87 octane and timing

[C-WOODS-70]

I've put about 400 miles on my car since purchasing it. It has had only 87 octane in it since I have had it. I have read on a couple threads that 87 is fine but the timing curve is most likely being retarded because of spark knock, thus giving up a little power. My question is, has the computer "learned" my driving and the probable spark knock? Will it take any time for it to re-learn when I start using premium? Or does it start from scratch every time the car is shut off?

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[JoeSpeed]

Why not just do 93? You get more power and mileage out of it, it pays for itself basically

 

[Kdelk4]

Joe I think that the person or dealer he bought it from out 87 in it and it just ran out not sure tho

 

[daSNAK3]

After a few miles with 93 I am sure you'd be fine. I don't get spending the money on a car like this and putting cheap gas in it. You ain't saving much.

 

[KeyLime]

I've put about 400 miles on my car since purchasing it. It has had only 87 octane in it since I have had it. I have read on a couple threads that 87 is fine but the timing curve is most likely being retarded because of spark knock, thus giving up a little power. My question is, has the computer "learned" my driving and the probable spark knock? Will it take any time for it to re-learn when I start using premium? Or does it start from scratch every time the car is shut off?

Maybe someone who knows more can chime in, but I believe the engine is actively sensing knock and adjusting accordingly. I don't believe there is any learning going on.

 

[Kdelk4]

I would say just put 93 in it and it will fix itself. Plus if you don’t have coyote tick then idk how

 

[AZlb5.0]

Please don’t tell me you’ve done WOT pulls on 87 octane.

 

[C-WOODS-70]

Why not just do 93? You get more power and mileage out of it, it pays for itself basically

Like I stated, I'm going to use premium. Question was will I have immediate results when switching from 87 or will there be a computer learning curve.

 

[C-WOODS-70]

Joe I think that the person or dealer he bought it from out 87 in it and it just ran out not sure tho

Yes, dealer filled 'er up and about a half tank of free gas from a station that only has 87. I won a contest.

 

[turbosc297]

The car is constantly adjusting. Whether you run 87 or 91 or 93 it will start with less timing and then ramp in more until it senses knock, this is happening on the fly, all the time

 

[C-WOODS-70]

Please don’t tell me you’ve done WOT pulls on 87 octane.

That's what the knock sensors are for. FWIW I have never heard it knock, even at WOT with 87. Don't worry though, I'm going to start pumping in the expensive stuff.

 

[AZlb5.0]

That's what the knock sensors are for. FWIW I have never heard it knock, even at WOT with 87. Don't worry though, I'm going to start pumping in the expensive stuff.

True but your engine has learned to work off that octane and alcohol content. 87 octane is going to have positive knock retard all over the place. Plus I bet that your engine will read the wrong alcohol percentage when you start using 93 so I would lay off any wot pulls and let your car drive around a few days days so it relearns all the fuel readings. Just some advice.

 

[ice445]

Maybe someone who knows more can chime in, but I believe the engine is actively sensing knock and adjusting accordingly. I don't believe there is any learning going on.

It's always riding the edge of knock, but there's definitely some learning going on. As far as I can tell, the only learning it does is how much timing it can start with. If it has to make large corrections at certain parts of the table, it will wind it down and start from a different point the next time. This is of course always changing, and the spark tables have tons of inputs, so knock control is just one aspect of this.

For some reason the adaptive fuel quality learning function is turned off on the gen 3 coyote.

 

[pmor4243]

To the op, as has been said, your knock sensors are always trying to find the sweet spot for the timing you can get with the fuel you have. I can’t remember if the octane adjust parameter is active on the stock tune but that could essentially learn a lower/higher value based on previous cycles and change ever so slightly what’s going on with your spark.

Either way, if you want more immediate results to maximize your fuel, just do a KAM reset and the let the car start fresh with anything it will learn moving forward.

I just do it through my SCT/HP tuners but you should be able to do it by disconnecting the battery terminals (look that up though). That will give you the quickest results in my opinion.

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