Friday, June 25, 2010

Track Day #13 -- 2010/06/24

So it's time for another track day. I came prepared for this track day with one change to the car -- I installed a front lip spoiler to see if I can generate some additional front downforce to help through turns 4, 6 and 10-12.

Unfortunately, things didn't go well for me today. In the very first session, after two laps to warm up my tires and brakes I got way out of shape in turn 2 (chicane). I gathered it up OK and figured I'd just gotten in too hot, but that wasn't the case. As I as going through turn 4 the front of the car started making this truly awful rubbing noise.

I thought perhaps it was a tire that went down and I was rubbing the spoiler, but interestingly the car was tracking mostly straight. Then I thought it might have been the spoiler itself broke and was rubbing under the car. In any case, I brought it around nice and slow to the pit lane.

Here's video of what it looked like from the driver's perspective:

Once in the pits, I went over the car and immediately saw that the spoiler was OK and all tires were inflated normally. There wasn't anything out of place under the car -- nothing rubbing, etc. So I had to start pulling wheels off. First comes the front right wheel, and everything seems nice and tight -- nothing. So I move to the rear tire and same result, everything is good.

It wasn't until I moved over to the left front wheel that I noticed that the entire wheel was a bit wobbly. It didn't take much to diagnose that I'd blown out the left front wheel bearing. Dang!

So, two hours later I'm at the dealer (couldn't think of where to tow the car to other than the dealer near my house), and another couple hours later I hear the bad news. The bad bearing allowed enough movement of the axle for the tie rod and hub to get damaged (had to be replaced). The cost was just a bit over a thousand dollars; and the shop mentioned that my brake rotor and caliper got damaged as well, so I'd have to look at them on my own (dealer won't touch after-market brakes).

Sigh... so that means I spent a little over $1300 for two warm-up laps! Definitely an expensive hobby.


I inspected the brakes over the weekend (the shop didn't lock-tite the bolts, so I had do do that anyway) and discovered nothing really wrong with the caliper or rotor. There's a little scratch that goes around the top-hat on the rotor, but that's it. Everything is buttoned up properly; ready for the next track day -- whenever that is...

Saturday, March 13, 2010

Track Day #12 -- 2010/03/13

My first track day of the year was hosted by the Porsche Club as part of their break out spring event. They originally planed for a massive event with driver coaching by none other than Mr. Speed Secrets himself (Ross Bentley). Unfortunately, with the bad economy there weren't that many people signed up, so the club ended up canceling most of the events -- leaving just the Auto-X, driver skills clinic and HPDE events intact.

Even then it was a pretty light showing with about 2/3 the normal size crowd at a PCA event. I only had something like 12 folks registered for my run group -- and the largest run group was the instructors (at 17). Made for some good track time with minimal distractions.

The weather was pretty wet and slick to start with. Not much rain during the event, but everything was sopping wet from four days of constant rain. Luckily, it didn't take much for the track to dry out -- about half way through the first session, we could already start to see a dry line forming up.

Now, most of the time I get pretty used to being passed -- when you're out there with tonnnes of Porsche cars, what else can you expect right. I get my revenge on mornings like this one. Even after a lot of warnings (and I mean a lot) from the track steward about how we really need to take it easy the first session because the track hasn't had much cars on it for a bit and lots of rain (yadda yadda)... even with all that, I followed a Porsche out onto the track who spun on turn 3. He didn't even make a lap! And to add insult to injury, another Porsche spun between turns 5 and 6 out into the mud causing the session to be black flagged while they towed him out. Meanwhile, I'm going "gee, it's a bit slick but nothing to really worry about..." :-) I love all-wheel drive for times like this.

All in all, the first session was mostly just a warmup lap. With the track drying out, and the WRX on street tires -- the best I got was a 1:43.10. Certainly nothing to write home about.

For the second and third sessions, the sun actually started coming out so I switched to my NT-01 race tires. As my customary guess, I pumped the tires up to 36 PSI cold figuring I'd bleed them down once they got hot. As it turned out, they worked great so I left them like that for the rest of the day. Nothing quite so interesting happened in this session; I was working on trail braking into the chicane -- and actually got some good results out of that too. The hard part of trail braking into the chicane is getting good corner speed and exit speed out through Turn 3. I've had a little bit of a chance to look at the data and see that I need to work on that part a bit more. The fascinating thing is how late I can be on the brakes when you trail them in -- traditionally, I'd brake at about the 500 mark. With trail braking all the way down to the apex, I can leave the brakes to just after the 400 mark (almost 350).

Anyway, I got a new personal best time of 1:34.20. It's just a tenth of a second faster than before, but I did manage to get ten laps under 1:35.00 whereas I only got two laps under 1:35.00 back in September. This means I'm getting more comfortable running under 1:35, and if I can just put everything together will have a cracking lap.

Here's some video of my fastest lap for the day

There's some new software that came out for the performance box called CircuitTools. One of the nice new features is the ability to calculate your ideal lap time by picking the best sector times through a complete run. This gives you a measure of how far away you are from your best possible lap -- if you did manage to pull everything together. Anyway, my ideal lap of the day was 1:33.19 so I've got quite a bit of work to do. I'm definitely capable of getting under 1:34.00 and should even be knocking on the door into the 33's, I just need to get everything right to do it.

The other thing that the CircuitTools does is show you exactly where you gain or lose time relative to another lap. The delta-T function was sorely missing from the previous software and I'm really happy to have it now. I'll play around with it a bit more and post up my findings.

Here's a screenshot of the new tool. My new personal best lap from today is in red and my best lap from September is in blue. The delta-T chart below the speed chart is really cool; it shows that I've got a lot of improvement I can make even on my best lap (especially around Turn 5 through 6).

For your entertainment value, I put together a quick shot of the very first couple of laps in the day. At the time, the track was pretty slippery and wet so while I slid around a little bit (easy to control in the WRX), the Porsche drivers had a lot more to worry about: