Sunday, March 22, 2009

Track Day #9 -- 2009/03/21

Overall it was another good day for me. I used my tire tail for the first time so I had both my street tires and race tires at my disposal -- and as you'll see below, I had need of both. To give an idea of what the tire tail looks like, here's a picture of the car loaded up the night before:

Once I got to the track, I unpacked my stuff and went looking for the other cars. Unfortunately, perhaps due to the economy, there really weren't that many cars at the event. I think I counted about 25 or so on the web site, and perhaps a few more walk-ins but nothing like last year.

Here's some pictures:

Nice looking racecar.

The blue alfa here ran in my group and when following him you really got a sense of how much the car is leaning over. I'm really glad I put on the stiffer coilovers...

These ran in the advanced group and were VERY Fast. I timed the black winged GT3 at a 1:27.

And here's a picture of my little beastie:

My game plan for the day was really down to these four things:

  1. Improve braking consistency, especially into T1. I felt that previously, I'd modulate the brakes in order to hit the turn-in speed I was looking for. This time, I was going to try to always brake on the threshold and hit the turn-in speed by varying my brake point.
  2. Improve my steering smoothness through T4. One of the comments from last year was that I was taking T4 with too much steering input; it should be nice and smooth with a single arc.
  3. Increase speed through T10 and into T11. In the FOPIR track day, I started wagging the tail a bit in T10 by getting off the brakes smoother and earlier and carrying more speed in; I wanted to continue the trend.
  4. Have fun!!!
This event was run by the Alfa club here in Portland, and is somewhat ironic because my very first trackday was with them (back in January of 2007). As I found out, I probably should have entered in the advanced group -- while it's great to see wonderful Alfas out there on the track, tearing it up, many of these machines are quite a bit older and have pretty small engines. Looking at them reminded me a lot of my old Triumph GT6 I used to have. In fact, to underscore my point -- there was even an MGB running out there in my run group. :-)

The weather started out looking promissing -- cloudy, but not too much wind or any rain. The track did have some dampness from the morning/evening, but nothing major. The first two sessions were nothing but traffic fest -- even with only about six cars out there (including me), I just kept coming up on traffic. Never got a clean lap in. My third session however saw a few laps where I was able to put down some clean laps. Even got a chance to better my previous best with a 1:34.9 (or 1:34.8 according to TrackVision). I believe that I could get even better, but just never had a chance to get in a groove... and trust me, I need time to get into the groove.

Here's the fast lap as compared with my previous best on the race tires (today's lap in red, the June 08 lap in blue):

Overall, you can see that I'm much faster through T4 and T10; but gave up a little ground in T5. Seems like the speed trace really isn't enough to tell the story, so here's a plot of the longitudinal acceleration (essentially how many g's I'm accelerating or braking):

Notice how much better my braking efficiency is for T1 -- not only am I harder on the brakes than I used to be, but I have a reasonably flat floor now rather than a peaky or rounded curve shape. This means I'm doing a better job at keeping the tires at their limit for the full duration. I did however, wimp out a bit on turn in rather than trail brake it all the way into the apex for T2. That's something I'll work on for the next one.

The slower speed in T5 shows up very well in the second trace as well -- it's just a matter that I'm hitting the brakes trying to kick the rear end over to help with my turn in. That's something I didn't do before -- call it an experiment. I was hoping this time that it would allow me to get a better drive out of T5 and into T6. It does help a bit, but not enough to compensate for the lower apex speed through T5 -- so I'll probably do that less next time.

Here's the video for my fast lap:

And for a bit of fun, here's a short video of me almost loosing it at T5. This was early in the first session where the track was a bit damp and the tires were still a bit cool (not to mention the driver):

As you can see, I slide a bit wide after the apex for T4 and ran up on the rumble strips. Other times when I've done this, I've been OK -- sure the car jolts around a bit, but you wait it out turn back in and all you've lost is a bit of lap time. This time however, I must have hit them harder than normal or the strips were slippery from the morning dew -- in any case, you saw the result. All in all, not a terrible thing; a quick bit of opposite lock catch the back end, then point it straight to prevent the fishtail and all is good and I can continue. It did serve to wake me up though. Other than a bit of a loose condition in my fast lap, I pretty much stayed out of trouble all day. And I didn't even get a black flag for it!

The fourth session was pretty interesting because it started to rain while I was out on the race tires, so I got to experience what it's like when you run on a wet track. It didn't rain enough to get standing water anywhere -- I would have brought it in to the pits if it did -- but it did get slippery out there. I ended up backing way off in the braking zones for fear of slipping off and just trudged around in about 1:44 kind of range. It was fun to get the car up on the rear tire for once and throttle steer it through T12.

As soon as I came into the pits everybody was changing over to the street tires, and I followed suit. It didn't really rain that much, but it never dried out either -- so the fifth session was pretty much a wash (literally). Again, nothing great here - just running in the 1:42 to 1:44 range; keeping it clean, but having fun anyway. As part of switching to the street tires, I moved the camber back to the 0 mark on the top plate. I've noticed in the past that street tires get really chewed up by the negative toe that you automatically get when you push the camber in.

On the final session -- yes there were six sessions, but short -- the track started to dry out and I was able to push the tires a bit harder. I think I got a best time of low 1:39s; nothing to write home about. I think it was a combination of the 0 camber and still-damp track, but that's all I was able to get (and yes, I was disappointed with myself...sigh).

Now, on to the mechanicals ... I didn't change anything for this day, so I was really just trying to dial my self in and have some fun. And as it turned out, the brakes and tires really worked pretty well. I put some temperature paint on the rotors for the first couple of sessions and my paint tells me that the rotors were between 1075 F and 1326 F (Yellow colour). The next colour up from that is green, and since it didn't have any green in the colour, I think I'm on the lower end of the spectrum. Once I got a look at them, the pads were a nice even wear with lots of life on them and the rotors looked great. So I really am happy that I've got the braking problem solved.

Unfortunately, on Sunday morning (the day after) I noticed a puddle underneath my car -- and no, it's not water from the AC. After jacking the car up, I got a look underneath and it seems like the fitting for the power steering rack is leaking. So I'll have to make an appointment with Carr Subaru on Monday when they open. Sigh... As things go, it's just one of those things I suppose. I'll update the blog when once I get the work done if there's anything interesting to report.


I took the car to the dealer (Carr Subaru) to have them look at it and they just called me back -- about 45 mins later. It was just a hose fitting that had vibrated loose. Nice and easy, and cheap.

They also reported that there's a minor exhaust leak so I'll need to replace the exhaust gaskets. So I'll look into that; I wonder if it makes sense to put in an up-pipe or something at the same time -- problem is, I doubt there's anything I can do and still be emissions legal. Worth a bit of research though...


The exhaust leak turned out to be the up pipe. There was some exhaust coming out between the heat shield and the flange. I had them replace it with an invidia up pipe, so everything is good.

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