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Old 08-06-2018, 09:24 PM   #20
alf
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Quote:
Originally Posted by steve99 View Post
Guys it true the ecu has timng compensations tiggered by the amount of knock the knock sensors detect but these compensations have limits
This motor is 12.5:1 compression and it needs decient fuel.


The minium recomended octane rating is 91 AKI MON (usa) and 95 RON in the european\australian\asian standard. This is from subaru\toyota



For best performance you need to un 93 or above MON and 98 or above RON fuels




Ive got logs of the stock tunes from peole running on the lower rating fuels ie 91 and 95 and the ecu is getting towards it maxium amount of compensation ie the IAM Advance multiplier as arround 0.2 or 0.3 and it was still getting FLKC knock indications of close to 4 degrees.


The IAM will be 1 when on good fuels and its minium value is 0.


So with 87 in tank its not going to be pretty your just going to get heaps of knock and the ecu wont have any compensation left. And 87 is way below the minimum​ standard recomended by subaru\toyota.


Here is a log from a srock car running stock tune on 95 RON fuel ie the minuim recomended. This wasnt on track this was jist normal road driving



https://datazap.me/u/steve99/south-a...8&solo=2-13-28

Steve, thanks for more technical insight. This is why I asked for OFT map which would eliminate knocking. For that leg of the trip, power does not matter.

I wonder though, in case I will not be able to get a map, if driving style (never WOT, stay below 4k RPM) would help eliminate some of results of using low grade fuel.
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