We took my Z4 M Coupe to its first HPDE at Horse Thief Mile (part of the Willow Springs race track complex in Rosamond, CA) on 2-17. SpeedVentures
hosted the event and I was very impressed at how organized and observant they were. I plan to do more events with Speedventures as soon as I can!
Horse Thief Mile doesn't look like much fun on paper, but thankfully you don't drive on paper! The elevation changes are extreme, and the lack of any proper straightaway means you are pulling Gs CONSTANTLY. Here is a pic of the Willow Springs complex. HTM is the small middle-right track:
Here is a pic from the top of a hill (about a 5 minute hike from the paddock). Below is 1/2 of HTM and you can also see part of Streets of Willow and the two short oval tracks:
Now for some chronological pics...
Will all this fit into the trunk of a Z4 M Coupe? I sure hoped so!
Luckily I did the battery relocation mod (if you don't know what that is, visit my M Coupe mods thread HERE
). I had to use all my Tetris experience, but made it fit:
And I even had a little rearward visibility:
We left early Friday afternoon, so traffic SUCKED, but what do you expect. Here's a shot of the hills near the 5/210 interchange:
On the 14, heading to Lancaster:
There was a gorgeous sunset Friday night. Here is a shot of it next to a Chili's that looked open from the street, but was in fact an empty shell
We stayed at Essex House, which was decent for the money. I've also stayed at The Inn of Lancaster, and it's quite nice for $80/night. Saturday morning we headed out to the track. Dawn:
Sunrise hitting the desert scrub:
I can see the track!
In this pic you can see turns 3 and 4 of Willow, and HTM (top right) and Streets (bottom right):
I noticed that the racetracks are included on the 2007 Navtec data disc. But HTM isn't on it, because it just opened.
This is a pic from our parking spot in the paddock on Saturday. This may look like a lot of elevation (you're looking at turn 6), but it's nothing compared to the drive from turn 1 to turn 3!
Here is a shot of the early morning sun's glare off the Streets of Willow track:
There were a LOT of different cars at the event. My Z4 was one of only three BMWs on Saturday. Here are some shots of the paddock:
On the CW grid in the Blue group:
This is a map I made of the line I used when running CW on HTM, as we did on Saturday. I'm not saying it's the ideal line, but remember my Coupe was still stock and the Continentals were pushed passed their comfort zone after about 1 lap. I was fighting understeer both days, but moreso on day 1 because of the way the shape of the track and the hills interacted. Note: The track is so new that there are no official turn numbers or names. So everything below is made up by me. Maybe this is how the track will be officially numbered, maybe not.
Here is a pic of my car going through the apex of turn 1. This shot really illustrates how much elevation change there is. My wife was standing on a hill only a little taller than turn 3.
In this shot I'm approaching turn 2 (The Kink). The Subi ahead is just passing the apex. The track to our right is part of a chicane that we didn't use either day. You do NOT want to get 2 wrong, because running in either direction the ground falls away downhill.
Some pics of me running through turn 3, the highest part of the track:
Turn 4 is a little bend in the downhill run to turn 5. Pretty simple, WOT and apex to leave yourself in a good position for braking.
Turn 5 was hard on brakes both days. Going CW it's a decreasing-radius turn, but at least it flattens out just before turn-in so understeer isn't as bad as turn 7 (below). Apex late and feed in throttle up the hill.
Turn 6 was tricky only because I kept braking too early and too much, which meant I was wasting time. You have to trust the uphill to scrub speed during turn-in. It's possible to get back on the throttle before the apex if you get good turn-in using late trail-braking.
Turn 7 was the hardest on brakes on day 1. You can't see it in the pics, but it's very steeply downhill all the way through the turn. This makes you compromise your front contact patches trying to slow AND turn the car against gravity. Late apex as with most of the turns on the track when running CW.
Here is turn 8. Not hard to get through the turn, just brake and apex late, but I never felt like I had the right combination of line and technique when running CW. I'm sure I was losing time there. In the second pic you can see the east pit entrance/exit.
Turn 8B is really just a kink thrown in to interrupt the track-out of turn 8. Basically, you need to be easy on your throttle coming out of turn 8 or you run the risk of running out of room at 8B.
Once past 8B, you are on the throttle to whatever extent your car will allow and swing down turn 9. This is a bit scary to watch from the paddock, as if a car spins out here it seems like it will land in your lap. But one of the cars did lose it in turn 9 and the gravel and a ditch stopped it well short of the paddock fence line - even before it would touch the CCW grid pavement.
Turn 10 is really a chicane, with two cones marking the limits of the pavement. I tended to apex turn 9 a little early, swing out and back in toward the first cone of turn 10 - similar to treating both as a single double-apex turn. Before the first cone I was at WOT, and after turning slightly to pass the second cone, track left to set up for turn 1.
The apex of turn 1 is just out of view, past the hill in front of us in this pic:
So ended day 1.
Sunday morning was a little overcast, but there were some beautifully subtle colors in the clouds and hills:
Many cars were different on day two. There were fewer Lotuses (sp?) and many more BMWs. Paddock pics:
This guy had the best paint/number combination:
This is a shot of the White (beginner intermediate) group on the CCW grid:
This is my map and line for HTM when run CCW. Note: This is not the ideal line for most cars. By day two my front tires were badly scalloped and I had significant understeer. My instructor and I talked about it and given the nature of the course (more like an autocross than a race track) and the lay of the land we decided the ideal line for my car in the condition that it was in (providing that I still wanted to drive it home on the same tires by the end of the day) was to tighten the lines in the slower corners. Since the understeer made me slow through many of the tighter turns, the tactic was to simply stay in the turn for the shortest amount of time. This meant a tight, slow entry but allowed for more WOT time between turns, much more straight-line braking and got me on the throttle much sooner without hurting the tires. It's the line I'd probably choose if I was driving a heavier car (like an M5) on HTM. But the proof is in the pudding. I ran about a second a lap quicker on day 2 and my mpg calculator in the car dropped by 1.5mpg - a good sign on a racetrack. Now that I have grippier RA-1s on the front of my car I'd probably be faster running a more traditional line (like my day 1 line above).
Here I am coming up out of 9 through 8B. I ran straight here (see map above) because it would have slowed the car and increased the lap length too much by pulling it right after 8B to set up for a traditional line into turn 8.
Turn 8, like 7, 6 and 5 when run CCW, were all slow-in, middle-apex turns. This got me on the gas faster and eliminated the extra strain on my front tires from holding a longer arc by fully tracking out and back in.
Turn 7 was essentially the same tactic, but with more traction going uphill and more track-out than turn 8.
Turn six is more of the same, but going uphill the brakes were hardly needed at all. On several laps when I got everything right I didn't even use my brakes - just maintenance throttle. Note: This first pic is an earlier apex than ideal. I was experimenting.
Turn 5 was the hardest on brakes on day 2. Unlike when run CW, the track does not flatten out at all before turn 5. On the plus side, it was a late apex corner on day 1, so the early apex on day 2 suited my strategy perfectly. Again, with better tires I would have swung a wider line, but this line still worked really well.
Going uphill through turn 4. This was pretty straightforward, just like on day 1. Just find a line that sets you up for braking into turn 3.
Turn 3 was pretty easy, very much like turn 8 but with less duration.
Turn 2 (The Kink) was scary for me running CCW. I never fully trusted my front tires, so I ran a little too slow there all day. Basically, you need to brake around the area of the chicane, and then get OFF the brakes and back on some sort of throttle to keep the rear end from coming around when you hit the dip at the apex. If you spin and go off at 2, there's nothing but downhill slopes and a 6' drop into a dirt parking lot later on. It was here that I learned that while the M Coupe is great in part because of its short wheelbase, that can be a detriment on off-camber higher-speed turns. If I was anything less than partly on the throttle coming into turn 2 the rear end would start coming around a little. I always caught it (thanks in part to sitting on the rear axle line), but it gave me an appreciation for how one needs to adapt one's driving style to the car and track. Once I had to brake as I was turning in because of another car suddenly slowing down in front of me. I think that was the most upset the car got all day, and to it's credit it was very controllable in a slide.
I took this picture to remind myself not to trust fuel gauges. I SWEAR I had a 16th of a tank left when I started my last lap of the day...but the coughing and engine shutoff going up through turn 4 disagreed. Anyway, I coasted back to the pits and Aaron (SpeedVentures organizer) was nice enough to let me borrow his gas can and Evo.
Here are my front tires - lots of tread left, but not all in the right places. Seriously though, these Contis weren't all bad. They held up better than PS1s under similar treatment. The Contis got bad quickly, but then never got any worse. Even thrashed they let go in a predictable manner - unlike my M5's PS1s near a certain guardrail.
Similarly, my neck suffered from the irritatingly non-adjustable M Coupe seatbelt guides. We need to produce a product to fix this!
I used a Stickypod camera mount to shoot some video. I promise I'll upload some laps running both directions, both inside and outside the car. I don't promise when...but I'm working on it.
Not shown in these pics are the tethering straps (part of the kit) than I ran through the front and rear edges of the decklid to keep the camera from swiveling in turns.
The end of day 2:
All that's left now are random shots that I thought were interesting. Some are mine, the ones where the Coupe is out on track are obviously my wife's.
Overall, I'd say the car was phenomenal. Even with undersized stock tires it ran similar times to other student-driven cars: Elises, Exiges, Subis, Evos and S2000s (even an R-Comp'd Mini Cooper-S)on a track where lighter cars benefited more. The Coupe's power was an asset going up the hills, but wasn't a major factor in lap times. I can't wait to go back with my RA-1s, and suspension mods as soon as we can get them in...
p.s. Once again, to follow the evolution of my M Coupe, subscribe to the following thread: http://www.bimmerfest.com/forums/sho...d.php?t=185835