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Anti wrap/Traction/Bam Bar

Posted: Thu Aug 08, 2013 2:01 pm
by Boyes
So I put a different engine in my Sj as it was so underpowered, and now it I get bad axle wrap on part throttle (30%ish or more) I'm reducing the size of my shackles in the hope this will help (I did want the smallest shackles I could anyway).

I'd like to build an anti-wrap/bam bar but I'm wanting one that won't restrict the vehicle's articulation (probably not much articulation but never the less) which design functions best without causing problems elsewhere, such as ground clearance issues.

I have attached a proffesional to scale drawing :brows: of a couple of designs that I have seen (simple idea's) including what is used on LR's :argh: & Vitara's with a balljoint mounted on top of the axle casing.

If anyone has used/tried/tested any input would be appreciated..

Re: Anti wrap/Traction/Bam Bar

Posted: Sun Dec 01, 2013 11:08 pm
by Ladaman
Did you ever get around to doing this, or have you put up with it?

I'm also interested in doing this now, as I destroyed my rear springs on Saturday, and I think it was due to axle wrap.

The drivers side has snapped two of the three leafs, and the passenger side is permanently bent, pointing the diff upwards at a serious angle.

But I suppose having 140Nm of engine torque compared to 75Nm as standard, and an overall gear ratio in low first of 56.9:1 instead of the original 30.9:1 gives a torque at the rear axle of almost 8,000Nm instead of the original 2,300Nm (I believe).

I'm now going to have to fit my YJ's a little sooner than planned. Will they be "man enough" on there own, or do I also need to make some anti wrap bars as well? Does anyone know the original anus YJ set up?

You guys with YJ's already, what's your thoughts?

Re: Anti wrap/Traction/Bam Bar

Posted: Sun Dec 01, 2013 11:18 pm
by Edweird
I've seen YJs both on and off at Wagtail. They're certainly beefier looking than standard springs.

Re: Anti wrap/Traction/Bam Bar

Posted: Sun Dec 01, 2013 11:22 pm
by dan_2k_uk
If I was going to make one I would go for top left design.

None of the Yj sprung sjs on 33s I know of run one though...

Re: Anti wrap/Traction/Bam Bar

Posted: Sun Dec 01, 2013 11:37 pm
by Ladaman
The top left one is the only one worth making. It might be better by bringing the lower link to around the bottom of the axle, but that would possibly compromise ground clearance.

I did think about one like the top right, but with the rose joint on the axle rotated 90 degrees, so the fastener is horizontal, not vertical.

And you're right Ed, they are a lot beefier than normal SJ ones.

Mmmmm, what to do????

Wait for more comments first I think.

Re: Anti wrap/Traction/Bam Bar

Posted: Sun Dec 01, 2013 11:45 pm
by Edweird
Could you not just run an anti-wrap bar from the top of the axle to the leaf spring mount on the chassis? Surely the distance to that rigid mounting doesn't change much?

Re: Anti wrap/Traction/Bam Bar

Posted: Mon Dec 02, 2013 12:02 am
by Ladaman
Edweird wrote:Could you not just run an anti-wrap bar from the top of the axle to the leaf spring mount on the chassis? Surely the distance to that rigid mounting doesn't change much?
I was considering that, but the spring from the axle to the chassis will be trying to control the torque. Something I'm sure it can, if it can handle the torque of a YJ engine. I think two points on the axle would be better though.

Re: Anti wrap/Traction/Bam Bar

Posted: Mon Dec 02, 2013 1:51 pm
by ScottieJ
Ed that won't work as the leaf spring length will change slightly during flex, as the spring flattens and flexes the distance between those two points will change.

This is my favourite design, but it's also the most complicated to make.

http://www.jeepaholics.com/tech/bambar/

You can still get a bit of wrap on YJs but they do fight it well, depends on the set up and condition of the springs, i think I get a tiny bit but not enough to worry about. you always get a small amoutn with leaf springs anyway.

Re: Anti wrap/Traction/Bam Bar

Posted: Mon Dec 02, 2013 5:08 pm
by Ladaman
Oooh, I like that.

I've just printed the write up out, for a good read later.

I'm not too keen on the welding to the diff casing though, thats sounds tricky, especially when still assembled.

I wonder if I can machine the front of the diff housing and machine a split ring to clamp the front instead? I think that would be better solution.

Re: Anti wrap/Traction/Bam Bar

Posted: Mon Dec 02, 2013 9:46 pm
by Boyes
Ladaman I havn't got round to making one been trying to get rid of a hideous vibration, but I may have cured it as of this weekend so after a few lights, the horn and a washer this will be on the agenda again as I get a metallic Clanking on & off throttle.

A lad on here (has a black Sj which had a 1.9TD pug engine in but then went to a 1.6 Vit engine) had a bambar which bolted between the pinion and casing flange & also had a U bolt, he said it worked well.

I'll find his build thread in a moment as there's pics on there (unless he comes across this thread :) )

Found it http://forum.suzukiclubuk.co.uk/vi ... =22&t=6382

He's called GP7186 :lol: