Will half tank of 87 and half tank of 93 make 90 octane?

 

Isn't Sunoco using something like this to mix their octane?

 

Interesting.

 

Started using mid grade and my mileage increased. And no I am not driving any differently. (But not an old Florida guy in the left lane doing 45 for sure)

 

I know mileage is being discussed on another longer thread. Without wanting to repeat discussion, my question is around track record and engine longevity of fuel type use. For those that have had their 2011 or 2010 RX350s for 6 months or longer:

- My 2011 RX350 is just one month old. Lexus recommends Premium (91). Dealer said 89 is what they recommend, to prevent injector issues.

- Any Issues with 87 Octane (regular grade)? With Maintenance, acceleration, pinging?

- Any Issues with 91 Octane (premium grade)? Has it been worth it - better mileage or acceleration or smoother engine sound?

- Anyone else using 89 octane (mid grade) and noted any issues with maintenance, engine sound or effects on mileage?

Thanks for sharing.

 

The only grades available here are 87,89 and 93. I used 93 for over six months and averaged about 22mpg. I then decided to try 89 for a while and get about 23-24 mpg and sometimes even better. No power loss or pinging and a bit cheaper. Was kind of mad for wasting money on the "good" gas for that long. Go mid grade!
I have almost 35k on my ride in just about a year so I get alot of data to back up my post. Hope this helps.

 

I've been using 87 for 8 months now, nothing negative to report. NO Difference at all. I feel good I'm not giving the extra $$ to the middle east and greedy traders!!

 

Interesting replies. I have 2000 miles on my RX350 so far, all during break-in period ofcourse, and used 89 Octane so far. Just today, switched to 92 Octane - per suggestion from X-Men.

Its not a huge price diff, but I hear now and then, that higher octane does provide slightly better mileage, 1-2 MPG, which becomes a break even.

I would rather not risk damaging the engine performance over long term.

I kept my last Lexus (ES300) for 13 years, 180k miles, and still traded it for 5 grand. I hope this lasts even longer. I maintain my vehicles well - incl synthetic oil changes every 5k miles.

 

I have used 89 in my RX450h since new with no problems to date. My wife drives an '04 GX470, and has always used 89 in it without any problems either; it now has about 80,000 miles. I was told by the dealer that I could run 87 octane in my RX, but would probably lose a few mpg doing so.

 

To my understanding, lower octane is easy to burn than higher octane right? ECU on newer cars adjust accordingly to what fuel you use to prevent knocking.

 

I may be stupid but always use 93 all the time in any car (accept rental ). Don't feel ok when bumping 87 for any new car .

 

If the Lexus engineers thought a grade lower than 91 should be used they would have stated so, and Lexus marketing would love to sell a vehicle that could run on regular grade. Alas, the recommendation is 91 so that is what I use. The designers know A LOT more about this we could ever hope to. Why second guess the people who designed and built the damn thing?

 

We traded a 2001 RX with just about 100,000 miles for the 2011. I would have to guess, but I feel almost certain that the last 85,000 miles on the 2001 were on regular gas, even though it was supposed to use 91. We never had a problem with the engine. No knock, ping, etc. My mechanic said it ran as smoothly and quietly as a sewing machine. That was quite a compliment coming from him.

As an aside, I do not understand why Toyota/Lexus engines require premium gas. Our 2008 CTS had sightly over 300 hp and requires regular gas. With todays prices for fuel, I just don't get it. Oh well, it is what it is.

 

So you bought a 40k + car, and are worried about a few cents?

If you go into the upper revs you best be using whats required. If you want to be el chepo and run lower grade, thats fine just dont go into the high revs.

 

With near $50k invested in my RX350, I think I will not take a chance and stick with "X-Men"s advice and fill with 92 Octane.

I was not planning to go with Regular grade (87)anyways, but the 10 cents diff per gallon diff from mid-grade 89 to premium 92 - is something I can happily sleep with.

Filled up yesterday with 92 Octane and same from this point on.

Interesting point to note - I dont know if its a psychological thing or not - but the RX350 drove quieter (engine noise) today, and I leaned on the acceleration a bit more just to "flush" it out.