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      03-18-2019, 10:47 AM   #180
Obioban
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Drives: M3, M3, M5, M5
Join Date: Apr 2008
Location: West Chester, PA

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2008 BMW M5  [0.00]
2017 BMW i3  [0.00]
2005 BMW M3 Coupe  [0.00]
2001 BMW M5  [0.00]
I had the car on track this weekend with flat ride for the first time. Setup: 1.84hz front, 2.09hz rear, for a 1.13 bounce ratio, with a FRC of 68%. 3.25 front camber, 1.8 rear camber, square tire setup, square hot tire pressures.

The car DID settle down much faster, so I think I'm really going to enjoy flat ride, but... holy shit was it over steer city with that 68% FRC. It made it hard to think about anything else.

So, before my next event I'm debating the following options:
1) stock M3 rear sway. This would move me to a 69% FRC (1% change)... not overly significant change
2) remove the rear sway completely. This would give me a 76% FRC. Feels like this might be too significant of a change and make the car all understeer all the time.
3) remove the rear sway and change to stiffer rear springs. This would let me get any FRC I want, but make the rear of the car stiffer than I'd like
4) stiffer front sway. I'd rather not do this if possible.
5) increase rear bump travel/decrease rear droop travel. This will put the front into the bump stops before the rear, which should push the car into understeer more at the limit.

I'm pretty surprised how oversteery the car felt at 68%, given than the stock M3 is 68%! Maybe the oversteer/understeer limit feeling is more determined by the on bump stop FRC? In which case stock is 71.6%...

Anyway, I'm open to input as to which route to proceed with. I'm kinda sorta leaning towards stock M3 sway (moves me to 69%), but don't really want to spend another with the car wanting to spin on me every turn. I had quite a few pucker moments

Do we really think 75% is neutral? Seems like the stock M3 is biased towards understeer, and it's 68-72%...

I think I'm initially going to do a combination of 1 & 5, and see how she feels next event.
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2005 M3 Coupe, 2004 M3 Wagon, 2001 M5 Sedan, 2008 M5 6MT Sedan, 2012 128i M sport
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