My Harness Setup

Discussion in 'Fiesta ST Autocross' started by CrookedRacer, Jul 10, 2014.

  1. CrookedRacer

    CrookedRacer Active Member

    I just finished installing a harness in my Fiesta ST... so I thought I'd share.

    There were a lot of comments and suggestions and warnings and cautions and caveats and questions and cautions and warnings and....

    Well, I genuinely appreciated these contributions. I made several changes and did much additional research as a result.

    At the same time, I think I've arrived at the final configuration of the harness, at whatever risk that happens to represent to life and limb, and I'll be using it this weekend at two events.

    Here's the writeup:

    Here's the harness I bought:

    Here's the seatbelt extender I bought (because I'm just too busy to be shlepping to the junkyard to find a belt tab):
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  3. jasyatz

    jasyatz Member

    Nice work! Question on your front Koni insert install.. Why didn't you just use the Koni insert that mounts from the bottom with a single bolt and use the rubber o-rings and bootie like the RSX/8th Gen Civic use? I looked into both these options on my Mazda2, but I couldn't get a coil over perch on the strut tube low enough (because of the sway bar bracket location and the high spring perch) so I abandoned the project.

    Chris from Redshift Motorsports has been doing struts like yours for a couple years now if you need help with the welding. He is who I was conferring with while I was investigating struts for this platform. The Mitsu Eclipse rear shocks work also, as do later gen Focus stuff. The Focus bodies actuall match right up to the stock Fiesta mounts.

    On your harness, why not get another one of the extenders and mount it to the outer chassis bolt for the rear seat belt lower mount and use the rear seat belt buckles to hold in the harness in an "X" design? I mirrored the design of a Schroth quick fit harness using OE Ford seat belt extenders for an Escape. Heres the Quick Fit design [​IMG]

    I can snap a few of my harness if you'd like to see it.
    Last edited: Jul 13, 2014
  4. CrookedRacer

    CrookedRacer Active Member


    On the Koni's, I could have gotten the single adjustables and been done already. But I had to go the difficult route and get double-adjustables which don't connect that way - they have to be captured with a ring nut. So, I guess the simple reason is stubbornness and hard-headed ness. And principle. :)

    I talked to Chris from RedShift, actually. He had some threaded pieces but they were too short. And expensive. And I'd need to buy two of them for each side and weld them together all stacked up. I really felt like one seam was enough to contend with, let alone two and all the potential for misalignment that comes with doing that.

    I used my harness for both events this weekend. And it worked out perfectly. I liked that the attachment point for the shoulder harness was fairly level with my shoulders, and not diving down to the seat buckles at a potentially spine-crushing angle. I loved having the feedback that comes from being part of the car.
  5. jasyatz

    jasyatz Member

    Sounds like you covered all the bases like I did and we all gain from information sharing! I bent my rear seat back hook in my MINI attaching it there, and that was just from tightening the belts. I figured Schroth wouldn't design and market it if it wasn't safe. And attaching it to factory anchors, even at autocross speeds and slightly steeper angles is acceptable( according to schroths reccomended belt angles).

    Doubles in the rear?...I put the AGXs in the rear to test fit them (since they were $112 shipped new for the pair from Summit) and see how much more shock was needed from there.. Doubles are Definately needed in the rear, but I think singles would suffice for most regionally competitive cars.. We need the fronts yesterday though...I here Koni is very close to having singles ready for the Fiesta/FiST/Mazda2 chassis. not sure what the holdup is, valving or fitment, but I've heard they'll be here before the end of the season..(Oct/Nov)
  6. ryst

    ryst Active Member

    This might sound silly, but what about running the top two belts off both the left and right rear seat mounts? Then it wouldn't pull toward one side, and you'd get twice as much strength. Since you're not using the back seat during AutoX it should be fine. With the shackle setup it shouldn't be a problem to add another point.


    Also your writeup on the shocks and safety harness is amazing. I love seeing people do this kind of stuff. I was wondering about adding 4 point harnesses to my car and where they would attach.
    Last edited: Jul 14, 2014
  7. CrookedRacer

    CrookedRacer Active Member


    Your idea isn't silly. It's a great idea, and I think it would work, but I don't have any more of the submarine straps. The harness only came with one. You probably wouldn't get twice as much strength, though, because the lateral components of the angled forces of the two straps would also be terms in the equation.

    The offset of the shoulder strap extension isn't perceptible at all. You can't tell when you're wearing it or driving that it's not centered.

    I inspected the rear seat latch bar and it was solidly square and in place after my weekend's events. I'll keep an eye on it.

    Also, I didn't do double-adjustables in the rear. They're single-adjustable Koni Sport Yellows. (adjustable for Rebound only)
  8. ryst

    ryst Active Member

    Yeah you're right, I forgot about physics.

    Using some rough calculations and guessing on the angles, you would probably reduce the load on the point on the drivers side by about 20-30% which isn't bad, considering perfect load splitting would only be a 50% reduction. The load on the passenger side would be lower than the load on the drivers side, because of the angle.
  9. Nik17

    Nik17 Member

    I also added a four point harness sometime ago. I did post this somewhere else (but it escapes me where).

    It's a Schroth Rallye 4 which is bolted in to the seat belt anchors in the rear. It's one of the only street legal harnesses because of it's ASM features, although I almost never use it on the street as it's obviously restrictive of movement and is instead used solely at autocross where it keeps me from sliding around in the rather bolsterless base seats.

    k757 and jasyatz like this.
  10. CrookedRacer

    CrookedRacer Active Member

    Interesting. How did you attach the inside and outside lap belt connections?
  11. Nik17

    Nik17 Member

    For the lap belt, one is bolted into the same bolt as the seat belt receptacle. The other one is I believe bolted to the bolt that connects the seat to the floor, but I will have to double check. The place I bought it from (the US Schroth importer, HMS Motorsport in Danvers, MA) did the install for me.
  12. eRic

    eRic Active Member

    Mightymango and KKaWing like this.
  13. Mightymango

    Mightymango Active Member

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