Last weekend I had the chance to drive and instruct on the extended Jefferson Circuit at Summit Point. Below is my analysis of the changes and a description of my line around the track. This works for me in a FWD MINI on summer street tires. Your results may vary. No wagering. (In-car video by ReplayXD.)
The extension (turns 4 – 9) adds about a half a mile to the old track and doubles the number of corners. I think most old-timers would have preferred if they had just renumbered the new section as corners 4a to 4g instead of renumbering all of the corners, but we’ll use the new numbering scheme. The old track could be run in both directions. The new layout only works in a counter-clockwise direction (though you can still use the old course in the other direction.)
Google Earth hasn’t yet uploaded a new image of the circuit so the plot shows the path through open fields, but it is actually paved, just not well (more on that in a minute.) How to read this chart: Turn numbers are in circles. The color on the path of the car shows acceleration (green) or deceleration (red). Note that deceleration might just be lifting as in between 2 and 3 or the apex of 4 or 8. Green speed readings on the track show max speed before deceleration and red shows apex speed. The bars in each corner show relative lateral G load. Green bars are .4 to .8 Gs. Yellow bars are .8 to 1.1 Gs. Notice the lateral load where the new track rejoins the old track and in the middle of the back straight. There the car is going straight and the lateral load is from the unevenness of the surface. You see some of that on the front straight from 14 to 1 as you drive across the crown to set up for turn 1. Red arrows show apex visuals. If you already know the old Jeff, then jump down to Turn 4.
When you enter the track from pit-out, stay to the right all of the way to the apex of turn 1, otherwise, when at speed cross-over from right to left on the front straight and look down the track to the flagger’s bucket. RWD cars set up to the left for turn-in. The road is crowned so FWD will want to be more in the middle of the left half of the track or you’ll never get over the crown to the apex.
The apex is very late and almost at the end of the curbing. You can ride the middle part of the curbing, but stay off of the end as it will unsettle the car. Stay to the right upon exit and let the car settle before turning-in to turn 2.
Turn 3 is one of the few corners where you can ride up on the curbs without unsettling the car. Apex is very late and carry as much speed as you can. Don’t worry about track position on track-out as the entry to the next corner is rough and you’ll probably have to lift anyway to get back to the apex.
Turn 7 is the most difficult corner on the track. You must be patient, especially when your tires are cold. It is a decreasing radius corner. Look for the path of the patch. Set your entry squarely in the middle of the patch and then pinch-off the apex. Trail-braking helps. If you don’t sufficiently load the front-end, expect to under-steer through the apex and off the other side of the track. Track out to mid-track.
Stay 3 feed from the edge in the braking zone to 11 to avoid more bumps. Turn 11 will really hook up when done right. Release the brakes as soon as the car starts to turn-in and power through the exit using the full track width. Cross over from right to left to set up 12.
Stay off of the curbing on 12 as it will really unsettle the car. Downshift and brake for 13 in a straight line. Some people are able to carry enough speed to brake once through 13 to set up turn 14. In the FWD MINI I have to release the brakes in 13 to get the car to rotate and can actually accelerate a little up the hill before turning-in for 14.
The apex of 14 is very late. Stay off of the curbing. If you are tracking out to the edge of the track before the pit-in lane, then your apex was early. Cross over from right to left and do it all again.
Larger photos here.