EAT chip and silver (89 octane)

[rickm]

The mrs was driving home last night and she decided to refill my car...with 89 instead of the 91 I normally use due to having an EAT chip. Anything to worry about? I heard no pinging when I went out this morning but it has been unusually cold here and my chattering teeth were probably louder than the pinging.

[MarkD]

The mrs was driving home last night and she decided to refill my car...with 89 instead of the 91 I normally use due to having an EAT chip. Anything to worry about? I heard no pinging when I went out this morning but it has been unusually cold here and my chattering teeth were probably louder than the pinging.


Hello Rick,

the 89 octane should not be a problem in your car for just a tank as your
car has knock sensors. The M50tu and M60 were the first BMW motors in NA to have them.
If you do hear some pinging, just don't drive as hard with this tank. What
you may notice is a reduction in power if you accelerate hard, as the knock
sensors could retard the timing.

Mark

[Martin in Bellevue]

I haven't been able to induce knock with 89 octane, a JimC chip, & the maf set from a dyno session. I can, of course, crank the maf settings over to induce plinking hell, but that helps nothing. With 9.0:1 compression of the stock m30 with relatively clean combustion chambers, 89 octane, at damn near sea level here; my 535 has been fairly happy.

My pistons were quite gunky once the head came off. It may have been the original gasket. A tar built up on the piston tops causing all kinds of hell. I packed grease over the ring lands & only worked on pistons up near the top of the block, or some such.

http://www.bimmer.info/bmw/Martin5er/pistons.jpg

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