Talk Me Out Of a 200

[Zill]

I suspect I won't change your mind, but as a tuner in a previous life and working on engine development programs...

For the next person. This isn't just a feel thing in low load use. Modern engines have knock sensors. Calibration for different octanes have very real differences to riding the knock sensor (persistent low grade knock) versus the knock sensor acting as a rare mitigation to the unexpected lower grade fuel (little to no knock). There is no sensor that measures octane directly. It will find that boundary via persistent low grade knock, if it is tuned for higher octane fuels (i.e. LX570). Just as described in the manual.

Do what you will with gentle commuting. As one that is constantly between in town use and heavy weekend trip use, that low grade knock in gentle commuting may be real damage with sudden high load use. I don't want to be second guessing what I last filled with and delay a trip because I'm trying to save some bucks.

View attachment 4094446

If we were talking about an extreme tune, that’s a different story.

We are talking about a large displacement naturally aspirated V8, that Lexus tuned with 2 more HP (383 vs 381)… a .52% difference in power. That tune is not pushing the 3UR engine to its max by any means.

Over 100k miles, if there’s a dollar per gallon difference and you average 13 mpg, that’s $7,692 in fuel savings by using regular gas. Over 200k miles, that’s $15,385 which nearly buys you a new engine. People have been running regular gas in these LX’s for many miles and years with no long term ramifications. You have a larger issue with head gaskets on these engines than you do them grenading due to unintended detonation and pinging (of which I have never experience any pinging at all using 87).

When was the last time you saw a 3UR wear down or grenade due to using 87? The only real engine issue you see are valve springs dropping and head gaskets going out.

Even towing with high engine load, there’s an argument to use 87 even then, because that pinging just really isn’t there in real world testing.

 

[TeCKis300]

If we were talking about an extreme tune, that’s a different story.

We are talking about a large displacement naturally aspirated V8, that Lexus tuned with 2 more HP (383 vs 381)… a .52% difference in power. That tune is not pushing the 3UR engine to its max by any means.

Over 100k miles, if there’s a dollar per gallon difference and you average 13 mpg, that’s $7,692 in fuel savings by using regular gas. Over 200k miles, that’s $15,385 which nearly buys you a new engine. People have been running regular gas in these LX’s for many miles and years with no long term ramifications. You have a larger issue with head gaskets on these engines than you do them grenading due to unintended detonation and pinging (of which I have never experience any pinging at all using 87).

When was the last time you saw a 3UR wear down or grenade due to using 87? The only real engine issue you see are valve springs dropping and head gaskets going out.

Even towing with high engine load, there’s an argument to use 87 even then, because that pinging just really isn’t there in real world testing.

We can disagree. I'll put forth domain informed knowledge and data rather than just opinion.

87 to 91 is not a small difference. Even the difference between Arizona, California, Nevada prevailing 91 octane to rest of country 93 octane can warrant ACN specific tunes. Engineering thresholds are informed by margins, not absolutes. Toyota's are reliable because they keep more margin. Margin out the door when using the wrong fuel.

Octane isn't as correlated to max HP in an N/A truck engine, as it is to max cylinder pressures at lower RPMs. Margin in designs have to be there not so much for nominal (commuting) usage, rather it also has to be there in stressing use cases. Knock is a significant factor to head gasket failure. We'll see as the 200-series gets into higher mileage with more aggressive use cases.

Commuting is whatever (and there is a percentage MPG efficiency difference), but arguing to use 87 (in an LX) for heavy use? I can tell you absolutely there is a difference and performance falls off. Can't feel the knock, but the ECU is actively compensating. Here's that Death Valley 87 octane, whereas the Knock Correction (KCLV) is usually closer to 19 with the right gas. It fell off significantly here and the ECU is compensating based on knock it is actively detecting. If one is feeling the knock, that's at catastrophic knock levels so I hope no one actually ever finds that.

 

[LC Lurker]

I’m not talking you outta s***. You only live once, get a 200

 

[coleAK]

I suspect I won't change your mind, but as a tuner in a previous life and working on engine development programs...

For the next person. This isn't just a feel thing in low load use. Modern engines have knock sensors. Calibration for different octanes have very real differences to riding the knock sensor (persistent low grade knock) versus the knock sensor acting as a rare mitigation to the unexpected lower grade fuel (little to no knock). There is no sensor that measures octane directly. It will find that boundary via persistent low grade knock, if it is tuned for higher octane fuels (i.e. LX570). Just as described in the manual.

Do what you will with gentle commuting. As one that is constantly between in town use and heavy weekend trip use, that low grade knock in gentle commuting may be real damage with sudden high load use. I don't want to be second guessing what I last filled with and delay a trip because I'm trying to save some bucks.

View attachment 4094446

90 octane is the highest available in Alaska. Outside of Anchorage 87 (and some really remote places 85) is all you can count on. I’ve towed the camper easily at least 50k miles on 87, none of that flat highway with my 2013 LX. And my LX has never seen >90 octane (well except when it was shipped up to the AK Lexus dealer where I bought it). 13 years and 145k miles (with 60-70% of those miles towing the camper) and my LX has at most had >90 gas one tank, knock on wood, no issues.

That said I still fill up with 90 when available. But also I notice no difference at all between 87 and 90 even when towing my 24’ 7600 lb camper through the mountains of Alaska.

Another variable could be that we don’t have ethanol in our gas, I wonder what the difference would be between 90 with no EtOH and 91-93 with EtOH?

 

[bloc]

Actual data in this thread.

Thread 'Regular VS Premium - let’s put an end to an ongoing debate?'

Dec 24, 2020

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...

• airdzi
• Replies: 118
• Forum: 200-Series Cruisers

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[Sinister]

Why would we want to talk you out of one? The more crazies we get in the asylum the better, so jump on in the waters are wonderful. You absolutely will NOT be disappointed, in fact I think you’ll kick yourself for not getting one.

Good luck.

 

[TaishoCruiser]

That might be why I’m here. For the confirmation bias. It helps my small and quit smooth brain.

Confirmation bias, when the end result is helpful, isn't that bad .

FWIW - every time I get out of an LC200, one variation or year is the next vehicle I'm looking at. Every. ***. Time. Case in point my only off road rig in the stable is an L663 Defender V8. Love it for tooling around town and trips but it has me scouting for a low mileage LX or LC to supercharge and tune. On fuel and tunes...

I didn't read the whole thread but saw the mention about gas. I know people who have LX570's and GX460's who've run them on 87 for years... but I also appreciate the type of insight Teck shared... and fwiw I ran 91-93 on my LX. If you're tooling along flat road with light load I don't think 87 would kill you. If you're I a built rig (heavy), hauling a trailer, or hauling @$$ I would run 91 or 93, personally. If it was a concern, I haven't worked with him, yet, but Loi (TunedByLoi in the social media world) does remote tunes. You could always work with him to get a tune specific the the fuel and type of driving you are doing. That is probably the route I am going to go with my next build.