26 replies to this topic

[GML-31]

big horsepower and they will bend otherwise

[Litre8]

When you nail the throttle the lower trailing arms come under compression as the diff housing tries to rotate in the opposite direction to the wheels. Boxing them adds strength and helps prevent them bending or kinking.

[marko1au]

good found one of the posts i've been looking for. can anybody explain to me how this is done as in what is required and the correct way to do it.. oh and pictures speak a thousand words. hint hint thanking you's mark

[rodomo]

There is another thread about rear end movement that you might get some info from. Plenty of pics too.

http://www.gmh-toran...showtopic=23896

[marko1au]

thankyou big T as i said a picture speaks a thousand words now that i have seen it i fully understand what needs doing, no need to take any measurements but what gauge do you think the steel is......1/8th maybee a touch thicker thank's again mark

[mag5000]

you can also change (lower) by drilling ? the top diff control arm bolt holes on the body to help even further.

[boblhslr]

you can also change (lower) by drilling ? the top diff control arm bolt holes on the body to help even further



Mag5000 What do you mean by this.

[mag5000]

"Trick tips for torana rears"



artical from old mag - Building a Tougher Torana No1 - A Technical Guide , page50

[mag5000]

this is page part of another mag - Torana Power - No3 page 41

theres a sentance that starts (By simply) that tells of whats what.ive tried both boxing and lowering diff arms all work well and no big budget required

[TerrA LX]

I have never seen a Tory arm bend or a mount rip out but Commys are notorious for it.
What is happening is when you plant the right foot the shock of the tyres rotating is transfered to the diff which tries to rotate in the opposite direction, so you either bend the arms or rip the top mount off the body.

[Toranamat69]

I've seen a few LX's rip the lower control arm brackets off the floor.

Big slicks and an 11 sec pass and you are getting into the danger zone.

I wouldn't be using poly bushes in the top arms or boxing them.

Both the arms and the bushes are designed to flex for a reason.

Don't make me post a pic of my boxed upper arms with the failed polyurethane bushes again. I had only done about 10,000k's when they failed and they were the softest grade available. Clearly a result of not being able to flex as a bushing needs to be able to do with this style of rear end.

Don't worry, when I was young and silly, I wouldn't be told when it came to these types of things but guess what - some of those guys were actually right.

The top arms won't bend under accelleration because they are under tension.

Making everything mega stiff is fine for the drags but if you want to go round corners, it will make the car go round corners on 3 wheels which it will do slower than it will on 4 wheels.

Oh btw, if running a panhard, rubber upper control arm bushes are a must.
You will have a very shite setup for cornering if you use stiff bushes.

A converging arm 4 link already has a roll centre defined. Installing a panhard defines a second centre much lower and guess what? The rear end can only pivot about 1 centre, not 2 so unless you have some compliance somewhere in some rubber bushes, you will either break something or you will make the weight transfer worse than the original shite setup.

I think you will find all the old touring cars that used panhards also had rubber bushes - they knew the converging arms sucked but were stuck with them - they did the best you can really do without removing everything and changing the whole fundamental design.


Two things those magazine articles fails to mention about lowering the front mount of the top control arms is

1. It will make your rear end more prone to tramping under really hard braking.
2. It raises an already discustingly high rear roll centre even higher which will make your car handle worse around corners - one of those articels even bullshits and says it helps in all forms of racing. Typical low level bullshit that comes out in those types of mags.

That lowering the front mount of the top control arm is only a drag racing modification.

M@

Edited by Toranamat69, 12 January 2008 - 10:47 PM.

[Tiny]

Very Interesting topic guys! And thanks M@ for the great info.

It's funny... but in the HQ which is the same setup as an LX torana... Koni adjustable shocks, Whiteline springs ( 1.5" lower than std), boxed lower arms and nolathane bushes with rubber uppers seem to work fine for what i do with the car (Street/strip). Oh.. ive got swaybas front and rear too!

No 90/10s, nothing else trick, and running a pretty easy 11.9 on drag radials... Interesting to see tricks like this spoken about but i dont think i personally would bother!?

Cheers!

[StephenSLR]

Don't expect miracles.

I read it can quicken your 1/4 mile time by up to 0.1 second.

They give you better throttle response.

s