Upgrading Sway Bars To Stagea

[RubyRS4]

Been a bit busy and decided to fit GTR sway bars to the Stagea.

Now most of you would know that the rear sway bar doesn't exactly fit properly ... forcing the links/bushes to sit at angles they're not designed for. Well I've taken the liberty to pull my stag apart for the week and machine up some adaptors:

Above we can see how the narrower GTR sway bar does not quite line up with the links/bushes of the C34 stagea.

above, we also see how the narrower GTR sway bar doesn't quite fit with the mounts either. Forcing it to fit and prematurely wearing out the rubbers is not my style.

I had these fabricated as extensions to the end of the sway bar to meet the links/bushes at a more natural angle.

I also had these mounts fabricated so the mounting rubbers of the sway bar and offset inwards by 25mm each side, allowing for a more natural fit of the sway bar.

Above is the sway bar relocation mount in position on the chassis.

And above is the finished fitting of the adaptor. Neat and in a more natural position on the sway bar. The plate used is 6mm thick.

Above is the finished fitting of the adaptors for the ends of the sway bar, allows the links/rubbers to sit at a more natural angle. The plate used here is 8mm thick due to the much heavier loads exerted upon it so there is no flex or give. The sway bar mount plates are 6mm thick only as they sit flush and are supported by the chassis rail.

All nuts and bolts used were high tensile and tig welding required to fab the threads to the mounting plates. Very happy with the job.

Refitted the wheels, removed the stands, and I gave the Stagea a good rocking, and she only swayed on her own tyre pressures. Yet to road test ... but I'm quite certain it'll pass

And the beauty of it is that there is no permanent welding of the plates to the chassis or sway bar, allowing for the bar to be removed and a stock one refitted in no time at all.

[chef_stagea]

Looks like the end links might soak up all ur gains there roo?

[RubyRS4]

Did you read the description or just look at the photos only. Besides, that image was taken before I tightened up the fittings for the purpose of taking photos. This idea was all worked out with an engineer over the week. 8mm thick plate with a 25mm offset for the mounting means there is virtually no 'soak' you speak of. Engineer mentioned 6mm thick plate, but we went with 8mm just to be certain. The width of the sway bar end matches the offset, so there is no chance of any 'leverage' against the high tensile fittings used ... creating any 'soak' whatsoever. Engineer is happy, I'm happy.

[chef_stagea]

Did he get a template of coke can to replsce the subframe or arm thats custom salt Rusted?

On that note its over and out for the stag section:)

[Tangles]

Nice write up; obviously an option. 8mm thick is a good choice, I cant see that altering shape (flex/cracking), looks like a great "set & forget" option.

[Daleo]

Interesting piece of lateral thinking Ruby , well done.

A couple of things;

With the chassis mounts; the welds for your studs don't look to have much penetration. I can see the gap around the stud where the weld has been ground back. If the weld fails; there's nothing stopping the stud pulling through the plate.

Did you consider using 10 or 12mm plate and using a grade 8 or 10 countersunk screw into a threaded, countersunk hole in the plate? That way the plate and the bolt are taking all the load rather than a weld that looks like it might just pull free?

A couple of flats ground on the tapered head would give you enough area to lay a couple of small fillet welds to lock the screw in position without compromising the strength of the screw.

They would also sit level with, or below the surface of the plate. There's no way the stud can pull through the material this way.

I don't think 6mm is nearly thick enough to take the load you are applying to it; regardless of what you're engineer is saying. an upgrade to 4140 plate or similar would also be advised.

For the sake of a few millimetres of material thickness; I'd go for excessive, rather than "adequate". Two pieces of plate that size will weigh barely 500 grams.

I've worked as a Fitter for 20 years now, in heavy industry and now in the Pharma industry and I always over spec load bearing components by as much as material thickness and clearance will allow.

The other concern I have is the torsional load you are applying to the arm of the Sway Bar; and in particular to the flattened mounting tab of the Bar.

I believe the long term consequence of the twisting force being applied to the tab will result in its failure The straight edge of the plate you've bolted to the Sway Bar tab will become a point of localised stress and will fatigue the bar; thus breaking it.

For the trouble you've gone to; I'd have asked a spring maker or boilermaker to heat the bends and spread the arms of the bar then re-temper the bar. That way you could pull straight on the bar link mounting points.

Not trying to put you off, but fatigue is a gradual process, that is almost invisible until the component reaches the point of failure. Keep an eagle eye on it please.

A new set of link rod bushes wouldn't go astray either.

Cheers, Dale.

Edited August 27, 2011 by Daleo

[RubyRS4]

Interesting piece of lateral thinking Ruby , well done.

A couple of things;

With the chassis mounts; the welds for your studs don't look to have much penetration. I can see the gap around the stud where the weld has been ground back. If the weld fails; there's nothing stopping the stud pulling through the plate.

Did you consider using 10 or 12mm plate and using a grade 8 or 10 countersunk screw into a threaded, countersunk hole in the plate? That way the plate and the bolt are taking all the load rather than a weld that looks like it might just pull free? A couple of flats ground on the tapered head would give you enough area to lay a couple of small fillet welds to lock the screw in position without compromising the strength of the screw. They would also sit level with, or below the surface of the plate.

I don't think 6mm is nearly thick enough to take the load you are applying to it; regardless of what you're engineer is saying. an upgrade to 4140 plate or similar would also be advised.

For the sake of a few millimetres of material thickness; I'd go for excessive, rather than "adequate". I've worked as a Fitter for 20 years now, in heavy industry and now in the Pharma industry and I always over spec load bearing components by as much as material thickness and clearance will allow.

The other concern I have is the torsional load you are applying to the arm of the Sway Bar; and in particular to the flattened mounting tab of the Bar. I believe the long term consequence of the twisting force being applied to the tab will result in its failure The straight edge of the plate you've bolted to the Sway Bar tab will become a point of localised stress and will fatigue the bar; thus breaking it.

For the trouble you've gone to; I'd have asked a spring maker or boilermaker to heat the bends and spread the arms of the bar then re-temper the bar. That way you could pull straight on the bar link mounting points.

Not trying to put you off, but fatigue is a gradual process, that is almost invisible until the component reaches the point of failure. Keep an eagle eye on it please.

Cheers, Dale.

Ah, some constructive input. I like to see that.

You make some very good points, and clearly you've got a background in metals and worth listening to.

The 6mm mounting plate is basically sitting between the chassis and the sway bar mount, and in this position it will take an upwards compression force, not any shear forces which will threaten the integrity of the bolt or its welds. The bolt (or studs I should say) is predominantly there to seat the sway bar bush in place, and not deal with any shear forces. The engineer who welded this up is close to 60yo and has been welding for over 40 years, so I'm very comfortable with what he has done and the penetration he achieved with the welds ... far, far better than what I can do.

Not dismissing the option of using a 10-12mm plate and tapping the holes to accept a stud. Will certainly try that also if we feel like doing a 'version 2'. However, we beleive what we've done is more than sufficient.

Got to ask, why would you think the arm of the sway bar would take "twisting force" as we had discussed the different forces that would be exerted upon the arm adaptor. I know the sway bar itself is designed to resist/minimise twisting and hence body roll of the wagon. The arm of the bar itself flattens down to some 6mm to the mounting point, and we decided to go bigger with 8mm. He had believed that an option like heating the bar to extend the 'reach' of the arms would be what would weaken the bar.

I will be keeping an eagle eye on it. And given some valid points you've made, I'll give it some 'lock wire' to prevent it from dragging on the road in the event that it does break. However, we are quite confident that it won't. I respect the comments you've made above, but I have to disagree with you on the arm mounts. the plate is 8mm thick providing a 25mm offset, so we don't believe it offers any form of stress to itself or to the sway bar arm beyond its capabilities. I don't beleive the extra 25mm offset/length will pose any leverage contributing to any weakness to the sway bar. Thoughts?

Happy to chat to you more a bit indepth about this if you like. If it results in a far better design, I'm happy to try it.

[RubyRS4]

BTW a new set of link rod bushes are going on too smarty pants I threw things on for photographic purposes. Its all painted up now for looks, and I'm changing all the bushes for new.

[Daleo]

Ah, some constructive input. I like to see that.

You make some very good points, and clearly you've got a background in metals and worth listening to.

The 6mm mounting plate is basically sitting between the chassis and the sway bar mount, and in this position it will take an upwards compression force, not any shear forces which will threaten the integrity of the bolt or its welds. The bolt (or studs I should say) is predominantly there to seat the sway bar bush in place, and not deal with any shear forces. The engineer who welded this up is close to 60yo and has been welding for over 40 years, so I'm very comfortable with what he has done and the penetration he achieved with the welds ... far, far better than what I can do.

Not dismissing the option of using a 10-12mm plate and tapping the holes to accept a stud. Will certainly try that also if we feel like doing a 'version 2'. However, we beleive what we've done is more than sufficient.

Got to ask, why would you think the arm of the sway bar would take "twisting force" as we had discussed the different forces that would be exerted upon the arm adaptor. I know the sway bar itself is designed to resist/minise twisting and hence body roll of the wagon. The arm of the bar itself flattens down to some 6mm to the mounting point, and we decided to go bigger with 8mm. He had believed that an option like heating the bar to extend the 'reach' of the arms would be what would weaken the bar.

I will be keeping an eagle eye on it. And given some valid points you've made, I'll give it some 'lock wire' to prevent it from dragging on the road in the event that it does break. However, we are quite confident that it won't. I respect the comments you've made above, but I have to disagree with you on the arm mounts. the plate is 8mm thick providing a 25mm offset, so we don't believe it offers any form of stress to itself or to the sway bar arm beyond its capabilities. I don't beleive the extra 25mm offset/length will pose any leverage contributing to any weakness to the sway bar. Thoughts?

Happy to chat to you more a bit indepth about this if you like. If it results in a far better design, I'm happy to try it.

The lack of penetration around that weld on the right is not something I would be okay with as an experienced welder; especially if it was going on someone elses car. At the very least, I would've ground a taper on the stud, and countersunk the hole to ensure I could lay a decent bead and have some weld left when it was ground back. If I did it with my TIG; you wouldn't need to grind; the weld would lay flush anyway.

From the first section I've bolded and coloured red; "in this position it will take an upwards compression force, not any shear forces which will threaten the integrity of the bolt or its welds." This is totally incorrect!

In a corner; one side of the bar is pushing up and the other is pulling down with equal force. So the mounts are alternately in tension AND compression.

Don't believe me? Loosen (Don't remove) one "D" mount; and go for a drive around the block; you won't need to listen too hard for the massive bang you'll hear as the loose mount pulls away from the body, then belts back into the subframe.

For the second; "heating the bar to extend the 'reach' of the arms would be what would weaken the bar." The bar is a tubular length of spring steel; I've never seen anyone cold bend Spring Steel, you have to heat it to bend it; other wise it'll just spring back, or fold in half. as long as it's heated correctly, and re-tempered, there should be no issue.

Also the plate you've added does twist the arm "along the beam"; if you will. and this, I believe, will fatigue the tab, as you are concentrating all the load on the tab.

With the rubber link bushes; this load is much less concentrated; and twists only on the long centre section of the bar; where it's supposed to.

Cheers, Dale.

Lol; I figured the bushes and bare metal were just trial fitting phase; but had to have a stir!

[4bidn1]

would it not be more affective in time and performance just to go a brand new whiteline set up with new link bushes ect for about 300 bucks that way the bar is also set to the weight of the stag not a gtr ?? not that i dont like custom work and cheap performance mods i have done more than my fair share over the decades but there comes a time to spend some pocket shrapnell

[Raysboostin]

would it not be more affective in time and performance just to go a brand new whiteline set up with new link bushes ect for about 300 bucks that way the bar is also set to the weight of the stag not a gtr ?? not that i dont like custom work and cheap performance mods i have done more than my fair share over the decades but there comes a time to spend some pocket shrapnell

+1 for that. the different subframe is the real issue. did u look at other options for swaybars?? like gts-t or gt-t??

[Daleo]

would it not be more affective in time and performance just to go a brand new whiteline set up with new link bushes ect for about 300 bucks that way the bar is also set to the weight of the stag not a gtr ?? not that i dont like custom work and cheap performance mods i have done more than my fair share over the decades but there comes a time to spend some pocket shrapnell

I just finished running a Group buy for just this purpose; http://www.skylinesa...-bar-group-buy/

Response was a little underwhelming.

Not everyone has the dollars at the time; that's life.

Also I was trying to help, rather than shamelessly self promoting; which I now appear to have failed at.

Edited August 28, 2011 by Daleo

[RubyRS4]

I tackled this job because I like to get my hands dirty and try what no one else has tried. I've undertaken many "fruitless exercises" and successful mods in my time, including a supercharged SR20DE powered 200B, and will continue to do so for as long as cars interest me.

There will always be an easier option ... but then there is always the left-field option.

Mod on

would it not be more affective in time and performance just to go a brand new whiteline set up with new link bushes ect for about 300 bucks that way the bar is also set to the weight of the stag not a gtr ?? not that i dont like custom work and cheap performance mods i have done more than my fair share over the decades but there comes a time to spend some pocket shrapnell

Compared to the stock swaybar, the GTR bar would be better for the 'rolling' weight of the stagea body. Whiteline would be better still I admit, so I'm not ruling out another upgrade in the future.

I'm never afraid to spend money where it is best deserved. I've purchased new 3076 and many brand name parts. But as i said above, I like to have a crack at things myself.

At the end of the day, it beats forcing the bar on and having the bushes at wrong angles to the bar, causing premature failure/wear.

[Daleo]

Nothing wrong with having a go mate.

If you decide to upgrade the bar to a Whiteline, let me know; I should be able to match the GB price.

Cheers, Dale