Hey all,

Thought I seek some good advice from this forum. A while back, I lamented about not having a LSD (the mechanical device not Timothy Leary's vitamins) in my non-M E46. Not that it's not available but priced at $3k to $4k, it is quite a major investment to consider. The question of "do I really need one" pops up every now and then.

So here is the proof:

http://www.bimmerfest.com/photos/data/500/need_LSD_or_no1.jpg

Looking at the graph and the map. I was running this configuration in a CW fashion. There is a berm on the left beginning of sector 7. What I usually do is brake a little prior to 7 and ride on the berm. The graph shows GPS MPH, ENGINE RPM and MPH from wheel sensor. If you notice a little after the 6000 mark, both ENGINE RPM and MPH spiked up a little, whereas the GPS MPH remained smooth. To me it makes complete sense that the satellites sense a smooth transition for that corner.

Could this be the evidence that my rear wheel was in the air for a brief moment?

Sounds like it to me. That's classic wheelspin. You wouldn't even need the GPS to know that something is out of place.

Yep, looks like inside wheel spin.

On a side note, considering we have like 50 DAQ threads going on, this is also what the benefit of having Data acq with different capabilities, say 4 wheel speed sensors. All you would have needed to do is compare data from each sensor and see which one is higher. Would allow you to see if an inside wheel is lifting, or which wheels are locking up, for how long, etc.

Thanks fellas. Always look forward to both of your opinions and experiences.

Steve, you're right. Suddenly there's a wave of DAQ threads!

I agree on the wheel spin diagnosis (now turn your head and cough...)
FWIW, I'd avoid that inside berm before Riverside.
I brake early and gas early in the 6-7 sector there, with the conscious effort to avoid picking the inside rear up on that berm.