F55/F56 Premium still required?

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#51

05-20-2018, 08:00 AM

gjxj

4th Gear

Join Date: Apr 2015

Posts: 344

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Quote:

Originally Posted by yesti

If you run 87 I'm sure the computer will compensate for it,...

you'd think in that case the computer would warn you about it..

#52

05-20-2018, 12:57 PM

yesti

5th Gear

Join Date: Jun 2012

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Quote:

Originally Posted by KitGerhart

The "top tier" consortium, of which BMW is a part, indicate that "top tier" gas helps re. valve carbon. No, I don't have proof.

If the Honda engine is lower compression than the MINI S engine, it is running much more boost to produce a third more power from the same displacement. Running more boost would also create conditions where pinging might occur. Again, what is BMW doing wrong, if the mildly tuned MINI S engine, in any way, really needs premium gas? I'm curious.

I'm sure the additives in "top tier" gas do help valve carbon ... in engines where the gas contacts the valves. Mini had to redesign the valve cover to lessen the problem between the N14 and N18 engines so that tells you something.

The honda does run more boost than the mini, and it can at least due to lower compression ratio. My N18 ran 12-14psi stock and made 180hp. After tune, now it runs 20psi and puts out 230. Does that delta look familiar? The 2L should be good for 300hp, btw. The X1 has the JCW spec, my sister-in-law has it. Guess what, it has a lower compression ratio than the S spec engine and makes more power with more boost.