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      10-24-2018, 09:52 PM   #40
SeanWRT's Avatar

Drives: E90 M3 & F87 M2
Join Date: Sep 2015
Location: Shanghai

iTrader: (1)

I'll just chime in with below three points:

1) SAE and STD difference is 3%, or roughly 10whp. Not 5%.

2) N54/S55 and N55 CAN be compared. Boost is the measurement of the flow restriction at manifold, or sometimes pre-throttle. Combined with IAT, it effectively means air mass for a given charging system. Twin or single turbo is the technology to make boost. But boost is boost downstream of turbo. 17psi means the same either from single or twin turbo.
Keep in mind, the power out of the same boost can also be dictated by back pressure, that's another topic though.

3) OP you just need to adjust your expectation. From my experience, on pump gas, different N55 EWG variants makes quite different result. 135/235 will always make NOTICEABLY more than 335/435/535, everything else being equal. Again, ON PUMP GAS.

But with octane improved, that difference will be neutralized.
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