Sway Bars Cracking Subframe?

[InsTwin]

So I was on reddit looking at our car's subforum when I clicked on this imgur link:

http://imgur.com/a/qNe3o

Noticed a comment from some anon on the internet claiming to be a Ford engineer for the Fiesta ST and asking the poster not to add sway bars to the car because they cause the subframe to crack.

Anyone have any comments on this besides 'don't believe everything you read on the interwebz'?

 

[JasonHaven]

I sent him a message linking to here, to see if he'll drop by and talk about it/back it up with data or something.

 

[D1JL]

I find this difficult to believe.
Although I must clarify that I am not an engineer as I do not drive trains for a living.
This would mean that those with standard Fiestas must be having a lot of problems as they have a larger front sway bar as OE.


Dave

 

[InsTwin]

Nice! Great idea, hopefully we get some response.

Edit: Also, looking at his post he says 'please don't upgrade front or rear' but there is no rear sway bar even to upgrade on the FiST?

There are mounting points (which I thought was strange since it doesn't come with a rear sway bar).

 

[RAAMaudio]

The standard Fiesta bar is not all that big so likely not an issue but I have seen cracked sub frames, fixed a few, on other cars with this issue.

 

[mxq]

Hi guys. I think it was my original post you are commenting on. Just to be clear I am a designer and vehicle engineer for a race team that designs things for Ford and Ford Performance (Formerly Ford Racing) . We build a set of beefed up sway bars for the fiesta, and they worked really well. The problem was the mounting areas on the sub were too thin and the added stresses eventually cracked it. Its a relatively easy fix but we couldnt do it, as it would change the sub frame and therefore the product would void the Ford factory warranty so we couldnt do it The fiesta doesnt have a rear sway bar but we added one so the car could be corner weighted and better balanced. Again, it worked great but broke the sub.

Also, the factory designed one is pretty good to be honest and will last the lifetime without breaking the subframe, so no worries there.

 

[Young L]

For me I feel like they aren't even necessary, with just my h&r springs and rear TB brace to me the car corners pretty flat.

 

[mxq]

They really arent necessary for daily use thats for sure. Ford did a really good job with it. But if you are going to seriously lighten it and race it, you will need them. Balance is not great on the car and you need to corner weight it. Its about 60/40 disrtribution with the front being heavy.

 

[JasonHaven]

So, if I were to get one of the two:

http://www.piercemotorsport.com/2014-2016-fiesta-st-rear-torsion-bar/

http://www.piercemotorsport.com/2014-2016-fiesta-st-lateral-rear-trunk-brace/

Which would be safest/best performing?

 

[D1JL]

So then it sounds like using the factory front bar form the non ST and an Eibach bar or beam stiffener from Pierce in the rear should work just fine.
Then with a set of coilovers (like the ones designed by Ford) for corner weight adjustments you would have a great setup.
Frame bracing would be an added plus.



Dave

 

[JasonHaven]

So then it sounds like using the factory front bar form the non ST and an Eibach bar or beam stiffener from Pierce in the rear should work just fine.
Then with a set of coilovers (like the ones designed by Ford) for corner weight adjustments you would have a great setup.
Frame bracing would be an added plus.



Dave

Link?

 

[D1JL]

Link?

I was referring to the B-Spec set designed by Ford, built and sold by Eibach.
However any good adjustable coilover set would work as well.


Dave

 

[Young L]

They really arent necessary for daily use thats for sure. Ford did a really good job with it. But if you are going to seriously lighten it and race it, you will need them. Balance is not great on the car and you need to corner weight it. Its about 60/40 disrtribution with the front being heavy.

Oh dang I forgot I had the Pierce rear strut bar also, I can see it getting a little more loose after lighten it a bit. So far all my laps on the Ring or Hockenheim have been full weight +/- a passenger and whatever fuel I had left.

 

[RAAMaudio]

I am running the stock front bar with stiffer bushings everywhere, no rear bar, DIY two point front brace and the "race" spec BC coilovers with stiffer springs. I changed the rear camber so my car is not ever going to be like other FiSTs so I have to do my own testing but as it sits I am quite satisfied with and only expect modest improvements a the most.

It is always better to deal with spring rates to control body roll as much as possible and still make the car streetable if so used. The spring rates I am running are far better than the stock rates for ride and handling, I will try the next level in stiffer springs before sway bar changes.

After that and fine tuning the shocks, again, then I will test the none ST front sway bar and the 5-way DIY modded BMW rear bar I put a lot of time into making fit and building good mounts for.

During the testing I will see what gains I get from a couple of more chassis braces though I do not think this car really needs them beyond a 2 point and perhaps STB. I will test for actual gains and not how it feels which can sometimes be deceiving.

If one is building an all out handling car THE LAST THING TO TUNE WITH IS SWAY BARS but for most street and street track applications built below a full race car there is not much choice but to use them sooner for most owners needs. That is why I am doing those last as want the absolute best handling FiST as I can make it and still a great car to go site seeing

 

[wspec]

This is different but kind of the same umbrella. I had to replace the driver side front wheel bearing today, It is probably 5k miles or less on it. It is not the OEM one, it is the one I put on when I changed out my hubs, it was whatever brand the auto parts store had in stock. I am putting a motorcraft one back in this time to make sure its at least OEM quality.

I have upper brace, 6 pt lower brace, cobb sway bars, bushings, coilovers, and a bit of camber on it. In concert with the sticky 225 section tires I run I am not sure if it was just a bad bearing or putting so much cornering load on it, or a combination of both. I going to back of the camber a degree or so and will have to watch it to see if I have anymore issues with it.

But now I will also have to keep any eye out for my subframe staying intact. Thanks for the worries

 

[Joszer]

I upgraded to the bigger front and rear sway bars almost immediately when I got my fiesta. So far I have placed 18000 miles on the car with over a dozen hard track and autocross days. I'll take a look at the mount points to look for possible signs of cracking. So far the car feels great. What really made the car shine with the bars was the addition of some swaybar endlinks.

 

[FORZDA 2]

I also have the Eibach f/r bars and they're perfect for the instant transitions in typical autocross. A strut suspension FWD car doesn't follow the standard suspension setup rules. The most limiting factor is front grip. Whereas conventional setup says smaller front bar that is almost the worst change you can make. The very poor camber curves of the strut fwd car go towards positive camber/less negative camber which reduces front grip in heavy load cornering. A spring stiff enough to prevent such body roll/camber loss is very near rigid and requires very expensive dampers to prevent bouncing. Just saying based on my 40+ years of autocross solo and pro solo/drag racing and motorcycle racing. You can check out one of my performances on this vid.
https://m.youtube.com/watch?v=6lOlO67dC0M

 

[FiSTicuffs]

Here's a long shot as this thread has been dead for two years. Just picked up a 2017 FiST and was curious to see if anyone running front/rear sway bars has had issues with the subframe cracking as noted above??? I bought this car with the sole intention to autox it, picked up a conn stg 1 pack and some eibach sway bars and found this out. Before I install them I was hoping to hear some long term reviews....thanks fellas.