GoHuskers

Wait....These numbers do not directly relate to MPG; however, I will take the higher power anytime (you pay to play).

Thanks Dinh.

DINH300

These cars are rate 275/257 are Engine horse power but do to drivetrain loss buy the time the power hit the pavement its reduce by 15%-25%.

Marqevans

Now I wonder if you used mid-grade at 89 octane if you would pick up most of the difference in horsepower? That brings up an annoying question: Why is mid-grade only 89 instead of 90?!!!

DINH300

These got wet when we left the dyne so bare with me these will have to do

2011 RX350 93


2012 RX350 87

xfirechief

Premium at my local station is 10 cents more the reg on Mondays. Great deal so I stick with Monday fillups whenever possible.

dctex99

Mid-grade should ALWAYS be half way between regular and premium,,,,,remember your gas station only has 2 TANKS;;;one for regular, one for premiium.......when you dial in Mid-grade they just mix them half and half....l f!!!!!!!!

2011RX350

So a 15 HP loss at the wheels means you will lose around 20 HP of the engine rating at maximum engine loading. Since this system is tuned for the rated HP with 91 octane, the 93 won't provide much benefit except for very hard driving at high engine temperatures like what you would see on a track or on a dyno test like this. For normal street use, the 87 is going to satisfy >90% of drivers. 87 is cheap and does not knock under normal use, but if you are going to run a track event or pull a trailer at 80 mph in 125F dessert temperatures, you definitielly want the 91 octane (or 93 if you can get it).

Marqevans

The stations in the Chicago area have 87, 89, and 93 octanes.

dctex99

So apparently when mixed they lose some octane; all the more reason to stick to Premium; in California we have 87, 89 & 91, but are on "summer gas" now from cracking plants plus some
stations are partly ethanol!!

Marqevans

In Chicago they use ethanol at most stations. I think that's how they get to 93.

runscissor

This is purely anecdotal, and probably of no use to anyone... but I used to own a 2006 RX400h and only put regular gas in it for the 3+ years I drove it. I averaged about 23-24 mpg (combined). I now own a 2010 RX450h and have been going exclusively with premium. My combined average is now 29 mpg... a 5 mpg increase. My driving habits (I'm a fairly aggressive driver; always in a rush) and driving routes have been unchanged with both vehicles. Now I understand that the 450 is more efficient than the 400 but by only 3 mpg (per the EPA). So while I can't chime in with any opinion on increase in torque or hp... I believe premium does increase fuel efficiency by some margin. Maybe not much, but I would say it's definitely a noticeable difference.

Personally, I think it's a complete no-brainer to go with premium here in Hawaii as the difference between 87 and 91 octane is only about 20 cents/gallon (<5% difference).

sweetboy02

Really? , One of the gas station in my town has 87, 89, 91, 93 level.

Based on what you said, when i pick 89, they mix more of 87 than 93. And if i pick 91 then 93 more than 87? How i can i trust that :-p

Marqevans

The station I go to has three tanks marked in the ground they are color coated. We have 3 grades.

dctex99

It might vary by companies or state; I asked a tanker driver at our Conoco/76 station one day, and he was pulling two tanks; one was regular, one premium. I had asked him if the premium or mid-grade get stale as so many small cars use regular, and that was why he told me. Both mid grade and premium have premium in them and he said they sell alot of all. He said that when gas goes up "the old people put mid grade in their Caddies to save a buck!" kind of funny!

aznboi88

Been reading quite a few threads, but nothing seems to be real pinpointing the answer to my question. Recently purchased a 2013 RX 350, and when i bought it i was told that i should use regular fuel, and not to ever mix it up. Then i hear from other people, that i should use premium fuel because later on in the future, its gonna bite me in the , and damage my fuel sensor. So what really is it? I do not mind either to be honest, whats a few bucks extra for premium gas when i got a 40g+ k. Just want to get it right, Thanks. Oh, and i basically try to find places to go since i got this car.