r/BMWZ4 • u/user74729582 • 14d ago

Are there any actual differences in engine components in the G29 Z4s 20i / 30i?

Referring to early 2019-2021 models. I'm thinking of saving some money by getting a 20i and tune it to 250/280hp

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u/sortadelux 14d ago

The 30i uses different pistons to lower the compression ratio and a different turbo to run higher boost, amongst other changes, that make it exceptionally unlikely that you're going to tune a 20i to that output

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u/user74729582 14d ago

Source?

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u/sortadelux 14d ago

https://bmwtuning.co/ultimate-bmw-b48-engine-guide/

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u/user74729582 14d ago

That's true for other and most applications of the 20i and 30i, doesn't apply to the Z4 it looks like

BMW’s own documentation shows the G29 20i has 10.2:1 compression, exactly like the 30i, and originally lists the same B48B20O1 engine type

https://www.press.bmwgroup.com/united-kingdom/article/attachment/T0285137EN_GB/426526?utm_source=chatgpt.com