UZ214

i only put 93 or at times which is rare 91 octane, i tried putting regular and my MPG went down on average of 2 MPG. Synthetic oil and clean air filter is a must for good gas mileage.

afpj

93 octane? Man, can't get that in the high desert southwest. 91 at most. Even higher elevations than where we are regular is at 85 octane. Just curious if any one on these long trips was hauling a Thule or other hard or soft luggage carrier, and what that does to gas mileage.

Regards

UZ214

your car runs fine? no check engine light ? ever

afpj

uz214,

I always use 87 octane. Never had the occasion to use the 85 stuff as I come back "down" to 2500 ft and my Chevy knocks if I use that stuff and don't stay at altitude. I've had the car for a year and no CEL (knock on wood). Of course we're talking 05 rx330 I hope, and the owner's manual does say 87 minimum. I have had no engine ping either.
Regards

catdaddylo

I also own a 2005 ES330 and it runs fine on 87 octane. The RX350 engine has a 11:0 compression ratio and 91 octane is required for best performance. At altitude lower octane would work fine. I live in LR,AR and altitude is about 330 ft above sea level. The normal octane here is 87,89 and 93. I try to fill up my tank at the halway mark alternating between 89 and 93 octane to avg the 91 octane blend. Today 93 octane's price was $4.15 a gal and 89 at $4.05

lexus114

I have learned re;this octane stuff,that you are basically de-tuning the engine on 87.(I know I`ll start something here)But I am trying to run mostly 87 due to the out rages fuel prices.But my millage dropped 1-1.5 mpg and the highway performance is for sure not the same.So I look at this as down tuning the motor.Even the 01 RX like I have is a 10.5 to one compression engine.

Orzel

iTrader: (1)

We've noticed a distinct difference in performance if we use regular fuel v. premium, and also a difference in mileage on our 05 (32k miles now). We live almost at sea level plus maybe about 100 feet, and if we run with 93 octane, we can easily pull 25 MPG + on extended freeway type driving (our last trip to Seattle and return, about 200 miles, was 25.2 MPG and I do not drive gently). When we did our tour of the Western states a couple of years ago, we experienced all manner of conditions, including sea level to 12k feet (a couple of the Colorado mountain passes), high winds, heat, rain, and some snow. Using premium fuel we averaged almost 24 MPG for the entire 4,600 mile trip, many times cruising at 80+. Given the improved mileage and performance, we pretty well stick to premium for our RX, our IS requires it.

lexus114

I`m glad you agree with me on this,most people will say it isn`t required so you don`t need it.This is very true except you really don`t get the performance,or millage out of regular.Hence the 10.5 comp. and the lexus tweaked up motor,one really should use higher than 87.For me right now,it`s the cost.I need to sit down and really figure out the cost difference/millage to see if it is really worth using reg.fuel.

Orzel

iTrader: (1)

Lexus 114, I, for one, have never doubted that the higher octane improved both the RX performance and mileage. Our 2000 RX 300 would run far better on 93 than it ever did on 87. When we purchased our 05, once broken in, the difference in performance, granted a subjective judgment, was quite obvious to me, especially since we regularly traveled over mountain passes here in the NW Washington state. Prior to my Mother passing this last January, we were running Stevens Pass every other week for visits with her. Round trip was 400+ miles and the few times we put 87 octane in the RX, it was notably sluggish when trying to pass, and would down shift much sooner. We also noted a drop of approximately 1.5 to 2 MPG running regular, and I track my mileage closely. That was enough to convince me that a for a few “pennies” more, I think we break even with the improved mileage. The 4,600 trip really capped it though as when we were driving from Phoenix to Palm Springs, we bucked some really bad head winds, and saw mileage drop to 16 for a good part of that drive. If we’d managed to avoid the winds, I expect that the total MPG for the trip would have been far closer to 25.

Lex2000TL

I concur. With 93 gas mileage is about 1.5-2 mpg better.
Not only it is better for overall engine-transmission performance and longevity, but also simple math proves that makes sense economically to run 93 vs. 87.
2 mpg improvement with 93 gasoline that will offer about 25mpg average comes as 6%-8% improvement. The price difference between 87 and 93 is typically $0.20 and on $4.45 per gallon of 93 (Chicago area!) it comes to about 4.5% price increase.
So, it is cheaper to run 93.

lexus114

You guy`s are awsome! I have been kicking this Idea around since the price of fuel reached $4.00 a gallon.I probably seem like a fence sitter,but it`s not an easy decision to make on your own sometimes.Especially when you see/read that most of the RX owners use 87.(trust me I know to each their own)I really don`t want to start anything with this because I know people are tired of hearing about it.Thank you very much for your input on this whole thing....

Orzel

iTrader: (1)

The nice thing about our great country is we all have the freedom to make our own decisions, dumb or otherwise! Based on our experience witih the RX's in our lives, we pretty well stick to 93 octane. I figure in the long run, we either break even, or maybe come out a bit ahead if we do a lot of highway driving. Besides, I do like getting max performance out of the RX, even though in my not so humble opinion it really isn't a "sports" utility vehicle.

grouch

I'M JEALOUS.
Not that almost everyone is getting 25+ MPG, but that your seats are comfortable enough for those long trips. I'm also surprised that the larger 350 get better mileage. My 330 gets 25/26 at a steady 65, but the seats limit our trips to 100 miles. After that we need to stop, get out and walk around to get the circulation back. Both driver and passenger. I even put a 1" foam pad on both seats. It helped, but not a lot.

lexus114

Thats odd,I find the RX seats to be very comfortable.My last car (87300E) seats were not as comfortable as the RX seats are.But I will mention my wifes C-280 seats are very comfortable.

tfischer

If you can't sit in an RX for more than an hour, then either the seat or your *** needs an adjustment. I admit that it took some fiddling around with the seat settings when I first got it, but after a while I found a good setting and find the seats very comfortable, and have enjoyed trips of up to 8 hours. I think it's a very comfortable car for long drives.

PS: I think a foam pad would be counterproductive. You want a firm, supportive seat, adjusted to fit to your back. A foam cushion, I would think, would be less comfortable, and may be the reason for circulatory problems (although I am not a doctor (any more)).