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      07-16-2019, 01:13 PM   #18
DrifterX
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Drives: 2016 340i M Sport 6MT+RWD
Join Date: Sep 2014
Location: Toronto, Ontario

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Quote:
Originally Posted by kylejdavidson View Post
Drove the X3m Competition yesterday back to back after the new m340i. Noticeably more lag in the X3M comp from a standing start/at very low rpms, but obviously pulled way harder as the rpm's rose. Would probably be negated completely with launch control/from a roll.
Yeah, the power difference in the mid-higher RPM range will definitely be more noticeable than in the low RPM range. Regarding the lag, I realized the S55/S58 have two mono-scroll turbos whereas the B58 has one twin-scroll turbo; not a very apples-to-apples comparison as the two types of turbos spool differently.

Quote:
Originally Posted by upsidedownfunnel View Post
I doubt the intake piping is why the powerband is shifted to the right. It's still a more efficient design than using an FMIC and piping it all around the engine bay.

It's probably because they are using larger turbochargers for more power. There's no way of getting around bigger turbos for more power leading to turbo lag. That's why something like a McLaren has a lot of turbo lag and a car like the BMW 330i does not.
Intake piping is definitely not the cause of any change powerband; it's just how they designed/tuned it.

Good point on the bigger turbo vs lag but according to the document: "The S58 engine has a twin-turbocharger system using mono-scroll turbochargers as also used on the S55 engine." (pg 69). Leads me to think the turbos aren't too different between S55 & S58.
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2016 Estoril Blue II 340i M Sport | ///MPPSK | 6MT | RWD | Fully Loaded
BM3 Stage 2+ 93 | B58TU HPFP | VRSF v2 Catted Downpipe | 550i Clutch
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