The Best of 2021, #3: Resurrecting Project FR-S: Wisefab Track Suspension

We changed our rear spring from the standard KW 7 kg to 8 kg as we were experiencing some high-speed rear squat due to aero loads.  We changed our front spring from the standard KW 6 kg to 10 kg to make up for the change in motion ratio and to keep the balance the same after increasing the rear spring rate.

We installed the Wisefab front suspension, replacing the OEM parts. We adjusted the front lower control arms out to their maximum length to get our front track as wide as possible.  This is a trick we do to a lot of cars to reduce understeer by reducing weight transfer to the outside wheel.  We had Victory Function wide fenders so we had plenty of room to do this. We were also getting some rub at full lock on the insides of the wheel wells so this was going to help.

We kept our Vorshlag camber plates.  Since we were using the adjustment in our lower arms to increase track width we used the caster offset built into the Vorshlag plates to maintain our 6 degrees of positive caster.  We also feel that the Vorshlag plate with its beefy sealed angular contact thrust bearing is a superior, longer-lasting design.

We wanted to get rid of the stock anti-dive geometry of the front suspension.  Anti-dive causes the wheel rate of the front suspension to rise under braking.  If you trail brake to get more weight on the front end to reduce understeer, the wheel rate will rise due to suspension torque reaction binding.  This will increase the car’s tendency to understeer under braking counterproductively. Ever wonder why most race cars with bespoke chassis like Formula cars have zero anti-dive? This is the reason.  We raised the front control arm pivot point by swapping the high misalignment spacers around to get rid of about 70% of the OEM anti-dive.

One of the problems you will now have is the control arm will hit the unibody under compression.  With the arm in the standard configuration, you can bend the unibody with a hammer or slightly grind on it for clearance.  With the spacers flipped this isn’t enough.

22 comments

  1. This sounds like a weird consideration but I wonder if that adapter for the front upright is to save costs – it looks like if that was made as part of the same machined upright, the billet would have to be an inch or two “taller” and everything but that one mount would have to get turned into chips.

    It seems like the geometry changes the Wisefab kit makes make a lot of sense but I’m with you in feeling weird about the whole idea of going down in rod end sizes, plus the skeletonized arms… I don’t know.

  2. “We hope that Wisefab might consider some of the issues we have with the kit and make some small improvements to it.”

    It looks like the current kit on sale has already improved on some of these issues. The rear lower control arm and the bent toe arm look signficantly beefier.
    About the front adapter, perhaps it’s for the guys who want to run massive offset wheels so they can attach the strut to the outer mounting points and have less radial load on the shock absorber shaft.

    1. That’s great that the parts are beefed up! I still don’t see why the adaptor is needed. The strut hits the wheel without it. Why cant the upright just be made with it incorporated into the design? One thing is that Wisefab has great customer service. Our kit was missing a few small parts and they had them in our hands in two days with one email!

      1. I do a bolt on strut mount on the Evo uprights (SSB Designs) for 2 reasons. 1, its a 3″ tall block to machine instead of a 5.5″ tall block. 2, Flexibility in offset, height, and camber. I get requests for a bunch of different flavors like a reduced ride height version for a Mirage Proto in Singapore or my Extremely long version to push the strut to the inner wall for max tire clearance.

        Single piece is fine, but there’s very little drawback in separate parts in practice.

  3. It is great that you saw even more improvements in the handling of the car- it really has been a fantastic project car (followed closely by the cayman). It is equally valuable to hear of the challenges with the installation, and the concerns over aspects of durability. Hopefully further design and component refinements are made by WiseFab- the adjustability of this setup really makes it an appealing option for any 86/BRZ that sees regular or dedicated track use.

    Regarding the bearings and the decreased self-centering of the steering- is it an issue of the small bearings binding under a load that would be distributed more evenly with a larger bearing? Do you know if they use a bearing with a low friction liner, or grooved liner designed to be used with lubrication?

    Disclaimer: I went straight to google after reading this article – the SKF bearing website had a great “principles of selection and application” section, which lead me to ask about the type of bearing, and whether that could be an issue. Prior to that search, my knowledge was limited to “yep, that is a spherical bearing (heim/rose joint)” 😀

    1. I think higher quality bearings would help and when these bearings break in. After one day at the track, it was getting much better so I think another day at the track will do it.

  4. y’all should ditch the front and make your own double wishbone setup like HKS did with their “look what we can do but we’re not gonna sell any of these parts” time attack 86.

          1. my memory has betrayed me… I was remembering a fab’d A-arm out of small diameter tubes…

          2. It is not RX8 parts, if anything they are similar to VA Impreza parts. The RX8 has upper control arms, this is McPherson strut.

          3. We’re talking about the HKS car which did a double wishbone conversion (well, added an upper arm). see youtube link Rich posted.

  5. Placing rods so the stud is in bending stress is bad engineering. It’s a common error and just makes me cringe when I see it on suspension parts.

  6. I wish the wisefab kit wasnt so $$$. Do you have any experience or knowledge regarding the quality and design of the Partshop Max kit for the FRS? It looks like it offers similar features as the wisefab.

  7. This article should be named “Hella flush done correctly”
    Just a question: why didn’t you keep the 8 degrees of caster you used to run before without wisefab kit?

    1. I have been running less caster with wider wheels and tires as of lately. I have been finding that I don’t like the weight jacking that a lot of caster causes, especially with strut cars.

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