I get what you are saying but Technically, lets clear something up here. So if you say the driver may not know the difference that's one thing, maybe, maybe not? I'll come back to that one.

But to say the Stock ECU in :their cars", that was Tuned with a MAP for Timing Advance knock and Retard is totally incorrect. That's the very purpose of the knock sensor and Mapping of the ECU. The ECU knows so much that it actually has monitors, mappings, and adjustments and, a KCLV reading for it. Now if one does not really understand this, saying it wont make a difference is true. There is actually nothing for fact to discuss until one has the knowledge and/or experience. So yes........ it does not matter, in fact nothing matters that one is not knowledgeable about exist.

About a Driver knowing? There are a few thread here that were started saying "do you notice one day your GS feels peppy and fast, then another day it just does not, fell as fast"? Yea keeping thinking that if you are driving aggressively, and your KCLV is very low, then another day your KCLV is very high that you wont feel a difference. Ok, like I said before......... if you don't! lol! I think it so strange that all the other CL Model Forum are so aware of this and discuss it all the time, except, here. If you don't think the more efficient you engine runs the better gas mileage you will get. Ok.

 

Looking for a couple of simplified answers on KCLV. Since joining this forum, I had never heard of it. I have read some of the threads where it has been discussed. So, I'm wondering does a higher KCLV number equal better efficiency and/or performance? How do we raise the KCLV in our cars? Thank you in advance for any response.

As for the gas, I've only used quality gas from brand name sources in my cars for the past 20+ years. I read an article from a well respected mechanic 20+ years ago that explained why this is a good practice. He also suggested not filling up if you see the tanker truck filling the station tanks, not letting your tank get below 1/4 if you can help it and avoiding most fuel injector cleaners while recommending Chevron Techron. With that being said, Mobil and Sunoco are probably the only quality gas stations in my area, with Mobil being much more available in all areas that I travel regularly. Mobil doesn't offer a 91 octane gas so, 93 octane Mobile is what I use and will continue using through the gas price hike. I don't see the 30 or so cent difference per gallon being enough savings to take any chances on messing up my car. If I really needed to save $5 per tank fill-up, I probably couldn't and shouldn't be affording this car at all.

 

Nope. Gas has eclipsed $5 per gallon here for the first time ever and I'll continue using premium. I also don't drive too much, I've been filling up only twice a month this whole winter.

 

There are multiple ways to do this. If you search KCLV in the, 3rd Gen GS350, IS F, IS350, RC F, GS F, forums you will start to understand better. It not that hard at all to get there and keep it High. I keep mine monitoring at about 26 or higher. I don't want to get into here with the nothing makes a difference crowd. lol!

You are right on point with everything you just said above. There was some good researched and test info just not to long ago in the GS F Forum, that showed that the Shell 93 Nitro and the Sunoco 93 were the best for efficiency. I was kinda surprised that the others like BP, Chevron and others did not rank so high. If you have some of the stuff done in the link below, RR has test results showing that a bottle on Walmart Lucas Octane Booster does wonders to get the KCLV up quit a bit and it will stay there with as little as one bottle treatment in the Tank.

Here is one of many. many links to get started. I can tell the difference when my KCLV is up and stays up high. I have been as high as 29.4 On one of the Forums explains how you can get a $50 Amazon Scan tool and monitor the number on the fly with a phone app. I now have the Toyota Techstream. It's so simple to get there it not even funny. It will wake the GS350 motor up too!

The high value equal both peak efficiency of the engine design, and best performance too.

https://www.clublexus.com/forums/is-...and-power.html

BTW: I like Sunoco, and just paid 5.05 a gallon for 93 today.

 

My wife's first car was an '02 ES and she used 87 and it lasted 186k miles until we traded it for an RX. I don't think it affects the engine's reliability. Probably not good for gas milage and performance.

Her current IS..if I drive it, I put in 91. If she fills it up, she puts in 87....It's her car so it's probably 87 90% of the times and 91 10% of the times.

We had the conversation but that didn't seem to help. It's at 70k miles now so no problem so far.

My GS is always 91 (if she fills it up, she puts 87) and I think I notice it (but it could be a placebo effect...because when I adjust the seat and the tank is full, I just feel a bit different)

 

Hit a record today 7.3. All highway cruising, 98

premium fuel, barely touched the accelerator.

 

That's a great Wife story but....... if you understood the Lexus objective in the programing of Engine Management Mapping and performance efficiency.

You likely feel good about buying cheap gas, but realistically spent about $100 - $150 more in fuel per year, than buying what the car was mapped to for it to run at peak as much as possible. The KCLV was likely stuck at like a low 18. The ECU definitely knows what it was loaded to do which is perform at peak, or not, and dump in more fuel to protect and run detering engine knock by Retarding timing and adding more fuel. The ECU will very well make changes based on the readings it receives for better or worst. It 100% percent has a effect on mpg.

Someone will come along and say the Lexus ECU Software Mapping loaded was wrong (BTW: Lexus has one of the best in the Industry at adapting to change fuel curves = Gas used). Even though they can't start or drive the car without the ECU controlling the entire Engine and Transmission, and have not ever seen the MAP's loaded. But.....What would it know. lol!

 

Pretty simple equation, does using Premium increase gas mileage enough to outweigh the additional cost over Regular. I have never measured it. But if Premium gas costs 10% more per gallon, then to break even, gas mileage should increase by 10%. Does it? By that measure, do I get better gas mileage with Costco 93 Octane over Mobil 91 Octane? Or is 91 the sweet spot, and anything higher does not add increased MPG’s. And for that matter, how many people don’t put 0-20W oil in their vehicles and use something else. My point is, it is your car, do what you want. It is only a car. They make more. In fact, i always see commercials telling me my life will be much better pursuing perfection in a Lexus……. Just my way of saying everyone is entitled to their opinions. Experiment if you want. Have fun.

 

So you think we have more to reinvent the wheel and determine this than Lexus Resources did in their R&D on their car? Not talking about Advertising or Marketing.

If you have some R&D Data that says Lexus got it wrong, can you please share it? Likely none. That's really the point. It's already had the Factory from a Car company that has some of the Best R&D in the World decide what's best already for you. But what would they know.

By that thinking even the like, would say there is reason for a Hybrid Owner to re-decide if the Hybrid development needs to be re-thought by a Owner. lol! The thoughts by some here are simply amazing.

 

Might not hurt the car with lower fuel, but is that the point?
I put 14 gal in the other day and it cost $70. Ouch. Im driving a bit slower these days but not too slow.

 

I paid $75 for a 13-gal fill up twice now. I've been training my right foot to do Eco foot and the range went from 300 to 330 after yesterday's fill up. Aiming for 400 miles range.

 

Its cool now most places.

Adjust the air to a low temp, or high temp. Go into Climate and cut a/c off. Without it being 95 degrees it will still blow Warm or Cold air, with the entire climate off, or run with Climate on and a/c off. That also cuts off the a/c compressor. No, you wont get Hybrid gas mileage, but it will help some Not running the a/c compressor Clutch. The only thing is.... if it's raining for Defog inside you want the a/c back on. Try it.

 

Right. Do the math the savings equals about a little over 1 gallon by cheeping out with Reg Gas for a whole Full tank cost. I assure you the KCLV lowering will cost you to use 2 extra Gallons using Reg Gas vs Premium. Go figure? Its like driving to a cheaper Gas station 30 miles away, there and back. You just drove 60 extra miles to save a little more than a $5+ dollar on a whole fill up cost. But if it makes one feel good, ok.

Lexus Built ECO mode for you. Learn how to use it with the most efficient fuel they said use. 99% don't understand and don't know how to Drive ECO. Instead post about reinventing the wheel to out smart themselves is ones choice. lol!

Mostly City Miles with the 13 GS350 Lux 6speed.

 

Car and Driver had an article about this many, many years back. If I recall correctly, it does not damage the car but you will lose a little performance. A quick google search I just did mentions modern car computers can adjust for the octane difference, but using regular gas long term could result in the engine making a knocking sound.

 

continuing your good post........... as a result with Reg Gas, you will use more fuel.

and when the ECU Detects the knock it Retards the engine Timing and adds extra fuel for a good while and many miles. Enough times it stays in Retard, (low KCLV), and then you keep a very Low KCLV number. The Lexus Computer and programed Lexus ECU Maps are much more Advanced than most other cars. So now you run a less than efficient, less performance than designed for Fuel/Air and Timing MAP. It doesn't take long for it to sense knock. The ECU wont let it knock, and as soon as it hears the slightest knocking it pulls timing and dumps more fuel. Now someone will come along and tell you different than what Lexus Designs and happen, and tell you it does not matter. Likely will even have different info with Zero R&D, and Zero knowledge and experience and never saw the maps ever. lol! Now if they have hacked and have the Data, I would love to see it.

I have the D3 Performance Pro Tuner. I Download saved, and looked at my Factory Maps from my ECU, and uploaded and installed the D3 Tune Map. I can change some things also. So before someone ask, yes I do. I have also talked to D3's Tuner many times about those Fuel/Air, Timing Maps, Lambda, AFR readings, and other, and 2 others who Retune the Lexus computer. In fact using good Premium gas, they can Re-Tune for just fuel economy also (less fuel) but not if it's cheap octane gas, because it will knock and then the ECU will...... guess what? To be clear also this is related to a Bone stock Lexus. A modded Engine would also fall along the same lines.