The First Rule of Fight Club.

Today, I took the car to 949 Racing in Lake Forest, CA.  From my deep roots in the miata community, I’ve known Emilio Cervantes, owner of 949 for a long time.  He has developed a reputation as a racer, manufacture, and curious mind.  He is the miata community’s Tyler Durden from Fight Club.

Tyler Durdan himself

The first rule of 949 is you don’t talk about 949.  So while we took a ton of measurements, and Emilio filled up a pad of paper with notes and took pictures, he won’t talk about his plans for the chassis. But he clearly is fascinated with this new car.  I appreciate the way he approaches product development, and look forward to whatever he ends up releasing. But because of rule #1, I’ll strictly be discussing our findings and measurement with wheels/tires/and brakes, and very little about 949’s plans.

Wheel & Tire fitment

949 made a small run of a 17×9 +48 wheels in a 5×100 bolt pattern.  They had one on the shelf with a 255/40/17 Nitto NT01 mounted on it.  This tire has a 10.35” section width on a 9” wide rim.

949 wheel mounted with a 255/40/17 Nitto NT01

Not all 255’s are really the same size – an important point to remember when you are cramming so much tire under the front fender of these cars.  This combination initially hit the spring on the +48 offset.  We added 2 3mm spacers, essentially creating a +42mm offset wheel.  This was enough to allow the 255 tire to clear with all stock components in their stock location.

checking stock camber

Stock camber will make this a tight fit on the wheel well. Stock, our front camber is -.4° on the driver side front while -.2° on the passenger front.

The 255s would hit the fender at this setting as the strut doesn’t camber in under compression like other geometry configurations.

Stock crash bolt vs the one available from Subaru

By replacing the front crash bolts in the upright with Subaru crash bolt part # 901000394 you can pick up another degree of camber making the tire tuck under compression.  For reference the Subaru bolt is a M14x60. All it is is a slightly smaller diameter bolt to allow some slop in the upright.  Not the most eloquent solution, but for $5 each, they should get the job done.

Only problem with this configuration is that by leaning the upright in closer to the strut, a tire this big would rub against the stock spring and perch.  So the real long term solution is either run skinnier tires, or run an aftermarket coilover with a thinner diameter spring coil. If you do this yourself, remember you will need to reset the toe in the alignment as that will change if you re-angle the upright.

clearance of +42 17×9 with a 255 on stock camber. You can see the bolt that is replaced with the subaru unit at the top of the upright in this photo. If you lean the upright in toward the spring to get more camber, they’ll hit. So answer is smaller diameter springs or thinner tires.

255/40/17 clearance on a 17×9 with +42mm offset and .2 degree of camber.

Same wheel/tire combo on driver’s front as photo above. With a practical front camber number, this will move from hellaflush to hellafunctional.

We then test fit the wheel in the rear.  There is definitely plenty of room here.  I assume the car will like the square set up more, but if for some reason it oversteers, we can add more wheel in the back pretty easy.  The challenge in the rear will be adjusting for camber.  There doesn’t appear to be room for offset ball joints.

Sorry for publishing a blurry picture. I didn’t realize it would come out this way when I took it. You can see a little of the cast upper control arm here, and the stamped lower one.

Unless there is another solution already on the market for another Subaru, the best way to get camber to adjust looks to be an aftermarket control arm.  The upper one is cast and scalloped for clearance, and not one I’d try and replicate, but the lower stamped piece looks easily copy-able.  A quick modification to the toe link would then give us adjustable toe.  If there are already solutions that translate from other chassis for this, please reply in the comments section.

Brakes

I have had great experiences with Carbotech pads on my miata, So I’ll be using them again on this chassis as well.  I wanted to test fit pads before the first time the car went to the track as I wasn’t completely sure the info we were finding online was correct.  The FR-S will wear XP10s in the front, and XP8s in the rear.  This is a common S2k setup, so I expect it will be a good place to start.  The operating temp range starts at 200°F and goes all the way to 1650°F for the XP10 and 1350°F for the XP8.  They don’t chew up rotors, even when cold.  And while they do dust a lot, it isn’t corrosive dust like other pads that eat the finish on wheels or paint.  I’ll likely keep these pads on for the street as I am too lazy to change them over for the street.  They will make noise and dusty, but I don’t think it will bother me.

The slight inconvenience of these pads is you can’t swap back and forth with the stock units as the transfer layer of brake material from the carbotechs isn’t compatible with that of the stock pads.  So you either need 2 sets of rotors, or you need to turn them every time you want to change pads. If I find a cheap source for rotors in the next couple days I’ll just have 2 sets.

front pads on the left fit the car. the pads on the right don’t.

Short version of our findings are as follows: Front pad is properly listed on Carbotech’s website as the CT929.  If you are looking at other brands of pads, just look for what fits the ’04 WRX as these cars share pad design. There is some info out there that says the rear WRX pads fit this car as well.  They don’t.

The shape is right, but the tab that slides into the caliper is shaped differently.  They would fit, but the pad would slide around.

You can see if you look closely at the difference between the stock pad on the right and the one ordered. A quick call to Carbotech has corrected the issue.

The proper pad, while I have not personally fit it, comes from the 2010 Legacy GT.  This is the CT1124 on the Carbotech site.

The Coming Test

The next stop is the track. This is the test procedure we plan to use.  If there are any other suggestions on things you want to see, drop me a note:

  1. 100% stock
  2. Upgraded pads and rotors
  3. Legacy front crash bolts for added front camber and realignment

I suspect that will be all we can cover in that day.  Depending on the wheel/tire combo I end up with, maybe we will test that as well.  But I am a little worried that a 17×9 with a wide tire won’t be accommodated by the change in crash bolts, so that may need to wait for dampers.

The Arms Race

A couple shops in SoCal have gotten FT86’s.  And I’ve talked to more than one that is quietly targeting the 2 minute mark at Buttonwillow Raceway in config 13 clockwise.  It might not be the brightest thing to do considering I don’t even have a baseline stock lap time for the car, but I am publicly stating that is my goal.  I want to be the first person to pilot a naturally aspirated FR-S to the 2 minute mark on this track.  Not sure yet what it will take to get there, but that is the goal. Let the race begin.

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