This is just a WILD guess (flame all you want lol), but maybe the rim design is keeping in heat, causing cracked rotors and toasted bearing...Every time I see you post on FB, its a cracked rotor!
Any way, thats my contribution....
[/quote]
That's a pretty good wild guess as well. Mike is going to be more sad. He's very impartial to the BBS.

 

Quick recap for those just joining:

Car setup (everything is OEM unless otherwise noted):

2008 S2000 CR
Brake ducts (front only, 2.75" diameter)
J's 70RR (currently off the car)
Flashpro (used only with the exhaust)
Shorai LiFePO4 battery
ACT HDSS clutch
ACT prolite flywheel
BBS RG-R 17x8.5 non-staggered

Consumables:
255/40/17 RE-11 non-staggered
Carbotech XP12/XP10 pads
Motul 300V 5W40 oil (usually 5W30; experimenting with 40 weight, will be posting UOA)
Motul Gear 300 (transmission)
Motul Gear 300LS (differential)


Approximate (incomplete) timeline
- Car starts mildly oversteering; I run a personal best on the very minimal oversteer, which I've never again gotten close to, yet.
- Oversteer gets worse (eventually becoming uncontrollable)
- Mods are taken out (namely, exhaust) to see if weight change is a possible cause. It's not.
- Tires are swapped out (Federal 595RS-R to Bridgestone RE-11), doesn't change anything
- Car is re-aligned to my "old" setting; alignment was changed immediately before the oversteer issues started. Alignment change ultimately doesn't help.
- Car inspected by three well regarded shops familiar with the s2k in SoCal (Evasive, Rising Star Motors, West End). Only thing found is a bad wheel bearing, which is only 5 track days old. Bearing and hub are both replaced
- Car is initially better, relative to the terrible condition before.
- Rear wheel bearing starts to make noise again (only 8 track sessions and some street driving old when I started hearing!)
- Car is indeed NOT fixed; confirmed this weekend at SoW. I drove a lot of different s2ks, all set up differently, all without my horrible oversteer, including a non-staggered AP1 without BSK and without sways.


Things I'm considering:
- Going back to LE1605 diff fluid (I swapped to Gear300LS right before this happened)
- Swapping the rear subframe, and all arms with one from another car (I had a big sideways off the track day before this started; there is no visible damage to my car)
- Replacing all shocks and springs with another set of OEM CR (My rear is starting to sag, but is not making any noise, and is not leaking)
- Swapping (temporarily) another diff on to test with.
- new wheels (in conjunction with a BBK to address my breaking rotors; I'm averaging 1 broken rotor per track day for the last ~8 track days; I've tried both resting the car, short cooling session in the pits, and long cooling session in the pits; they all don't seem to help)


Things I'm pretty sure are not the issue:
- Swaybars; both are connected and (visibly) undamaged. No weird noises. Car was neutral on OEM sways and non-staggered tires
- Wheel bearings; the bearing going bad is a symptom, but I'd like to know the root cause causing the bearing to go bad.
- Loose nut behind the steering wheel; most drivers faster than me say I'm overly conservative and not aggressive enough.


If I can't get this sorted out, I may resort to selling this car and buying another s2k. GPW CRs are hard to find


side note: BBS will be retired for strictly street duty (with spacers), eventually.
side note: Engine mounts and tranny mounts will be replaced shortly, as the ones I have on right now are bad. I don't however, believe this is related....

 

Put in some new (to me) rear shocks and springs. Shakedown this weekend....

 

hope that works

 

I hope so as well. tired of seeing mike at the track but not behind the wheel of his own car.

 

you forgot to add...and watching him epically fly off the track.

I'm just kidding. Hope it works out and hope to see that GPW CR on the track again.