VIDEO: GST Impreza Sets Lap Record at Auto Club Speedway

VIDEO: GST Motorsports Impreza L Sets New Lap Record at Auto Club Speedway

by Jeff Naeyaert

Last Wednesday at Superlap Battle we were bummed we never had the opportunity to put our cameras in the Sierra Sierra EVO only to witness them take down the Buttonwillow track record; however, luck turned in our favor last weekend at the final Redline Time Attack of the year at Auto Club Speedway!  With only 30 minutes before Sunday's first session we were able to throw our Traqmate GPS data acquisition system and a few ContourHD cameras inside the GST Motorsports Impreza "L" just minutes before Jeff Westphal drove it to a new track record of 1:35.548!   Check out the video and data below!
 

That smoke you saw filling the cabin and oil that began covering the side mounted camera was from the oil catch can overflowing...  Looks more dramatic than it probably was but damn was the Traqmate hot when we pulled it off the floorboard of the Impreza! 

The Traqmate acceleration/braking zone map shows the periods of acceleration (green), braking (red) and coasting (black).  While the data seems to indicate Jeff braked going into turn 1 I don't see his leg moving in the video... Perhaps the aerodynamic drag at 170mph is so great that when he got off the throttle the sensors in the Traqmate thought he was braking...

The purple dots in the Friction Circle plot indicate sustained loads rather than high sharp peaks that can occur.  Here you can see the car was seeing sustained lateral g's approaching and even going over 2 g's (this from the banked oval section of the course).  Note the much higher G loads that you have seen before in other data session with us from the Berk car and others.  This is attributable to the GST car's R-Compound Hankook C91 gumball tires and its aerodynamic aids like wings, diffuser, splitter, canards and barge boards.  The GST car pulls a half a G more in lateral accelleration and braking than your typical class winning Street Class car.  It also pulls more than twice the G load of your typical sports car!  Look how many data points are outside one G!

A graph of Lateral g's vs Time...  If you want to look up the g forces from a particular point on the course the "0" value corresponds to the starting line (when the timer pops up on the screen).  There is a little discrepancy between the g forces seen on the Friction Circle vs the plot (no point on the graph goes above 2g's whereas the Friction Circle seems to indicate otherwise).  This is because the trace is an average reading where the friction circle includes instantaneous data. The high lateral load area is on the oval where the aerodynamics are the most effective.

Stay tuned for a full feature of the GST Impreza coming soon!  Special thanks to the GST crew for letting us get in their way while setting all our stuff up!  Congratulations guys!

GST Motorsports