NWARC Lapping Day

Contents

Summary

• Highlights
  • The new brakes (SCE 35mm Rotors) are awesome - no fade at all, even with using them as much as I wanted to!
  • I used an average of 2% of my brake pads for each 20-minute session. That means that, in theory, a set of pads should last 10+ days of track driving! Also, there was negligible wear on the rotors, so they should last a really long time...
  • Thanks to some pointers from my instructor (thanks, Steve!), I learned a new line through 5A-5B-6 this time, and it feels MUCH smoother and faster.
• Lowlights
  • My coolant and oil temps were a hotter than last time, and I didn't think anything significant changed... more investigation on that next time.

Track Map

Track Description The Pacific Raceways Road Course is an SCCA and NASCAR certified, 10-turn (9 turns with a "kink" in the main straightaway), 2.25-mile course. There is a total elevation change of 125 feet, of which 100 feet occurs in 1/2 mile. The course winds through natural wooded terrain, making it one of the most unique and challenging courses in the United States. ©2004 Pacific Raceways, Inc.

©2004 Pacific Raceways, Inc.

Note that this track is run counter-clockwise.

Turn 1	Turn 2
Turn 3a	Turn 3b
Turn 4	Turn 5a
Turn 5b	Turn 6
Turn 7	Turn 8
Turn 9	Turn 10

Track Report

• The big light bulb for me this time was my line for 5A-5B-6. My instructor suggested I turn in a little earlier for 5A, which made an earlier turn-in for 5B flow better. With this line, I turned in for 5A a little before the turn-in cone, hit the apex a little earlier, and continued toward the left side of the track. Rather than "go straight" for a portion of the track between 5A and 5B, I'd immediately turn the car back to the right as I got to the left side of the track at the exit of 5A. This was well before the turn-in cone for 5B, but the car would rotate immediately and predictably and I'd end up carrying a decent slip angle under power through 5B, clipping the apex dead on. From there, I'd continue with to the exit of 5B and then immediately turn back to the left for 6. As I'd turn in for 6, I'd get on the power very quickly (well before the apex) and got WOT up the hill. There are no more straight sections between the turn-in of 5A and the exit of 6. It requires carrying a little more speed and trusting the car a little more, but 5A-6 becomes a linked series of left-right-left with nothing separating the corners. It feels much better through that section now :-)
• As I carried more speed into Turn 1 and thus had more speed to scrub off in the braking zone for Turn 2, I had a little bit of a scare during braking: I hit the brakes pretty hard, and the rear end got really light and started to wiggle around a little. It was enough that my instructor noticed from the passenger's seat. At 50 or 60mph, it wouldn't have rattled me that much, but at 110-120mph, it sorta gets your attention :-) That braking zone isn't the best surface in the world - it's a little rough - but the wiggling rear end really startled me. I set my suspension to "Tour" for the next few laps and concentrated on braking earlier and with a little less force. I eventually worked back to using the suspension in "Sport" mode and braking later. By the end of the day, things seemed to be fine, although I'm probably not using maximal braking force in that corner. I figure the looseness in the rear end was either due to braking hard enough that there was not enough weight on the rear end to plant it or (less likely) due to the front brakes not being warmed up and the brake bias shifted too far rearward.
• My instructor also coached me not to head right toward the turn-in cone for 7 as I head up the hill. I tend to head right for the turn-in to make 7 a later (safer) apex since that turn still makes me a little nervous. Turn 7 has you crest a hill while turning, knowing that heading straight means getting intimate with a tire wall. I worked on making 7's apex a little earlier, but driving up the hill between 6 and 7 headed straight toward the apex cone for 7 (toward the left, not toward the turn-in cone on the right) is still a bit intimidating for me.
• Toward the end of the day, I was trying something new for 3B... instead of focusing on the turn-in cone, I started looking at the apex cone (out the driver's window) as I slowed for the turn-in. I'd gauge my turn-in by where I needed to be to hit the apex, which ended up being a lot earlier than the turn-in cone for 3B. It also made me less "reactive" and jerky in my turn-in for 3B, which I hope will help with outer shoulder wear on my RF tire.

Video Highlights

Video (720x480) (5507KB)

This is a comparison of my line through turns 4-6 from July, 2004 with my line through the same corners in this session. The sync-point for the videos is the turn-in cone for 5A. It shows the difference in lines through these corners as described in the Track Report section - there's about a 1.5sec difference through here between the two videos!

My Car Setup

• Brakes
  • Porterfield R4 Front Pads (AP531)
  • Porterfield R4-S Rear Pads (AP631)
  • Supercar Engineering W-I-D-E Front Rotors (35mm)
  • OEM Rear Rotors (89,000 mi)
  • OEM Calipers with SCE Spacers
  • 3SX Performance SS Brake Lines
  • ATE Type200 Brake Fluid
  • OEM Front Dust Shields Removed
  • SCE Titanium Pad Backing Plates
• Tires/Wheels
  • 275/40/17 Toyo Proxes RA-1 Tires (Full Tread)
  • Cold Inflation Pressures: 42/34R (@ 60F)
  • 5Zigen FN01R-C Wheels (17x9 +35)
• Suspension
  • Saner 28mm Front Anti-Sway Bar, Poly Bushings
  • TEC Performance Front Strut Tower Brace
  • Saner 25mm Rear Anti-Sway Bar, Poly Bushings
  • Cusco Rear Strut Tower Brace
  • OEM ECS Springs/Shocks (89,000mi)
  • ECS Shocks set to full stiff (Sport Mode)
  • Front Alignment: -0.5deg Camber 0.00" Toe
  • Rear Alignment: -0.2deg Camber 0.00" Toe
• Engine
  • K&N Aircharger Filter
  • ek2 Development Downpipe
  • High-flow Pre-Cats
  • OEM Main Catalytic Converter
  • OEM Cat-Back Exhaust
  • Blitz DS Boost Controller (R:47 G:9, 0.78kg/cm² sustained)
  • Near-stock (11psi) boost levels.
  • OEM Turbocharger Bypass Valve (BPV)
  • ERL Aquamist 2s Water Injection System (170cc/m peak)
  • Red Line 10W40 Synthetic Oil
  • 3SX Performance Polyurethane Motor Mounts
  • HoseTechniques Silicone Vacuum Hose
• Fuel
  • Supra Fuel Pump (Hotwired w/ 8ga wire)
  • AEM Fuel Pressure Regulator (52psi differential)
  • OEM 360cc/min Injectors - Cleaned and Balanced by RC Engineering
  • Shell 92 Octane (14gal) and Sunoco 100 Octane (6 gal) Fuel
• Cooling
  • 30/70 Coolant Water Mixture with Redline Water Wetter
  • Custom Front-Mount Setrab Oil Cooler
  • HKS Side-Mount Intercoolers
• Driveline
  • Redline MT-90/MTL Mix in Transaxle
  • Redline MT-90/MTL Mix in Transfer Case
  • Redline 75W90 in Rear Differential
  • Solid Shifter Bushings (engine bay and interior)
• Electrical
  • MSD 8224 Ignition Coils, Magnacor Wires
  • OEM NGK Spark Plugs at 0.039"
  • Upgraded Engine Grounding Straps
• Instrumentation
  • Full Defi BF Series II Sensors/Gauges
  • MirageCorp Mitsubishi Hybrid Datalogger for Palm
• Camera
  • Sony TVR-25 Mini-DV Camcorder
  • 0.5x Wide-Angle Lens
  • 6" Suction Cup Mount from FilmTools.com
  • Camera mount mounted to inside of sunroof glass

Equipment Report

• Brakes
  • So this time I didn't hold anything back from the brakes... I went around turn 1 between 100 and 120 regularly and maintained that speed until the braking zone for Turn 2. I usually take Turn 2 in the high 50's or low 60's (mph), so that's a fairly substantial deceleration. I also used the brakes fully between 2 and 3A, even trail-braking into 3A. Not once, ever, during the day did I get even a hint of brake fade or overheating. Every time I hit the brakes, they had a nice bite and consistent engagement for the duration of the braking period. I even had to adjust my braking style a little for Turn 2 because the rear-end would get light/squirrelly on me if I hit them too hard or too abruptly!
  • I can finally say I'm completely happy with my brakes. I threw everything I had at them and they didn't blink. I only used about 6% of my brake pads in three 20-minute sessions (and one 10-minute, relatively easy session in the dark). The rotors were 100F to 200F cooler when entering the pits when compared to OEM rotors. This setup should be more than adequate for my current power level and driving ability. I might need to revisit this issue if I start doing 150 down the front straight, but that won't be for a while...
• Tires
  • Still getting used to the R-compound tires and their extra grip and lack of audible feedback. I'm getting a little more wear on the outer shoulder of the front tires than I'd like, but I suppose that's to be expected with a heavy car and only -0.5 degrees of camber.
  • Upon pulling into the pits, I'm consistently seeing that the outer shoulder of the front tires is cooler than the middle and inner shoulder. Not sure what's up with that, especially since I'm seeing more wear on the outer shoulders.
• Engine
  • Still seeing a little knock every once in a while, especially under partial throttle conditions... pretty much the same as I see for street driving. Race gas didn't seem to help with this very much.
  • My coolant and oil temps were considerably hotter than last time (April, 2005), and I'm not sure what's up with that. I ran a similar boost level, and my lap times weren't a whole lot faster. The ambient temperature was similar (68F - maybe 10F warmer), so I didn't expect much of a difference. Also, I checked the timing map from this track day (experimentally) and compared it with that of my previous track day - they're virtually identical. That means that I don't think I can attribute the increased temps to the ECU running more aggressive timing for some reason.
    
    The only things that were different with this day vs the last one are that I used 30% race gas, I have my new brakes, and in my previous track day, I was using 3rd and 4th gears exclusively - i.e. I wasn't grabbing 2nd for the exit of 3B. I've heard that grabbing 2nd for the lower-speed stuff can tax your cooling system, so perhaps I can test that theory next time. I can't see how the brakes would make a difference in coolant/oil temps, and as far as race gas goes, it should reduce temps (if anything) as it burns slower than lower-octane gas.

Numbers and Data

• General Data (Metric)

  		Typical		Extreme
  		Low	High	Minimum	Maximum
  Water Temperature	C	97	101	97	102
  Oil Temperature Post-Cooler, Pre-Engine	C	114	117	114	121
  Exhaust Gas Temperature Post-Turbine with Water Injection	C	620	720	580	750
  Oil Pressure	kg/cm2	5.5	6.8	1.9	6.9
  Fuel Pressure Differential, Pre-injectors	kg/cm2	3.5	3.6	3.2	3.9
  WOT Manifold Pressure	kg/cm2		0.78		0.91
  Knock	ECU Count	0	5	0	21






• General Data (Standard)

  		Typical		Extreme
  		Low	High	Minimum	Maximum
  Water Temperature	F	207	214	206	215
  Oil Temperature Post-Cooler, Pre-Engine	F	237	243	237	250
  Exhaust Gas Temperature Post-Turbine with Water Injection	F	1148	1328	1076	1382
  Oil Pressure	psi	78	97	27	98
  Fuel Pressure Differential, Pre-injectors	psi	50	51	45	55
  WOT Manifold Pressure	psi		11.1		12.9
  Knock	ECU Count	0	5	0	21

  
  




• Brake Rotor Wear Data

  Discard Depth: 33.4mm (Front) Orig. Thickness: 35.0mm (Front)		Front		Rear
  		Left (Driver)	Right (Pass)	Left (Driver)	Right (Pass)
  Rotor Thickness (Before Event)	mm	34.83	34.86
  Rotor Thickness (After Event)	mm	34.82	34.86
  Wear (Due To Event)	mm	0.01	0.00
  Wear (Due To Event)	%	0.03	0.00






• Front Brake Pad Wear Data

  Orig. Total Thickness: ~15.0mm Orig. Pad Thickness: ~10.0mm		Left (Driver)		Right (Pass)
  		Outboard	Inboard	Inboard	Outboard
  Pad Material Thickness (Before Event, Leading Edge, including backing plate)	mm	14.48	13.93	14.45	14.45
  Pad Material Thickness (Before Event, Trailing Edge, including backing plate)	mm	14.45	13.88	14.35	14.36
  Average Pad Thickness (Before Event)	mm	14.46	13.90	14.40	14.46
  Pad Material Thickness (After Event, Leading Edge, including backing plate)	mm	13.52	12.95	13.67	13.95
  Pad Material Thickness (After Event, Trailing Edge, including backing plate)	mm	13.50	13.22	13.82	13.51
  Average Pad Thickness (After Event)	mm	13.51	13.08	13.74	13.73
  Average Pad Wear	mm	0.95 (9.5%)	0.82 (8.2%)	0.66 (6.6%)	0.73 (7.3%)






• Tire Pressure Data

  Note that this is after the cool down lap, immediately after entering the pits.

  In-Garage Pressures: 39F/34.5R		Front		Rear
  		Left (Driver)	Right (Pass)	Left (Driver)	Right (Pass)
  At Track, Before Driving	psi	42.0	42.0	34.5	34.5
  After Session 1	psi	49.1	50.9	39.9	41.3
  After Session 2	psi	49.3	51.9	39.7	41.2
  After Session 3	psi	48.7	51.2	38.7	40.4