I have a 2009 Z4 sDrive35i with the sport package and I love it. What is the story with these after market chips? Fuel economy is not my top priority in this car I use only when it is my intention to drive agressively. But are these chips a good idea or not? Is there a significant power increase? Finally, is there an effective and reasonable way to tighten up the steering some? New owner in SC
I'm no expert, but since no one has replied, I'll take a crack at it. Vehicle of your vintage don't really have chips that can be replaced. You can do software upgrades which reprogram turbo-boost, fuel, timing etc and have the same effect as an old fashioned microchip replacement. There is great variability in the performance of the various software, but apparently some truly do cause substantial performance improvements to a stock engine system. Until turbocharged BMWs, chips and 3rd party software hadn't yielded much for a stock car for quite some time. They basically just changed throttle pedal profile, redline limit, top end limiters and stuff like that. BMW Inc hasn't left much on the table for tuners to extract just through simple software changes. There was a time, at the start of electronic fuel injection, when chips had a substantial impact. You literally took apart your ECU, pried off a microchip and plugged in a replacement. Most significantly, third parties could reprogram the car to exploit higher octane fuel (87 octane vs 91 octane) as well as remove "conservatism" that BMW built in. By the early 1990s most of this had already been done by the factory. Custom chips or special software are still needed for any car which has had substantial non-stock engine modifications.
