Quote:
Originally Posted by Xorbitman
The twin scroll turbo in the 4 cylinder cars and especially the new modern turbocharged sports cars like those from Porsche and Mercedes have almost zero lag. The issue is that certain manufacturers including BMW use software ECU programming that favors a more comfortable approach to pedal sensitivity rather than abrupt instantaneous acceleration for safety reasons. There are ECU maps out there now that allow customization of this ECU "feature" to minimize the built in (software) lag. And in fact there are mapping tunes that work on BMW X1 B46 and B48 engines however not yet available for the X2 M35i. Drive safe everyone.
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I agree with this. There's no discernible turbo lag in my 25i (=28i in the US), but throttle response — especially in Eco mode — is an issue, especially when combined with the Aisin A/T, which is quite a bit less responsive than the ZF8AT you'll find in 3 series with the same motor.
That said, neither are as bad as I've experienced with the various DSG transmissions in VAG products — they're getting better, but unless you make the key decision to change gears manually in certain slow traffic situations, where suddenly you need response (eg, roundabout entry), you can be left...er...wanting. That's because the transmission is less responsive. In the X1 25i, it's also because of slow throttle response in Eco and Comfort modes. "Sport" mode resolves this; so, too, will certain products: Sprint Booster is one — it says it does all sorts of things, but really all it (or any of them do) is change the throttle mapping in the ECU; you can actually achieve 90% of the same effect with a bigger shove on the accelerator pedal!
My solutions: 1. use manual shifts when you expect to need responsive acceleration; 3. Harder acceleration pedal pressures; or 3. Use "Sport" mode