Maranello. Weissach. Milford?

Ferrari's and Porsche's factory test tracks are legendary, as much for their layouts as for the cars developed on them. GM hopes to at least partially redress this imbalance with its prosaically named "Milford Road Course" and the vehicles developed on it.

Standing looking out at the Le Mans-like front straight of the Milford Road Course (MRC) brings into sharp focus just how scarily three dimensional the real thing is compared to the track map and overhead photograph nearby. An outer oval–formerly used for testing medium-duty trucks–encases the squiggles that make up the North Course and South Course, each of which can be run separately, or joined together with parts of the oval to create an extremely challenging high-speed track just shy of three miles long. Determined to move chassis development within the company forward, GM engineers copied sections from race tracks around the world and worked with the natural topography in order to get the cambers, banking, hills, and valleys they desired. Simulations were created to make certain the track was not unduly dangerous, and that it met the needs of the various development teams across the company. Once complete, this information was ported to a video game so the track could be "driven" long before the first tree was cleared or the first shovel full of dirt moved. MRC opened in November 2003.

"It took about three years to create the MRC," says John Heinricy, GM Performance Div. director, "and lots of discussions with the various vehicle groups to determine their particular needs." The final layout came out of discussions chaired by the top development drivers in the company, a group that must love hills. For example, from the peak of the 140-mph front straight the track dives down to turns 1A and 1B, a pair of 45-mph decreasing radius turns. These lead into an uphill section before eventually plunging down into a challenging 45ºº angle bowl. (It's already had its guardrail repaired twice.) Other hills, valleys, and surprises follow.

"In the planning stages we had simulations done based on the capabilities of a professional driver in a Z06 Corvette, and that was ported to [the video game] Grand Prix Legends so that we could drive it and make changes before any trees were cut or earth moved," says Heinricy. Ironically, the accuracy of the simulation was called into question by the engineers as the MRC began to take shape. Simulation numbers showed a track that was challenging but within the capabilities of a "Level 3" (Nurburgring rated) development driver piloting said Z06. Heinricy's eyes, and those of his cohort, didn't believe the numbers. "We looked at the course as it was being built," he says with a look of awe, "and couldn't believe it would work. So we asked the simulation guys to recheck their calculations." They did. It passed. No changes were made.

Part of the corporate drive behind construction of the MRC was to reduce the number of prototypes through more coordinated testing of fewer vehicles. Another part was to reduce the expense of shuttling cars and people to test and race tracks around the world for chassis and systems development. Still another came from the desire to have a facility close to home where dynamic tests could be performed quickly, results correlated with those gained offsite, and rapid changes made. "Because they're in Stuttgart, Porsche and Mercedes can go to the Nurburgring 15 to 16 times a year, and quickly correlate their chassis data. We can make it to that track maybe three times in one year." says Heinricy. It is, he states, a distinct disadvantage when developing high-performance vehicles.

With the MRC, unforeseen changes will have a much lower probability of derailing a test program because the track literally is in GM's back yard. Budget-conscious bosses will be more likely to approve a test regimen with low outside costs. However, Heinricy–who notes the track will be used to test trucks and SUVs as well as cars in a number of areas, including some that previously have been too expensive to justify the return–is under no illusion as to the track's true importance: "In terms of chassis dynamics, we will be second to nobody."

By The Numbers

8 (entrance)
10 A, B
11 W–14 W
11 E–14 E
15, 16
17 A, B
Tunnel to Turn 1
1 B,2–9,10 A
North Loop Return
11 E–14 E,15–17
South Loop Return
The Glen
Road America
Sear Point
Le Mans
North Loop
North Loop
South Loop
South Loop
Decreasing Radius
Uphill Esses
High banked corner
Constant radius—right
Large swell
Constant radius—left
Increasing radius
High speed Esses
Low speed Esses
Reversing corners
Front straight
Moderate speed
Low speed cornering
Dynamic Event
Steering while braking.
Transient cornering w/rev. vert. loading.
Cornering w/large vertical loading.
Steady state cornering/oil starvation.
Braking with reverse vertical loading.
Steady state cornering/oil starvation.
Braking while turning
Turning while accelerating.
High speed transient cornering.
Low speed transient cornering.
Transient roll while cornering.
Turning while accelerating.
High speed stability & braking.
(See above)
Turning with large steering angle.
(See above)
Turning w/large steering angle/Hard acceleration & braking.