Graduate 818 #575

[Dave 53]

My build goal has been to build a safe and reliable track car. I have planned to “graduate” it after attending a track day and leaving without a needed modification (as opposed to maintenance item) on the to-do list. It took 17 track days!

Modifications I did to turn my 818S from a street car into a proper track car:

Safety
• Raised broomstick roll bars under hood and behind seats
• Fire suppression system with cockpit and engine compartment nozzles
• 5-point harnesses
• In addition to helmet - fire suit, HANS, arm restraints.

Engine
• Speed Density Tune 265whp
• Oil cooler with 2 fans
• Arctangent oil control plate
• Killer B pan and pickup
• High visibility low oil pressure warning light
• High visibility oil temp gauge with warning light
• Motul oil
• Transmission temp gauge
• Quaife LSD

Fuel System
• Holly Hydromat (not needed with surge tank)
• Fuel surge tank/pump
• Used plastic water bottle tank vent catch can

Misc.
• Front and rear tow eyes
• Sparco race seat
• Brake bias in cockpit
• Falken RT 660 tires (current)
• Camber 1.5 front, 3.5 rear (current)
• No plans to wrap or paint body

Looking at this list, it sure seems short considering the effort it took on top of building it as a street car. It’s been a very enjoyable experience over the last 2.5 years! I enjoy wrenching on it as much as driving it. I’m not too worried about becoming board – keeping a track car running is a lot of work and I’m sure the track specific modifications aren’t done - something will come up (wing? 818R springs/shocks? Maybe someday). But, coming home from the track for the first time without a modification project to think about is a big milestone!

Thill 2 2-24-23.jpgMe and car.jpg

[lance corsi]

Dave, congratulations and n your car. I’m looking forward to finally finishing mine.

[lance corsi]

Congratulations on finishing your car.

[Rob T]

Congrats. I'm sure you are loving it. BTW. Which track is the first picture from?

[Dave 53]

Congrats. I'm sure you are loving it. BTW. Which track is the first picture from?

Thunderhill East CW in the rain.

[Bob_n_Cincy]

Hi Dave
Thanks for you list in post#1 above. I should also make a list.

What did you do for brake pedal and calipers?
Bob

[Dave 53]

My brakes are the standard 4 piston Wilwood disc and calibers from FFR and Subaru OEM master cylinder and peddle. Great setup for a street only 818 as well as a track car. No issues other than...

I do wish I could swap out for a master cylinder with a smaller bore for less effort / more peddle travel. I don't recall the Subaru OEM bore diameter, but if a Wilwood master cylinder could be had with a smaller bore, I would go for it. I actually have a Wilwood peddle kit out of an 818 that someone gave me, but I don't have the FFR firewall parts. And it would be a huge job to switch out from an OEM Subaru peddle set up a Wilwood setup in an already built car. If I had a do over when starting the build and could get a smaller dimeter bore with Wilwood, I would. At this point (12,000 miles), I'm use to the brakes and have no serious plan to change them unless someone can point me to a smaller bore Subaru master cylinder - I've looked with no luck.

I did move the brake bias proportioning valve into the cockpit. Not sure that is really needed on a street only 818. But it sure is nice to have on a track car. I was at Buttonwillow last year when my bias knob was under the hood. I pulled off track to adjust the bias in a big rush to get back out on the track. I took the hood off and set it down in front of the car, made the adjustment, jumped back in the car and ran over the hood!

The Wilwood brake kit came with BP-10 pads which is a street first / track second pad. If I had a street only 818, I would stick with the BP-10's. I've been using the BP-20 pads which are track first / street second. An option would be to drive to the track on BP-10's, then switch to BP-30 pads at the track which are track only pads, but I'm not good enough to justify all the effort. Chatter at the track is G Loc and Raybestos also makes some excellent track pads that would fit, but due to supply chain issues and cost, I've been sticking with the BP-20's. After much searching and confirming in stock availability, late last year I bought the last 2 sets of BP-20 pads on the internet!

I'm using Wilwood high temperature fluid. It's almost $30 a bottle. On a street only car, I would use the cheaper "normal" fluid.

The 818 Wilwood front calipers have rubber piston dust boots. After many many pad swaps and inspections, my rubber boots got chewed up at $9 each x 8 boots. Now I spray soapy water to lubricate the rubber before sliding the pads out and into the calipers.

[J R Jones]

Dave when your braking gets aggressive enough to boil the brake fluid you will burn off the piston boots. Our EVO SCCA T2 car did that and blackened the caliper paint. Brake rotors were somewhat expendable too.
Post session we had to roll the car a couple of times as it cooled down to keep the hot calipers from spot-warping the rotors.
jim

[aquillen]

Great post and info - keep enjoying and nice job!

[Dave 53]

Dave when your braking gets aggressive enough to boil the brake fluid you will burn off the piston boots. Our EVO SCCA T2 car did that and blackened the caliper paint. Brake rotors were somewhat expendable too.
Post session we had to roll the car a couple of times as it cooled down to keep the hot calipers from spot-warping the rotors.
jim

Over time, we'll see if my lubing the boots before moving pads helps. The front calipers have boots, the rears don't. In fact, it seems most Wilwood calipers don't have boots. How important are the boots and why are there even boots on our Subaru calipers and very few other Wilwood calipers? I assume they are there for a reason and that's why I paid $72 for new ones, but what if they were just removed....?

I had a BMW M Roadster that I use to track. Even with proper cool down, 50/50 chance that I would warp the OEM rotors. I never tried floating rotors on that car because they were so expensive. But I did try pricy cryo frozen rotors and they warped too. After that experiment, I started using the cheapest rotors I could buy and conceded they were going to warp. My business school education taught me a $30 rotor with a 90% chance of warping was better than a $150 rotor with a 30% chance of warping.

No signs of my 818 Wilwood rotors warping. The Wilwood rotors that came via FFR are drilled. I heard a great Flatirons podcast with a brakes expert guest. He explained how drilled rotors are 100% for looks and have no performance benefits while the slots do have benefit. When I do eventually replace my rotors, no holes.

Another note while we're nerding out on brakes. Brake pad wear isn't linear. In other words, if I start a track day with brand new 12mm thick pads and use up 2.5mm, that doesn't mean I can start another track day with 4mm pads and have 1.5mm left to drive home on. Same track, start with 12mm and I'll use 2.5mm of pad - start with 4mm and I'll end at zero. Never start a track day with less than 5mm without being prepared to change pads during the day. When the pads get down to about 1mm, chunks of pad material will start to break off the backing plate.

[Bob_n_Cincy]

Dave
Back in the day when I was sorting my brakes, Factory Five's Wilwood suggestion was a setup that was for a front heavy WRX.
I had to come up with my own solution of putting the front impreza calipers on all 4 wheels.
It looks like FFR corrected the problem with the current Wilwood caliper offer of using the same(front) unit on all 4 wheels.
I do not think you will have any problem with brake heat as the 818 only has 57% of the mass of an STI. Plus with the rear heavy 818 the braking is spread out equally between the 4 wheels compared to most front heavy cars. So get back out there an don't be afraid of getting aggressive with your braking.
Bob

PS: I am using POWER STOP Z26 Street Warrior; Carbon-Fiber Ceramic pads

https://www.rockauto.com/en/moreinfo...&pt=1684&jsn=4

[Dave 53]

I agree the 818 is very easy on brakes weighing a fraction of the Subaru car that they are matched for. It will be very difficult to warp the rotors and of course the pads and rotor wear will last longer than the same set up on a Subaru car. The low cost of consumables on the light 818, namely pads and tires, is a nice benefit of the 818. And I get 30mpg driving to the track. I was pitted next to a brand new Camero ZL1 - very fast! 3,900 pounds to my 1,940. More than double my weight! We joked that he can't feel when he has a passenger, and I can very much feel the added weight of a passenger. The owner bought it because the warrantee is valid on track - and it's a fast track car! But he was thinking about selling it because it ate up brakes and tires. I hope to get 10 days out of a set of tires to his 2-3 days for tires and pads. For fun I just checked tire prices. The cheapest 200tw tires for that car, assuming 9 track days, including mounting, he'll burn up almost $7,000 in tires plus probably 3 sets of front pads at $200 a set. I'll use about $1,000 in tires and 2 sets of $70 front pads.

While similar in size, the front and rear calipers are different. Since switching to the BP-20 pads 14 track days and about 7,000 miles ago, by my eyeballs, the rear pads look to be at about 50%. Front pads are lasting about 5ish track days. The forecast is for 5-6 sets of front pads for every set of rears. I thought maybe I didn't have enough rear bias, but it's not too difficult to feel too much rear and dial it back a bit.

[Rob T]

If I can jump on this thread....I have 50 heat cycles on my tires with no real drop in performance. I am running Federal FZ201M tires. My track has a new surface which probably makes them wear longer and I am probably a 7/10 driver. I tend to run a 20 minute session. As for brakes (no street driving) I run R303.16 up front and R303.12 with ST45 compound from Porterfield brakes. I have Wilwood calipers. Porterfield gave me a great suggestion. When the fronts wear to under 12mm, I swap them to the back as long as there is nothing wrong with them. The only difference between the pads front to back is the thickness.