Does LX Really Have 2 More HP?
- Thread starter Evoking
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As a software developer, you would also know that often, the same hardware and software baseline are installed to many different deployments. And a software config or switch may detect the deployed context and select the right maps and settings for that platform. Not hard to do these days with so many matrixed sub-components and sub-computers on a vehicle, for which the LX likely has unique or uniquely identifying ones. Replacing an ECU generally requires a VIN to be registered via Techstream, along with a specific procedure to to initialize, as the the ECU also has to be registered with the immobilizer and key which are certificate based. None of this is an end user thing and requires dealer only IP. Basically lots of opportunity for the right config/maps to be enabled. So the fact that they share hardware ECUs really proves nothing.
This could be viable, as 2 octane points is much much closer than 4 octane points.
Timing is a curious thing. Ride the knock threshold gently, and knock can be easily quelled within a few combustion events, such that power can be just kept at just about optimal levels. Overstep that knock threshold, and you'll paying for it, many multiple combustion events later, because of the heat that's been put into the cylinder chamber, such that power loss will be more dramatic.
My opinion is that 4 octane points is a pretty big gap on a "requires premium" tune.
On a side not, the LX470 previously required only 87 octane, just like the LC sister of that generation. Both engines were spec'd to use the same fuel and made the same output. There's been a conscious change in the LX570 the caused both octane requirements and output to differ. That's not posturing in my mind, but a conscious design decision.
Personally, I don't know why the LC owners are so caught up with this discussion. They don't have a requirement to spend extra money for premium. If I owned an LC, it'd be 87 every time. It's specifically an LX discussion that does not effect them.
I've never tried to register an ECU or download the firmware, so I'm not familiar with the procedure. But if there's any potential for difference between the LC and LX ECUs I would still expect Toyota to provide two different part numbers. Yes the ECU developer could rely on some other system to indicate it's an LX instead of an LC (i.e. "if hasAHC()==true && hasPowerLiftGate()==true then applyFirmware(LX) else applyFirmware(LC)") but it would be really bad practice to do so. Imagine in the (totally fabricated and hypothetical) above example if the Aussie LC has AHC but not a power lift gate and then someone in marketing decides to add a power lift gate as an option, and suddenly the ECU mapping changes for all new vehicles. Any time you're relying on external systems/indicators you break the containerized model and risk affecting other systems you weren't expecting, particularly in something like an ECU which might have hundreds of thousands or even millions of lines of code. IMO Toyota's electronics are generally extremely reliable simply because they dont' intertwine them unless absolutely necessary.
Again, admittedly I don't actually know how Toyota's ECU installation works. I would have assumed that a replacement ECU would come with firmware on it already and you could install a new ECU from Toyota without applying a new firmware if you so desired (though there may be reasons to apply a new firmware). Even in my world where a multi-million dollar EMC storage array requires a technician to burn a .bin file into the array before we can use it the controllers still come with a base (uncustomized) firmware applied. I would be shocked if the ECU firmware is actually different between the LX and LC.
Arguably the scientific way to answer this of course is to dyno an LC and an LX on regular and premium fuel and see if there is any measurable different in HP. Alternately if someone had access to an LX and an LC ECU firmware for the same manufacture dates it might be trivial to determine if they're actually the same.
You're trying to make a case based on your layman assumptions. And furthering those assumptions based on more bad assumptions. This is like those endless oil forums where some layman end user thinks he knows better than the factory to run some other oil weight because it gives him better gas mileage (at the cost of engine wear). The factory spends millions validating exactly what will ensure the motors output, efficiency, and longevity. It states explicitly in the manual what the potential impact is of running 87 octane under load.
I'm telling you, I've been in the world of tuning, flashing, and actual manipulations of maps. Dyno tuning, and output differences. Knock is a real thing with the wrong octane. Modern cars have so many different maps, that they switch between based on incredibly subtle differences. You may know that VW with diesel gate changes behavior based on things one would have never considered like steering angle. To think that the same part number ECU couldn't key on something that you might not have considered, or that procedural installation of an ECU couldn't toggle a mode or config, is short-sighted. It could be that the same ECU is completely backwards compatible in both models when being repaired, yet LX's coming out of the factory are indeed configured or setup differently.
Sorry if I feel strongly about this as this is my wheelhouse of tinkering. It's just incredibly funny to me for owners of 80k++ cars to save money over comparatively trivial monies.
Another member posted this question to Toyota with a not very helpful response:
FYI for anyone that is interested, I posed the following question to Toyota:
ES | Detailed Specifications and Lexus Certified Pre-Owned – Model Library – ES 2010.
As the engine is the same in both model years, this change may be due to fuel map adjustments necessary to allow the use of 87 octane fuel, or simply due to the fact that 91 octane fuel has more energy per gallon than 87. We apologize that we do not have technical information on the specific differences between vehicles that share the same engine block.
As to your question regarding research octane numbers, this is the most commonly used unit of measure for rating fuel in markets outside of North America. You might consider the relationship between research octane ratings and "normal" octane ratings to be analogous to that of gallons and Imperial gallons when discussing volume.
Toyota can only recommend that you use the type of fuel that is specified for your Toyota or Lexus in the year that the vehicle was built. Use of 87 octane in the Lexus LX 570 may cause engine knocking, which may over time cause damage to the vehicle. Damage caused from the use of non specified fuels may not be covered under warranty.
6/
The fact is, assumptions are being made because Toyota has not come and and said what accounts for the difference.
On another thread, someone reached out to Toyota, and received a not very helpful response:
Query to Toyota:
The Toyota LC and the Lexus LX are both URJ200 vehicles utilizing the 3UR-FE engine.
For the LC200, the engine specifications are:
Required octane: 87
HP: 381 @ 5600
TQ: 401 @ 3600
For the LX570, however, the specifications are:
Required octane: 91
HP: 383 @ 5600
TQ: 403 @ 3600
Both engines are manufactured in Japan as opposed to the Tundra/Sequoia 5.7L engine which is built stateside.
The question is, why the difference in required octane, hp and torque figures? I'm especially interested in the octane requirement as page 90 of the URJ200 manual states, "Use unleaded gasoline. (87 Octane Rating [Research Octane Number 91] or higher)".
Second, what does "[Research Octane Number 91]" mean?
Response:
Thank you for contacting Toyota Motor Sales, U.S.A., Inc.
We appreciate the opportunity to address your inquiry.
While we understand that the Toyota Land Cruiser and the Lexus LX 570 are similar vehicles that share some mechanical components, each Toyota vehicle is designed to its own set of specifications. Vehicles that share engines may be tuned to different standards depending on their specific engineering goals and intended use. Additionally, differences in engine bay and transmission design may necessitate changes to the layout of the intake and exhaust systems in similar models, resulting in differences such as those you have brought to our attention.
Perhaps speaking more directly to your concern regarding Octane Ratings, Toyota's published horsepower figures are based on the recommended fuel for the vehicle. You may be interested in comparing specifications for the 2011 Lexus ES 350, which requires 87 octane fuel, and the 2010 model, which required 91. As our recommendation changed, the 2011 model's output was lowered to 268 hp @ 6,200 rpm from 272 hp @ 6,200 rpm. Details for both model years can be viewed at ES | Detailed Specifications and Lexus Certified Pre-Owned – Model Library – ES 2010.
As the engine is the same in both model years, this change may be due to fuel map adjustments necessary to allow the use of 87 octane fuel, or simply due to the fact that 91 octane fuel has more energy per gallon than 87. We apologize that we do not have technical information on the specific differences between vehicles that share the same engine block.
As to your question regarding research octane numbers, this is the most commonly used unit of measure for rating fuel in markets outside of North America. You might consider the relationship between research octane ratings and "normal" octane ratings to be analogous to that of gallons and Imperial gallons when discussing volume.
Toyota can only recommend that you use the type of fuel that is specified for your Toyota or Lexus in the year that the vehicle was built. Use of 87 octane in the Lexus LX 570 may cause engine knocking, which may over time cause damage to the vehicle. Damage caused from the use of non specified fuels may not be covered under warranty.
As you can see, the response states that it could be based on fuel map adjustments, or it could be due to the fact that 91 octane allows more compression to get better use of the energy of gas (their response that 91 octane has more energy is not accurate).
As you can see from the ES350 example they give, the difference in HP between 87 and 91 isn't far off from the 200 to LX. So I will also make an assumption that rather than do a different fuel mapping that would only give 2hp, they are mapped the same, but the difference in octane gives more output. I also see a small gain in mpg when I run 91 in my 200.
FYI for anyone that is interested, I posed the following question to Toyota:
ES | Detailed Specifications and Lexus Certified Pre-Owned – Model Library – ES 2010.
As the engine is the same in both model years, this change may be due to fuel map adjustments necessary to allow the use of 87 octane fuel, or simply due to the fact that 91 octane fuel has more energy per gallon than 87. We apologize that we do not have technical information on the specific differences between vehicles that share the same engine block.
As to your question regarding research octane numbers, this is the most commonly used unit of measure for rating fuel in markets outside of North America. You might consider the relationship between research octane ratings and "normal" octane ratings to be analogous to that of gallons and Imperial gallons when discussing volume.
Toyota can only recommend that you use the type of fuel that is specified for your Toyota or Lexus in the year that the vehicle was built. Use of 87 octane in the Lexus LX 570 may cause engine knocking, which may over time cause damage to the vehicle. Damage caused from the use of non specified fuels may not be covered under warranty.
6/
The fact is, assumptions are being made because Toyota has not come and and said what accounts for the difference.
On another thread, someone reached out to Toyota, and received a not very helpful response:
Query to Toyota:
The Toyota LC and the Lexus LX are both URJ200 vehicles utilizing the 3UR-FE engine.
For the LC200, the engine specifications are:
Required octane: 87
HP: 381 @ 5600
TQ: 401 @ 3600
For the LX570, however, the specifications are:
Required octane: 91
HP: 383 @ 5600
TQ: 403 @ 3600
Both engines are manufactured in Japan as opposed to the Tundra/Sequoia 5.7L engine which is built stateside.
The question is, why the difference in required octane, hp and torque figures? I'm especially interested in the octane requirement as page 90 of the URJ200 manual states, "Use unleaded gasoline. (87 Octane Rating [Research Octane Number 91] or higher)".
Second, what does "[Research Octane Number 91]" mean?
Response:
Thank you for contacting Toyota Motor Sales, U.S.A., Inc.
We appreciate the opportunity to address your inquiry.
While we understand that the Toyota Land Cruiser and the Lexus LX 570 are similar vehicles that share some mechanical components, each Toyota vehicle is designed to its own set of specifications. Vehicles that share engines may be tuned to different standards depending on their specific engineering goals and intended use. Additionally, differences in engine bay and transmission design may necessitate changes to the layout of the intake and exhaust systems in similar models, resulting in differences such as those you have brought to our attention.
Perhaps speaking more directly to your concern regarding Octane Ratings, Toyota's published horsepower figures are based on the recommended fuel for the vehicle. You may be interested in comparing specifications for the 2011 Lexus ES 350, which requires 87 octane fuel, and the 2010 model, which required 91. As our recommendation changed, the 2011 model's output was lowered to 268 hp @ 6,200 rpm from 272 hp @ 6,200 rpm. Details for both model years can be viewed at ES | Detailed Specifications and Lexus Certified Pre-Owned – Model Library – ES 2010.
As the engine is the same in both model years, this change may be due to fuel map adjustments necessary to allow the use of 87 octane fuel, or simply due to the fact that 91 octane fuel has more energy per gallon than 87. We apologize that we do not have technical information on the specific differences between vehicles that share the same engine block.
As to your question regarding research octane numbers, this is the most commonly used unit of measure for rating fuel in markets outside of North America. You might consider the relationship between research octane ratings and "normal" octane ratings to be analogous to that of gallons and Imperial gallons when discussing volume.
Toyota can only recommend that you use the type of fuel that is specified for your Toyota or Lexus in the year that the vehicle was built. Use of 87 octane in the Lexus LX 570 may cause engine knocking, which may over time cause damage to the vehicle. Damage caused from the use of non specified fuels may not be covered under warranty.
As you can see, the response states that it could be based on fuel map adjustments, or it could be due to the fact that 91 octane allows more compression to get better use of the energy of gas (their response that 91 octane has more energy is not accurate).
As you can see from the ES350 example they give, the difference in HP between 87 and 91 isn't far off from the 200 to LX. So I will also make an assumption that rather than do a different fuel mapping that would only give 2hp, they are mapped the same, but the difference in octane gives more output. I also see a small gain in mpg when I run 91 in my 200.
Good info but if your conclusion was correct it would state premium fuel recommended not premium fuel required? Right? They wouldn’t be talking about engine damage in the LX and then recommending 87 octane in the Land Cruiser if they’re the same?
The octane change in the ES 350 from 2010 to 2011 in the manual is "required", even though they are the same setup, but the HP changed by using a lower octane.
Well then the required doesn’t make any sense
I agree, unless they want to show higher HP numbers and there is a legal requirement to require the corresponding octane to get to those numbers. My 03 V8 4R manual stated:
For improved vehicle performance, the use of premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher is recommended. They quit adding this phrase in later model years.
If it were a large difference in HP, I would think advanced tuning or fuel mapping is involved, but for two HP? Logically, it seems the gain from advanced timing due to higher octane would be the cause for that vs. different fuel mapping.
I also saw someone that asked the question about an identical model sold between the U.S. and Canada. The Canada model required a higher octane than the U.S. model, even though they were identical. Sounds crazy, could Canada have different requirements? The LX is sold in Canada and the 200 is not. Normally I would not consider that except for the question raised here:
Why would the exact same car call for gasoline with a different octane reading in Canada?
Also, the Lexus website states:
383hp*
*Ratings achieved using the required premium unleaded gasoline with an octane rating of 91 or higher. If premium fuel is not used, performance will decrease.
Well higher octane give you better EPA numbers?
I think it could give you better MPG. I stated earlier that with premium I know my 200 does a bit better. The MPG rating are the same for both the 200 and LX. The LX weights almost 200 lbs more. Not sure if that would impact MPG enough to up the octane to keep the MPG the same or not.
The EPA states, on average, removing 100 lbs. can increase MPG by 2%. So that is the case, the LX could fall to as low as 14.1 MPG without other tweaks. To be conservative let's assume the extra weight loses 3%:
13*.97=12.61
17*.97=16.49
Average 14.55.
2% or approximately 1% per 100 lbs:
12.74 city or 16.66 hwy or 14.7 average.
I would say I get close to 1 MPG better with 91 octane after very unscientific testing on a few tanks. That very well could be the reason...
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Markuson
SILVER Star
Even Toyota/Lexus only claims a "power gain" of about 1/2 of 1% between the two specs.
Surely one isn't likely to bump up one's MPG a full 1 MPG with only a 0.5% increase in power. If you average 14MPG on regular... an increase of 0.5% would bump you all the way up to......... 14.07MPG.
As for gas expenditures...the deal on Premium is grim...
As of today, December 19, 2017 in the US:
Average price of Regular fuel: $2.421 per gallon.
Average price of Premium fuel: $2.974 per gallon.
So for about 0.5% supposed increase in power...one must pay (based on current average in US) about 18.6% more.
Crappy deal if ever there was one.
Surely one isn't likely to bump up one's MPG a full 1 MPG with only a 0.5% increase in power. If you average 14MPG on regular... an increase of 0.5% would bump you all the way up to......... 14.07MPG.
As for gas expenditures...the deal on Premium is grim...
As of today, December 19, 2017 in the US:
Average price of Regular fuel: $2.421 per gallon.
Average price of Premium fuel: $2.974 per gallon.
So for about 0.5% supposed increase in power...one must pay (based on current average in US) about 18.6% more.
Crappy deal if ever there was one.
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Correct. I tested it multiple times with Exxon 87 and 93 (not 91) and there is never more than a .1 mpg difference between tanks.
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You guys keep returning to the MPG argument. In regards to the LX (which is the focus of this thread), that is not necessarily the right lens to look through.
Someone above mentioned 93 octane. In my tuning world, the difference between 93 and 91 is enough, that I have to use a specific CA/NV/AZ calibration because these 3 states, only have 91 available (no 93). Flashing a 93 octane map in my Porsche Turbo, registers notably more knock when run on 91. This is enough that I have to tailor a 91 octane calibration. This is the same motor, same compression, same boost, WITH knock sensors. Yet different tunes produce different objective results when logged. Not seat of the pants subjective "feel". Not I think get get more range with inaccurate fill-up calculations. Knock occurs in the engine, especially at high loads.
To the person that says oh, it's turbo. I've tuned the Toyota 2JZ-GE naturally aspirated I-6 extensively. (also 2JZ-GTE). In chasing NA performance, relatively little power can be picked up by advancing timing. Because the OEMs already are riding this threshold masterfully - because they themselves need to maximize emissions, power, and efficiency. Advance timing slightly, and with right tools, knock feedback is readily seen. Same with running lower grade gasoline. More knock, on an NA motor. It's only when there is ancillary mods done, like intake, exhaust, headers, that the OEM map can optimized again for more power via timing.
I would like to think most of us take care of our cars, with regular maintenance and upkeep, because we take pride in our cars. Even those that run them hard on the trail. Running the right octane (for LX!) is without a question to me, the right thing to do.
Someone above mentioned 93 octane. In my tuning world, the difference between 93 and 91 is enough, that I have to use a specific CA/NV/AZ calibration because these 3 states, only have 91 available (no 93). Flashing a 93 octane map in my Porsche Turbo, registers notably more knock when run on 91. This is enough that I have to tailor a 91 octane calibration. This is the same motor, same compression, same boost, WITH knock sensors. Yet different tunes produce different objective results when logged. Not seat of the pants subjective "feel". Not I think get get more range with inaccurate fill-up calculations. Knock occurs in the engine, especially at high loads.
To the person that says oh, it's turbo. I've tuned the Toyota 2JZ-GE naturally aspirated I-6 extensively. (also 2JZ-GTE). In chasing NA performance, relatively little power can be picked up by advancing timing. Because the OEMs already are riding this threshold masterfully - because they themselves need to maximize emissions, power, and efficiency. Advance timing slightly, and with right tools, knock feedback is readily seen. Same with running lower grade gasoline. More knock, on an NA motor. It's only when there is ancillary mods done, like intake, exhaust, headers, that the OEM map can optimized again for more power via timing.
I would like to think most of us take care of our cars, with regular maintenance and upkeep, because we take pride in our cars. Even those that run them hard on the trail. Running the right octane (for LX!) is without a question to me, the right thing to do.
Y'all keep discussing this while I get in to my LX then smile every time I throw the peace sign at every Toyota 200 I see. They know I'm really throwing "the 2" at them... Buuuuurrrrrrrnnnnnn!!!!!
I've tested literally 60 - 80 tank-fulls (probably still have the notes and spreadsheet around here on an old computer) of various brands of Top Tier 87 and 93 Octane fuels in my GX 470, LS 430, and LX 570. I always tried to drive the same way on all fuels in order to make the testing as valid as possible. NONE of these vehicles showed a statistically significant MPG increase on 93 octane vs. 87. On some tanks mileage was actually better on 87 (not really surprising to me). The LS seemed to show perhaps a tenth or two MPG improvement with 93, but I'm not sure. I feel like I wasted my money, but nevertheless I ran 93 octane in the LS except for the ~10 tank-fulls of test fuel.
After the testing I have since run Top Tier 87 in the GX and LX. 50K miles later for the GX and 25K miles later for the GX, all is well, just as one should expect.
I sold the LS 430 to my brother who puts about 25K miles on it per year (so the $.50/gallon premium adds up) and he thinks he gets a LITTLE bit better mileage on 93.
