grippgoat's 2023 BRZ non-daily hopefully track/hoon build

[grippgoat]

I made an account to PM X25 about his car for sale. One thing led to another, and here we are.

My daily is a 2018 Golf R 6MT that's way better as a fun-but-still comfy street-only car than I ever managed to make my 2005 STI over the 13 years I owned it. But it's really not happy pushing past about 8/10s.

I bought the BRZ because I was getting the itch to turn wrenches and hit the track again (it's been about 12 years since my last track). Miatas are too small and convertible (poo on squeaky/leaky hard tops). S2000s are still too small, and also convertible. C5 Corvettes are just old, and tough on consumables. C6 Z06 is just too fast (again, consumables). 350z too heavy. Caymans are a bit spendy (to buy and to mod), and I didn't love mid engine back when I had an NSX. RX8s are RX8s lul. I almost bought an EG Hatch, but I've been there (it's the car I miss most of all my past cars), and I want to do the RWD thing again. 86 fits that "Like an S2000, but big enough for me to fit in comfortably, and a fixed roof, while being light and slow enough to not eat through tires and brakes" sweet spot.

I originally was looking at old first gens, but they were all $5k+ over-priced, in really rough shape, or sometimes both. So when I saw this car in my favorite color with the shocks and brakes I wanted anyway, and lots of other quality mods and spares, I went for it.

Previous Owner's build thread: https://www.ft86club.com/forums/show...91#post3537891

The end of that thread is the condition I bought it in.

First items on my TODO list are:

1. Get the driver's seat moved back to a comfortable driving position for me.
2. Put some race wheels and tires on for the glamour shots.
3. Probably put the stock wheels back on, but with the rears on the correct sides.
4. Maybe see if I can get fit the sliders I've had sitting in my garage for 10+ years into the stack-up, so I can let spouse/friends try it out.

After that, we'll see. I'll probably dial back the alignment to something more streetable and stick with the stock wheels and Falkens while I just get to know it. I haven't driven RWD since my 94 miata back in the mid 2000s. Hands and feet will need some re-calibration. I also won't be towing it to the track, so I'll probably need to compromise on setup. I need to at least be able to drive it a few hours on the highway without cording tires or being so miserable that I'm tempted to turn it into a jersey barrier.

In terms of further mods... there's a lot already here to play with and get dialed in to my liking. The MCS traction mod (or maybe GKTech's take on it) looks interesting, though... 🤔

My limited first impressions so far, driving it home with my chin on the steering wheel:

1. My butt and thighs do fit OK into the seat, barely. It's quite snug, but it's not pinching anything, and I don't get stuck in it.
2. The throttle response is much more smooth and linear than all the first-gens I drove. They all felt like they had featherweight flywheels, and throttle mapping that puts 80% of the power in the bottom 50% of the pedal travel.
3. The engine feels much stronger and torquier than the first-gens drove. I haven't even given it full beans yet, because...
4. Holy cow, this car does _not_ want to go straight! It's hyper-sensitive to road crown / camber. This is definitely a track-only alignment.
5. The suspension has some business to it as you'd expect from the spring rates, but it's surprisingly smooth in the way it does it.
6. There's a weeee bit of clunk over bumps that I guess is common from the Karcepts/MCS rear shock package.
7. The brake pedal feels so, so much better than the Golf R. Maybe even better than my old STI. I can't imagine what these brakes are going to do when warm.

That's it for now.

[grippgoat]

Reserving a spot to copy/paste the above post down the road when I have other more meaningful things to fill the first post with.

[grippgoat]

Spent more hours than I want to admit messing with the driver's seat.

First I flipped the side mounts around to position the seat further back. Then I removed the lap belt eyelets from the rear bolts that go into the chassis, which solved the clearance issue that X25 was experiencing. That let me get the seat pushed nice and close to the tunnel.

I got it in a position that felt pretty good. I couldn't decide on tilt. All the way back felt good, but probably a bit too far back with tight harnesses. One step more forward felt more vertical than I wanted. I wish I could drop the rear of the seat one more hole, but then it would hit the nuts that hold the side mounts to the base.

The next issue was belts and harnesses.

Since I wasn't using the eyelets on the rear seat to chassis bolts, I needed another solution. I put the outside belt on the stock belt bolt like the BK harness bar instructions indicated, but that put the length adjuster of the lap belt right at the hole in the seat, which wasn't going to work.

On the inside, the stock seat belt receptacle needs a bushing I don't have to really work properly, and is also bent at an angle such that it's tucked up under the rim of the seat, and really hard to get buckled. The BK lap belt eyelet also put the lap belt adjuster right at or slightly inside the hole in the seat, which again wasn't going to work. My hips completely fill the seat, lol.

Even if I sorted that out, I didn't have a workable solution for the anti-submarine belts. They were previously on the front bolts that go into the chassis, but after some research and consultation with a friend, I decided I wasn't comfortable with that. They really need to go straight down or backwards. If they go forwards, they will get looser instead of tighter in a crash, and thus not function properly. I could possibly mount them to the rear bolts, but that brings back the clearance issue, and is moot since I didn't have a solution for the lap belts.

So I ended up just putting the stock seat with the stock belt back in for now, so I can drive safely and work on other things. I'll revisit the race seats later.

[grippgoat]

I decided to put the stock passenger seat back in, too. Reassembling that was fun. I was able to figure it out by zooming in on pictures in x25's build thread, and referring to Kevin Vo's video for how to route the seat belt wire. Let's hope it all works properly when I get it back in the car!

EDIT: It did work properly.

[grippgoat]

I spent some time this afternoon playing with camber in the front end. My methodology was as follows:
1) measure camber using an angle cube stuck to a length of 3/4" square tube, while the car is on the ground, and write it down. There's some imprecision here because the length of tubing was too big to measure on the rim, so I had to use the tire sidewalls.
2) measure with a long level across the tops of the struts, with the angle cube on top. I measured 0.25* with passenger side lower.
3) lift car on QuickJack.
4) Measure camber with the car in the air, and write it down
5) check floor slope with the long level on top of my r/c droop blocks. Came up with 0.25* here, too.
6) add camber on the ground and the floor slope adjustment together, then subtract my target camber, to figure out the change I need. Then take the in-the-air measurement, and add the change, to get the in-the-air target value.
7) took the front wheels off
8) stuck the angle cube to the brake rotor, and confirmed the measurement there was close enough to what I got on the wheel/tire.
9) tilted the camber plates out as far I could without moving the holes the screws are in, which put them a bit inboard of centered in the hole. This gave me a range of about 2-4 degrees at the knuckle. I have factory 14mm bolts in both top and bottom holes.
10) Loosened the strut from the knuckle and adjusted to my target there.

Aaaand, that's where I stopped for the day. I'm sort of dreading toe adjustment, and finding out how far off my adjustments are. 🙈


While I was in there, I noticed there's more space between the ears on the strut and the top of the knuckle than I ever remember seeing on my STI across a few different strut setups.


I decided to measure it:



1.0155 - 0.9805 = 0.035, which is almost 1mm. That seems like a lot. The ears are almost 1/4" thick:


In order to clamp on the knuckle, the bolts are going to have to bend two 1/4" steel ears enough to close a nearly 1mm gap before actually clamping on the knuckle. I don't know how to run the numbers for whether that matters, but it certainly doesn't seem ideal. Tightening the bolts down to 120 ft lbs I could really feel something flexing. It felt a lot like bolt stretch, hitting maybe 60 ft-lbs pretty quickly, and then very slowly ramping up to 120 over a lot more additional rotation than felt comfortable.

I'm starting to wonder if it'd be worth trying to find / make some shims to put in there to fill the gap, and hopefully get more of that torque going into actual clamping.

[grippgoat]

Got the springs swapped out. Was 450f/550r. Now 400f/450r. Car rides much better and less clunking from the rear it seems. Still need to check ride height and fiddle with damping. I put the spring up 6mm in front and 9mm in the rear, but the rear is probably lower now because motion ratio. :/

I think I messed up the math on camber for floor compensation. I've still got more in the right front. Will fix that soon. Also switched the camber plates from the 6* caster position to the 7*. Not sure that's helping anything.

I noticed the front swaybar doesn't want to pivot while disconnected. I wonder if that's contributing to the incessant front end jiggle. I also wonder if maybe I got some of the bad batch of bushings. I'll have to pull that down and try the washers under the brackets to free it up.

Also while I was doing springs, I found the left front was 1mm higher than right front, but left rear was a full 6mm higher than right rear. I'm sure that was the result of corner balancing, so I left it alone. But it's enough of a difference that if the endlinks are set to fit at full droop, it could put a nice tweak in the car. Gotaa see if I can reach things with the car on the ground.

-Mike

[grippgoat]

Been sitting on this post for quite a while, because I wanted to add some pictures. But, I'm just gonna send it, because I have other more recent stuff to post. ��

I measured my floor:

I first marked where the tires were using some masking tape. Then I backed the car out, set up my laser level I forgot I had bought like 18 years ago, and measured a bunch in the area where each tire sits. I just tried to get an idea of the range for each corner, I didn't try to like map a whole grid or anything.

What I found is that there's a slope down of about 0-3mm from left to right in front, 0-5mm from right to left in the back, and about 25-30mm slope down from front to back. I decided this is good enough to stop trying to figure out a compensation for camber measurements.


Front Camber:

Right front was measuring -3.2 which is about where I wanted to be, so I left it. Left front was down around -2.6, so I really must have screwed up my math last time. Anyway, I got this adjusted and now both sides are reading -3.15 on the angle cube. Rears are reading -2.1.


Swaybarsn't:

First I removed the rear swaybar, to see if it might be contributing to Jack's complete lack of traction (in like some kind of weird weight jacking or binding or just being too stiff way). Traction did seem maybe a bit better without it, so I left it off for a bit. It definitely helped with some of the weird bind-and-release behavior I was getting in the back even during light cornering with bumps. And I knew it was making steep parking lots / driveways worse from past experience on other cars. Lifting the inside rear in an STI isn't such a big deal. On a RWD car that's kind of a big deal.

Then I removed the endlinks from the front bar to see if the tight front bar might be contributing to some ride and handling weirdness. Holy cow the car felt way better. The persistent jiggly bounciness in the front was completely gone, as was all the over-reaction to road imperfections. The bar was bound up so bad, it didn't even move in a couple trips around the neighborhood touge with the endlinks removed.


Corner balancen't:

While starting to feel good, the car still felt "tweaked" in the r/c vernacular. Throughout all of this, I was noting that it felt like regardless of situation, it was always the right rear that broke traction way before the left rear. There should be more weight on the left because of my substantial girth, but this just felt wrong. My miata was never like this.

So I started suspecting the uneven spring perch heights, remembering that the rear left was substantially higher than the right. I had changed enough that the previous corner balancing was almost surely invalidated.

I had always set up my previous cars by just setting the perches evenly and letting corner weights land where they may, and it had always worked fine for me. So I looked up some stock corner weights for the 2nd gen cars, and found they're pretty well balanced, with the right side a bit heavier, which would flip the other way with my weight in the car, but not too badly.

The instructions for the Karcepts coilovers said the trend they noticed is that a well-balanced 86 will have the rear perches set the same, and the front left 3/16" (4.8mm) higher than right front, and was what they recommend as a baseline. Since it wasn't clear to me whether that actually applied to 2nd gen cars, I decided to go half way. With the sways disconnected, I did another couple passes at right height, targeting 336mm front and 342mm rear. (330mm = 13 bananas). I ended up with the rear perches even, and the front left about 2-3mm higher than the front right. With this, the car was really starting to feel good to drive.


Tire Pressures:

While the traction was improved with the spring perch changes, it was still pretty bad. It occurred to me that maybe my tire pressure was too high for the Goodyear SC3Rs. I had them at the OEM 35 psi. So I threw all the things into https://tiresize.com/pressure-calculator/ and it spat out 31 psi. Dialed that in, and traction is much better now. The weather getting warmer (like 60s and 70s these past few days, instead of 40s and 50s the past few weeks) is also helping.


Front toe:

I did a lazy string box by wrapping the strings around the back edge of the rear tires (toed in, so only touched at the rear) and lining them up just a couple mm off the front tires. This way, I measured 1mm toe out on front left, and 2mm toe in on front right.

So I lifted the car, threw the thread gauge on the tie rod and found 1.5mm. So one turn on the tie rod moves the outer 1.5mm. But it's not all the way out to the radius where I'm measuring toe, so it's probably more like 3mm. But then the other side of the wheel moves the same amount in the opposite direction, so it's probably like a 6mm change in measurement. Cool, so 1 hex flat = 1mm (remember, this is from-the-butt head math, not actual verified math).

So I screwed the left front 1 flat towards toe in, and the right front 2 flats towards toe out. Wheel's nice and straight now, and front end feels good. But I should still measure one more time to verify.


Swaybars Continued:

I decided that since the car felt _so much better_ with no swaybars, both in terms of ride and handling, that I definitely wasn't putting the Perrin bars back on. But the front did feel a little overly sluggish, and no front bar at all just sounded like a bad idea at high cornering loads, so I decided to put the stock sways back on. Holy crap there's a lot of stuff to unbolt / unclip to get at the front bar!

Once I got the undertrays off, just to see, I grabbed it with one hand on each end and pulled down to try and get the bar to rotate. I lifted my entire upper body off the creeper before it moved! Yikes.

So anyway, out it came. I forgot the previous owner had replaced the bolts in the bracket, so was very surprised to find 13mm heads. I did mess around a bit to see what it would take get the bar to free up, and found results pretty similar to Spuds thread here: https://www.ft86club.com/forums/showthread.php?t=152754 .

I threw the stock rear back on as well. I still kept the whiteline endlinks. They were super duper stiff and I was hesitant because I thought even that could be contributing to the weirdness I was feeling. So I stuck a hex key socket in and cranked / spun them around a bit, they loosened up, so I went ahead and put them in. I don't have a good way to de-tweak them at ride height, so I did it at full droop, since I know my ride heights (at least without driver) are very close to even side-to-side. I measured length as a baseline, completely threw that out the window as they flopped and spun around while putting them into the car, and then just tighened up one side, and felt for the spot where the turnbuckle had like a 1/4 turn of nice smooth movement to know it wasn't jammed up or down.

While I was in there, I found the bolt that was sheared off in this post lol: https://www.ft86club.com/forums/show...06#post3555406
It's the one at the very tip of the undertray, at the back of the transmission, so I guess that's going on the list to try and fix.

I also thought I got everything back together, but I have one left over plastic clip. No clue where it could possibly go.


Helmet:

My Bell M3 is SA2005, so it's no-go for basically anything nowdays. I briefly looked at carbon helmets in the $5-600 range, since that's what the new Bell M8 costs, but they were generally like 3.3 lbs versus 3.5 lbs for the non-carbon version, and just didn't especially seem worth it. So I was looking at the lower end of the market, in the $250-400 range.

I had a friend who got a RaceQuip. Simpson looked like they had some decent options. I ultimately ended up ordering the Zamp RZ-62, since they advertise fitting very similar to Bell, their support said that model is what they recommend for glasses, and they have the option to add air, drink, and radio should I need them, all for what seemed like a good price. I've only worn it for about 5 minutes so far. The head feels good, but the cheeks feel a bit tight (but so does my M3 when I put it on after 10 years later, tho).


Bling:

It only took a couple rounds of wheel removal to get tired of fussing with lug nuts I can't reach with my finger tips down in the pocket, and messing with spline drive adapters. I wanted something like the Muteki SR48, but they had very mixed reviews online, and seemingly high risk of counterfeit. Then I found a similar style lug nut from Dorman for $37. Then for some reason Amazon was selling the red ones for $7.64. Bought two sets.

Then I needed some valve stem caps. 4 normal plastic ones were $2 at the auto parts store. But I have 14 wheels that were all missing the caps. So of course I got the red aluminum ones from Amazon for $6/12 to match the lug nuts.


Final Thoughts:

The car finally feels like something I'd actually want to take on a race track, and be able to tolerate the drive there and back. I think the dampers could probably use a click here and there, but crucially it now feels like they're what's actually controlling the way the car reacts to inputs and bumps. The car is doing what I tell it to do, and very little that I don't tell it to. I have just enough self-centering in the steering, and the tramlining is much more manageable.

I'm running out of excuses now. Hopefully I can hit the track in the next few weeks!

[grippgoat]

So, I did hit the track a couple times. The Ridge in Washington.

First day was new car, new track, and a loooot of rust, so didn't go very fast. Shocks were too soft so anything over about 85mph felt really scary.

Second time out, I got the shocks closer, started going faster and learning the track better. Still leaving a lot on the table. Still need to get the shocks better (still too soft, at least in front, I think). It does feel like it's got some push in the setup. Got down into the mid 1:58s, and had a couple high 1:57s killed by traffic.

Here's a vid!

[grippgoat]

Wow, it's been a minute since I updated.

Lots of changes over the winter...

SPL front control arms and tie rod ends. I wanted roll center correction. This was the only option that worked with the 2022+ BRZ aluminum knuckles. The aluminum knuckles are fatter and require longer threads on the ball joint and tie rod studs. It really tightened up the steering feel to super-nice status. I did my best to replicate the stock arm shape, and I think I succeeded given how close my alignment still was after installing them. There's noticeable increase in noise and bump impacts, but didn't really make the ride much harsher. Well worth it for the steering feel, and checking of "spherical bearings" from my car mod bucket list.

SPL rear control arms. This was one of those "if I'm spending this much on SPL parts, might as well..." mods. They added quite a bit of NVH. Tolerable for my usage, but TBH I probably would have skipped them if I had realized the stock outer pivot is already a spherical bearing. Still, it's kinda nice having extra holes for the swaybar endlinks, and I might fiddle with some of the other adjustments some day.

RacerX front and rear endlinks. I went with them mostly due to price, but wanted something lower-profile than Whitelines, which rubbed on my inner wheel wells under hard compression like turn 2 at the Ridge. They accomplished that. I also wanted turnbuckle-style adjustment in the rear, and spherical bearings instead of the stiff bushings in the whitelines. The downsides are that the spherical bearings feel looser than I'm used to new ones feeling, so we'll have to see how they hold up. And also, the number of different wrenches that aren't 12/14/17/19 required to adjust the rear is pretty frustrating.

949 Racing steering wheel spacer. It works, and let me move my seat back a bit. Mine's a tiny bit crooked, but not enough to worry about imbalanced steering after aligning it. For the price, it seems worth it.

Super-duper cheap perforated leather steering wheel cover from amazon. It started off awfully shiny and greasy. I probably didn't do the best job stitching it up, because I knew it wasn't gonna be pretty anyway. Once it broke in, it did give me a fatter, softer, grippier steering wheel, which is much more comfortable to hold than the naked stock steering wheel. Well worth the $20.

Ansix Auto oil pressure sensor and CAN bus thingie and OBDLink MX+. Install was straightforward. Now I have all the dataz (see later vids).

I found someone local on Facebook Marketplace who wanted to trade an Evo XL QRT for an Evo L QRT. Pulled the trigger on that, and got the seat in. Still tweaking the seating position.

Sparco 6-point harness with pull-down lap belts and wrappable ends. I bought this to replace the Schroth belt that came in the car, that had pull-up laps and sewn-in clip ends on everything but the shoulders, that I didn't have a good way to actually get mounted in the car. I welded a square steel tube across the back of my PCI seat mount to wrap the sub belts around. And I bolted in the lap belt, and wrapped the shoulders around the Brey-Krause harness bar. Lap belt angles aren't ideal, and real race shops would poopoo on bolting one side of the lap belt to the seat bracket and also having the subs connected to it. But I'm confident it's at least as safe as the stock belts.

Cusco front and rear tow hooks, because black friday. Hopefully I never need them.

MTEC shifter springs. Install was a bit of a pain, but really not too bad. Shifts feel much nicer now, and the 2-3 shift coming onto the straight at the Ridge isn't as much of a struggle.

I put the Perrin 22mm front bar and 19mm rear bar on, and drove it for a while. It felt ok on the street. Not so much on the track. The car was way too loose, and I went slower than last year.

I hit the track on april 5th with Turn 2 lapping. I was on the stock rims with old Falken RT-660s, because I wasn't confident enough in the weather to put on the SuperCar 3Rs. There was some rain on the commute, and it started dumping rain on the track before my 2nd afternoon session, so I went home early. I did set a new PB by 0.2 seconds in the first session, but I wasn't able to replicate it for the rest of the day.

Vid:

[grippgoat]

After the previous track day, where I was fighting a loose car, I took off the 19mm rear sway and put the stock 14mm back on. I also lowered my rear spring perches 5mm, because the car had over 10mm rake (measured at the jack points), which is too much from all the reputable sources I can remember.

Hit the Ridge with Hooked on Driving on april 13th, and the car was incredibly much better. I was able to imrpove my personal best to 1:55.9. I think the car is a bit pushy, and I'm going to try more camber (especially front, which is only about 3.2) to see if that helps. I still have some work to do on the driver mod. And I think I've got another day or two of tread left on the SC3Rs. So hoping to find a couple more seconds at least.

In the previous vid, when I wasn't going as fast, the oil pressure drops were present but honestly not concerning. They were all a fraction of a second at part throttle and lower RPMs. Going faster makes them way, way worse. There's an overlay in the video, but I can share RaceChrono data if anyone wants it. I wonder if Varus would send me a prototype pan and baffle for testing. I want some of the 900 BRZ Oil pressure.

I also took an oil sample when I changed oil a couple weeks ago, but haven't sent it out for analysis yet. I should do that.

Track vid below. Skip the first half if you don't care to see what happens when you go out with 26 psi front and 28 psi rear to see how low is too low. But once they got up to about 31 front and 30 rear, the car started hooking up better than it ever has, and I was able to just keep pushing harder and driving the lap time down. I also had my front left compression damping set two clicks higher than I thought, which might be why I went tokyo drift in turn 12 when I was on pace for a 1:55.9. Managed to keep it clean two laps later. Also, there was a drift event in the super tight left-hand turn 11 that involved an add clunk / rattle that I didn't notice when I was on track, but it's pretty loud in the vid. No idea what it was. I don't think I clipped a curb or anything. Maybe a really sloppy downshift? :shrug: