which to do first? front or back

[DaveG99]

Rear torsion bar or front 2 point brace? Which one should be done first

 

[MeisterR]

What is the reason to do it?
What are you trying to improve?

The first reason to modify a car should be knowing what you want to achieve and what is lacking now.
Then you can pick what parts to change to achieve the specific goal.

Jerrick

 

[DaveG99]

Just looking for improving the handling of the car. I have been told to install the rear first by a guy local to me.

 

[MeisterR]

Okay, what else been done to the car at the moment?
Also, what do you use the car for? Is it a daily, occasional track day, etc?

Jerrick

 

[Zormecteon]

The real achievement of Ford with this car is that it comes with BALANCED handling. Therefore anything you do at one end will upset the other and throw the car out of balance. You need to do both at the same time. If you can't afford to do both at the same time, buy one end and WAIT till you can.

 

[Plainrt]

The real achievement of Ford with this car is that it comes with BALANCED handling. Therefore anything you do at one end will upset the other and throw the car out of balance. You need to do both at the same time. If you can't afford to do both at the same time, buy one end and WAIT till you can.

I'm not sure I buy this lol.......

 

[DaveG99]

I can afford both. Just wondering what direction to take and what the affects are of installing these parts. Im new to suspension mods. The rear torsion bar just keeps the rear bar from flexing as much. And the front keeps the front end from flexing as well. Don't see how that could change the the "balance". I dont think these cars are designed to flex. Reducing flex anywhere should only help theoretically. Right? I guess the best thing would be to just get the street kit from pierce motorsport

 

[Zormecteon]

If a car oversteers, (loose in Nascar parlance,-or tail happy) you put on a front bar. If a car understeers (tight in Nascar speak -or plows) you put on a rear bar. Balance is the goal, .. or tune for driver preference. Drivers prefer different settings,

 

[D-resonant]

The purpose of front lower 2-point (4-point, 6-point) brace is to help maintain front suspension/steering geometry. For me the 2-point help tame the snap drift/oversteer caused by suspension flex.

Adding the rear torsion bar without any front bracing may make the snap rotation worse.

 

[808FiST]

Yes. Get the Street Kit and install 1 piece at a time for your own assessment at your convenience, if you like. I installed the strut tower brace first, but I did not notice much of a difference. I then installed the 2-point and torsion bar braces at the same time, and I would say that those made the most noticeable changes in the handling dynamics of the car. When I added TB Performance's 4-point brace to the existing Pierce pieces, it lessens the chassis flex even more, thus enhancing the effects from the Street Kit that much more. I also added TB Performace's mid brace as well, since it's lighter than the OEM's mid brace. Bottom line, you will not regret getting the bracings for the chassis.

I can afford both. I guess the best thing would be to just get the street kit from pierce motorsport

 

[MPA]

they don't take long to install, so I'd say just install both at the same time. The strut bar took me the longest because I took the wipers and cowl off to make it easier - and it's not too hard to remove.

I installed the street kit last weekend and went on a nice drive on Friday, and the car felt great with it.

 

[FreshST]

Any negative effects of running a 2pt brace and strut tower without the rear torsion bar? My brace just showed up today and was thinking of going for the mountune strut bar next...

 

[D-resonant]

None. Running factory strut/springs with 2-point, Mountune upper brace, pierce trunk brace (no rear torsion). Works well for me on local canyons. FiST now drift/oversteer only if I initiate it.

 

[MeisterR]

Personally, looking at what you are trying to achieve, I say a set of adjustable coilovers will probably be a better way forward.
I am not saying all the added parts does not work, but changing out the core of the suspension with something better will yield better result.

With adjustable coilovers, you get linear rate springs that are a bit more predictable.
You can adjustable front top mount so you can tune your front camber.
And you get adjustable damping that you can adjust ride quality, as well as suspension bias.

The adjustable damper is the main thing, because if you feel the rear isn't loose enough, you can stiffen the damping to get the rear to step out more.
If the front isn't griping well, you can soften the damper to let the front get more traction.
This adjustable damping allows you to dial in a setting that is right for the driver, help you to tune out understeer if it is something you do not want.

In the end, you get a different and much better car to drive than OEM springs / strut with added brace.

Jerrick

 

[Ryephile]

The real achievement of Ford with this car is that it comes with BALANCED handling. Therefore anything you do at one end will upset the other and throw the car out of balance. You need to do both at the same time. If you can't afford to do both at the same time, buy one end and WAIT till you can.

Balanced handling is not what the FiST has. It still understeers at the limit during steady-state cornering. You can Scandinavian-flick it into a corner to get it to oversteer but it is not its normal state. Also, using terms like "upset" and "throw out of balance" is quite sensationalized and quite subjective. If I gave you a back-to-back with a stock FiST and one with 5% more rear wheel rate almost nobody would be able to tell the difference on an imperfect public road.


The OP is mentioning "improved" handling, but we still don't know what that definition is for them. Is "improved" decreased understeer, increased positive caster for a stronger centering effect, increased low speed damping to improve weight transition quickness, or what?


The rear torsion bar will increase rear suspension roll couple and thus cornering wheel rate, which will reduce understeer by making the rear end "looser" at the limit. The front chassis brace does not change wheel rate but it might improve geometry fidelity and give a more precise sensation but it won't change the inherent handling balance.

The whole chassis brace thing is going to be either placebo or minor sensation, because no matter what the spring rates are much softer than any chassis flex or bending. Spring rates versus typical chassis bending force is way over an order of magnitude. You'll bottom out the suspension, bend a control arm, snap a wheel before bending the chassis a whole degree. That's just the physics of it.

 

[MeisterR]

Since we are getting into a bit technical, another thing to put in is adjustable damping as I said before.
One of the way you tune understeer out of a FWD car is to use the rear compression force.

When you get the rear damping stiffing, the increase in rear compression force will help dial out that understeer.
That is why that adjustment is important as it will help cater to the driver preference.

Some like the rear really "loose", and other rather the car understeer so they can power under through a corner.
It will depend on each particular driver's preference, and so that adjustment is pretty necessary if you want to fine tune your car's behaviour.

Jerrick

 

[Ryephile]

Keep in mind that adjusting damper settings only changes transient behavior, not steady-state cornering. e.g. if you prefer to make it easier to flick the rear out on corner entry, increase rear low-speed compression damping.

Nevertheless, adjustable damping is yet another tool to match vehicle dynamics to driver preference. Until the OP says what his goals are, we're just throwing ideas into thin air.

 

[Zormecteon]

Balanced handling is not what the FiST has. It still understeers at the limit during steady-state cornering. You can Scandinavian-flick it into a corner to get it to oversteer but it is not its normal state. Also, using terms like "upset" and "throw out of balance" is quite sensationalized and quite subjective. If I gave you a back-to-back with a stock FiST and one with 5% more rear wheel rate almost nobody would be able to tell the difference on an imperfect public road.


The OP is mentioning "improved" handling, but we still don't know what that definition is for them. Is "improved" decreased understeer, increased positive caster for a stronger centering effect, increased low speed damping to improve weight transition quickness, or what?


The rear torsion bar will increase rear suspension roll couple and thus cornering wheel rate, which will reduce understeer by making the rear end "looser" at the limit. The front chassis brace does not change wheel rate but it might improve geometry fidelity and give a more precise sensation but it won't change the inherent handling balance.

The whole chassis brace thing is going to be either placebo or minor sensation, because no matter what the spring rates are much softer than any chassis flex or bending. Spring rates versus typical chassis bending force is way over an order of magnitude. You'll bottom out the suspension, bend a control arm, snap a wheel before bending the chassis a whole degree. That's just the physics of it.

I bow to superior knowledge.

 

[Ryephile]

I understand we're all coming from different places. It's just key to understand that suspension tuning is not black & white, nor is it black magic; it's a complicated interaction of kinematics and compliances. Understanding all the facets is not something that can be understood in a short period of time.

Ford Performance did do a great job on the FiST given the platform and budget. I have absolutely no complaints from that regard. There is however room for improvement depending on your particular budget and application. The tough part is filtering through all the aftermarket products to discern which combination of parts will give the desired outcome. Admittedly it's not easy given the general trend of vendors and manufacturers offering minimal information. Seeing torsional stiffness measurements of stock versus whatever torsion or sway-bars being offered is super rare, along with application specific damping curves, selectable spring rates for the tires being used, and fleshed-out packages that are track lap-time proven for customers running certain tires would be a nice improvement for the industry in general. I'm not sure I've ever seen a chassis brace offered with actual torsional stiffness data behind it other than some anecdotal evidence.

 

[Joker328]

Balanced handling is not what the FiST has. It still understeers at the limit during steady-state cornering. You can Scandinavian-flick it into a corner to get it to oversteer but it is not its normal state. Also, using terms like "upset" and "throw out of balance" is quite sensationalized and quite subjective. If I gave you a back-to-back with a stock FiST and one with 5% more rear wheel rate almost nobody would be able to tell the difference on an imperfect public road.


The OP is mentioning "improved" handling, but we still don't know what that definition is for them. Is "improved" decreased understeer, increased positive caster for a stronger centering effect, increased low speed damping to improve weight transition quickness, or what?


The rear torsion bar will increase rear suspension roll couple and thus cornering wheel rate, which will reduce understeer by making the rear end "looser" at the limit. The front chassis brace does not change wheel rate but it might improve geometry fidelity and give a more precise sensation but it won't change the inherent handling balance.

The whole chassis brace thing is going to be either placebo or minor sensation, because no matter what the spring rates are much softer than any chassis flex or bending. Spring rates versus typical chassis bending force is way over an order of magnitude. You'll bottom out the suspension, bend a control arm, snap a wheel before bending the chassis a whole degree. That's just the physics of it.

Really good post and nice to see someone who knows what they are talking about w/r/t suspension and handling. Haven't seen much useful info on these forums and so I just haven't bothered with suspension mods to this point. Rather not spend money on something if I don't know what it's doing.

One point I just wanted to clarify is that when you say "The rear torsion bar will increase rear suspension roll couple and thus cornering wheel rate, which will reduce understeer by making the rear end "looser" at the limit," isn't the reduction in understeer technically sacrificing overall traction? If I understand correctly, with a stiffer torsion bar, the body roll of the car when cornering (though possibly reduced) exerts more of an upward force on the inside rear tire so that it has less traction and therefore the rear is more likely to step out. But it's not like you are picking that up with increased traction up front, so you may be losing traction overall. In the end, you may not be picking up any actual time. Is that right?