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Rear strut brace

Posted: Fri May 09, 2014 1:56 pm
by QkslvR83
FYI I bought and just fitted this: http://www.ebay.com.au/itm/Rear-Upper-S ... 2a1d454f7c

Works well, no more creaking noise from the boot and handles way better. Only had to trim the boot interior plastics a little.

Posted: Mon May 12, 2014 9:22 am
by etking
nice work - installation pic?

Posted: Wed May 14, 2014 7:20 am
by QkslvR83

Posted: Wed May 14, 2014 9:01 am
by etking
fits a treat! :D

Posted: Thu May 15, 2014 4:53 am
by photoglossy
Nice fit! Did you just buy it and hope for the best?

Posted: Thu May 15, 2014 7:34 am
by QkslvR83
I've always been on the lookout for one that would fit so I wouldn't have to make one. Just kept on searching ebay until I saw one that looked the part. This one had the measurements in the description from hole to hole, so just measured bolt to bolt in the boot, done. Wasn't that big of a gamble, I thought if it was going to be 'out' it would only be by a few mm and the brackets had enough on them to be drilled out a little more.

Posted: Fri May 16, 2014 5:53 am
by Damo
Well done. This could probably prompt a sticky to suggest parts from other makes models which fit our beasts.


Damo

Posted: Fri May 23, 2014 10:46 am
by tassuperkart
That is a cool find/fit. Looks really good.

HOWEVER, and no offence at all here to the OP, but im going to rain on the parade.
There is a fundamental flaw in the fitting which IMHO renders that rear brace as close to eye candy/bling as using a bit of tie-wire.

The idea of any strut bracing is to prevent the strut tops flexing right inwards/outwards by tying them together?
This flexing is cause by high suspension loads from bump and cornering bending the strut towers causing undesireable geometry changes and loss of fine suspension (spring AND damper) control. the entire uppper front end quarter is acting like a big spring and has a resonant frequency and actually contributes to the springs/dampers in an undesireable way.

Moving along:

Firstly, the N12 rear suspension/wheel is geometry is NOT controlled in any way by a strut top like the vast majority of front suspension types where flexion is really bad...like our N12's.
Its simple trailing arms swinging on a big-arsed fabricated transverse chassis rail securely ties into the floor pan.

Second, the rear "strut top" (unlike some cars with rear McPherson stru type suspensions) only carries a simpleshock absorber (no spring) which works in a single linear direction. Up and down. No side or bending loads imposed by a shock. The spring is contained between the trailing arm and the big arsed chassis member.

Next, the top of the shock shaft is NOT a tight/solid fit in the mounting plate and is actually retained and isolated by a rubber bush. To reduce noise. Its able to move about quite freely withing the springing limits of the rubber bush.

Attaching a brace across the top of the shock absorbers does little more that actually tie the two shocks together.
There is no way in hell there is sufficient effort from a shock enough to deflect the shock mounting and what difference would that make anyway since the movement of the tower would be in a plane inline with the damper and a brace perpendicular to that damper, totally isolated in rubber will have NO effect whatsoever in controlling damper movement, let alone contain geometry and springing oscillations and movement.

I could see a pillow-ball type top shock mount would securely tie the brace into the shock mount. Or securely bolting the brace mounts directly onto the spring tower top, tying the spring tops together but its very doubtful that containing any lateral flexion in this area would achieve anything at all.........

If the brace is fitted with a view to looking cool then its a spectacular win and cool it looks. I actually love it from that view.
If its fitted with any view to controlling suspension movement or rear chassis flexion, then its pointless.

I do have my firesuit ready just in case but i dont think Ill need it.

Oracle

Posted: Fri May 23, 2014 6:28 pm
by QkslvR83
I understand totally. The best way I thought to make it would be welded L brackets to the wheel well with the poll across and "v"d to the floor.
Due to my lack of welding skill :P and also wanting to fit a sub in the boot I went this option. (sub will be reverse firing into spare wheel well).

I knew it would be an eye candy gamble. I thought of maybe modifying those bracket into the L shape I was referring to, but after test drive I was happy as it was.
It may not be enough for a race application but for what I wanted it works. Going around corners does feel different and that annoying creaking sound up gutters/driveways doesn't happen anymore.
Good tip on the rubber by the way, thought it looked solid enough to not make much variance.