Would this stolen section of bridge help at all?

[jdmspilner]

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Just wondering if this would do anything worthwhile.

 

[DoyoFCT]

considering the time spent on that, they could have just put a roll bar in, how much is that thing? im sure it does something, but i dont think the upper part of the car twists that much. Correct me if im wrong. just seems like it would make more sense to tie the subframes together or at least bolt something to the lower part of the chassis rather than using some crazy strut tower bar. shrug WTF

 

[eclipsh]

My buddy Rick and I are planning something similar only running it vertically from the strut tower brace down to the brace behind the seats. Same X pattern but I suspect a bit more functional as it will tie the upper body to the floor boards better.

 

[jtmcinder]

2Gs actually twist quite a bit, especially those with a sunroof. But those bars are (a) mounted too close together on each side to do much if any good and (b) not where the car twists in the first place. They would also bump you to E/Mod for autocrossing, as recently discovered (the hard way) by an ex-member of this site.

If you think of it as the world's heaviest (and illegal) upper rear STB, then I guess it's OK. But be ready for the justified, negative comments.

- Jtoby

 

[eclipsh]

Where exactly does the car flex? Is it the same for 1Gs? Rick and I tried lifting the car two feet up from different corners and couldn't find any body flex. It'd be great to know where it was so we can make our efforts worthwhile.

 

[bjones18]

Looks uncomfortable for the rear seat passenger.

Anytime you add real structure, you also add weight and modify the cg location F/R & height. Adding aluminum strut bars do not add much weight. Wimpy sheetmetal attachments on most strut bars minimize results. Overall objective should be planned when adding significant structure. To accurately assess before/after results, specific maneuvers should be run keeping speed and steering input consisitent. The response of the vehicle to identical inputs is easiest to assess on same-day changes by a trained driver.

Specific to the attached picture;The first cross-tube added will minimize "butterflying" of the rear towers. Tying it in with the x-brace appears to provide structure where the "hatch-hole" is. I'm not sure why this is needed unless it is extended to provide a roll bar.

Camber stiffness, lateral stiffness, & chassis twist are usually the reason for adding structure. Cross-car members between suspension attachments (lower & upper) impove camber & lateral stiffness. Rockers tied into A-pillars, roof & rear towers improve twist stiffness. Sounds heavy right?

It comes down to how fast are you going to be driving, and how close you are going to be to guys trying to go faster than you. Sounds like race classifications!

 

[Jon Lane]

If you mentally remove the hatch, doors, and sunroof, and then twist the shell in your hands, so to speak, it seems that this frame actually makes sense -- the shell alternately elongates and compresses, among other areas, between each rear shock tower and the opposite A pillar as the shell twists. Like I say, among other places.

I'd think that this rig would reduce this tendency, although tying the forward points to the front seat belt tack points at the B pillars would intuitively seem substantially better than tying them to the rear seat belt tack points.

The tower-to-tower bar then does the obvious.

In the interest of making another improvement, it seems an X member between these seat belt positions and the opposite floor, just behind the seats, would add more anti-twist stiffness.

Lateral stiffness remains largely as it was, but I'm guessing that a pair of X members positioned as above would tighten up the back of the car noticably and have it integrate with and track the front better.

Where did this assembly come from and are they available for sale? How about a modified / expanded version?

 

[jdmspilner]

They make and sell them in Japan for 600 or so.

 

[Locke]

My opinion, it is more for appearance than anything. Yes, it ties the shock towers together, but for the X-member, it is too small to be very effective. It's function would not justify the expense, IMO.

 

[knighteclipse1]

They make and sell them in Japan for 600 or so.

I'd really be interested in knowing where you find such products.

 

[jdmspilner]

Just searching around for EDM/JDM tails for a 2g and found this.

 

[Morphius]

Poor design largely due to the braces that run diagonal. The ends are curved or bent, which will induce another point of bending. Those beams won't carry the load like they should.

Location may/maynot be bad. Hard to say without some serious analysis.