DISCLAIMER: My opinion is based on my novice AutoX experiences.
This is my first AutoX in since BMWCCA event in late '05. Today was somewhat hot with a little wind thrown in. Being 95 degree under Southern California sun, it would sucks if you have to work the course. However, Speedventure came up with the idea that you pay and play, NO NEED to work the course.
The event was held at Autoclub Speedway in Fontana, California. I decide to bring both the M3 and 335i to see how much I fun can have on the track. My brother-in-law was nice enough to drive out the 335i and run it too...
First: THE TIME
TIME FOR COMPARISON
'07 SOLO2 prepared Blue Subaru WRX on R-comp with a veteran driver right behind me laid down consistently 44.00-44.1 (in the picture)
'08 Corvette Z06 best time was 45.34
NOW MY TIME
'08 E90 M3 (stock with 2 baby seat in the rear) - started out in the morning at 49.7 and finish around 2pm at 45.437
'07 E92 335i - 18" OEM M3 with Toyo T1R 225/255 otherwise stock everything.
I did two runs during the day at 49.5xx and 49.7xx
'05 E53 X5 4.4i - stock worn out 19" (33k on the car). I did one run in the early afternoon at 52.1xx
E92 335i - I drove only two laps with the car since I didn't want to loose any seat time in the M3. First run was with DTC on and second was with DSC off. The fastest time was with DTC on. The car has good torque and balance to it. I feel that 225 is way too small for this car if once wish to AutoX regularly. The sport suspension is soft, you can feel like leaning to the ground under hard corner, beside that fact that it understeer while doing it. The power is decent. LSD would be a big help but not a major thing. With stickier rupper and better shock & spring, it would give E90 M3 a run for the money.
E90 M3 - What can I say? I drove the car with DSC on and off. The fastest time was DSC off and Power button off. I didn't think it would do that well. It obsorb bump and rebounce better than E46 and yet less body roll. Even with 265 rear, I can get the rear to slide out just enough to rotate the car. Had I ran 265 PS2 up front, I think I can knock another 1 to 1.5 second off.
Even in 95 degree Socal sun, the temp stay between 215-240. The tire held up really well. I had the pressure up to 41 front and 43 rear. With just 1600 miles on the car, it just gets better. The break was consistent, no fade - how can you fade at AutoX, right? The only complaint I might have is front being somewhat small for this application. Otherwise, it is good right out of the box.
E53 X5 4.4i - My wife decide to bring a few of us two box of Costco pizza. Right before she left, a friend suggest for me to take the X5 for a lap of fun run. I did just that and surprise MANY people. Being so high and heavy, X5 out handle several cars out there today. The best time of 52 second was faster than a few E36 M3 and E46 coupe out there. Well..maybe a worn out Diamaris handles well.