Regular VS Premium - let’s put an end to an ongoing debate? (1 Viewer)

[airdzi]

I read many informative posts on this site, some scientific and some speculative but truly nothing very conclusive. Even emails to Toyota drew little assurance. I historically ran Regular gas in my LX with great results even while towing. I recently found a very good source of 93 Premium as local Sams Club opened up gas station. They only offer 2 grades of gas Regular 87 for $1.995 and Premium 93 for $2.279, well that made me think, why not. With very little tuning experience I geared up with real time OBD2 device and programmed some custom gauges and gave it a go.

Hopefully we could get some experienced tuners involved in this conversation.

Couple of conclusions from prior posts were that all 200 Series cars run well on regular gas. Slight improvement in mpg is so minimal that it does not justify higher cost of Premium. Another one is that both Toyota and Lexus use the same engine configuration and the same engine ECU - it is the same part number and likely same programing for LC (requires Regular 87) and LX (requires Premium 91) Lexus tech specs list slightly higher HP (close to nothing) and Torque.

So rather than beat on the dead horse, Toyota truly no help, I did some real time monitoring and on line research and found some valuable information.

My conclusion to date and I could be wrong - it s all in the software. Did not I just say both LC and LX use the same software? Well that is correct. My current conclusion is that our stock 5.7 is fully capable of running both Regular and Premium. What is of importance is to be consistent with what you put in your tank and not to switch back and forth between grades often as by doing so you would give your ECU a rather hard time figuring out which tune to use.

Well I just gave out the answer. My research and testing leads me to believe, that a ECU stores multiple tuning tables. Looks like there is a High Octane Table (better performance with more advanced timing) and Low Octane Table. Depending on how sophisticated programming is, there could also be an additional in between hunting table for those who switch between grades often or for situations where you fill up with some bad gas.

So how does it work? Well you decide what grade of gas you put in your tank and that is about all you can do unless you are into custom chips and advanced tuning. ECU software does the rest. It monitors the knock sensor microphone output at various above idle RPM ranges. If it dectects knock it updates real time tables and looks for consistency and reoccurrence in predetermined RPM ranges. Based on the data it collects over time (May take a full tank or 2) it adjusts your knock PID parameters like Knock Correction Learning Value and Knock Feedback Value. It takes time as it looks for consistency and that is where you can help. If you buy SheLL Premium - stick to Shell premium, if you buy BP Regular - stick to BP Regular. I believe it is consistent Knock Feedback Value ECU uses to determine if it should use High Octane or Low Octane Tunning Profile table. 89 Octane could be your worst choice as your ECU could go into constant hunting mode (kind of undecided). If you run 89 mid grade it is likely you are not doing your ECU a favor at all.

I believe the true reason why Lexus manual calls for a Premium 91 Octane is simply the luxury aspect of the brand and they want us to have better overall experience with best possible performance, hence they want us to use High Octane Tuning table.

I believe If you own a LandCruiser you would accomplish same results and performance gains benefits with Premium, most important more timing advance = unquestionably more power. Keep in mind that process takes time - up to 3 tanks full according to some tuners for you to notice (or not) the benefits.

 

[04UZJ100]

Lets exhume another dead horse.

The LX and Cruiser have the EXACT SAME fuel mapping.

The LX and Cruiser are both sold in third world countries where premium gas does not even exist.

Use whatever fuel you want - will not make a difference to reliability or longevity. I highly recommend Costco 93 as that's what I use in my 5 Toyota V8s.

 

[NoClue]

It's 87 octane for me until I get a supercharger. Then I'll be married to 91 octane minimum

 

[stonepa]

Ive run 85 octane regularly in all of my LCs and LX570. Zero issues.

 

[Phalen302]

120k miles on 87 octane on my previous lx570... no issues at all and saved a bunch of money.

 

[Madtiger]

Well, if you guys say that there is no difference and computer adjust to whatever, then why in hell should anyone use 93 Octane? Waste of money. Our pig-on-wheels are slow and cumbersome...what’s the point of non-existent performance “difference” with premium gas?

Not sure about you guys, but where I am at, there is a HUGE difference in gas prices b/w 87 and 93!!

So, unless there is definitive data, this thread is about as useful as previous...which is all speculation and useless.

Regardless of octane, i ALWAYS try to use top tier gas stations.

 

[TeCKis300]

I read many informative posts on this site, some scientific and some speculative but truly nothing very conclusive. Even emails to Toyota drew little assurance. I historically ran Regular gas in my LX with great results even while towing. I recently found a very good source of 93 Premium as local Sams Club opened up gas station. They only offer 2 grades of gas Regular 87 for $1.995 and Premium 93 for $2.279, well that made me think, why not. With very little tuning experience I geared up with real time OBD2 device and programmed some custom gauges and gave it a go.

Hopefully we could get some experienced tuners involved in this conversation.

Couple of conclusions from prior posts were that all 200 Series cars run well on regular gas. Slight improvement in mpg is so minimal that it does not justify higher cost of Premium. Another one is that both Toyota and Lexus use the same engine configuration and the same engine ECU - it is the same part number and likely same programing for LC (requires Regular 87) and LX (requires Premium 91) Lexus tech specs list slightly higher HP (close to nothing) and Torque.

So rather than beat on the dead horse, Toyota truly no help, I did some real time monitoring and on line research and found some valuable information.

My conclusion to date and I could be wrong - it s all in the software. Did not I just say both LC and LX use the same software? Well that is correct. My current conclusion is that our stock 5.7 is fully capable of running both Regular and Premium. What is of importance is to be consistent with what you put in your tank and not to switch back and forth between grades often as by doing so you would give your ECU a rather hard time figuring out which tune to use.

Well I just gave out the answer. My research and testing leads me to believe, that a ECU stores multiple tuning tables. Looks like there is a High Octane Table (better performance with more advanced timing) and Low Octane Table. Depending on how sophisticated programming is, there could also be an additional in between hunting table for those who switch between grades often or for situations where you fill up with some bad gas.

So how does it work? Well you decide what grade of gas you put in your tank and that is about all you can do unless you are into custom chips and advanced tuning. ECU software does the rest. It monitors the knock sensor microphone output at various above idle RPM ranges. If it dectects knock it updates real time tables and looks for consistency and reoccurrence in predetermined RPM ranges. Based on the data it collects over time (May take a full tank or 2) it adjusts your knock PID parameters like Knock Correction Learning Value and Knock Feedback Value. It takes time as it looks for consistency and that is where you can help. If you buy SheLL Premium - stick to Shell premium, if you buy BP Regular - stick to BP Regular. I believe it is consistent Knock Feedback Value ECU uses to determine if it should use High Octane or Low Octane Tunning Profile table. 89 Octane could be your worst choice as your ECU could go into constant hunting mode (kind of undecided). If you run 89 mid grade it is likely you are not doing your ECU a favor at all.

I believe the true reason why Lexus manual calls for a Premium 91 Octane is simply the luxury aspect of the brand and they want us to have better overall experience with best possible performance, hence they want us to use High Octane Tuning table.

I believe If you own a LandCruiser you would accomplish same results and performance gains benefits with Premium, most important more timing advance = unquestionably more power. Keep in mind that process takes time - up to 3 tanks full according to some tuners for you to notice (or not) the benefits.

View attachment 2533724

View attachment 2533725

View attachment 2533728

It's great to see that you put a hypothesis to this and logged some data. I'm not going to change your mind here and it's an age old debate because we don't have direct access to Toyota's IP. It's to the individuals prerogative what they believe and do to their own vehicle. But for every person that wants to parrot some internet opinion out there as some end all truth, it's worth hearing maybe the other, more informed side.

As you asked for a professional opinion and you can decide whether mine is worth any pennies. I live in the engineering world and own projects that have tuned piston aircraft motors. In my spare time, I've tuned cars over a couple decades now. Standalone, piggyback, N/A, turbo, diesel.

You're making some huge leaps of assumptions. With data from a single personal vehicle. In nominal conditions. Enough to jump to said conclusion? Let's just say I have my doubts. Even if the LC and LX shared a driveline with the same octane requirements, I would bet there are detail differences in the calibration based on the intended end user alone.

As I said, I tune cars. I have ACN91 (AZ, CA, NV) 91 octane piss grade tune in my Porsche right now. I could flash it in a minute with a 93 octane tune that the rest of the lucky US has access to. Who cares right, and I could just run whichever and let the ECU handle it. It's just 2 octane points. Nevermind the 4 octane points you're talking about. Sure cruising the freeway, I see the timing pulled a bit, it's no big deal right? Let's push the car and run the wrong octane with the wrong tune, the stakes are different and real stuff can and does happen.

Given Lexus manual requirements, I am running 91 only. Particularly as I tow and operate the motor in the higher load tables where pre-ignition is more likely to happen. It couldn't be stated more clearly as a requirement, without any wishy washy words.

Food for thought
- Manuals are not run by the advertising department. Not even close to the same functional group. They surely could advertise without requirements in a manual
- Yes, modern engines have feedback loops. In order for the ECU to pull back timing, it would mean it has experienced knock. Rinse repeat for the lifetime of the motor, how many knock events is that? Hope that knock event wasn't during a high stress point.
- Each event contributes to a high pressure uncontrolled flame front event, potentially adding microscopic stressors and deposits to the combustion chamber. Rinse repeat, what does your motor look like over the life of the engine. Will the engine continue to run well with hot spots from deposits potentially causing reduced knock thresholds, because it ran great on 87 yesterday when I tested it?
- Calibration (i.e. software) is not the same as a hardware part number
- Calibrations are engineering decisions made against margins. Consider what may happen if you have a motor made on Friday, get a batch of bad 87 octane, on the hottest day of the summer, with the whole family in tow, history of hard use, and perhaps engine wear from the previous owner that also ran 87 because of your post.

If you decide my insight isn't worth any pennies. Here's another professional opinion I found awhile ago

I work at Ford Motor Company as an Advanced Engine Development Engineer and I’d like to clear some things up, since there is some inaccurate advice on that post,

My views/comments are my own and do not necessarily represent those of my employer (We have these monthly online training sessions, and one of them told me to put this if I identify who I am, so hopefully I don’t get in trouble...)

First Some Background on how Octane is determined:

Octane on the fuel pump is known as Anti Knock Index or AKI, and is the average of a fuels Research Octane Number and Motor Octane Number [(R+M)/2]. The MON and RON are determined by using a special engine with variable compression ratio, and comparing the knocking qualities of a given fuel to that of reference fuels, isooctane and n-heptane. MON and RON have different engine operating conditions, like engine speed, intake temperature, etc. The slope created by these two numbers are important to us engineers in understanding a fuel’s knocking quality in various engine conditions (like boosted, vs non boosted). To the average Joe, the average of these two numbers (what you see on the pump) is what matters.

Next, some background on what knock actually is, and what Octane does to prevent it:

In a spark ignited engine, combustion does not occur instantly at all points in the combustion chamber. Combustion starts at the spark plug and propagates outward roughly spherically. Flame speed is determined by many factors, such as tumble, swirl, piston design, etc. The biggest impact on flame speed is engine speed, so as the engine spins faster, combustion occurs faster. (This is very convenient in terms of designing ignition advance and valve timing)

So, what is knock? Well, as the flame front is propagating across the combustion chamber, the unburnt portion, or end gas, experiences and increase in pressure and temperature. If the increase is high enough, the end gas will spontaneously combust. This spontaneous combustion is very fast and rather violent, so it causes the engine structure to resonate. The resonance is what we hear as knock.

What does Octane do? An increase in octane rating of a fuel represents an increase in the fuel’s auto ignition temperature and pressure. It does not change combustion speed or anything like that. So, if the fuel has a higher auto-ignition pressure and temperature, it takes higher pressure and temperature for knock to occur. The actual mechanics of how this works is complicated chemistry, and this post is long enough already...

Now some background on knock sensors.

A knock sensor is a piezoelectric device. When the piezo crystal inside experiences a force, it generates a voltage. That voltage is then measured by the PCM. The important part of this signal is the frequency of the signal. All engine components create vibration, so the PCM must analyze the signal, looking for specific frequencies associated with engine knock. The PCM performs an FFT (Fast Fourier Transform), or some other proprietary algorithm, to translate the signal from time domain to frequency domain. The results of this FFT are then analyzed to determine if the engine is knocking. If it is determined the engine is knocking, timing is reduced to prevent knocking. This is computationally intensive, so it is difficult to do for transients, like tip-ins, tip-outs, engine shifts, etc. Also, if an engine component creates frequencies near the knocking frequency, it can be difficult to distinguish. So, knock detection is mathematically difficult and computationally intensive, so it can be difficult to do in all circumstances.

So, what happens if you put a higher octane than your car requires?

In short, nothing. Absolutely nothing (except waste money). If the engine calls for 87 octane, then the timing is set for 87 octane. If you put in higher octane, say 93, there is no cause for knock concerns, since it is designed for 87 octane.

What about special additives in premium fuels?

Premium fuel does not have any additional detergents, or anything like that. All fuels must meet strict regulations on detergents, octane levels, sulfur contents, etc. etc. This means, other than octane rating, all fuels are created equal, within a certain standard. This standard is actually very important to engine design, so that we engineers know, within a tolerance, what fuel you will always have in your engine. Now, I say within a tolerance, because fuel formulation can change. One particular example is in colder temperatures. In colder temperatures, the evaporation temperature (Volatility) of the fuel can be lowered, allowing for the use of less expensive additives to meet the octane requirements. This is why you may notice a change in fuel economy when comparing summer to winter.

What happens if you put a lower octane than your car requires?

In short, MAYBE nothing. This one is kind of a big risk. The stack exchange article says that a modern knock sensor will correct for lower octane fuel. This is true, but only in steady state conditions; like cruising down the road, or steady uphill, etc. Transient conditions are where the problems lie. Since it does take time to analyze the knock sensor signal, fast changes in engine load or speed, are difficult to prevent knock. Every automaker is going to be different in this regard, since the ability to analyze this knock quickly depends on the skill of the programmers and calibrators and even the speed of the PCM processor. So, if you put in a lower octane fuel, and then go drive your car hard, press the accelerator quickly, it is possible to experience heavy knock, and possible engine damage. I will say, it is unlikely to actually happen in cars produced in the last few years, but you are certainly exposing your engine to the possibility. ALWAYS, ALWAYS, ALWAYS use the fuel recommended in the owners manual of your car, or any signs on the fuel door or cap. When engineers say to use a certain fuel, we have good reasons for doing so.

Always follow what your manual recommends. If your engine calls for 93 octane, USE 93 octane. Don’t risk engine damage."

 

[bloc]

Displayed knock feedback and learn values is the most actual evidence we’ve seen yet of different “calibrations” that the ecu has to respond to the environment provided by the fuel.

OP’s hypothesis is pretty solid and by far the most thorough explanation I’ve seen yet of the what and why of octane in our vehicles. Thanks for posting.

 

[BigBlueTLC]

I could not decide... so I split the difference and went 89 non ethanol

 

[Moby]

I'm not trying to be a jerk here, so please don't take it that way, but this is an interesting to me as well. I will probably always run premium, but that isn't the RON that the owners manual calls for. But I am very interested in the 'how' here.

I've been a software engineer for 25 years, and I have done rudimentary ECU tuning. While I have done x86 assembly programming, ECU/Embedded and other, very close to the hardware scenarios, are not my fields. My specialties have been enterprise servers, meaning complex multi-threaded workloads that need to run for weeks, months, years without reboots, programming frameworks and, for the last 10 years, very high scale services. But I really like closed loop, self healing/tuning systems, which is a primary concern in the services I'm responsible for (it is not acceptable to take a minute of downtime because one data center goes down and the system has to shift load to another, even if that is automatic). So this is both semi-professional and hobby level interest

I do think that your observation around sticking to one octane is reasonable, given an ECU's learning ability. Absolutely not required, but likely optimal (although optimal for what is an interesting question - optimal here would mean the ECU would have to unlearn or change learned values, with the result either being slightly more detonation when going higher to lower, or less power when going lower to higher).

OK, that said I take the use of "table" here to mean a completely distinct tune. Meaning a completely redundant set of fuel/timing values for a given amount of air entering the engine. If that isn't what you meant you can probably disregard the rest of this.

So, is it actually using 2 distinct tuning tables? While we won't know for sure until someone cracks the ECU (I believe that HPTuners has up to 2016). A few things to consider here, and this is all speculation on my part:

1. There are 100 different ways to implement a given requirement in code. Could this be implemented using multiple fuel/timing tables? Sure, it could. But it could just as well just be using the knock sensor. And it is very common to learn, as you say. This was true even in very early ECUs because engines vary a little bit engine to engine. So there is compensation on top of the tables built in for safety (slightly overfueling is OK, underfueling is not - it's all better than a carb though). But learning doesn't require a separate pre-programmed table. It just requires memory and storage. So it is also entirely possible that you're just seeing stored adaptive learning and not a separate table. The ECU sees a lot of knock and "learns" to correct via closed loop testing how much timing to pull under different scenarios. It records and refers to it when the same scenario occurs again. This is not a separate tune. It's learned optimizations on top of a tune. This is how I would personally approach coding up a problem like this. I would not attempt to switch tunes unless I knew there was significant other issues, like flex fuel (which requires a different target A/F ratio). But again, this is not my domain of expertise.
2. Detonation is affected by many things, but once the engine is designed, and assuming it is healthy, we're probably mostly talking octane and timing. At least those are the things that the ECU can react to and control. Too lean can induce detonation, but again given a safe base tune the interplay of octane and the timing in that tune is likely the most common cause (followed perhaps by altitude?). So given a safe base tune it is unlikely that adding fuel would be a detonation prevention strategy unless the A/F is waaaay off. Which suggests a different problem. So it is hard to see "needing" a completely separate table if all you need to do is pull timing. And of course A/F is a learned optimization as well. This is why Harrop claims that you can add a large supercharger, change the size of the injectors, and let the ECU do the minor corrections. I don't personally buy this, but I haven't seen dyno runs either to see how well this works. Worse case your engine blows up. Best case the tune is sub-optimal but within acceptable standards.
3. It takes a lot to build a fuel/timing map that is safe under all conditions. I know that there are tons of tuners out there that can eck out a few hp or adapt a base tune to a cam or other changes, but an OEM has to build an extremely safe tune under a huge range of conditions to avoid massive recalls and warranty costs. It's hard to see them doing this twice.

FWIW

 

[stonepa]

Next time i buy gas for my LC from some rando backroads dude in Nicaragua I’ll be sure to ask them if it’s premium. Until then it’ll be 85 in the mountains and 87 everywhere else. The whole point of a Land Cruiser is that it will run on just about anything resembling unleaded fuel i put in the tank (as long as it is clean and dry). My LX 570, 100, and 60 ran just fine as well. In 33 years of buying some super sketch fuel i only have had one bad experience and that had zero to do with octane rating.

 

[airdzi]

Well, if you guys say that there is no difference and computer adjust to whatever, then why in hell should anyone use 93 Octane? Waste of money. Our pig-on-wheels are slow and cumbersome...what’s the point of non-existent performance “difference” with premium gas?

Not sure about you guys, but where I am at, there is a HUGE difference in gas prices b/w 87 and 93!!

So, unless there is definitive data, this thread is about as useful as previous...which is all speculation and useless.

Regardless of octane, i ALWAYS try to use top tier gas stations.

The answer to your questions is performance - High Octane Tunning table would provide more timing advance to the base timing table which would (to a degree) result in more power produced on each stroke and better performance.

Many of us would not pay double for Premium but would justify 30 cents more for better performance buying 93 Octane at Costco or Sams. After couple of tanks you may also see slight mpg improvement and less carbon buildup within the cylinders.

 

[TeCKis300]

The answer to your questions is performance - High Octane Tunning table would provide more timing advance to the base timing table which would (to a degree) result in more power produced on each stroke and better performance.

Many of us would not pay double for Premium but would justify 30 cents more for better performance buying 93 Octane at Costco or Sams. After couple of tanks you may also see slight mpg improvement and less carbon buildup within the cylinders.

While this is a useful perspective for an LC owner, the analogy for an LX owner may not be the same.

For an LX owner, it may not be only a question of more or less power. By going to an octane below the base table, which would be the safe assumption from what the manual tells us, you'll not only loose power and performance - you may loose some margin of safety. That's what the data you've collected could be telling you as the ECU is obviously seeing more knock and and pulling timing with lower grade fuel.

IIRC from other Lexus and Toyota, most KLTV values after a reset should be 15. Healthy engine numbers fed specified or better fuel should see KLTV numbers after some learning cycles in the 18+. I've seen healthy examples from performance models in the 20++. A KLTV of 16.9 tells me that it's not exactly a healthy motor or perhaps bad or lower octane than necessary fuel. That's speculation however based on other models as we'd need to profile them for the 200-series.

It would be interesting if an LC owner could do the same experiment. With enough examples, we could understand what's expected and may actually be able to draw some safe conclusions. Until then, the manual is what we've got.

 

[04UZJ100]

While this is a useful perspective for an LC owner, the analogy for an LX owner may not be the same.

For an LX owner, it may not be only a question of more or less power. By going to an octane below the base table, which would be the safe assumption from what the manual tells us, you'll not only loose power and performance - you may loose some margin of safety. That's what the data you've collected could be telling you as the ECU is obviously seeing more knock and and pulling timing with lower grade fuel.

IIRC from other Lexus and Toyota, most KLTV values after a reset should be 15. Healthy engine numbers fed specified or better fuel should see KLTV numbers after some learning cycles in the 18+. I've seen healthy examples from performance models in the 20++. A KLTV of 16.9 tells me that it's not exactly a healthy motor or perhaps bad or lower octane than necessary fuel. That's speculation however based on other models as we'd need to profile them for the 200-series.

It would be interesting if an LC owner could do the same experiment. With enough examples, we could understand what's expected and may actually be able to draw some safe conclusions. Until then, the manual is what we've got.

How are you losing a margin of safety if the fuel mapping is identical between the vehicles?

 

[Markuson]

To paraphrase...

“Not tobeat a dead horse...
...but...ready those whips,boys! ...cuz it’s time to beat the ol’ Swayback... one..mo..TIME!”

 

[TheEvilPrince]

I've read previous debates, but I absolutely love the information in this thread and will be watching. I will be buying an LX soon and was already leaning toward 87. I find it doubtful that producing the LC and the LX in the same facility in Japan that there is any difference in the ECU.

 

[Lou Gill]

I only run premium, so there!

 

[airdzi]

To paraphrase...

“Not tobeat a dead horse...
...but...ready those whips,boys! ...cuz it’s time to beat the ol’ Swayback... one..mo..TIME!”

... but if we get an inch closer to figuring it out = we get better in understanding what Toyota does in the back end of ECU we could in fact eliminate a lot of speculation. Someone out there must know. Lets get technical and we could figure it out and many heads are always better than one. Also Toyota is known to play it on the very safe side with their tuning characteristics. Lots of valuable comments so far so please contribute! If not we may have to ask some guys from the Subaru forums as that is where I have been finding most valuable information. Toyota and Subaru - do not they work together on some projects?

 

[TeCKis300]

How are you losing a margin of safety if the fuel mapping is identical between the vehicles?

How are you making such a conjecture when the manual and available media tells us otherwise? I'll be happy to concede if we learn otherwise. Until then, there is only one safe position which is not to make any assumptions.

As I said, many other models have variations in calibration for fuel. It's pervasively done in the industry.

Since Subaru and Toyota were brought up - we know the BRZ/FRS/GT86 are sister cars that share exactly the same driveline. They even require the same 91 octane. Yet we know the calibrations are completely different as it's been widely published that each parent company takes ownership to tune based on their philosophies (perhaps reliability) and vehicle character. Same with the sister Supra and Z4.

It's very likely the LC and LX are calibrated differently for not only octane, but for feel. We know the Tundra surely is calibrated differently for it's truck character and it shared 99% of the the driveline.

So based on what are you so sure that you presume them to be identical?

The LC and LX are not identical. We can't see software, but this detail is an affirmative difference - this LX labeling sure is not mincing or using verbiage that allows any debate here. They probably even anticipated hence adding the word "only".

 

[airdzi]

How are you making such a conjecture when the manual and available media tells us otherwise? I'll be happy to concede if we learn otherwise. Until then, there is only one safe position which is not to make any assumptions.

As I said, many other models have variations in calibration for fuel. It's pervasively done in the industry.

Since Subaru and Toyota were brought up - we know the BRZ/FRS/GT86 are sister cars that share exactly the same driveline. They even require the same 91 octane. Yet we know the calibrations are completely different as it's been widely published that each parent company takes ownership to tune based on their philosophies (perhaps reliability) and vehicle character. Same with the sister Supra and Z4.

It's very likely the LC and LX are calibrated differently for not only octane, but for feel. We know the Tundra surely is calibrated differently for it's truck character and it shared 99% of the the driveline.

So based on what are you so sure that you presume them to be identical?

View attachment 2534688

Speculative but I would think of Subaru as being more aggressive in their tune. Also they sure seem to have the huge following among tuners and tweakers.

Lots of good information, here is just one example, Always learning and it is a good thing

RomRaider • View topic - How To: Understand And Use Learning View's Knock Information