We had an exciting weekend of testing the Vitour P1 tires at GRIDLIFE Willow Springs, along with the first autocross outing for the C8 Z06! If you're looking to get your hands on these impressive tires, check out VitourP1.com.
Testing the Vitour P1 on the Mazda RX-8
I drove my basic track/street car, a Mazda RX-8, with a stock motor, full interior, good shocks, wheels, and tires. The car weighs about 2,900 lbs without a driver, pushing an optimistic 200hp. I’ve added a sizable wing to help with downforce and was running the 245/17 Vitour P1 tires. Willow Springs has had some sections repaved, which improved the track compared to my last run a few years ago when I was on 255/17 Yokohama A052s.
I managed to shave about 5 seconds off my previous best lap time! While there were too many variables (track and car improvements) to make a direct comparison, I ran every session to the checkered flag and was impressed by the performance of the P1s.
- Camber Setup: -3.7 front, -2.7 rear
- Toe Setup: 0 toe front and rear
Here are my best lap times from Day 1 and Day 2:
- Day 1: 1:37.35 (transponder)
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Day 2 (morning session):
- Lap 5: 1:37.246 (transponder) / 1:37.231 (phone)
- Lap 3: 1:37.539 (phone)
- Day 2 (afternoon session): Conditions worsened slightly, but I still managed clean laps of 1:37.7 and 1:38.0.
After consulting with Scott Robertson, we agreed that a bit more rear camber and lowering the pressure by 2 psi all around would likely result in an improvement. Despite the slightly worse conditions, the P1s held up well without any substantial fall-off during the sessions.
These P1 tires already had about 3 track days on them prior to this event, and I didn’t flip them before testing. After swapping fronts to rears from the Vegas event, the wear after 5 track days was still impressive—especially the rears, which looked great. The front left, which takes the most beating, wasn’t bad either considering the mileage.
Daniel Leavitt's Run on the P1
Daniel Leavitt, running a 2900lb LS1-swapped 240SX in the Trackmod class, also used the Vitour P1 in 265/18 front and 315/18 rear. He liked the pace and noted slight fall-off after about 4 flying laps. He had previously used the Bridgestone RE-71RS and felt that the P1 gave him similar performance with better wear.
Kevin Burke's Viper ACR Testing
Kevin Burke’s testing with his 2010 Viper ACR on the 295/25/19x11 and 345/25/19x13 P1 was an interesting challenge. After scrubbing the tires in, he ran 5 laps with consistent times but felt the P1 was off the expected pace compared to other tires. He later switched to the Nankang CRSv2 and went faster, but there were many variables to consider, including the tire sizes and setup differences.
The Viper’s sensitivity to rake angle and camber settings (around 2.5/2.2 degrees) might have played a role in the result. We’ll revisit the data and likely do more testing with closer tire sizes for a true A/B comparison.
In Andy Hollis’ Grassroots Motorsports Magazine test, the Vitour P1 came out as the faster tire compared to the Nankang CRSv2, so I suspect we’ll see different results with further testing.
C8 Z06 Autocross Debut
The same weekend, we ran the exact same P1 sizes on a C8 Z06 in an autocross event at Grissom AFB in Peru, IN. In SS trim with the P1s, the C8 Z06 was the fastest 200TW car for the first half of the day, leading a field that included 315/18 Yokohama A052 CAM-S cars and a 315/18 P1 Corvette. Although conditions improved in the afternoon and Mike in the C8 Z06 left after lunch, the early performance was promising.
We’ll also be testing Nankang tires on this C8 Z06 in both autocross and road course settings in the coming weeks.
What’s Next?
Next weekend, I’ll be testing at my home track, Putnam Park, with the Corvette. If everything works out, I’ll be running the 315/18 P1 on my high-horsepower, high-downforce time attack car on Saturday, followed by the first IndySCCA Solo points event in the Lotus on Sunday.
Stay tuned for more updates as we continue to push the Vitour P1 to its limits!
