Your engine looks great visually. You allowed needless wear though because your oil analysis service did not identify these issues. We really don't know how efficiently this engine was tuned via oil analysis because there was no accurate measure of raw gasoline fuels NOR combustion dynamic. Only symptoms.

The reason the wear-in ring alloys aren't showing it's never identified as an issue and the fuels are being under reported. Fuels dilute will wash out the oil surface reactive chemistries and allow that wear instead of the data showing seating. Having FTIR work done really allows you to see some things you ordinarily can't.

 

FTIR? I am not familiar with that acronym. What test is most accurate for fuel dilution? Mass spec won't tell you that, it's not really good for organics. Really awesome for nuclear isotopes though. I would expect gas chromatography would be pretty good for determining ratios of light to heavy organics, but I never used it for that, only for target gases related to nuclear enrichment, and no, I won't say any more about that.

The other damning thing about this is the UOAs others have posted in the IS F forum don't look a lot different from mine (save my last one, it looked horrible IMHO with 35 ppm iron, and I fully understand the best lapping compounds start with the best lubricants). Does that mean this engine and its factory tuning lend itself to widespread fuel dilution? I know well from my Supra days, Toyota errs on the extremely rich side at WOT (Supras often measured 10.5:1 AFR with the factory tune at WOT), and I do spend some time at WOT, more so than the typical owner especially since I installed the OS Giken TCD limited slip spool. But I am very curious now to see if this is endemic and not unique to my instance.

 

My brother was a chemistry major who worked at local CP rail loco. depot. I am retired now since early 2000. I was in
IT as a Sr. Systems support Specialist on mainframes(in super computers)

 

yeah we test CP oils and fuels.....

lobuxracer........Design cam phased valve overlap in stock engines, especially performance engines is a major issue we identified 20 years ago. Add in aggressively rich fuels mapping and then poor fuels that make deposits that exacerbate the problem. Why our tuning using was critical in our customers NOT experiencing damage or needless wear from the effect. The street cars made into track cars suffer even more.


Regardless of the issue we can mitigate the effects or eliminate the problem using analysis service because we look at the what the engine is DOING near real time vs sensors or assumptions that are just a distorted view.

Also, you have to remember the manufacturers have to make power, reliability and emissions. they have to make concessions on these 3 all the time.

 

FTIR Spectroscopy is a statistical analysis technique that provides information about the chemical bonding or molecular structure of materials. The analysis provides an early warning of fluid degradation and contamination. The presence of chemical degradation products due to oxidation, nitration, sulfate formation, lube breakdown, and anti-wear additive depletion, and contaminants such as soot, water, ethylene glycol and unburned fuel is used to measure the degradation of the oil.

Fourier Transform Infrared Analysis - FTIR is incredible, it's not 100% accurate which is why we use it as a back up on all of our testing, it does extremely well showing combustion dynamics in the engine. There's only been a 4-5 cases over thousands of tests, that FTIR didn't pick up fuel. IT is however 1000x more accurate than flashpoint, which is an old school tech from the 50's that doesn't work with today's new fuels and engines.

 

I was always told by dealers to use synthetic in my 2015, not sure if the recommendation has changed since.

 

The official recommendation by Lexus is conventional for reasons other than what oil is actually best for the car. Dealers make recommendation on their best guess and the "conventional" knowledge that synthetic is better.

 

So what you are saying is it is OK to use synthetic Mobile ONE 5W-30 as long as still following the 5k service interval (not 10K like other Lexus models).

 

The Lexus dealership here in Seattle (actually Lynnwood), uses exclusivey 5W/20 even though the filler cap on my 2007 GS 350 says 5W/30. Is this because of sludging issues, better gas mileage (fractionally), or only having to buy one type of oil for the whole dealership? I don't know.
That said, having sat in recently on an oil seminar given by a Chevron rep, running dino oil in your car, then running synthetic (or visa versa), is not detrimental to your engine. Similarly, mixing the two has no negative effects (think "blends"). Basically, oil is oil. Synthetic is a bit cleaner, and all of its molcules are the same size.
Run the right viscocity of the best oil you can afford. My $.02

 

Well what I'm saying is that it is ok to use synthetic, personally I think there is a better formula for this vehicle, but M1 works well. I think what you really need to do is look at the data and make the decision there. Personally? I'd stick to 6k while still getting data back. I will be posting my reports on my 2UR-GSE, shortly, for all to see. There are ways to get 15k on the oil on these engines, like Lobuxracer was originally doing, it would involve more filter changes both air and oil and running a different oil. But it's not optimal, it's not designed for those long intervals and one failure and game over. This car was designed to make reliable power. I think we all get caught up in the trying to maximize this or that in this game, and forget sometimes that you're talking about pennies and it becomes a game for most of us, myself included. Extending the oil to 15k vs going 8-9k, is a few dollars if you do your own maintenance.

 

I've called a few dealers for this post as an experiment, the first answer I usually got was......"no, you need to put synthetic 5W-20 in your RC-F, my computer is even showing 5W-20" "Sir, lexus would not recommend conventional in an RC-F"......"sir, let me put you on hold, I want to check something with my service manager".............you really don't want to ever mix oils, unless you have no other choice and you're on the side of the road. The oils have different formulations, additives and detergents. Mixing them would lead to an oil that behaves different than intended and additives that can counter act each other. Detrimental maybe not for one run, but again what's the question here? Is it good to run mixed oils? It's like starting a diet and deciding you're going to mix two diet plans together, while it might feed you short term, you probably won't see the benefits in the long run and will probably end up with nutritional deficiencies. Your best off sticking to one oil that works for that engine.

There's a lot more to that but it's toooo long to get into, but you can damage the engine switching to synthetic in certain circumstances.

 

Overdoing is wasting. Synthetic is superior to conventional oil. Unless one is racing , driving like maniac, driving under extreme conditions 10K change interval is good,
Also speaking of filter, have ever cut up the used filter? Most of them looks very clean. Now all cars are using unleaded fuels.

 

you need to look at the data before you start tossing out numbers.......every car is different and driven differently......10k might work for some but not for others......you don't know until you actually see facts......you need the data to make these summaries.....otherwise we might as well go back to 14k and run our cars to the ground. cutting up a filter and looking at it is the wildest thing I have heard so far. All these filters will look great to the eye, these aren't 35 liter cat crawlers. If you really want an analysis on the filter, you need something called a patch test. You need to remember the particles you're looking at are measured in microns and are invisible to the eye and most microscopes.

 

My brother was in charge of oil analysis lab. at CP rail loco. depot. He is old navy guy. I have a university alumni who was a tank unit commander, also a good friend who is a mechanic for light and heavy duty equipment. He spent lot of times working in arctic zones where it is so cold hydraulic oil freezes. Stories I heard from all this guys,
I learned a lot. I myself am retired PE in EE. Numbers are just numbers. Real experiences in the fields are real knowledge. I have been driving for almost 70 years.
Never damaged or lost my vehicle from oil related problem. Data came from field. Now computer simulation often replaces actual data collected over time. Same with new drugs They apply computer simulation instead of time consuming clinical testing. Have tried HPLC analysis of any liquid?

 

ironically CP now farmed out the job to us.......

have the equipment to run HPLC and the way of the future will be applying watson to data.

10,000 miles is not always 10,000 miles.

We see blown engines by the dozen every single day, so while you may have been good on maintenance, some others have not or at least not been lucky.....