Quote:
Originally Posted by VenomGT
Hey guys, while on the knocking subject, I know our cars can run 91 (I notice a slightly knock and retarding on heavy load) but the manual recommends 93 in states that don't have 91, I was mixing 100 and 91 to get roughly a 93 but while cruising through forums I noticed that gt86 and international manuals recommend 98 ron. Now given that that makes out to roughly about 95 on our index I was wondering if they merely recommended 93/91 to get it in the hands of most car owners that pump at a typical station and not necessarily what is optimal in a perfect world. Idk if it makes a difference engine wise but I've been filling up with 95 ethanol free at a gas station off the 101 and bell called Tom's Thumb and I have noticed fuel efficiency rise both under low and heavy acceleration and I swear that it feels a little more responsive but I was just wondering everyones take on this one.
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What are you using to monitor knock?
The ECU is ALWAYS correcting timing based on learned knock values and active knock values which depending on the amount of correction
could potentially be felt physically (it would have to be pretty significant). I don't know what all is done to your car but if stock it should be practically negligible. So much so that mixing fuels is more a waste of time and money IF it's in relatively in stock form.
"Responsiveness" can be the sensation when timing is advanced so I guess the question is again, how are you monitoring knock? If you are, the answer will be right there in the numbers. All you have to do is see what corrections if any are occurring between your fueling and driving scenarios.
If you are not actually monitoring knock values then you physically knowing it's happening is practically impossible unless it's severe knock. In that case something else is wrong. The ECUs of today are way too fast at correcting such issues that even the most acute of listeners and seat of the pants observers would not be able to tell it's happening.