I have a Turner Motor Sport (TMS) chip in the '86 535i. I noticed an
increase in HP, torque, redline, engine smoothness as it revs, and much more
stable idle. I lost 2-3 mpg and the instructions recommend 91 or better at
the pump. I run 89 and I notice a slight difference between the 89 and 91
octane. The 10% ethanol doesn't help and it may be why I can feel a
difference in the 89. The 91 doesn't have the ethanol, or it isn't
advertised as such (89 is). I feel it was worth the $250 I paid and I have a
spare original backup ECU, just in case. Check out the TMS site. The claims
I experienced coincided with the advertised.
I have a stock m30 b34 from 11/85 production.
Bill in Omaha
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