Labor Day is coming up, which means that it's time to attack WMR's Grattan autocross event with my Impala SS. This is different than the typical parking-lot course in that it runs a bit more than halfway around Grattan raceway, running in reverse direction down the straightway towards turn 12, continuing down through the aptly-name The Bowl, and finishing between turns 5 and 4. Two slalom sections are used to reduce speeds on the straightaway and on the sweeper between turns 10 and 9. I'll get more into event preparation in posts over the next couple of days, but keep reading below if you want a description (to the best of my recollection) of a run.
The starting line is set up at what would normally be the paddock exit. Hooking the car up is difficult with the
rear tires inflated to autoX pressures, and a bad launch can add a second or two to a run. There?s room to hit over 60
MPH before the entry to the slalom, at which point I need to bleed off about 10 MPH or else I end up on the hill to the
north of the straight, picking grass and mud from the bead of my tires. With a 116? wheelbase, the goal is not to be
fast through the slalom - it?s just to make it through without hitting cones.
Upon exiting the slalom, it?s onto turns 12 and 11 while dropping downhill. It makes for some tense moments as the suspension unloads. After exiting 11, it?s WOT time (where my car really shines - duh) before braking and downshifting in turn 10. That?s normally narrowed with cones, so it?s even tighter than it may appear on the map. With my current setup, I fight just a bit of understeer going into a turn on the brakes, but it occasionally snaps the tail around. In other words, smooth and early braking is important.
As I progress through 10, I can expect a transition to oversteer as I roll back into the throttle. This is to be expected when trying to hook up about 375 RWHP with a contact patch that?s already feeling overworked. It?s difficult to keep the rear from passing the front before hitting the slalom that?s placed prior to the entrance to turn 9, and frankly that?s going to be the story for the rest of the run. There?s another elevation change as 9 drops into turn 8, and I?ll typically roll into the gas just enough to bring on some oversteer through this banked right-hander. There have been a few times where I?ve gone through The Bowl looking out the driver?s side window instead of the windshield, but that?s not really a fast way around the track.
The rest of the run can best be described as a roller-coaster ride. Turn 8 goes into the slightly off-camber and downhill turn 7, and then the track rolls over 6 and 5. It?s almost like a paved motocross course at this point. It?s all about modulating the throttle and countersteering.
My best year here was in 2001, the first time out with the stroker motor but still with the stock automatic (that transmission perished shortly afterwards, and I went to a T56 6-speed manual). Since then, I?ve either had to miss the event with mechanical problems, or rain has hampered my ability to put down a decent time. Hopefully, we can expect dry weather this year, and the car appears to be willing to stay in one piece at least long enough to get to the track.