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

[04UZJ100]

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".
View attachment 2534688

We are talking about a large displacement low stress engine with port injection. This is not an engine that rev’s out to 8k and is boosted with some sort of FI. This also isn’t an engine that’s smart enough to know when it’s on regular or premium gas and adjust the tune significantly enough to have a noticeable difference in output.

If there was a material difference between the fuels, there would be a material difference in the LX’s engine output. Fact is, 2HP difference is absolutely nothing. 381 vs 383. Seriously?

What do you run when out in the middle of nowhere when premium is not available? Do you plan your trips around premium station availability? What about all the Uber high mileage LX 470’s that have lived on regular? Do you have documented failure of LX engines when running regular?

As I am sure you know, the Tundra/LX/Cruiser have different throttle input settings within the drive by wire - but to think there are material differences between how the engines are operating and fuel delivery is simply unrealistic.

Lastly, I know you hold the LX on a high horse with all its “accoutrements” but at the end of the day, the same engine and same ECU are in both the Cruiser and LX.

Lastly, the LX calls for 0W-20. Don’t you use heavier weight oil? Even though it clearly says not to? Don’t let the sticker discount your intuitive engineering mind.

OVTUNE says LC and LX ECU Fuel Mapping are identical

I know there has been a lot of talk on this subject. I wrote to OrangeVirus Tuning to see if there was a difference in fuel mapping between the LC and LX, and to see about getting the Harrop Supercharger. OV said that Toyota's have a primary map and a safe map which reduces timing. Unlike what...

forum.ih8mud.com

 

[TeCKis300]

We are talking about a large displacement low stress engine with port injection. This is not an engine that rev’s out to 8k and is boosted with some sort of FI. This also isn’t an engine that’s smart enough to know when it’s on regular or premium gas and adjust the tune significantly enough to have a noticeable difference in output.

If there was a material difference between the fuels, there would be a material difference in the LX’s engine output. Fact is, 2HP difference is absolutely nothing. 381 vs 383. Seriously?

What do you run when out in the middle of nowhere when premium is not available? Do you plan your trips around premium station availability? What about all the Uber high mileage LX 470’s that have lived on regular? Do you have documented failure of LX engines when running regular?

As I am sure you know, the Tundra/LX/Cruiser have different throttle input settings within the drive by wire - but to think there are material differences between how the engines are operating and fuel delivery is simply unrealistic.

Lastly, I know you hold the LX on a high horse with all its “accoutrements” but at the end of the day, the same engine and same ECU are in both the Cruiser and LX.

Lastly, the LX calls for 0W-20. Don’t you use heavier weight oil? Even though it clearly says not to? Don’t let the sticker discount your intuitive engineering mind.

OVTUNE says LC and LX ECU Fuel Mapping are identical

I know there has been a lot of talk on this subject. I wrote to OrangeVirus Tuning to see if there was a difference in fuel mapping between the LC and LX, and to see about getting the Harrop Supercharger. OV said that Toyota's have a primary map and a safe map which reduces timing. Unlike what...

forum.ih8mud.com

As a tuner, yes I have tuned V8 naturally aspirated motors. Qualifying it as a large displacement low stress engine does nothing to change the fact that a given physical motor can be calibrated for different octane fuels. Once tuned with more timing advance to take advantage of that octane, it's very necessary to use the appropriate octane fuels or there will be more knock and less reliability. Relying on knock sensors to ride the knock threshold is bad form. Many fly by night tuners have done just that, cranking up the timing and letting the ECU correct, until they grenade an engine.

Like I said, I won't change your mind. But as an insider with firsthand engineering and tuning knowledge, I'm not making my points from opinion as the interwebs is apt to do these days.

I had an LX470. Not all of them required premium. They received different calibrations depending on the model year and fuel price dynamics in the world.

2007 LX470 Manual:
Fuel types
Use premium unleaded gasoline. (91 Octane Rating [Research Octane Number 96] or higher) Source: https://drivers.lexus.com/t3Portal/document/om-s/OM60C81U/pdf/OM60C81U.pdf page: 63

2006 LX470 Manual:
Select Octane Rating 87 (Research Octane Number 91) or higher. For improved vehicle performance, the use of premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher is recommended.

Source: https://drivers.lexus.com/t3Portal/document/om-s/OM60C51U/pdf/OM60C51U-edited.pdf (page 22)

2005 LX470 Manual:Fuel type
Unleaded gasoline only
Octane rating 87 (Research octane number 91) or higher
Source: https://drivers.lexus.com/t3Portal/document/om-s/OM60B45U/pdf/OM60B45U.pdf page: 379

Carry on and have a Merry X'Mas.

 

[HGB]

As a tuner, yes I have tuned V8 naturally aspirated motors. Qualifying it as a large displacement low stress engine does nothing to change the fact that a given physical motor can be calibrated for different octane fuels. Once tuned with more timing advance to take advantage of that octane, it's very necessary to use the appropriate octane fuels or there will be more knock and less reliability. Relying on knock sensors to ride the knock threshold is bad form. Many fly by night tuners have done just that, cranking up the timing and letting the ECU correct, until they grenade an engine.

Like I said, I won't change your mind. But as an insider with firsthand engineering and tuning knowledge, I'm not making my points from opinion as the interwebs is apt to do these days.

I had an LX470. Not all of them required premium. They received different calibrations depending on the model year and fuel price dynamics in the world.



Carry on and have a Merry X'Mas.

how about the oil question 04 posed? Genuinely curious as maybe not everything indicated by mfgrs should be taken as gospel?

 

[04UZJ100]

how about the oil question 04 posed? Genuinely curious as maybe not everything indicated by mfgrs should be taken as gospel?

Written word by Mr T, or any manufacturer, is not the gospel.

Porsche recommends Mobil 1 oil. Are there other options that work? Absolutely.

Toyota recommends 10k oil changes and “lifetime” synthetic transmission fluids. Surely those are not in the best interest of a long term owner. Right?

@TeCKis300 will follow the rules about fuel written on a sticker by his gas gap but knowingly and publicly exceed the GVWR of this 200 by thousands of pounds with modifications (35” tires, wheel spacers) etc. that are far outside the bounds of what his drivers side door sticker says is acceptable.

So, what gives? “Judgement” with regards to weight and towing capability but a black and white approach to fuel? Makes no sense when taking about a car designed to run on gas distilled in Ethiopia from an illegal refinery.

 

[airdzi]

As a tuner, yes I have tuned V8 naturally aspirated motors. Qualifying it as a large displacement low stress engine does nothing to change the fact that a given physical motor can be calibrated for different octane fuels. Once tuned with more timing advance to take advantage of that octane, it's very necessary to use the appropriate octane fuels or there will be more knock and less reliability. Relying on knock sensors to ride the knock threshold is bad form. Many fly by night tuners have done just that, cranking up the timing and letting the ECU correct, until they grenade an engine.

Like I said, I won't change your mind. But as an insider with firsthand engineering and tuning knowledge, I'm not making my points from opinion as the interwebs is apt to do these days.

I had an LX470. Not all of them required premium. They received different calibrations depending on the model year and fuel price dynamics in the world.



Carry on and have a Merry X'Mas.

Can you possibly explain to us how knock sensors PID values Knock Correction Learning Value and Knock Feedback Value work together in relation to timing advance?

What exactly is IAM (ignition advance mapping) in relation to above and base timing table?

Also does engine type truly matter as same standard PIDs are used across all engine sizes, types and manufactures, only algorithms may vary?

On the knock feedback value, as I read someplace -1.41 to -2.82 truly a golden spot and at what RPM? I recall seeing Toyota table with note to measure KFV at 44mph, does it make sense?

Mine KFV, as you could see in the original post was stuck at -3 using Regular 87 octane from BP. I filled my tank up with 10 gal of Premium 93 at Sams and saw KFV change to -2.8 at least temporarily?

The reason Im asking as long term 87 octane user is that my car 2010 LX570 truly likes 93 Premium in relation to fuel economy but it is not the same for everybody, it can not be just my light foot trained on my wife’s Avalon Hybrid?
See photos, the 19.8mpg was during 100 mile long higway run. I saw mpg numbers climb all the way up and stabilize at 19.7 -19.8 mpg for the last 40 miles or so, 20 mpg was after exiting the highway, I slowed down to 40mph.

Many tuners advice that it may take couple of tanks full for the ECU to learn and tune to proper table while switching from regular to premium. I did not observe that that is why I started with real time (in motion) monitoring.

I know logging data could be helpful but I did not figure out that part of my monitor as of yet.

I do honestly apologize if my questions sound dumb or do not make sense, feel free to correct me. Im a computer systems engineer by trade but my experience is mostly networking. I’m also an USCG Master Capitan with experience in the field of marine electronics so I understand the fly by wire, NMEA2000 networking (CAN bus), PID based digital switching and most of that OBDII maze of sensors and outputs but tuning is just a pure math to me.

Merry Christmas to everyone!

 

[Sandroad]

The numbers that may really count for us ordinary mortals are pretty eye-opening. Without going into detail on my back-of-the-envelope calculations, it's well within ballpark numbers to say that the difference in cost between regular and premium at the prodigious rate our 200s use gas, would pay for all tire replacements and regular maintenance costs over the first 100,000 miles of use. I vote for that instead of making oil companies richer.

 

[stonepa]

All i know is this: i bought a 1998 100 with the 4.7L V8 new 22 years ago. The sticker on the fuel door says “Premium Fuel Only”. I have driven that vehicle, as of last week, 437k miles. I have never ever used premium in that vehicle. In fact, I’ve run atleast 10,000 gallons of 85 octane through it with zero issues. Even when pulling an over weight trailer in the mountains. Never once have i had a fuel related issue and the vehicle still runs like new on its original injectors and fuel system. My wife had a 2007 Lexus RX400h hybrid that also ‘requires’ premium fuel. My son now drives the car and it has over 200k miles. Never a drop of premium. So just a couple of examples but it leads me to believe that for vehicles like this sold everywhere in the world, fuel octane just does not matter at all in reliability and durability.

 

[TeCKis300]

how about the oil question 04 posed? Genuinely curious as maybe not everything indicated by mfgrs should be taken as gospel?

Like many of us on these boards, I'm also here to learn the most we can about the platform, in order to make informed decisions to modify and stray outside of factory specifications. The mfgrs recommendations are sound and validated safe starting points.

Contrary to what people are assuming, I don't draw a hard line on octane as gospel, particularly Toyota and the 200-series that are conservative. I do believe an LX could survive on 87. But is it optimal and safe for the long run in all conditions? I eat junk food too and my Dr. will tell me it's not optimal.

I am more interested in a sound basis understanding because if we can't get that right, it's harder to make informed decisions and modifications beyond that.

I use 0-30W, an oil not available during the development of the 200-series.

Summer is Coming, Severe Duty Oil

It's oil change time again. With summer coming and planning for some long towing road trips through hot summer months, I'm stepping up the oil viscosity for my vehicle. For those that tow heavy or are built especially heavy, this would apply. Nothing is like motoring up a long 7% grade with...

forum.ih8mud.com

 

[HGB]

Like many of us on these boards, I'm also here to learn the most we can about the platform, in order to make informed decisions to modify and stray outside of factory specifications. The mfgrs recommendations are sound and validated safe starting points.

Contrary to what people are assuming, I don't draw a hard line on octane as gospel, particularly Toyota and the 200-series that are conservative. I do believe an LX could survive on 87. But is it optimal and safe for the long run in all conditions? I eat junk food too and my Dr. will tell me it's not optimal.

I am more interested in a sound basis understanding because if we can't get that right, it's harder to make informed decisions and modifications beyond that.

I use 0-30W, an oil not available during the development of the 200-series.

Summer is Coming, Severe Duty Oil

It's oil change time again. With summer coming and planning for some long towing road trips through hot summer months, I'm stepping up the oil viscosity for my vehicle. For those that tow heavy or are built especially heavy, this would apply. Nothing is like motoring up a long 7% grade with...

forum.ih8mud.com

thank you for the thoughtful response, it makes sense.

 

[Moby]

I do believe an LX could survive on 87. But is it optimal and safe for the long run in all conditions? I eat junk food too and my Dr. will tell me it's not optimal.

This.

As much as I enjoy designing closed loop self healing software, I don't personally think that closed loop bouncing off the knock sensor regularly to find optimal timing is great for longevity, nor worth it for power or mileage (optimal timing also implies a more complete burn; doesn't ensure it, but certainly helps). Closed loop fuel injection optimally works the other direction. Start a little rich and let the O2s trim it lean. That is a safe strategy because slightly more fuel is much safer than slightly too little. So work from safe to optimal. Knock sensor is working from potentially harmful to safe, like working lean to rich. This doesn't mean it isn't useful - it can save your engine. Just that I don't want to be regularly hitting it if possible.

This is why I said in my first reply that while I don't believe that premium is required per my manual I run and will continue to run premium. I also change my oil more frequently for the same reason.

That said I've never modeled knock sensor controlled detonation over thousands and thousands of miles so what do I know. I fully acknowledge that my comments are not based in formal or practical experience, other than experimenting with a J&S Vampire knock sensor to see if running on the bleeding edge of advance in my 2FE would make a noticeable difference. It did not.

 

[unclemat]

I use 0-30W, an oil not available during the development of the 200-series.

I remember using so-called German Castrol 0w30 back in 2005...

 

[TeCKis300]

Can you possibly explain to us how knock sensors PID values Knock Correction Learning Value and Knock Feedback Value work together in relation to timing advance?

This is from the Lexus IS which I've spent much more time with in tuning back in the day. It should largely carry over in concepts. Some of the magic numbers and thresholds may be similar or different however as it's a different motor.

What exactly is IAM (ignition advance mapping) in relation to above and base timing table?

There's large and many tables, equations, and parameters including sensor feedback used by ECUs for which specific timing advance may be computed. It would be hard to say for the specific Toyota implementation, and it's not going to be a singular value, rather it's interpolated across a table that the ECU may build. It should be highly correlated with the KCLV.

Also does engine type truly matter as same standard PIDs are used across all engine sizes, types and manufactures, only algorithms may vary?

There are some standards for PIDs and they generally stay the same within manufacturers. Across manufacturers, there are similar PIDs, but there are also brand specific PIDS. Algorithms and strategies, and tuning philosophies can hugely differ across manufacturers. Within brand and generational models, they generally share similar architectural constructs.

On the knock feedback value, as I read someplace -1.41 to -2.82 truly a golden spot and at what RPM? I recall seeing Toyota table with note to measure KFV at 44mph, does it make sense?

I can't vouch for specific numbers without contextual information and established margins. Only to say less is generally better. Specific numbers may help characterize the overall bias or trend.

Mine KFV, as you could see in the original post was stuck at -3 using Regular 87 octane from BP. I filled my tank up with 10 gal of Premium 93 at Sams and saw KFV change to -2.8 at least temporarily?

The ECU is seeing a beneficial change with less detected knock and therefore is able to run without as much retarded timing. It is worth repeating that it is indeed detecting knock with 87 and having to retard more. Whether that exceeds a safe threshold is unknown but the manual does caution us.

The reason Im asking as long term 87 octane user is that my car 2010 LX570 truly likes 93 Premium in relation to fuel economy but it is not the same for everybody, it can not be just my light foot trained on my wife’s Avalon Hybrid?
See photos, the 19.8mpg was during 100 mile long higway run. I saw mpg numbers climb all the way up and stabilize at 19.7 -19.8 mpg for the last 40 miles or so, 20 mpg was after exiting the highway, I slowed down to 40mph.

Many tuners advice that it may take couple of tanks full for the ECU to learn and tune to proper table while switching from regular to premium. I did not observe that that is why I started with real time (in motion) monitoring.

I know logging data could be helpful but I did not figure out that part of my monitor as of yet.

View attachment 2534780

This is good info and does tell us that using more octane is not water under the bridge. Two parts to this:
- ECU can and will leverage more octane
- We agree that less octane will have less power and efficiency, but does it put the LX tuning in a place where safe operation can always be guaranteed?

 

[bloc]

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.

Once tuned with more timing advance to take advantage of that octane, it's very necessary to use the appropriate octane fuels or there will be more knock and less reliability.

I agree with this logic, but don’t see how the LX is taking advantage of that octane any more than a LC, at least with regard to the published numbers. CR identical, power/torque within .5%, mileage is hard to compare due to tire/wheel/weight differences.

@airdzi just may have cracked this egg, in that the published power numbers were using the same octane, and BOTH are designed to safely handle both fuels, but to get the extra power/“feel” you need to run the premium fuel and let the ECU learn which fuel it is you prefer. Anecdotal as it is, there is plenty of evidence that a LX “requiring” premium can run RUG safely for a quarter or even half million miles.

I still believe it is an assumption that the Lexus “requirement” of premium fuel is based on differences in programming (at least in this case with the above listed similarities), until proof of those differences can be shown. And to that end, I want to see if anyone tuning with HPtuners locally can pull the files from my 2013 landcruiser and my friend’s 2013 LX570, and look for differences. They are even both white!

Again, thanks for the thoughtful thread and debate, on both sides. I’m looking out the window at my cruiser sitting in dry weather wishing there were snow to play in.. everyone have a great holiday however you choose to do it.

 

[Omega3651]

Wait till you try Ethanol free gas-i'm seeing easily 19MPG going 85-90MPH and almost 17MPG in the city.
Ethanol free is the real game changer.

 

[airdzi]

This is from the Lexus IS which I've spent much more time with in tuning back in the day. It should largely carry over in concepts. Some of the magic numbers and thresholds may be similar or different however as it's a different motor.
View attachment 2534793



There's large and many tables, equations, and parameters including sensor feedback used by ECUs for which specific timing advance may be computed. It would be hard to say for the specific Toyota implementation, and it's not going to be a singular value, rather it's interpolated across a table that the ECU may build. It should be highly correlated with the KCLV.



There are some standards for PIDs and they generally stay the same within manufacturers. Across manufacturers, there are similar PIDs, but there are also brand specific PIDS. Algorithms and strategies, and tuning philosophies can hugely differ across manufacturers. Within brand and generational models, they generally share similar architectural constructs.



I can't vouch for specific numbers without contextual information and established margins. Only to say less is generally better. Specific numbers may help characterize the overall bias or trend.



The ECU is seeing a beneficial change with less detected knock and therefore is able to run without as much retarded timing. It is worth repeating that it is indeed detecting knock with 87 and having to retard more. Whether that exceeds a safe threshold is unknown but the manual does caution us.



This is good info and does tell us that using more octane is not water under the bridge. Two parts to this:
- ECU can and will leverage more octane
- We agree that less octane will have less power and efficiency, but does it put the LX tuning in a place where safe operation can always be guaranteed?

Great appreciation for giving us the answers. On the Christmas Day, Thank You!

I’m truly a long term user of 87 octane Regular gas with no major issues, also while towing. I never truly considered Premium as in IL you pay huge premium for it. Recently I discovered freshly built gas station which offers 93 at reasonable price. I thought maybe I should reconsider, see photo

Yes, I could justify 28 cents but wanted to be certain I do actually get something for it. Looks like I do and big test would come when I put my boat back in tow. It is on the rack for the winter but I’m already gearing up for the test. My 2010 LX generally does worse mpg wise with boat in tow than my 2001 LX 470 did.

Unfortunately Ethanol Free gas is almost impossible to get around here and Im not driving to WI just to fill up.

I do understand manufacturer specific PIDs (custom PID) and Im using such with my OBDLink device to get transmission temp etc but my point was that they are the same across all the motors in Toyota lineup so small 1.1 or large 5.7 does not truly matter as someone suggested - engine alone is not very smart but in combination with ECU it learns and stores data as advanced as our personal driving characteristics and uses above data as it is designed to do so. ECU engine control unit is a computer capable of doing so and Toyota is never at the helm of latest technology (could be a good thing) but I would imagine Tesla ECU can be taken over from the sky thru satellite by factory techs because why not. On Star, Lexus Enform - you name it.

 

[04UZJ100]

Great appreciation for giving us the answers. On the Christmas Day, Thank You!

I’m truly a long term user of 87 octane Regular gas with no major issues, also while towing. I never truly considered Premium as in IL you pay huge premium for it. Recently I discovered freshly built gas station which offers 93 at reasonable price. I thought maybe I should reconsider, see photo

Yes, I could justify 28 cents but wanted to be certain I do actually get something for it. Looks like I do and big test would come when I put my boat back in tow. It is on the rack for the winter but I’m already gearing up for the test. My 2010 LX generally did worse mpg wise with boat in tow than my 2001 LX 470 did.

Unfortunately Ethanol Free gas is almost impossible to get around here and Im not driving to WI just to fill up.

View attachment 2535049

Costco near you? $.50 - $1.00/gallon cheaper

 

[Artie]

Wait till you try Ethanol free gas-i'm seeing easily 19MPG going 85-90MPH and almost 17MPG in the city.
Ethanol free is the real game changer.

Isn’t ‘ethanol free’ what real gas is, like what gas was before there was gas with ethanol?

 

[airdzi]

Isn’t ‘ethanol free’ what real gas is, like what gas was before there was gas with ethanol?

Real gas had some lead in it.

 

[bloc]

Well, I wont be comparing tuning tables soon. Just the credits to pull the files are $200 per vehicle. Not quite worth it for curiosity alone..

 

[HGB]

Well, I wont be comparing tuning tables soon. Just the credits to pull the files are $200 per vehicle. Not quite worth it for curiosity alone..

Group buy?