serenity now. breakdown later

 

 

For what it's worth...

Are you suggesting that the same UR engine in a Toyota product running regular gasoline will run rough at 80,000 miles, or need a walnut blast?

Also, what, then, would be the rationale for Lexus switching their recommendation in cars like the RX from premium down to regular without a change in the powertrain?

I don't doubt that premium runs smoother in many applications, but I do doubt that there is a substantial difference in how well the same motors run in a GX vs a Sequoia, an LX vs a Landcruiser, etc.

But I look forward to your GX test results!!

 

I've done some experiment for the last 2 tanks with 87, Costco gas and what I found was that, whatever the engine did to adjust timing and compensate for the lower octane I couldn't feel a thing.
The engine idle smooth, acceleration was the same and mileage is pretty much in the ballpark of when I had 91, maybe -.5 mpg less but it could be contributed to traffic etc....
If there was one thing I notice was that when merging from freeway ramp and if I'm between 50-55mph, the pedal had a tiny bit more lag before it kicked it, more or so than it was it 91. It happened a couple times on the ramp from my inner street to the freeway.

I'm back to 91 for the current tank but it's good to know that I can run 87 if I want or need to. The only concern I have is deposit build out with 87 overtime but I also run a bottle of Techron or Redline Fuel in the tank once or twice a year.

Btw, I almost exclusively use Costco gas for most of my cars except when I'm on road trips. I couldn't tell a difference between it and the Shell one light down. I may try Shell 91 on the GX and see.

 

Long answer is it won't run as smooth. Lexus wants that cushion feel....it's why there's so much rubber in their parts, etc. It's all in the name of comfort. Ever been inside the dealership where they have those posters showing how much more design they put into all their parts for comfort?

Look at your valves and pistons at 100,000 miles in a car run on regular grade fuel. They're gunked up and have deposits everywhere. Look at valves and pistons run on premium fuel from the big players, they don't look half as bad. Not amazing but not nearly as bad.

Here's where everyone is getting caught up. People will say, I put 93 in my tank or 87, etc, then say it ran great and I couldn't notice the difference. While those opinions are certainly fine, we can't quantify what comfortable is for you and what comfortable is for me nor can you quantify the long term ramifications in one fill up. When Lexus puts an engine on a bench cell for testing and the engineers come back and say, wow look at this reduction in vibration levels we just recorded using better fuel, these are all things that can be measured. These guys are spending their entire lives redesigning every component trying to ease out another decimal in NVH level reduction. If I remember properly, MB's V-12 can have a glass of wine at idle and it doesn't fall off the engine. The balance of the engine plays a huge role in comfort. An engine that is more efficient will be more balanced, and a whole lot more. To put in perspective, I once had an 80 minute conversation with engineers about how they wanted to change a race supplier in a bearing could reduce 0.09 decibels in the engine's noise output, not something any of us could ever notice inside the car. Tally up enough of these gains however and suddenly bam, you've brought down 10db, etc.

While Toyota and Lexus do not have the fuel dilution issue that some of the german brands suffer from, have you ever wondered why they're recommending throttle body cleanings and fuel injector treatments? Those fuel injector treatments and throttle body cleanings are also tacking the valve deposits.

When you start to get deposits in an engine, you can see huge measurement differences on dedicated equipment that shows vibration and noise emissions. At the end of the day, Lexus touts itself as more reliable, comfortable and luxurious than Toyota and all others. Using premium fuel helps achieve this goal.

2. Probably because the marketing department fired back that the competition isn't requiring premium. At the end of the day, you have to sell product and marketing departments usually get the final say. The RX is not in the same realm as the GX or LX. The marketing departments for the GX and LX are assuming people who own these cars won't have trouble spending an extra $10-20 per fill up since they're already getting 17mpg in a $70,000-$100,000 LUV.

I suggest to those that are worried or looking for a definitive answer here is what I would suggest......

Purchase an E85 kit or run E70 without the kit if you have E85 availability near by. You could alternatively use E30 if your station sells it. I'm still trying to boil down at what point the ECU says too much trim and throws the CEL but that plan has been put on hold for now.

1. Your engine will make more power and advance timing more than it could even with Premium. (E45 +)
2. You'll be supporting American made fuel vs supporting wars overseas and military budgets.
3. You will clean out all the deposits and gunk left behind by gasoline/gasohol in your engine on the pistons, valves and guides, etc.

If you don't want to purchase premium fuel, add a half bottle of VP Racing Fuel's system cleaner every 5,000 miles on regular grade fuel at a minimum. With good oil analysis you can determine how much you should really be using, but a half bottle is better than nothing.

If you don't mind paying for premium fuel, run the VP Racing Fuel's system cleaner every 5,000 miles anyways to really keep the engine tip top.

 

Great post.

I'm one of those who is using Shell 87 on Brand new '18 GX Prem. and I would take your advice and start using Fuel system cleaner. I've found this product on Walmart below is the link - can you check is this is the same product you have recommended and shall i also use this in my '18 Rx350 where Prem. is not even recommended?

https://www.walmart.com/ip/VP-Small-...&wl13=&veh=sem

 

Just to clarify, the use of higher octane fuel has nothing to do with the engine per se. It is dependent on the ECU mapping. If the map calls for higher octane fuel and you give it less, the ECU will pull timing to prevent pre-mature detonation. I also use a fuel additive occasionally (not every 5000 miles) I use BG44K (in my turbo Porsche).

 

I believe he was referring to this one

https://www.autozone.com/fuel-and-en...ive/847924_0_0





Start around 3:56 talks about this product.

 

I don't follow what you're saying. While this engine makes a low 10:1 compression if what you're trying to get at is the physical aspect, then you would be technically correct in the aspect that 93 isn't needed to correctly run. However, Lexus know that 93 or Premium, contains an entirely different grade of additives that greatly affect a lot of things such as comfort, longevity, reliability and performance. And while it can certainly run well on 87, it won't run as well as it can on a higher octane. It does and will ride better on 93 but I guess this can come down to a need vs. want. You don't need a nav system and ventilated seats, but it does make for a better ride. Eventually though as compression rises like in SkyActive engines, the direct requirement for higher octane will become an issue. It already is, example Mazda's sky active in Europe requires 93 as it is running a 14:1 CR vs 13:1 in the US.

Here's another tid bit of info. When we use higher grade octane fuel and premium additives, we suffer less fuels dilution. Fuels dilution account for probably 30% of your engines wear.

When you retard timing you increase the amount of fuel dilution the engine will suffer, it is why you want to advance timing as much as possible. These engines will suffer wear from 2 places and 2 places only (for the most part).

1. Start up, probably accounts for 70-75% of the wear.
2. Fuels Dilution, probably 25-30% of the wear.

You could tow all day and not suffer wear from the towing with a quality fuel, filters and oil. Now if this thing was tracked it would be a slightly different story but even then it would really come down to a fuels dilution issue.

The higher octane fuels also have lots of additives that help control fuels dilution on top of the timing advancements, which in turn leads the bearing to run smoother, less strain and wear. The more your bearing wears the louder the engine will become over time, something Lexus spends lots of R&D money on to avoid.

In the end it comes down to priorities. All engines will run better on "Premium" AKA 93, even engines that couldn't advance their timing will run better. The question is where does it fall in your list, is entirely subjective. There are ways to run 87 or regular and achieve very similar results to 93 but it'll never be quite the same. For me? I'm on a budget! So you won't find me shelling out $4.39/gallon.

Lastly on a brief side note, the reason Shell's V-Power Nitro 93 is really the best fuel on the open consumer market at the moment is because they are the only one that has been able to address the polarization of molecules pre and post combustion. This engine will briefly for thousandths of a second open up both the intake and exhaust valves to mimic the function of an EGR. It's quite smart and works extremely well in reducing emissions at the tail pipe. As a result when the cold and hot air blend they become polarized and stick and cling unlike ever before. Something few know and even know how to control. You won't find the polar deposit fighting add pack they're using in the 87 or 89 version they sell. As IC makes more advances, pressure will increase on fuels to perform better, sadly ethanol, likely the best fuel ever made, will take a long time to gather acceptance.

 

'

yep, that's the one, Autozone will usually have a sale on it as a BOGO 50% off.

 

A little OT... I have a CX-5... do you think there are benefits to the US tuned model on Premium for MPG, HP and engine longevity? Hoping this thing doesn't need a walnut shell blasting on the head for the intake valves someday but I assume that is a given on anything direct injected at some point. Another plus for the old school port injection on the GX.

 

 

Apparently a Shell in my hometown sells it. Not a lot here in WA state.

 

I would use a bosch purolator one filter, change the air filter every 10,000 miles. I'd start with Amsoil SS 0W-20 for the skyactiv engine.

Blend E25 fuel. Remember to pump gasohol first and then flex fuel. Assuming 83% ethanol in the current season's flexfuel, in a 10 gallon tank, that'd be 2.05 gallons of E85/FlexFuel and 7.95 gallons of 87.

That'd also put you at right about 91 octane. If you're able to do this at least once or twice a month, this will greatly keep down the deposit formation. Also use a half bottle of the VP every 5K.

 

I'm game. Gonna try this out in my cars. It isn't the cheapest cleaner but if it works worth it. I pick some up at Autozone today.