Sway bar sizes???

[Adsy01]

Hey guys, just because i'm too lazy to get under my car at the moment, do any of you know the size (diameter in millimeters) of the front (anti-) sway bar in a WP zetec?

I also wouldn't mind knowing if the WQ has a different sized bar and the size of the XR-4 one too if anyone can help.

While were on the subject, has anyone come across any info on the rear beam stiffness (rates would be good?) of the std versus the XR-4?

[xr4racer]

I haven't even measured the front bar but the key to getting a fwd to handle is to stop it understeering and to do that it needs a rear ARB. This is very difficult to fit and nobody makes one. I fitted a 14mm rear ARB from a KB Laser and that would be a great setup for a road car but it has now been replaced by a 24mm one.

The XR4 rear beam is stamped as 8.4mm (maybe 8.2mm ???). No idea about its stiffness.

[Adsy01]

Thanks for that, i've read that 8.4mm on the XR-4 beams is the thickness of the steel. i'll have to jump under mine and see if i can see a stamped size to compare.

I'm wanting to add a rear bar, but i'm also considering going bigger on the front too, but possibly only to a XR-4 sized one (hence the questions).

But I need to know what i'm doing on the front first (if i do go bigger on the front), so I can compensate any extra understeer with the rear bar when its added.

Here's what i'm currently thinking. Say the front to rear ratio of an XR-4 front bar, bear beam and the 14mm bar is perfect for a street setup and i choose to replicate that.
If I dont touch the front bar (use the WP std one) then I most likely can just add the rear bar in 14mm and all will be sweet. (sounds like a decent first step at this stage).
But if i go bigger in the front, say the XR-4 bar (there is a 22mm aftermarket bar avalible BTW) then I may need need to go a bigger rear bar to replicate the planned front to rear ratio on the WP due to the "thinner"(?) rear beam

Did you use the KB mounts too? does it mount within the beam or to the body? Any chance of pics? I know you're doing IPRA so i understand if you dont want to flash pics around as I spent a few years protecting our team's setup (an IPRA RX-7).

I only just woke so sorry if i'm waffeling on a bit... :-P

[xr4racer]

I had to add mount plates to the lower spring platforms for the ARB links and add a crossmember that goes thru the bottom of the spare wheel well, under the muffler and has a dropper that attaches to the RH chassis rail. I dont think it would fit under a standard muffler.

I will measure the front bar today for you.

[xr4racer]

I used that setup with standard camber and caster at Bathurst and it handled beautifully. It was quicker across the mountain than most of the more powerful cars but let itself down on the straights. It was able to go through the Chase on the limiter at 235kph and felt rock solid.

[xr4racer]

the std xr4 bar is 19mm.

[Adsy01]

The WP front bar is 18mm, which means the 19mm bar would give me 24% increase in roll stiffness going by my whiteline conversion chart.

Hmm, I wonder if the XR-4's rear beam is stiffer than the others by the same percentage?? I stuck my head under the rear but couldn't see a number stamped, but the car was still on the ground.

I also don't think you could mount the bar as you described on a street car (exhaust and practical ground clearance)... but this autospeed article gives a few more ideas.... Rear Sway Bars: Improving FWD Handling


Its also worth noting that changing your rear bar from 14mm to 22mm is an increase of a whopping 796% in rol stiffness!!!!!!!

[xr4racer]

The Fiesta certainly needed the 22mm rear bar for Barbagallo Raceway but the smaller 14mm was excellent for Bathurst and I think all that wud be needed on the road. The Autospeed article is good - maybe a bar like the Prius one could be fitted.

[Adsy01]

Mike what sort of spring rates and shocks are you running in that thing? does it step out if you get off the gas? anyhow it must be FUN :evil3:

I'm goning to have a hunt around the wreckers and see what i can find as far as a beam mounted bar. I've just ordered the parts for a rear disc conversion, so i think the bar is going to be a x-mas project, but it will take that long to reseach anyway.

I spoke to a former workmate thats still in the suspension trade (I was a suspension mechanic for 4 years) and he was trying to talk me out of it, he didn't see the worth in it. Although he can get me a custom made bar, if i give him the templet of what i want made.



Anyone know of a XR-4 rear beam for sale? :

[xr4racer]

I actually dont know the spring rates - it was a package from KW that included double adjustable shocks. We are still trying to decipher the instructions ????????? I think it is the same as used in the Fiesta St series in Europe.

I think you could mount the 14mm KB Laser bar on the beam and drop links from the leading beam mounting points.

My car only steps out if you back off mid corner and tap the brakes. Hopefully this is fixed now. I have separated the circuits so both rear are together and fitted a Wilwood proportioner and should be able to get the correct bias now.

[Adsy01]

I've been looking at the KW kit, the shocks are built by Koni, or so i'm told. Very nice gear, but i'm not so sure if i want coilovers for the street though (and the front rate would be a touch higher than what i need) . I'd never adjust it once set up. I'm currently looking at koni or bilsteins to go with my eibach's that are already on the car.

I'll measure up and sketch out the rear beam when i fit the brakes this weekend, then head on down to wreckers with a tap measure and vernier in hand!

[Adsy01]

Well i got a little ahead of myself today. I did some very quick measurments then headed down to the local wrecker. I picked up a 14mm KE laser bar, the KA/KB lasers they had there didn't have a rear bar on them.

I looked under every other FWD car there as well as a few small RWD cars but nothing else had a suitable shape and/or width.

Sometime over the weekend while fitting my rear discs i'll work out a way to mount it, if i can't make it fit, then i will modify this bar to use as a templet and get a new one made up at a later date.

Watch this space!

[Adsy01]

Well, so much for a "X-mas Project", my car is now fitted with a 14mm rear sway bar.

I've only had a single test drive, but adding a rear swaybar has done all the things you'd expect to the car's handling. The increased steering response is fantastic! The car steers to where you point the wheels with no sign of the dreaded FWD plough understeer. Body roll is is greatly reduced (but it's not stupidly stiff). Traction seems in be better too.

Pics....


The shape of the bar is not ideal, but it's close enough and it gives me the option of aftermarket bars without getting anything made up. Once i figured out how to fit it, the rest was pretty easy. It took me about 6 hours in total to plan, fabricate and weld everything.

Heres the run through, i've used the KE laser rear bar with its standard "D" bushes and "D" bush mounts that fit into custom fabicated mounts that are welded onto the rear beam. As you can see in the third photo, I've abandoned the traditional link pin set up for a short pin mount (an idea I pinched from whiteline), It only uses three rubbers and no crush tube. I've welded in mounting plates under where the spring mounts are. These have the cup washers from the Laser welded on to it to locate the link pin bushes (again the Laser ones). I also used new high tensile bolts. It currently has the old OE ford/Mazda rubbers on it, i'll have to order some new poly bushes for both bars at some stage.

I could go larger in size on the front and rear bars, Whiteline offer a few sizes for the laser and i've got two options for the front in the XR-4 bar @19mm or the H&R bar @ 22mm, but i'll leave it like it is untill after i can afford to get some decent shocks later on.

Thanks for the lead on the bar Mike!! Now I do believe i have the only Street driven mk6 Fiesta with a rear swaybay in the country, if not the world? :

[kiwijohn42]

Nice work.
Have you looked into axle spacers from the Ford Racing Puma to achieve a similar sort of result by widening the rear track?

[xr4racer]

Good work. I wish I had thought of beam mounting!

I am a little concerned about the effects of welding on the beam, but it may be fine.

I am pleased that you agree with my take on the handling improvement. The 22mm used on a race car would be excessive and probable unsafe on a road car. The traction is better because the front is not rolling as much.

[xr4racer]

Just a thought about the rear axle spacers - they may work but ST series racers in UK cant pick the difference. Something I found is that the rear can have as much as 7.8mm of Toe In. Ford do this to make the car track better but it does dampen steering response.

[Adsy01]

Mike, Welding onto the beam in the manner i've done is fine. If you look at the construction of it closely it's actually quite a crude thing thats held together with some slaggy welding, it's not a heat treated item either. Whiteline do sell U bolt mounted D bush mounts that will work just as well, i was going down that path, but just got on a roll. Plus i got change out of $50 :

You could lose the weight of the crossmember you've made for yours if you remounted??

I doubt i'd go up a rear bar size without going up in the front too (with my current spring rates at least). The next size up is for the Laser bar is 16mm, that with a 19mm front bar would give the car even more rear bias than now, but that should only be close to what you had with the XR-4, when you take in mind i've got a thinner rear beam.. (by the way it measured 7.2mm).

John, i have considered the 12.5mm spacers, infact i was close to ordering them this past week, I still may add them at some stage to help fill the arches. In the end i didn't think they would improve the rear enough on their own (Mike, Intresting that the UK ST racers seem to agree?), so I chose the sway bar. They're also tuneable, as there easy to change sizes/remove to suit different situations.

7.8mm of toe in! I might get mine on the alignment machine again soon and check it out, though the tyres arn't showing signs of that sort of toe in.

I see on the XR-4 forum that Whiteline are promising to do a bar in the new year now....
I think they'll use their clamp on D mounts close to where i mounted mine, but then run the bar around the coils and use link pin mounts that bolt onto the lower shock mount. This seems to be their most common way of mounting a rear bar in a FWD car.

[Adsy01]

Seeing as it's quiet on here I thought I’d post a bit of an update on the rear sway bar.

I've had the car in just about every legal driving scenario now and I can’t fault it! Wet or dry I’ve had no surprise oversteer. The steering feels very responsive, the rear doesn’t try to roll over and play dead like it used to and it’s near impossible to induce understeer at speed that are legal on the road. I guess I feel that the car is handling like it should have been to start with from the factory!


However, I’m not after a factory “sporty” handling, Nor do I want a race car setup. So while the front to rear balance is now great, the front still isn’t ideal as far as body roll is concerned, so I’ve decided to up the ante!
I’ve got a 19mm ST front sway bar coming from the UK and I’m awaiting a postage price to order the Ford 12.5mm rear spacers.

The idea is the front bar will stiffen up the front roll a touch (it’s the smallest increase I can go). This will induce a touch of understeer back in to the car. The rear spacers I wanted for cosmetic reasons anyway, but I’m hoping that they will help tune out some of the understeer introduced but the 19mm front bar. I will also get some new polyurethane bushes for the rear bar to ensure it works efficiently, as it still has the shagged bushes from the wreckers on it.

That in theory should give me roughly the same front to rear ratio as I’ve now got, but with another increase in roll stiffness.
I now doubt I’ll change away from the eibach coils I’ve got now, so I won’t have to change any of the bars once I do get up-rated shocks at a later date.

Also I think it would be a waste of time to fit the larger 22mm front bar and larger rear bar unless you wanted to run semi slicks, I think you would get to a point where street tyres would start to four wheel drift very quickly once they got any heat into them… and as Mike has shown on the track he doesn’t need a bigger (than 19mm) front bar anyway.


I'm looking forward to having all this gear, but i'm not looking forward to fitting the front bar :evil3:

[Fled74]

Nice work dude. I've been following this thread very closely.

[Piotr]

Has anyone change the front bar on the fiesta?

Getting my rear bar done ATM and they are having trouble with the front.

[Adsy01]

I've got the ST one here to go in...
I've had a look and i can't see a way of doing it without dropping the crossmember. I plan on dropping the ball joints and the crossmember mounts and supporting it on the jack, dropping it until i get the required clearance.

What size bars are they using?

[Adsy01]

just to clarify, the standard WP zetec front sway bar is 19mm not 18 as i had thought.

[Fled74]

Sorry for digging up an old thread, but I was planning on ordering a 22mm rear sway bar from Whiteline (through Pedders). However, the bloke at Pedders recommended the 24mm one which they use on their XR4.

Which would be better for a street-driven Fez with stock suspension?

[zetec jim]

I would say the it doesn't really matter, but i'd go for the less hardcore 22mm. Having said that, i've got the 24mm (off someone on xr4.com), even though its not yet put on...:(

there may be a shorter delivery time on the 24mm one too

[Fled74]

I'm going to Pedder's right after work to place the order; I'll probably go for the 22mm.
The softer rear bar should be enough - I won't be modding the suspension anytime soon.

[Fled74]

The 22mm sway bar is coming in this afternoon. Reade at Pedders South Melbourne (and on the XR4 forum) hooked me up.

Gonna pick up some jack stands on the way home today.

Quick question though: do I use the standard jacking points on the car for the stands? Or would ramps be less of a hassle?

[Ben85]

I'd go ramps, but you'll need planks of wood, otherwise they will be too steep for the car.

[zetec jim]

Originally Posted by Fled74

The 22mm sway bar is coming in this afternoon. Reade at Pedders South Melbourne (and on the XR4 forum) hooked me up.

Gonna pick up some jack stands on the way home today.

Quick question though: do I use the standard jacking points on the car for the stands? Or would ramps be less of a hassle?

Are you gonna do it yourself Fled? nice work, let us know how it goes?!

[Fled74]

I'm borrowing my mate's ramps tomorrow after work, and will fit the bar on Saturday.
Got plenty of timber in my garage that I can use to make the ramp angle shallower.