Wednesday, June 4, 2008

Track Day #6 -- 2008/06/02

So, yet another track day with new stuff. In addition to the rear brake upgrade I mentioned in the previous post; I also bought some new wheels and tires for dry track days. I ended up with fairly inexpensive wheels (SportEdition D5) from TireRack. I chose them because they were the lightest wheels I could get at a reasonable price.

For tires, I wanted something with more lateral bite and sharper roll-off on the traction vs slip angle curve. With street tires, the transition from grip into sliding is really vague and it can be hard to tell when you're pushing too hard. I wanted something that would be easy to tell when I went up to the edge of traction. For this purpose, I chose the Nitto NT-01 DOT Competition tire. I didn't go crazy with the size; just a tame 225/45-17 tire size. It fits easily without rubbing; but it sure does grip well.

The gameplan is the same as always, get used to the new tires and make sure that I'm not over cooking the brakes. Try to work (again) on T7 to try to avoid the understeer problems and maybe try out trail braking now that I have a bit more rear bias in the brakes.

All in all this was my best track day yet! The weather was cool and dry starting out overcast, but ending up with the sun occasionally obscured by cloud in afternoon. After the first session to check things over, I was able to start getting to work. Turn 7 seems so much easier now with the new tires; I can really drive it down into the apex with the throttle.

I also had an opportunity to hustle a bit more through T10 - T12; this is a place I generally have been pretty tame. I've seen lots of videos of folks spinning out at PIR, and Turn 10 seems to be the favourite spot. People will go too hot into there, and not be able to make the transition into turn 11 and end up sliding into the weeds. I didn't want to be one of those people; so I've been pretty calm through there. The new tires really gave me the confidence to start pushing a bit in Turn 10; carrying more speed than I normally do.

Here's an example of something similar to what I'm talking about. It's a little bit different in that the Porsche lost control after T11 entering T12 rather than leaving T10; but you get the idea...

My day was a bit better. I didn't have any scary moments at all (other than avoiding the Porsche, which wasn't really that scary). I didn't even run the last run session of the day. I figured I had such a good day I didn't want to jinx it with something going wrong in the last run group which was a shared run group from all levels (novices and intermediates together). Not that anything would go wrong, but I just didn't have a good feeling about it so started packing my gear; and as luck would have it, just as I hit I-5 raindrops started falling on my windscreen. I would not have liked to be out on a wet track with R-compound tires; so I think it was the right decision.

When I got home, I took a look at the data from the PerformanceBox and saw that I ran a new PB of 1:35.4; nearly 4 seconds faster than my previous best time! I figure that 3 of those seconds are purely in the NT-01s, but maybe 1 second is there because of the increased confidence I got from the setup.

Here's a plot comparing my previous best time (blue) against my new best time (red):

And here's the fast lap on video:

On the brake side, everything looked great when I got home. The pads did NOT have the taper any more and were only 20% used; so they'll be good for another couple of track days maybe three. Seems like I finally got everything clicking. Now I can leave things alone and just concentrate on my driving without worrying about stuff.

UPDATE -- 2006/06/04

I've been having a pulsing sensation in my brake pedal ever since I put the street pads back on the car since the last track day. I figured it was just some pad accumulation on the rotor that I'd have to deal with (e.g., sand it off, or similar). This can happen sometimes when you switch from one pad to another (like I've been doing). Well, unfortunately when I got home from work today, I took a look at the rotor and found a crack in one of the slots that went all the way to the edge of the rotor. Maybe I shouldn't have been so smug as to think I have everything figured out, eh? Also -- note to self: when checking the brakes after a track day check the rotors too!

I haven't taken the rotors off the car, but from what I can tell I have only the one crack. Hopefully it was an isolated deal. For now, I've got to call up TCE and order some new rotors. I really can't run on a cracked rotor for long -- even on the street.

UPDATE -- 2008/06/05

I talked with Todd from TCE today and ordered the new rotors. I got the 12.2" rotor, so it's a tiny bit larger than before (was running 12"). I don't think that the extra 0.2" will help prevent cracking by itself, but it won't hurt either. After talking with Todd for a while, I did walk away with a few things. Chiefly, damage to rotors is usually not done by the braking event itself; rather, what causes the damage is usually caused by not cooling off the brakes well enough. If you just come into the pits without cooling the brakes, the pads will heat soak the rotor and cause thermal expansion issues between the hot part of the rotor (where the pads are) and the cooler part of the rotor (away from the pads). The thermal stress can cause the cracks. There was a black flag in the first run group and I went straight from the track to my pits (where I measured the rotor temps to be about 750 F), and in the first track day with these rotors I got meatballed twice for what turned out to be tire noise. Again, I just went to the pit spot after the meatball. So, I think my takeaway lesson is that if the run session is stopped due to a black flag or I get meatballed, I should run for a little bit in the pits (or maybe even out around the block) to cool down the brakes. I really am not looking to upgrade my brakes again at this point. :-)

UPDATE -- 2008/06/14

The rotors came really quickly, about a day earlier than expected, so everything was set for me to dig into the brakes and get the rotors replaced.

Here's a picture of the cracked rotor:

And a closeup of the crack:

The new rotors are 0.2" larger, so maybe, just maybe, I won't crack these as quickly. We'll see. Here's a comparison shot with the new (very slightly larger) rotor nice and shiny (at least until I bed them in):

I sent the rotor pictures to Todd at TCE and he thinks that I'm really pushing these brakes pretty hard. The purple colour of the brake hat is one of the clues. I guess I'll be looking at a BBK for next year -- probably go with the 13" Wilwood kit. This will require 17" wheels, which means swapping out my street wheels for 17" ($$$) -- hence why it will be next year. :-)

Depending on how my rotors pan out, I figure I'll run the July 29 event and maybe one more August or September and call it a season. I was hoping to run 6-8 Track days this year, and five isn't too bad.

Track Day #5 -- 2008/04/09

After I came home from the previous track day; I took a look at my rotors and pads and saw that they were pretty much shot. Running without the chicane meant that instead of braking from about 105 MPH into T1, I was now braking at about 125 MPH into T4. Physics tells us that energy of movement goes by the square of speed; so that extra 20 MPH increased the energy by 42% which the brakes had to deal with. Clearly they were not up to the task! The pads came out all crumbly and the rotors had deep grooves in them.

So, I went shopping for brakes. I didn't want to spend a tonne of money upgrading wheels, tires and brakes together; so that limited my choices quite a bit. None of the big brake kits would fit; I had to look for smaller upgrades. In the end, the decision came down to a 4 pot upgrade kit from Racing Brake and a Wilwood kit from TCE. I eventually selected the Wilwood kit; it had a really good selection of brake compounds with detailed information (Cf charts by temperature; etc.). If you're in the market for upgraded brakes, definitely checkout TCE's offerings of Wilwood kits.

The installation of the brake kit is all pretty straight forward. Just remove the old caliper, bolt on a new bracket, put together your rotors (they're two piece design that you need to bolt together and safety wire), and attach everything. The only "tricky" part is getting the shims right so the caliper is centered on the rotor and stands off the right distance from the rotor.

So for this track day, I was (again) evaluating some new equipment. The first session was all about feeling out the new brakes and making sure everything was OK. Being Portland, the first session was wet and rainy; so the lap times were pretty low (1:44.1), but the brakes tested out OK.

For the second session out, the track started to dry out a bit and as I was pushing more, I began to hear a buzzing noise coming from the front tire wheel area. It only happened in T7 where I was still fighting understeer problems; I just could not get the car to rotate properly towards the apex. Eventually, the buzzing noise got loud enough that the turnworkers started hearing it and I got meatballed. The meatball is a black flag with large orange dot in the middle (hence the name). It means that "something is wrong with your car, please come talk to us." So I went in to talk with the official, where he told me that they thought it was my brakes clicking under load and that I need to check it out.

I tried looking at it; and figured (wrongly) that it was expansion noises coming from the two-piece rotors (they snap, ping and pop a little bit as the hub portion is aluminum and the rotor is steel -- as they heat up they expand at different rates, causing noises). So they let me out again for the 3rd session, but (naturally) the noise came back and I got meatballed again. That pretty much ended my day -- I did manage a new PB of 1:39.3; but had some work to do to figure out what was causing the buzzing noise.

Fearing the worst, I did some tests to ensure that it wasn't the bearings or the CV joint (expensive items). I also took the brakes apart, and figured that I wasn't rubbing anywhere. While I was in there, I took out the backing plate to help cool things down. I also noticed that my race pads (Polymatrix-B) that I got with the Wilwood kit were about 60% used up! I was hoping to get a bit more than one track day out of a set of pads! And they had a pretty severe taper to the pads as well (thicker at the trailing edge of the pad than the leading edge). So now I had two things to worry about.

In the end, I got everything sorted out. With the help of YouTube and the nice folks at NASIOC; I was able to determine that the buzzing noise was nothing more than the tire rolling over itself. It would have gone away if I pumped up the tire pressure a little bit more.

The pad wear problem was solved by improving the rear brakes. I had so much forward bias by upgrading only the front; that it was doing nearly all the work. A quick couple of calculations convinced me that I needed to upgrade my brakes at the back to even things out and cool the front down a little bit. This will help with pad wear.

The solution was to order a Racing Brake OEM big brake kit for the rear. It is really little more than a bracket to relocate the caliper out from the axle just a little bit and replace the stock rotors with upgraded slotted rotors of the right size to match the increased diameter of the new brackets. My only complaint was that it took a long time for them to ship me the kit -- it was backordered for about 4 weeks. But it eventually came and I was able to put it on prior to the next track day. I also purchased some Hawk HP+ pads for the rears to help move the bias more to the rear.

Track Day #4 -- 2008/02/24

It's been a LONG time since my previous track day. PIR was closed for a few months because they were repaving the track and slightly reconfigured Turn 7. They made it MUCH wider in T7 and increased the length of the track just a little bit -- now it's 2 miles around which I heard was important for some race organisations who won't run on tracks less than 2 miles.

Here's a few pictures from the event; I got some nifty reusable vinyl numbers from IZoom Graphics (check the vendor lest to the left for a link). The first is a shot of me going through the twisty bits in T6 and the second shows me passing someone on the T9 back straight. No good side shots showing the lettering, but the reusable numbers sure beat using the soap marker pen (of car dealership fame) -- the only thing is that you really want to attach the lettering to the window rather than the painted door panel. It's tough to get off without a razor blade and you really don't want to scratch your paint getting the numbers off.

Anyway, this track day was to celebrate the opening day for the track after the repaving; sponsored by the Friends of PIR (FOPIR) organisation. If you live in the Portland area and enjoy PIR, you really need to give your support by joining FOPIR. You can do it at their web site (

With the long layover from the previous event, I had time to research, purchase and install some coilovers. I chose Megan Racing coilovers with 8kg/mm front and 6 kg/mm rear spring rates. This was a compromise choice as they'll be pretty harsh on the street, but they have lots of built-in adjustments you can make (ride height, damper setting, camber setting, etc.). And, they're pretty cheap at about $1000 for the set. While I was there, I also upgraded the front brake lines to stainless steel brake lines. That gives me a firmer brake pedal.

My goals for this track day were pretty simple -- learn the new coilovers. I wanted to figure out what camber setting to use, see if the damper settings really did anything, and just figure out how the car was going to handle with them on there. I also wanted to improve my situational awareness (e.g., being sure to look at all the flag stations on every lap), improve consistency, improve smoothness, etc.

All in all, it was a good day. Because this was for PIR's opening day, we ran the track with cars and motorcycles (not at the same time); so they configured the track without the chicane. This means that the lap times don't compare directly with my other track days. That's on top of the changes that they already made to turn 7 and the repaving, which changes things. Here's a comparison map showing the differences in the track. The red line is the new configuration:

This was also my first track day running in the intermediate group without an instructor -- going solo, if you will. I was a bit nervous, because I didn't want to hold people up too much being put into the next group up; but it turned out to not be a problem. The changes to the track were new to everybody, and being so long since the last track day meant that everyone was a bit rusty, so we all pretty much took it easy to get used to the track.

The track started out cold and wet; but the sun came out and warmed it up by the end of the day. My lap times were starting out at about 1:43.5 range (remember there was no chicane; so it's about 10 seconds faster than my other track days!); but got a best time of 1:30.7 at the end of the day as it dried up and warmed up a bit.

In terms of my driving... I had a heck of a time trying to get to grips with the new T7. It's Soooo wide it's amazing, but somehow when you drive it, it just doesn't seem to let you keep your speed up. There's something deceptive about the way that the exit of T7 funnels into T8 that prevents you from getting good corner speed there; and my mistake was consistently going in too hot and scrubbing speed with really bad understeer.

Track Day #3 -- 2007/08/03

For this track day, I made a few changes to the car. First, given the brake problems I've been having, I upgraded the brake pads to Hawk HP+ on the front (stock rear pads). I also installed a Schroth 4-point racing harness with ASM (anti-submarine technology).

If you search around the 'net, you'll see lots of people saying that 4-point harnesses are a death trap. Stay away at all costs... and that would be true for Schroth EXCEPT that they use an ASM module. Reading through the Schroth web site, the ASM module is designed to stretch just a little bit in the event of an impact; causing your upper body to rotate slightly. This twists your hips and locks you in place; kinda like a cam lock. This cam lock effect keeps your hips from sliding under the belt. Anyway, after a bit of research, it seemed like a good thing so I went ahead and bought it.

The really nice thing about the belt is that they have a quick-fit version for WRX that clips into the stock harness points (and some new mount points that you install); so you can remove the harness in about 30 seconds. Very nice for track days, or auto cross events.

The driving was good again; no problems to speak of. The brakes are a bit low in the pedal, but held on well with no fading. I had lots of problems with traffic, but that's pretty normal; it's sometimes really hard to get a clean lap, especially in the novice run group. My instructor spent some time getting me to push out of the corners earlier. I still have a lot of characteristic novice habits like overdriving the car on entry -- going in a bit hot and scrubbing speed in the middle of the corner instead of balancing it for a nice clean exit.

My PB dropped down to 1:41.3 right at the last lap of the day. All in all a good day; still lots of room to go, but overall getting better. Here's a comparison of the best for this (red) day vs the previous day (blue):

Here's a track map:

Looking at the data trace and the map, you can kind of line them up. The crests in the plot are the straights and the dips represent the corners. Anyway, I make up most of my time in T4-6 (the twisty bits), which is a reasonable place to start learning because there isn't that much to hit out there if you get it a little bit wrong.

Track Day #2 -- 2007/05/24

I can't remember why it took me four months to get back out to the track; but I eventually made it back out there. This time, I wanted to be a bit better prepared, so I started keeping notes of things (tire pressures, weather, etc.).

I also bought a Performance Box. It's a nifty little data logger that attaches to your wind screen with suction cups and uses GPS technology to record your position, speed, acceleration (lateral and longitudinal). With the software that comes with the device, you can plot out your driving line (on top of a google-earth map if you like) along with graphs for things like speed vs distance, braking, acceleration; and it tells you lap times. By nature, I'm one of those nerdy, engineer types. I like having real data to look at and thought it would be interesting to really see how my skills evolved by examining the data logs.

Here's a plot of speed vs distance of my fast lap:

By itself, it's not that interesting... however, it does show how fast I'm going around the circuit.

Using the performance box; I noticed a few things. First, my consistency sucks -- I never really seemed to drive the same line more than a few times. Second, my braking was maxing out at about -0.7 Gs -- I need to get closer to 0.9 to 1.0 of negative Gs. Clearly some better brake pads are needed. Finally, my best lap time of the day was 1:43.8 towards the end of the last session which is actually not bad for someone with only one other track day under his belt. I really liked the fact that I was improving steadily throughout the day and had my PB right near the end. That means I'm able to keep learning and improving.

Track Day #1 -- 2007/01

So my first track day was with a borrowed helmet on a cold, rainy day in the Pacific Northwest at Portland International Raceway (I'll just call it PIR). About the only thing I did for preparation was to put on some "high performance" brake pads from NAPA (Akibono) which are really bad. No, I mean they are absolute junk for track days -- they don't fade, but they also don't have any grip either.

Anyway, I naturally signed up for the novice run group and requested an instructor. Once I get to the track you have to get the car through "tech" which is where someone checks over the car looking for bad things -- checking lug nuts, battery tie downs, clean car, etc. I've never had a problem getting through tech; but I'm pretty thorough about removing anything that isn't physically attached to the car -- spare tire, junk in glove box, CDs, floor mats; I remove EVERYTHING before going through tech.

After getting through tech, you go to a drivers meeting where they tell you the flags and introduce you to your instructor (for novices). I already knew the flags because I used to be a turn worker way back when I was at university; and as you might imagine, they haven't changed.

I don't remember much of the rest of the day; it was just my trial run to see if it was something I wanted to keep doing, so I didn't keep notes or anything. I do recall that I had no idea of the gearing for corners -- downshifting to 2nd on nearly every corner; having a blast, but surely not going very fast either.


I have no idea at all if anyone is ever going to read this blog; but in case, here's a little bit of background that should help set the context a bit.

I have been driving my car around the local race track during lapping days since early 2007. It really started as a whim -- one of my coworkers did track days and I became curious so thought I'd try it out. I borrowed one of his helmets and signed up for a Alfa Club day; and I have not looked back since.

The format of this blog will be pretty simple; I'll create entries for individual track days really trying to focus on the transformation from complete novice driver to whatever I'll become in the coming months/years/whatever. Along the way, I'll talk about some of the changes I've made (and will make) to the car; the mistakes and successes.

If you like this kind of thing, you might want to check out these blogs too:
  • DP Cars is a great site with plenty for everyone. His main track day car of the moment seems to be a Mini, but he's got lots of descriptions of his current cars/motorcycles, past cars/motorcycles and even tonnes of info on his prototype track-only car the DP1.
  • Bemused and Confused is a blog about the experiences of getting into track days, buying a track-only car (BMW) and the work involved in getting it track worthy.
  • David's Vehicles page is somewhat similar to DP Cars site with lots of cars/motorcycles and stories about them. It's a bit dated though, the last update was June 27, 2007; but still a good read.
I'm not really trying to compete with those great sites; I think I have something slightly different to talk about. My theme is really about my experiences as pretty much a novice working through the sport and seeing where I end up. As you'll read, I've had some good moments and some difficulties; sometimes driving related and sometimes mechanical. In some distant future, I hope to be able to look back at these blog entries and realise how far I've come; but that will have to wait for now.

So, if you're still awake... off we go to the first track day!