[ztech]

My Dinan Throttle Booster definitely helped. The car is much more responsive and convincingly feels quicker, even though numbers may only minor acceleration improvement (.1 to.2 second drop in 60 times). It's actually amazing how much throttle response affects drivability. Another improvement was the FTP (hot) intake a high flow cone filter . Wider intake pipes like Arma and MST did not have as much improvement in response. Finally the muffler delete and downpipe feels like it freed 25 whp.

[TGPCanada]

Compared to cars of the past, this turbo lag/throttle response in the 330i seems miniscule. All automotive companies have done a phenomenal job with turbocharging over the past decade or so to be able to extract 300 hp from a "tiny" 2.0L inline 4 whilst getting mpg's in the high 20's. (I say 300 hp for 330i instead of 255 hp because it's the worst kept secret in the automotive world that BMW's turbocharged engines make significantly more power than advertised.)

[ztech]

Originally Posted by TGPCanada

Compared to cars of the past, this turbo lag/throttle response in the 330i seems miniscule. All automotive companies have done a phenomenal job with turbocharging over the past decade or so to be able to extract 300 hp from a "tiny" 2.0L inline 4 whilst getting mpg's in the high 20's. (I say 300 hp for 330i instead of 255 hp because it's the worst kept secret in the automotive world that BMW's turbocharged engines make significantly more power than advertised.)

It is higher. Dinan measured the BMW 330i G20 at around 276hp crank/ 245whp. But the B48tu engine compression is 10.2: 1 , compared to, for example, the Audi A4's 9.6:1 . The higher compression puts it closer to the knock limit and so tuners can extract about 345hp (crank), before it becomes risky. If you want more power, you need a bigger turbo-more boost, so you can run less timing (less risk of detonation). On the other hand, the Audi A4s engine can be tuned with stock turbo/internals to ~390hp. On all popular tunes for the A4, the low end RPM, in-gear, response is extraordinary, maybe because tuners will feel comfortable with more aggressive low rpm timing/boost profiles. But on the B48tu all the tunes (except ONE), IMO have very poor responsiveness - I mean like Toyota Corollas feel more gutsy within their powerband.

Recently, I set throttle booster setting to 9:1 (10% pedal = 90% throttle) and that is the only thing that can emulate the great responsiveness I experience on one of my tunes (DME Tuning), which mysteriously never felt the same after a couple days. There may be an issue with my car, instead. But what I know is that I'm hitting all aggressive boost targets and MAF/MAP sensor reading are suggesting engine is getting air, so apparently the response lag is rooted in either conservate low end timing, or some more complex air/fuel issue (slow spooling turbo) OR, perhaps some tuners will actually include very aggressive pedal mappings, like my 9:1 with my throttle booster, to give a super-responsive driving experience. Still don't know.