 4,800 Nm/deg
Ford Mustang Convertible (2005) 9,500 Nm/deg
Jaguar X-Type Sedan 22,000 Nm/deg
Jaguar X-Type Estate 16,319 Nm/deg
Koenigsegg - 28.100 Nm/degree
Lambo Murcielago 20,000 Nm/deg
Lotus Elan 7,900 Nm/deg
Lotus Elan GRP body 8,900 Nm/deg
Lotus Elise 10,000 Nm/deg
Lotus Elise 111s 11,000 Nm/deg
Lotus Esprit SE Turbo 5,850 Nm/deg
Maserati QP - 18.000 nm/degree
McLaren F1 13,500 Nm/deg
Mercedes SL - With top down 17,000 Nm/deg, with top up 21,000 Nm/deg
Mini (2003) 24,500 Nm/deg
Pagani Zonda C12 S 26,300 Nm/deg
Pagani Zonda F - 27,000 Nm/degree
Porsche 911 Turbo (2000) 13,500 Nm/deg
Porsche 959 12,900 Nm/deg
Porsche Carrera GT - 26,000Nm/degree
Rolls-Royce Phantom - 40,500 Nm/degree
Volvo S60 20,000 Nm/deg
Audi A2: 11,900 Nm/deg
Audi A8: 25,000 Nm/deg
Audi TT: 10,000 Nm/deg (22Hz)
Golf V GTI: 25,000 Nm/deg
Chevrolet Cobalt: 28 Hz
Ferrari 360: 1,474 kgm/degree (bending: 1,032 kg/mm)
Ferrari 355: 1,024 kgm/degree (bending: 727 kg/mm)
Ferrari 430: supposedly 20% higher than 360
Renault Sport Spider: 10,000 Nm/degree
Volvo S80: 18,600 Nm/deg
Koenigsegg CC-8: 28,100 Nm/deg
Porsche 911 Turbo 996: 27,000 Nm/deg
Porsche 911 Turbo 996 Convertible: 11,600 Nm/deg
Porsche 911 Carrera Type 997: 33,000 Nm/deg
Lotus Elise S2 Exige (2004): 10,500 Nm/deg
Volkswagen Fox: 17,941 Nm/deg
VW Phaeton - 37,000 Nm/degree
VW Passat (2006) - 32,400 Nm/degree
Ferrari F50: 34,600 Nm/deg
Lambo Gallardo: 23000 Nm/deg
Mazda Rx-8: 30,000 Nm/deg
Mazda Rx-7: ~15,000 Nm/deg
Mazda RX8 - 30,000 Nm/degree
Saab 9-3 Sportcombi - 21,000 Nm/degree
Opel Astra - 12,000 Nm/degree
Land rover Freelander 2 - 28,000 Nm/degree
Lamborghini Countach 2,600 Nm/deg
Ford Focus 3d 19.600 Nm/deg
Ford Focus 5d 17.900 Nm/deg

[Beedub]

when my roadster is stiffer than a lotus exige..... i really dont not worry about the car flexing ;-) The z4 was always designed as a roadster so was inherently super stiff, when the added the roof, it became twice as stiff and beat alot of them :-)

Like i said.... those 2 bars underneath the car will do Sweet F A :-) Strong strut are just creating waves so people buy shit they dont need to :-)

id love some new figures with the hardtop and strut brace in place for the roadster:-)
when i stripped the hardtop down its a seriously beefy frame that connects the car together, that will Definitely make a difference.....

the coupe figures are just WOW.......

again, has any EVER heard someone complain about the stiffness of a mclaren f1 or a lotus exige??? :-)

[Finnegan]

+1 on the rear brace comment Beedub. I like Strong Strut, have their Strut Tower bars on one of our cars, but the rear brace is unnecessary. (In fact, the strut bar may be overkill as well, but I like the way it looks .)

The limiting factor on the rear "brace" isn't the brace itself but the fasteners. If you get something beefier, the weak point moves to the fastener. Beef that up and it moves elsewhere. Here's a very technical explanation of that (and another good thread on this topic). Bottom line, the car is tough little beast and plenty stiff in stock form.

[Beedub]

holy shit... the z3 must feel like JELLY!!! looooooooolll

[Shipkiller]

1

[Beedub]

guys i already posted these :-)

[Finnegan]

Originally Posted by Beedub

guys i already posted these :-)

Yeah, remind me not to get in an ok-corral type gunfight with you. You're faster!

(See my edit above)

[XMetal]

Holy cow...didn't know the X5 is the 2nd most stiff bimmer, right behind the coupe! I got 2 of the most rigid cars BMW makes

[phoenixbmwlife]

Thanks for all your impressions and opinions guys. I guess for me I noticed a slight flexing while taking a hard corner and thought why not investigate how I can spend more money on my car LOL. (Sarcasm hinted)

What about a Tower strut brace then? I would guess this would be a good investment since the non Ms dont have it and the Ms have it? I wish i just saved the extra money and bought an M to begin with. smh

[Finnegan]

No, the ///M doesn't come with a strut tower brace.

If you take your car to the track and really run hard you can probably notice a difference (this may be more noticeable in the Roadster, but as noted above, it's damn stiff too).

The only reason to really get one is that it looks good, track work, and distribution of force across the shock towers (as is a hard bump on one side would have the force distributed).

Where are you noticing the "flexing"? What's it like? Without a description, IDK, could be sidewall flex, a tired spring, bushings, other suspension bits, etc. How many miles on the car? I'd look at other potential culprits if you're really feeling something flex before jumping in to a strut bar. Hey, you might get lucky and find something that needs replacing. Trust me, that will help you spend more money on your car.

[phoenixbmwlife]

Originally Posted by Finnegan

No, the ///M doesn't come with a strut tower brace.

If you take your car to the track and really run hard you can probably notice a difference (this may be more noticeable in the Roadster, but as noted above, it's damn stiff too).

The only reason to really get one is that it looks good, track work, and distribution of force across the shock towers (as is a hard bump on one side would have the force distributed).

Where are you noticing the "flexing"? What's it like? Without a description, IDK, could be sidewall flex, a tired spring, bushings, other suspension bits, etc. How many miles on the car? I'd look at other potential culprits if you're really feeling something flex before jumping in to a strut bar. Hey, you might get lucky and find something that needs replacing. Trust me, that will help you spend more money on your car.

Oh sorry I thought the Ms came with it stock. I need an oil change and alignment so will get one on Monday. I'll ask them to check out the suspension same time. LOL on the last comment you made

[blender]

Question: Anybody got any factual stats on increase in chassis flexion as the car ages? ( call it 'break-in', or 'fatigue', or whatever.) Is it 2%? ...5%?

I am pretty confident that my six year old Roadster flexes more now that it did when new. 50K miles of spirited driving, track days and a few 'offs' have loosened things up, in spite of frequent and attentive maintenance. (Back your car down a driveway ramp at an angle if you don't believe me.)

Those beefier rear braces and a strut tower brace made a noticeable difference when applied to a (then) 5-year-old car, particularly on tight bends like those on Streets of Willow. And Finnegan was right on with other parts that also flex more with age. The equilibrium of the whole system changes over time as the parts break in, then slowly wear out. So maybe don't dismiss the benefits of added stiffening on well-used, broken-in cars. For a new or gently used car though, seems like misplaced $$, unless you want bling.

And off-topic, what the hell do they do to get the Rolls-Royce Phantom to a stiffness quotient of 40,500 Nm/degree?? That's nearly 30,000 foot-pounds of force per degree of deflection(!)

[Shipkiller]

I am not a mechanical engineer, or a metallurgist, but I don't think the chassis flexibility itself increases. If this were the case, then we would start to have metal fatigue and failures at the points of higher flex on the chassis. The only failure point I can think of is the front anti-roll bar bracket pads and I have only heard of two failures.

As you say, you think your six year old Roadster flex’s more now. I would be willing to bet if you changed all the wear items in the suspension system at the same time, the car would feel like new.
On just the rear axle alone, we have five bushings on each side that should be replaced. This does not take into account the bushings for the differential or the dampers.
Although, I could be completely wrong..

[Beedub]

the veyrons figure is nothing short of astounding......

[boondocksaint]

Originally Posted by Beedub

the veyrons figure is nothing short of astounding......

So is the price.