Quote:
Originally Posted by Carbonic
Hi, thanks for the helpful thread!
A few questions from darkest Africa:
1. The oil temperature guage doesn't have a "red" zone, only temp graduations. How hot is too hot?
2. I run my 135 on 225/40 18 semi-slick tyres on track days. What tyre pressures would you recommend as a starting point?
3. How will the car behave in DTC mode, i.e. DSC switched off but DTC still on?
4. With the above tyres, would your recommendation of a street / track compromise of -1.7 deg camber front and rear, toe out 1/16 still hold?
Thanks in advance for the advice!
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1) BMW engines in general tend to run hotter than other brands. On our cars, normal operating oil temp is 250*F or so; which would be nearing the "red" zone in most other cars. So, we are really careful with the Berk car... I let her cool down once she gets to around 270-280*F.
2) 225w is pretty narrow, meaning that in general you'll have to run slightly higher tire pressure than you would with a wider tire (due to the fact that a narrower tire operates at a higher slip angle to produce the same grip that a wider tire could produce at a lower slip angle, and therefore generates more heat, requiring a higher pressure to lessen heat generation). Aside from that general truth, I need to know specifically which tire you are running to be able to give a recommendation. Also need to know what type of weather you will be running in (cold, hot?)
3) In that mode, the only electronic aids will be ABS and TC (aka the E-LSD or "E-Diff"; it's basically just traction control). In that mode, if you break traction under power coming off a corner, the TC will kick in and brake the inside rear tire. It will cause the car to "hop" a bit, because the TC acts in an 'on/off/on/off' manner. I've only driven a 335i in this mode once on the street for a few minutes, so I can't comment on how it will behave on the track! Maybe someone else can chime in and help me out here?
4) Yes. Remember, if you're worried about tire wear, keep your toe near zero. Racers use toe to adjust the stability and response 'feel' of the car, but street car drivers are usually concerned about tire longevity. Big toe-in or toe-out will wear your tires down rapidly.
Hope that helps man, keep the questions coming!