Quote:
Originally Posted by crst4s
Car and Driver saw a significant decrease in 0 to 60 on their X3 M40i with a swap to smaller dia., lighter wheels. However, my X3M standard 20's with Pirelli Zeros weighed 67.6 and 71.6 lbs on a bathroom scale. This is actually heavier than the 21's with Contis as weighed by member RGSport (64.5 and 68.5 lbs). Wheel size apart, any performance difference between XM3 Comp and non-comp attributable to the extra top-end 30 hp is likely negligible compared to other variables such as track surface, track/tire/air temp, gas etc. Suffice it to say, both stock comp and non-comp X3Ms appear to be overachievers at the drag strip.
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Thanks for sharing, crst4s. Absolutely agree. And with my Sport+ Stoplight launches acting as a control for the DA differences between my Nov and Feb runs, I'm getting a sense that for this F97, at this Raceway (which has a smooth, prepared launch surface), it's coming down more to the tire-track interface. DAs were over 1000' apart yet the Sport+ results were nearly identical. The traction issue is something Drivers have discussed in the pre-staging lanes regardless of vehicle in my two days there, so right now that is my focus for improvement here. I need to dial in the right psi for this F97, at this track, to find that sweet spot. And then after that, my fourth day will be to change the octane. One step at a time.
BMW's engineering team did an amazing job with this one. Not sure why they underplayed the performance numbers as much as they have, but the end-result continues to bring a smile every time I drive one of our X3MCs.