Wilwood vs K-Sport BBK and Brake Bias

Discussion in 'Fiesta ST Chassis Upgrades' started by was-an-M, Mar 16, 2014.

  1. RodMoe

    RodMoe Well-Known Member


    Color is off as it was a quick photoshop of the TD wheels over my 15 inch snow tires I will be putting Coilovers on so I plan to loose a bit of fender gap but it fills up nice wth the brakes and did not look too awful these tires are 195/55/15 new size will be 225/45/15 so it is a 23.4 dia (snows) vs a 23.8 dia (summer tires) it should be close to looking like this as this picture has the STOCK springs in it yet...

    Oringinal pic yes i have red rotor and lost them in the quicke photoshop

    As it appears a 15 inch wheel makes a tight fit on brakes
    Last edited: Mar 16, 2014
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  3. D1JL

    D1JL Well-Known Member

    Yes, the OE size rotor is about as large in diameter as can be used in a 15" wheel.
    So, much more braking force is hard to achieve.
    Better heat dissipation will still require some rotor mass increase.
    This will of course will require more weight, custom rotors and calipers.
    Again this will surely result in a much higher cost.

    Please do not misunderstand.
    I am not saying that it cannot, should not, or even should be done.
    I am also not saying that any one type or size is the best choice for each of you.
    You must each do what is best for your requirements.

    My goal is to increase braking for the daily driver at a very economical price.

  4. wash

    wash Active Member

    McRib had 15" Sparco Assetto Gara wheels and BFG R1s at the Horse Thief Mile track day. There are pictures and it didn't look bad.

    Heat dissipation doesn't necessarily mean more weight, more cooling works too.

    My plan calls for a 1.25" thick rotor which has much wider vents that can flow a lot more air. The thickness will make them reduce warping too. As for weight, the aluminum hats will make them lighter than stock but on par for moment of inertia. If I can get them to fit under 15s, the wheel and tire will take care of the moment of inertia reduction.

    I'm trying to go for the biggest rotor I can fit in a small wheel and a Wilwood FNSL6r. Hopefully hydraulic pressure will be lower than the point where caliper flex becomes a problem. My rough calculations suggest the pressures will be around 1,000 psi while people have problems closer to 1,500.
  5. RodMoe

    RodMoe Well-Known Member

    In for info can always change wheels if needed :)
  6. D1JL

    D1JL Well-Known Member

    You can also go with RodMoe's idea.
    In the top photo he just left the rear calipers off.
    That will also save weight.

  7. RodMoe

    RodMoe Well-Known Member

    LOL gotta love a quick an dirty fotochop :)
    Some say that brakes just slow you down anyway ....
    Last edited: Mar 17, 2014
  8. D1JL

    D1JL Well-Known Member

    I explored almost that same set up once before for a different car.
    I'm sure it will fit your needs and work well.
    I just find that for the amount of track days I do now it is still cost prohibitive for me.

  9. McRib 1s Back

    McRib 1s Back Well-Known Member

    Yep, 15" wheels are fine. I posted the details of mine in the related wheel/tire thread (15x6.5"/42mm offset). They're an official test-fit listing from TireRack.

    Those puppies got very hot! I fused my centering rings to the hubs! I now have an extra set just in case that happens again. I think that was more about HTM than the smaller wheels, but I'll let you know after Big Willow.

    Speaking of brakes, I'm not in a hurry. I want a substantial improvement, and I'll put on 17" wheels if I need to. For now, I'm enjoying the cheaper spec Miata rubber! The SS lines, Motul 600, and Porterfield pads should hold me over...
  10. was-an-M

    was-an-M Member

    I'm looking forward to the Porterfield pads!

    I also second the Motul. I ran Motul then switched to ATE200 in my M3 and I think despite having similar specs the Motul was more fade resistant. Maybe it was all in my head, but the Motul seemed to be a little nicer.
  11. McRib 1s Back

    McRib 1s Back Well-Known Member

    Back in my SE-R days, we often debated Motul vs. ATE. Both seemed to work great. I'm partial to Motul, and won't switch unless I have a problem. I am going to try the 660 variety next time, however.

    The car really has decent brakes -- that doesn't mean we can't have better! I have a very good feeling about my minor changes; if this holds up to my track abuse, I'll call it good enough for now. My car isn't a DD, so I am willing to put up with more noise, wear, etc.
  12. was-an-M

    was-an-M Member

    I saw the 660 stuff. Then there's the Castrol SRF. But that's just silly expensive. The 660 isn't that much more than the 600 so it might be worth a go.
  13. wash

    wash Active Member

    Brake ducts and big rotor vents are my plan. That should keep the brake fluid and wheel bearings cooler.

    Rotor mass is important but going for more mass without cooling only delays the onset of heat issues.

    I think our dust shields are part of the problem, there is no easy path for air to get to our rotor hat and out through the vents.
  14. McRib 1s Back

    McRib 1s Back Well-Known Member

    I'll bring an IR thermometer to start collecting meaningful track use temps. Big Willow on 3/29!

    You're building for spirited street runs mostly, right? Are you regularly running autox yet?
  15. was-an-M

    was-an-M Member

    I typically just remove the dust shields. I was thinking of putting together some brake ducts if I can find the time.
  16. wash

    wash Active Member

    I see my plan as more of a "sprint" setup than "enduro" but you could run a taller caliper bracket and bigger rotor if you need more thermal mass or brake torque.

    The Wilwood caliper is probably not on par with Alcon, Stoptech or high end Brembo but for autocross/sprint I think they will do well.
  17. McRib 1s Back

    McRib 1s Back Well-Known Member

    Tell me more. I'm game to try an interim upgrade, but afraid my next stop is Mountune's Alcon setup. Awesome quality. You're right, the Wilwood setup is way off. In some ways it's a questionable upgrade over stock. StopTech is also excellent.

    Sprint racing in the context of street stop-light duels, canyon runs, or some kind of track event? I didn't think you cared much for it. Come to Big Willow for a proper race track event! :)

    I really like HTM, but it's very unique. Even SoW feels big compared to it. Both are hard on the brakes!
  18. wash

    wash Active Member

    I was using the Essex AP brake kit naming convention.

    They have sprint and enduro kits.

    The sprints have lighter, smaller diameter rotors, enduro kits have the big ones.

    For a 15", as much rotor as I can fit under the wheel is still smaller than what Essex sells as a sprint kit so I think its the right choice to go for the thickest rotor possible rather than try to find the stiffest caliper possible. The relatively light weight of the Fiesta makes me think its an OK tradeoff, we need less brake torque which means less brake fluid pressure and less caliper flex than a heavier car.

    I'm also cheap and don't want to spend much more on calipers than the Wilwood FNSL6R.

    None of the parts are terribly expensive but I don't think you can improve on them without spending a lot more. I just have to make caliper brackets, rotor hats, brake ducts, etc.

    My cost is going to be about double the Wilwood Fiesta front brake kit but it will cover all four corners, use better calipers and look very nice.
  19. wash

    wash Active Member

    I'm not going to sell kits, just make mine and hopefully someone will be interested in making a kit.

    The alternatives are just disappointing and I couldn't find anyone willing to even investigate the combo that looks workable. That means I have to do R&D that would be easy for someone in the industry but expensive and time consuming for me.
  20. joe@2j-racing

    joe@2j-racing Active Member

    I've completed 4 separated time attack track days with the wilwood kit - DTC60 pads. Stock rear brakes, pads. From 135 to 45mph, turn 10A, road atlanta. No bias issues. No ABS issues. Nothing but excellent feel, bite and no fade.

    I think some people speculate while other actually go out and do it for themselves. Dont fear, you can run large front brakes, race pads - and have no issues.
  21. was-an-M

    was-an-M Member

    Good info. I didn't mean to suggest there would be a bias issue.

    I think I'll need to hold out for OE size race pads cuz I went for 15" wheels and I doubt the wilwood kit will fit.

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