535i EAT Chip on 89 Octane

[John B.]

Since Mark spec'd 91+ octane with his chip thats all I've run in my car since installing the chip a couple years ago. I let my wife borrow the car the other day & she forgot & filled up with 89 octane. I expected to hear pinging & experience a loss of power but so far there is no noticeable difference. All our gas is a 10% ethanol blend & I have read that you get a higher octane with the blend then what's stated on the pump. Maybe our 89 is actually 90+?? No idea but I've been driving around for several days now and the car runs fine. If there is a power loss its negligible and I haven't noticed it. With the price of gas these days I'm going to run the 89 for a couple tankfuls & see if there are any issues.

[gale]

I did at most 1 tankfull of premium when I 1st installed the EAT chip, then went straight to mid-grade. When gas prices went sky high, I started alternating mid-grade and regular with each subsequent fill. Anymore I run regular, ~86-87, all the time and no signs of pinging. Perhaps I can get away with it since I'm at high altitude and have the 19 lb Mustang injectors and a 3.5 bar FPR? I think mine runs a little on the rich side and is more reluctant to ping because of it?

[winfred]

mine pinged like a bitch on 87 during a road trip with 19# mustang injectors, it was the last time i took it to va and gas prices were high as ****, i figured it wouldn't be a problem as i was at interstate speeds all day and for the most part it was fine, but pulling out of piss stops it sounded like a bucket of washers rolling down a hill, and maybe lost a mpg or two

[E34N]

I believe you don't get a ping immediately if you run a lower grade gas. If you consistently run 87, the car will then develop the PING. One tank of gas will not cause this problem.

[winfred]

unless you run it down pretty theres usually enough good gas to dilute the cheapo for one tank, mine rattled like a bitch right off the bat the 1st and only tank of crap i pumped, but the EAT chip is fairly hot, a less juicy chip may be more tolerant

I believe you don't get a ping immediately if you run a lower grade gas. If you consistently run 87, the car will then develop the PING. One tank of gas will not cause this problem.

[BigKriss]

I run 87 AKI, 91 RON with no problems - well not normally but recently I have for a few tank fulls and it was fine.