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( [ % Fuel A ] x [ Octane of Fuel A ] ) + ( [ % Fuel B ] x [ Octane of Fuel B ] ) = Octane of Mixture. so, yes.
Excellent googling sir
 

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@BrenTuning - You mention that we need not to be concerned with knock (detonation), because “... the ECU will learn out most knock correction by reducing ignition timing after it senses knock. The Bosch ECU's are very smart and can learn knock quickly, turning down ignition timing to avoid issue.”

An ECU itself cannot sense detonation. The Engine Control Unit can do a lot of things, but in itself does not sense “knock”. It can control it, via increasing fuel or retarding timing but the ECU still needs another system to determine that there is knock/detonation present. And to the best of my knowledge there is no knock sensor on K48 series engines.
 

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I've heard it on this board that there is no knock sensing but I find that hard to believe. I have to wonder where this information comes from.

There's more than one way to detect knock and not all require additional parts/hardware to do it and I'm sure the ECM is capable of it.
 

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I'm in Cali on the Stage 2 tune. Running 91 most of the time, almost exclusively use Chevron. I've heard no ping ever. My typical day trip is in the nearby hills, and I don't need a WOT to power this engine through the twisties. So maybe that's a factor in my experience.

I do occasionally add some 101 octane fuel because there's a nearby station that has it. That really smooths out the performance of the engine.
 

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I've heard it on this board that there is no knock sensing

There's more than one way to detect knock and not all require additional parts/hardware to do it and I'm sure the ECM is capable of it.
This. I know Harley used ion sensing on the Twin Cam, and there was no additional hardware, the spark plug itself was the knock sensor. Not saying this is the same system BMW uses, but they almost have to be doing something. It seems hard to believe that there would be no way for the ecm to deal with knock on these bikes, although I suppose it’s not impossible...
 

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I'm in Cali on the Stage 2 tune. Running 91 most of the time, almost exclusively use Chevron. I've heard no ping ever. My typical day trip is in the nearby hills, and I don't need a WOT to power this engine through the twisties. So maybe that's a factor in my experience.

I do occasionally add some 101 octane fuel because there's a nearby station that has it. That really smooths out the performance of the engine.
I've ridden all across the country with my Bren tune. Many times I've had to put 85 in the bike as that's all there was available. Honestly, I can't say I've ever noticed a difference. Certainly never heard it ping, even when the bike was hot enough to light up the dash.
 

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I've ridden all across the country with my Bren tune. Many times I've had to put 85 in the bike as that's all there was available. Honestly, I can't say I've ever noticed a difference. Certainly never heard it ping, even when the bike was hot enough to light up the dash.
Are you running the stage 2? I’m using the stage 1 with no issues, and I’m happy with it’s performance and rideability, but I haven’t given the stage 2 a try yet. Interested to know what you’re running
 

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I've ridden all across the country with my Bren tune. Many times I've had to put 85 in the bike as that's all there was available. Honestly, I can't say I've ever noticed a difference. Certainly never heard it ping, even when the bike was hot enough to light up the dash.
85's pretty lean. You really should carry some octane boost and use it when it's that low.
 
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Are you running the stage 2? I’m using the stage 1 with no issues, and I’m happy with it’s performance and rideability, but I haven’t given the stage 2 a try yet. Interested to know what you’re running
I have a 2016 so no stage 2.
 

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85's pretty lean. You really should carry some octane boost and use it when it's that low.
Not sure I would call that "lean". Low maybe. If the bike isn't suffering from pre detonation then adding octane booster will only lighten your wallet and really isn't needed. Besides, adding half a tank of 85 to a a previous fill of 91 will still put you at 87-88. The most common times you only find 85 is at elevation where you can't run the motor as hard as you might at lower elevations.
 

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I have a 2016 so no stage 2.
Ah, I misunderstood. I thought you were running 85 octane with the Stage 2 tune. Still, you're 6 octane points low from the 91 that the Stage 1 wants. Octane boost is probably a good idea, anyway.
 

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Discussion Starter #52
Couple of points to add to my original post.

I likely would not have heard my bike pinging had I worn ear plugs as I usually do. Secondly, if the bike's knock sensors dial the knock out automatically, then I have to wonder why the bike was pinging continuously on my ride over the course of over a few hours? Personally, I can't take much if any comfort in knock sensors compensating for poor fuel quality or too aggressive of a tune for the available fuel. I've had many modified and tuned modern vehicles. Running inferior fuel with an incompatible tune is ALWAYS ill advised to put it politely. Any credible tuner will affirm that.

Again, when I loaded Stage 1 the pinging stopped and the bike ran great on the 91 in my tank. If people want to believe knock sensors are going to intuitively recognize detonation and promptly pull timing, that's their choice. I don't buy it for a second, nor am I willing to gamble for the sake of a bit of claimed extra power.

I just wanted to share this with the forum so all would have some awareness into what I was experiencing and what the remedy was for me. Could I have kept Stage 2 and used octane boost? Probably, but to me it just isn't worth the hassle.

Do as you wish, it's your bike.

The fear monger....lol
 

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Couple of points to add to my original post.

I likely would not have heard my bike pinging had I worn ear plugs as I usually do. Secondly, if the bike's knock sensors dial the knock out automatically, then I have to wonder why the bike was pinging continuously on my ride over the course of over a few hours? Personally, I can't take much if any comfort in knock sensors compensating for poor fuel quality or too aggressive of a tune for the available fuel. I've had many modified and tuned modern vehicles. Running inferior fuel with an incompatible tune is ALWAYS ill advised to put it politely. Any credible tuner will affirm that.

Again, when I loaded Stage 1 the pinging stopped and the bike ran great on the 91 in my tank. If people want to believe knock sensors are going to intuitively recognize detonation and promptly pull timing, that's their choice. I don't buy it for a second, nor am I willing to gamble for the sake of a bit of claimed extra power.

I just wanted to share this with the forum so all would have some awareness into what I was experiencing and what the remedy was for me. Could I have kept Stage 2 and used octane boost? Probably, but to me it just isn't worth the hassle.

Do as you wish, it's your bike.

The fear monger....lol
Well said. If there is a knock sensor and the ECU compensates, why did your engine knock?

I’m sure some will say YOUR bike has a faulty knock sensor, lol! 🙄
 

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I have Brentune Stage 2 loaded in the bike, and had read several were running that tune without issues on 91, which is the best we are allowed to consume here in the peoples republic of California.
I have not see premium as anything buy 91 and maybe 92 octane — depending on location. Regardless of state. If you want to use higher octane fuel, you need to buy racing fuel. VP racing fuel is readily available all over California, and it has an Octane rating of 101.
 

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What year is/was your bike? I know there were issues with early bikes.
The early bikes' problems were with the piston land rings, not the pistons themselves. My '12 had it but, thankfully, was under warranty. @KCMO Steve had the same issue at the same time. My bike was totaled a few thousand miles later but Steve's is still going strong.
 

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The early bikes' problems were with the piston land rings, not the pistons themselves. My '12 had it but, thankfully, was under warranty. @KCMO Steve had the same issue at the same time. My bike was totaled a few thousand miles later but Steve's is still going strong.
The lands are part of the pistons. It's what broke in the picture of the broken piston in this thread.
 

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The lands are part of the pistons. It's what broke in the picture of the broken piston in this thread.
Ah, maybe I didn't look at the picture closely enough. I thought it looked like damage to the piston, itself.
 
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