Wondering about sway bars

Discussion in 'Fiesta ST Chassis Upgrades' started by salagahle2000, Dec 2, 2014.

  1. salagahle2000

    salagahle2000 New Member

    I saw an interesting video on YouTube this afternoon discussing the hidden drawbacks to sway bars. The guy making the video seemed to be talking specifically about his experiences with sway bars on Miatas. His argument was basically that sway bars reduce grip because while it keeps one wheel planted it unloads the opposite wheel. Anyway he seemed to have some success running his car without sway bars. I'm wondering if someone here has some meaningful insight or experience with running their fiesta sans sway bar or with a modified setup.
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  3. FORZDA 2

    FORZDA 2 Member

    The video was specifically addressing cars with "real" suspension, not FWD struts. I have 2 Miatas and have autocrossed both FWD and RWD cars for about 3 decades. The FiST needs a bigger front bar to keep the nose from rolling too much and killing the front grip with positive camber. All of the suspension tuning guides are addressing RWD cars, not FWD cars. The big issue with strut cars is the very shallow or even reversed camber curves. A well-designed suspension (like the Miata) has an aggressive camber curve meaning that as the suspension compresses, the camber goes much more negative to counter the body roll. Strut cars have very little camber gain and may even have a positive camber curve that actually goes more positive as the suspension compresses. This is usually designed into a crappy handling car to ensure massive understeer so when you're going to fast and hit something, the car is headed straight towards it so the airbags save you from your poor driving ability.

    A FWD car "with strut suspension" will ALWAYS benefit from the largest front bar you can fit. Usually around 25 to 30 mm, depending on the front weight of the car.
    Smokin likes this.
  4. Chuckable

    Chuckable Member

    Suspension tuning is a black art. I've read books on the subject, but am by no means an expert. Almost everyone has a different opinion. But, I think that Forzda 2 is on the right track in differentiating between differeing suspension designs. Here's a great series of articles on handling which touches upon the issue of sway bars: http://www.motoiq.com/MagazineArtic...categoryId/120/Ultimate-Suspension-Guide.aspx
  5. AlanBDahl

    AlanBDahl Active Member

    It really comes down to the individual car and driver as to what works best. I found that a bigger front bar on my NB Miata didn't help all that much until I replaced the sway bar brackets with the reinforced ones and added DA shocks. However on my NC Miata adding a bigger front bar caused the inside front to lift off as much as 10" so it definitely was the wrong approach there. WRT the FiST I think I'm just going to have to experiment. My educated guess is that slightly larger might help but if you go too big you'll loose traction. As to what the perfect size is I can't say but ideally I'd like something with adjustable ends so I can make minor changes trying to find the sweet spot.
  6. MacDubois

    MacDubois New Member

    While I absolutely agree with this, particularly on vehicles with torsion beam rears (basically just a big sway bar) and even more so on cars with LSDs (even electronic ones); I am curious to know if anyone has actually tried a big front bar on an otherwise stock FiST.
    I am considering the standard Fiesta bar for next years autoX season, but I haven't heard if anyone else has done it.
  7. AlanBDahl

    AlanBDahl Active Member

    Is the standard Fiesta bar bigger than the FiST bar? I thought it was smaller?
  8. RodMoe

    RodMoe Well-Known Member

    std is 22mm iirc and the ST is 19mm only know this cuz i went for powerflex bushings listed to fit our cars but were 22mm and while they fit the where too big and sloppy went back to stock and sold the 22mm to someone that is running a 22mm NA fiesta bar on front..
  9. Chuckable

    Chuckable Member

    Smokin, F1ST and Cligedy like this.
  10. salagahle2000

    salagahle2000 New Member

    I have started working with M Sport UK on my build so as I learn more about what they do I will share that. I figure that it may be pretty useless information though, as the goal is to convert the car to AWD which will completely change the dynamics of the car. That being said they do offer parts for their R2 spec car which is still FWD. and I don't think there is anyone in the business better at making a Fiesta go fast on a real road than M Sport.
  11. Chuckable

    Chuckable Member

    Thanks for the reply. In case anyone is interested, here's the link to M Sport: http://www.m-sport.co.uk/
    Please keep us updated on your progress!
  12. Golfguy11800

    Golfguy11800 Member

    M-Sport is THE source for all things that will make your Fiesta go faster.

    Am trying to figure out if we can "bolt on" a Reiger Fiesta R2 tarmac suspension to our ST's. All the suspension kits for our Fiestas are for track racing, I'm looking for some rough rally tarmac road suspensions that can handle jumps, smooth, and rough, no gravel/ dirt though.
  13. Slowclimb

    Slowclimb Active Member

    I am planning on running a stock fiesta bar upfront this season. On my miata I ran a bigger front bar and no rear bar for autocross.
  14. MrEss

    MrEss Member

    My plan is to stay with stock diameter front bar but change out to poly frame bushes and adjustable end links and side slip locks. Because i think "when" the bar becomes most effective in a turn is as important as "how much total effect" it has in a turn. I have seen no discussion of that variation of the issue of big vs little bars. I also like having the ability to adjust the balance a bit to compensate for a relocated battery and measured fuel loads. because once you have drained the washer fluid (minus approx 11 lbs, moved the battery to rh rear, deleted the rear seat assembly and adjusted the fuel load. That is about 170 lbs or so of shifted andor removed mass. It had a profound effect on how my basic fiesta handled with Koni sports. An ST with aluminum seats, lighter wheels, larger charge air cooler, a quaife diff' and a ECM reflash. will be a hoot on open track or solo courses. I think people get the notion that suspension is a black art because they do not take into account the fact that almost no two cars have the same driver weight/tire type/level of prep or equipment installed! IE; A FIST with a 190 lb driver that has a full tank of fuel and a factory sunroof rolling on full tread depth tires, will be a totally different animal from the one right behind it on the grid with a 120 lb driver, No sunroof and 1/8th tank of fuel sitting on shaved tires.
    Last edited: Feb 20, 2015

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