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, new)
  • OEM Rear Rotors (85,000 mi)
  • OEM Calipers with SCE Spacers
  • 3SX Performance SS Brake Lines
  • ATE Super Blue 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: 39F/34R (@ 65F)
  • 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 (85,000mi)
  • 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:55 G:9, 0.86kg/cm² sustained)
  • Near-stock (12psi) boost levels.
  • OEM Turbocharger Bypass Valve (BPV)
  • ERL Aquamist 2s Water Injection System (170cc/m peak)
  • Mobil1 0W40 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	98	101	96	104
  Oil Temperature Post-Cooler, Pre-Engine	C	114	116	113	117
  Exhaust Gas Temperature Post-Turbine with Water Injection	C	660	730	610	760
  Oil Pressure	kg/cm2	4.4	6.5	3.6	7.4
  Fuel Pressure Differential, Pre-injectors	kg/cm2	3.5	3.6	3.1	3.9
  WOT Manifold Pressure	kg/cm2		0.86		0.99
  Knock	ECU Count	0	8	0	13






• General Data (Standard)

  		Typical		Extreme
  		Low	High	Minimum	Maximum
  Water Temperature	F	208	214	203	219
  Oil Temperature Post-Cooler, Pre-Engine	F	237	241	235	243
  Exhaust Gas Temperature Post-Turbine with Water Injection	F	1220	1346	1130	1400
  Oil Pressure	psi	62	92	51	105
  Fuel Pressure Differential, Pre-injectors	psi	50	52	44	55
  WOT Manifold Pressure	psi		12.2		14.1
  Knock	ECU Count	0	8	0	13

  
  




• 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	34.89	34.91
  Rotor Thickness (After Event)	mm	34.82	34.91
  Wear (Due To Event)	mm	0.07	0.00
  Wear (Due To Event)	%	0.20	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	14.65	15.07	15.13	15.10
  Pad Material Thickness (Before Event, Trailing Edge, including backing plate)	mm	14.48	15.06	15.09	15.10
  Average Pad Thickness (Before Event)	mm	14.57	15.07	15.11	15.10
  Pad Material Thickness (After Event, Leading Edge, including backing plate)	mm	13.89	14.39	14.54	14.40
  Pad Material Thickness (After Event, Trailing Edge, including backing plate)	mm	14.02	14.55	14.44	14.57
  Average Pad Thickness (After Event)	mm	13.96	14.47	14.49	14.49
  Average Pad Wear	mm	0.61 (6.1%)	0.60 (6.0%)	0.62 (6.2%)	0.61 (6.1%)






• Tire/Wheel Temperature Data (Sessions 1, 2, and 3)

  Note: Session "0" indicates data from previous track day with street tires and OEM 17" wheels.
  
  

  After cool-down lap, immediately in pits			Left (Driver)						Right (Pass)
  			Outer		Middle		Inner		Inner		Middle		Outer
  Front Wheel Spoke	F	S0	95						111
  		S1	160						160
  		S2	177						175
  		S3	146						146
  Front Wheel (Inner Surface)	F	S0
  		S1	136						137
  		S2	141						144
  		S3	125						136
  Rear Wheel Spoke	F	S0	92						97
  		S1	148						148
  		S2	195						160
  		S3	134						141
  Rear Wheel (Inner Surface)	F	S0
  		S1	123						123
  		S2	125						131
  		S3	117						125
  Front Tire Sidewall (outer)	F	S0	115						127
  		S1	119						122
  		S2	118						124
  		S3	113						124
  Front Tire Tread	F	S0	108		140		113		148		128		133
  		S1	130		142		135		144		152		148
  		S2	125		137		140		134		134		128
  		S3	118		131		134		133		133		122
  Rear Tire Sidewall (outer)	F	S0	102						109
  		S1	107						111
  		S2	107						114
  		S3	101						105
  Rear Tire Tread	F	S0	105		105		108		110		111		109
  		S1	115		129		126		124		128		116
  		S2	109		127		131		134		134		128
  		S3	105		122		125		111		123		116






• Brake Temperature Data (Sessions 1, 2, and 3)

  Note: Session "0" indicates data from previous track day with OEM rotors.
  
  

  After cool-down lap, immediately in pits			Left (Driver)				Right (Pass)
  			Outer		Inner		Inner		Outer
  Front Brake Caliper	F	S0	220				280
  		S1	183				186
  		S2	200				213
  		S3	181				204
  Front Brake Pad	F	S0
  		S1	260				257
  		S2	312				301
  		S3	244				272
  Front Brake Rotor	F	S0	365		365		470		480
  		S1	225		175		227		239
  		S2	280		250		255		275
  		S3	257		215		237		278
  Rear Brake Caliper	F	S0	217				230
  		S1	195				199
  		S2	225				230
  		S3	155				215
  Rear Brake Pad	F	S0
  		S1	290				290
  		S2	310				342
  		S3	285				315
  Rear Brake Rotor	F	S0	255		255		300		310
  		S1	244		240		290		250
  		S2	300		290		312		317
  		S3	260		260		300		297






• 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	40.0	40.2	36.5	35.5
  After Session 1	psi	45.0	46.8	40.6	40.4
  Change in Tire Pressure	psi	-3.8 (to 41.2)	-2.5 (to 44.3)	-1.6 (to 39.0)	-1.6 (to 38.8)
  After Session 2	psi	42.1	45.3	39.3	39.4
  After Session 3	psi	41.6	44.6	38.8	38.8