redSerpente’s HPDE/86CUP Street build

[redSerpente]

2013 FRS HPDE/Track build

I built up an NA miata for HPDE last year, and it was a great learning platform. However I wanted just a little more power with a similar driving style so I could keep up with the pack in the advanced run groups. Forced induction on the miata seemed unreliable without heavy investment.

I saw this FRS pop up for sale right at the top of my budget, and bought it the very next day. It hit all the checkboxes for a good learning platform; NA, RWD, lightweight, easy to work on with cheap parts, and more interior space than the miata (I’m 6’3” so the NA was a very tight fit).

My plan is to make this car a reliable seat time machine - running lots of track days with minimal expenses and maintenance, so I can continue my development as a driver without burning through paychecks. Eventually, I plan to run the car in 86CUP street class once I get everything sorted out.



Current mod list:

Wheels and Tires:
Enkei RPF1 17x9 +45 wheels
245/40/17 Hankook RS4 tires
1320 Extended Studs
Precision 12mm hub centric wheel spacers

Brakes:
Centric 120.47021 front rotors
Centric 120.47031 rear rotors
Hawk DTC-60 pads front and rear
ATE Typ 200 brake fluid
eBay master cylinder brace
MTec stainless brake lines

Suspension:
BRZ Sachs Dampers
Hotchkis Sport Springs
Pedders offset front tophats
SPC front camber bolts
SPC rear lower control arms
-3.0f/-2.4r camber, +0.0f/+0.05r toe alignment

Engine:
EcuTEK bluetooth connector
Xero Limit e-tune
Skunk2 Alpha EL catless header
Perrin Oil Cooler
K&N airbox filter
Corsa catback exhaust

Interior:
OMP TRS-E driver seat
Sparco Sprint passenger seat
2x PLM Fully Adjustable Low Down Seat Rails
2x Racequip 6 Point Camlock Harnesses
Cipher Harness Bar
NRG Deep Dish 350mm wheel with eBay SRK-125H hub
Shift Solutions KR-3 SS shift knob
RAM phone mount
Removed rear seats and seatbelts

Misc:
Verus Hood Vents
Spec D Red Sequential Tail Lights
Whiteline transmission and diff bushing inserts
Perrin shifter bushing
2x OEM tow hooks
Sony XAV AX100 head unit
NATIKA backup camera

[redSerpente]

Part 1: The Beginning:

I bought the 2013 Scion FRS at the beginning of March this year. I run HPDE events with NASA NE, and their first track day was at the end of March, so I would have about 3 weeks to get the car ready. The car came with 17x9 RPF1s and a Corsa catback. It also had some nice interior mods such as the android auto head unit. The car was in good condition, but lots of work needed to make it track worthy. Much less rust than my old miata, and the bushings were in decent shape even after 96k miles. The previous owner also replaced the stock dampers with BRZ PP sachs dampers. The rear bumper got replaced after a small accident so it now has a Subaru logo. I made sure there was no structural frame damage under the bodywork. There is an annoying exhaust rattle, and the tires, rear rotors and pads are all completely shot. Here’s a pic of the car on the day I picked it up :


Here’s a pic of all 3 of my cars the day before I sold my miata to my friend to use as his first track car. The focus was the first car I ever tracked, but now it’s a full time daily driver


Once I got the car home, I washed the engine bay and cleaned out the whole car to make it nicer to work on. I scooped out several pounds of sand and rocks from the interior while pulling the rear seats. Ditched the rear seatbelts as well, but left the side panels since I don't want to fully gut the car yet. Free weight reduction is always good


After getting all the paperwork sorted, I had my first issue to solve; the 17x9 RPF1s that came on the car were the 45 offset variety, and I knew there would be a clearance issue with the Sachs dampers, even with a completely neutral alignment
Any stock size strut would rub the tires with these wheels. Here are some pictures of the distance between the strut and tire:




Less than a mm of clearance... The tires had scuffs from the spring perches.

[redSerpente]

Part 2: Suspension

I didn’t want to go to an aftermarket coilover system right away, so I decided to fix my alignment and clearance issue with some extended studs and 12mm spacers. Installing the studs up front was extremely easy - just knock the old stud out and pull the new one through. Sorry for the awful picture quality - it was getting dark as I was finishing up the job.


The rear hubs were a different story - passenger side was easy, but the driver side hub was very corroded and stuck to the axle. I had to take apart the drum brake assembly and beat the shit out of the metal around the hub to try and pry it loose

Finally managed to slide the new studs in at an angle after a few hours.


Next, I wanted to get a proper alignment so I wouldn’t destroy the sidewalls of my tires. The low budget suspension build would work for a few months until the CSG Spec Tein Flex A coilovers were in stock again. I bought some Hotchkis springs from another ft86club member (thanks aschnell! ) and got those installed, along with the Pedders offset tophats for the front. These would help me reach -3 degrees of front camber along with the camber bolts.


For the rear, I installed SPC camber arms to dial in the rear camber. I left out the eccentric toe bushing that came with the SPC kit since it was unnecessary for my setup - I could hit 0 toe on the rear without it.



Got my track alignment done for 80 bucks at Mavis, and got pretty close to the specs that I requested. Not bad for a chain store



With the 12mm spacers, I was able to install the camber bolts in the bottom strut hole, and the lower crash bolt into the upper hole. I still have lots of clearance on the inside of the tire, and the wheels don’t poke out past the fenders. I highly recommend this setup to those who want to run the 45 offset RPF1s on stock suspension. Here is how the fitment looks from the front and back:

[redSerpente]

Part 3 : Brakes

The brakes were next, with new rotors and DTC-60 pads all around. The previous owner also gave me some stainless brake lines to install onto the car. I got those all hooked up, flushed the brake fluid with ATE Typ 200, and threw on the new rotors and pads. I plan to run this setup for a while until I can afford the Essex Sprint kit. The rear rotors were some cheap blanks I bought from another BRZ owner on FB marketplace - I only discovered that the rear rotors are supposed to be vented after I put them on

Oh well, if they crack, I already got replacements.

[redSerpente]

Part 4: Engine

Now with the suspension and brakes sorted out, the next step would be to bomb-proof the engine. I knew from research that these engines run hot on track, so I purchased a Perrin oil cooler. This was the most painless install I’ve ever done; just pulled the bumper and bolted everything right up. The oil lines even fit with the stock airbox, so no cutting required




I had a great experience using Verus hood vents on my focus st, so I got a similar setup for the FRS to help evacuate hot air from under the hood. After reading about other members having coil pack issues, I bought a couple spare coil packs just in case. Hopefully the vents will help prevent that issue, and reduced lift at the front is a nice bonus. The paper guides from verus were great, and cutting the aluminum hood was extremely easy with an angle grinder





I also bought another OEM tow hook, rattle canned both hooks red, and installed them in the front and back. Only 25 bucks, and they actually work when you need to get pulled in, unlike the chinesium specials that are all over the internet.

The stock tune had strange, non-linear throttle response, and I wanted to eliminate the torque dip. I decided to get some cheap used EL headers off FB marketplace, and got an e-tune from Xero Limit. Removing the cat from the header would also help with temperatures when running the engine hard. I put in a K&N airbox filter as well. The whole EcuTEK tuning process is fairly intuitive, and the internet guides help a lot. After a few revisions, the tune feels great running on 93. I haven’t tried E85 yet; not sure if I need the flex fuel kit to effectively utilize it yet.





No ceramic coating or header wrap just yet - probably gonna do that soon.
Also I decided to swap the spark plugs just in case. This turned out to be a major pain, and I hope I don't have to do it again anytime soon (next time I'll probably jack up one side of the engine at a time to reach the plugs easier ).

[redSerpente]

Part 5: Interior

Now that the mechanical stuff got sorted out, I wanted to install my bucket seats that I kept when I sold the miata. For each side, I drilled 2 holes through the floor pan for anti-submarine belt eyelets, as well as one through the trans tunnel for the hip belt. The codder pins were installed after I took the picture:


I installed a Cipher harness bar for the shoulder belts. Ideally a rollbar is used for this, but NASA and SCCA both allow harness bars for non-competition use. I was quoted 2.1k for a rollbar install, which seems pretty steep; perhaps there is a better solution. I know this a hotly debated topic, so I would be open to suggestions on what I could do regarding roll protection. I don't plan on doing wheel to wheel anytime soon, but definitely time trials. I threaded the harnesses through, following all installation instructions regarding belt angles, and being careful to wrap the belts correctly. The harness bar seemed too high at first, but after getting all buckled in, all the angles were spot on.

I bought 2 PLM adjustable seat rails, which bolted up easily to both the OMP and Sparco seats, and got the seats mounted as low as possible, using the lowest hole in the rear, and 2nd lowest in the front. Both airbag sensors needed resistors to disable the airbag warning light.
For the passenger seat, I had to pull out the occupancy sensor mat from the original seat. I plugged this in and tucked it under the carpet - no more beeping noises. The passenger air bag stays off this way as well. I kept the 3 point belt receiver on the driver side so I could still have the belt buckled when driving to the track - New Jersey has laws that can get you ticketed if you only use a harness.


I installed a 350mm NRG deep dish wheel with an eBay hub. I plugged 2 resistors into the airbag wires, and taped them up. With the seat at the lowest position, I could fit pretty easily, see the whole gauge cluster, and not rub the roof liner with my helmet. The reach to the wheel is also perfect for me. The rails and telescoping wheel allow shorter people to get a comfortable driving position too, so others can drive the car as well



At this point, the car was pretty much track ready!

[redSerpente]

I did some minor appearance mods before the track - gotta look good for the pictures!

I plastidipped the curbed RPF1s to hide the scratches and protect them from the corrosive brake dust. I'll see how this holds up over time; hopefully it doesn't start melting on me when I heat the brakes up.



I thought I would install a backup camera as a fun little project, since the head unit had a connection for it. Wiring was a bit annoying but it came out great!





One of the taillights kept leaking, and despite my best efforts to bake it in the oven and reseal the gasket, the leaking continued. I discovered that the plastic housing was actually cracked. This was a great excuse to get some Spec D taillights, which work surprisingly well for how cheap they were.

[redSerpente]

First FRS track day on NJMP Lightning with NASA NE! Managed to run a 1:20.5 with Conti ECS tires, one pair half worn, and the other pair brand new. However, I quickly learned that having a mismatched set makes handling very unpredictable. With the worn tires on the front the car felt pretty good, but once I swapped them onto the rear, the car started trying to slide every corner, and powering out of corners was like walking on eggshells. Looks like the contis are now relegated to street/cruise duty, and I'll need another set of tires for track use until the Apex wheel group buy comes in.
The engine ran great on track even with 98,000 miles, and the seat/wheel setup felt excellent. Here's hoping it can go for many more

[redSerpente]

Ran the car at Lime Rock on RS4s and tried out the E85 tune. Looks like I'll need to run a flex fuel kit in the future, because the fuel quality varied quite a bit. Broke into 1:04s by the end of the day. The track feels perfectly matched to this car, so I'm excited to return in the summer!


After that, I did another event at Watkins Glen a few weeks later and got some good seat time in. Managed to cook the brakes (DTC-60s) after running the car hard for 30 minutes, so looks like a big brake kit is coming in the near future. My best time was a 2:24. Luckily Takumi788 was there for the weekend, so he drove my car for a session; I learned how much more time I can shave if I attack the curbing on the bus stop chicane. Also, getting on throttle earlier in the corners where there is more runoff - faster and minimal risk due to extra space. Both the car and the driver got some great development this month

[Code Monkey]

How are the lap times compared to the Miata?

[redSerpente]

Originally Posted by Code Monkey

How are the lap times compared to the Miata?

On NJMP Lightning, I was able to run a 1:23 with new Direzzas in my miata. I'm going back there at the end of the month with good tires to see what kind of difference there is. I should be able to hit 1:18 with this setup if all goes well. As for the other tracks, I didn't get to run the miata there - only Thunderbolt, Lightning, and Palmer.