Some Info and Tips (long)
JT - '02 330i said:
I've got a 330i without the sport package. (Long story wife hated the sport seats..)
For the past few months I've been autocrossing regularly. I'm looking for ways to better balance the car, it pushes far too often, and seems to lack grip in a big way. (I'm regularly getting beat by modded civics and celicas.)
The car is a daily driver, take co-workers out to lunch etc, so it's not a good canidate for the lowered look, nor would a ride that is much harsher than the stock sport suspension be a good choice.
Anyone have some suggestions? Ideas to consider?
Thanks!
The push you're referring to is the natural understeer of the car. Here's some tips on dialing it out mechanically:
- Higher Tire Pressure In Front, Lower In Rear - anywhere from 2 to 5 PSI difference
- Adjustable Sways - Softer in the front, Stiffer in the Rear
- Uniform Wheel Setup - The sport package comes with a staggered setup. Less understeer if all the wheels were the same width
- Shocks - If adjustable, softer in the front, firmer in the rear
Here's some tips on dealing with it at the AutoX
- Slow In, Fast Out. This means REALLY slowing down into a corner as needed and accelerating out. The more your tires are squealing, the slower you really are. It will actually seem that you are going slower, but trust me, its better.
- Look ahead. And I Mean 2 turns ahead. If you plan your attack, you won't be reacting to a turn, but attacking it instead. A better line into the turns at the right speed will prevent plowing into cones when you go in too hot.
- DSC level 1 off for sure. DSC level 2 off if you can control the car, when the rear end swings out (and yes it becomes alot easier with the 2nd level off).
As for suspension, I have Dinan Stage III. The drop is small, and handling is improved, but a word of warning: even on the softest shock settings, the difference in ride is noticable. More so, if you ride on performance tires where the sidewall is very stiff.
Upgrade the driver first. You can reduce understeer and your AutoX times, by simply gaining better driving techniques. When you're ready, tires offer bang for the buck. Kuhmo Victoracers are relatively cheap ($150 per), offer outstanding grip and will reduce your times by 2-3 seconds. Suspension mods next, and then tire pressures to fine tune. Engine mods won't make much of a difference in Autocrossing, although I do recommend Dinan Stage I at least as that improves throttle response noticeably.
Here's what can happen if you take my advice:
http://shinobi.bmw330ci.com/Awards/default.htm