Which Grade Of Fuel to use?
03-28-10, 02:12 PM
#16
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gasoline flavor
I traded my 2002 Acura TL Type S for my 2008 RX350. I ran mid-grade in the Acura for a while, monitoring the mpg carefully. I found it got about 10% less with the mid-grade. Easy enough to figure out if I wanted to run mid-grade or premium - just check the price differential! I could not detect a difference in response, etc.
I have not tried this "lab" in my RX yet - but am planning on doing so. If you look at the information from many sources about the different grades, you find most suggest a reduction in HP or response. Not noticable for most drivers or on most days. If, however, you drive you car to the limit, you probably should stick with the manufacturers recommendation. Otherwise, do the lab and see if your gas mileage differs (will depend partially on your driving habits as well).
I can find no information anywhere suggesting damage to the engine, converter, etc.
I have not tried this "lab" in my RX yet - but am planning on doing so. If you look at the information from many sources about the different grades, you find most suggest a reduction in HP or response. Not noticable for most drivers or on most days. If, however, you drive you car to the limit, you probably should stick with the manufacturers recommendation. Otherwise, do the lab and see if your gas mileage differs (will depend partially on your driving habits as well).
I can find no information anywhere suggesting damage to the engine, converter, etc.
03-28-10, 02:51 PM
#17
Lexus Test Driver
I know this may sound retarded and all,but mine seems to like the 87-89 octane the best ? 
Totally opposite of my 01,that thing ran the best on premium. Maybe it`s because the original owner used 87 for 59,000 miles ? And then had the tsb done for the transmission lag ? Who knows,I dont know. BTW,it`s not that I`m too cheap to use premium,if it ran best on it, I would use it. But this is the really screwey part,even the transmission shifts the best on the lower octane. Go figure ?
Totally opposite of my 01,that thing ran the best on premium. Maybe it`s because the original owner used 87 for 59,000 miles ? And then had the tsb done for the transmission lag ? Who knows,I dont know. BTW,it`s not that I`m too cheap to use premium,if it ran best on it, I would use it. But this is the really screwey part,even the transmission shifts the best on the lower octane. Go figure ?
03-29-10, 06:43 AM
#18
Lexus Champion
03-29-10, 08:24 AM
#19
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Regardless if you have an RX 330 or 350, the engine has a 10.8:1 compression ratio. This is a high compression engine so it can benefit from premium fuel if you are putting the engine under load by hauling extra weight, towing, or aggressive acceleration. I personally do not do any of this type of driving with this car so regular fuel works fine for me. I am not doing any damage to the engine by using regular octane either. My BMW has a lower compression ratio than the Lexus of 10.1:1 but it is still considered high compression and it calls for premium only. I would never think about using regular in this car because it is a high performance car & I drive it that way. I push it to redline regularly. So, if you drive your Lexus as what it is meant to be, an isolated luxury car, you’re really not going to see much benefit if any from using premium.
03-29-10, 10:02 AM
#20
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I have constantly had higher MPG with the 93 Octane fuel. 100% of the time, not just once in a while. When we towed our boat years ago it would not even run without engine pinging & it was bad too.
03-29-10, 10:07 AM
#21
Lexus Champion
vehicles are like people,even the same models will always act differently.some will run well on 87,and some will not.some run best on premium,while others might like 89 octane the best. their is no rime or reason,its just the way it is.
03-29-10, 04:13 PM
#23
I am sorry but I don't buy the "you paid for a premium vehicle..." arguement. If your vehicle runs well and doesn't knock, then the minimum recommended fuel works for me. Just my two cents worth.
03-30-10, 06:19 AM
#24
Lexus Champion
very true ^^ But I still have to see how it performs this summer with 90 degree heat,A/C on,high dew point`s etc. That will be the determining factor for me. 
But so far this is what I noticed with mine; runs pretty well on 87,no complaints. 89 octane gives me slightly more power,and .8-1.0 mpg more. Not really any difference in power from the 89 to premium. No millage difference at all between 89 octane and premium.
But so far this is what I noticed with mine; runs pretty well on 87,no complaints. 89 octane gives me slightly more power,and .8-1.0 mpg more. Not really any difference in power from the 89 to premium. No millage difference at all between 89 octane and premium.
03-30-10, 06:37 AM
#25
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Up here I generally get Premium for 10 cents more then regular. A dealer runs this special every Monday.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
03-30-10, 08:09 AM
#26
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Up here I generally get Premium for 10 cents more then regular. A dealer runs this special every Monday.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
03-30-10, 10:32 AM
#27
Lexus Champion
Up here I generally get Premium for 10 cents more then regular. A dealer runs this special every Monday.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
At an average of 12 gals. per week that comes to $4.80 per month or $58 per year.
I don't see any problem getting higher MPG & higher horsepower for $58 per year.
Even at 20 cents more that would be $116 per year.
Thats a good deal chief. I would go that route myself.
03-30-10, 06:46 PM
#29
You guys are lucky. Premium (93 octane) in my area is mostly 40 cents more than regular (87 octane). I was fortunate yesterday I happened upon a Shell station 25 plus miles away that was only 27 cents more for premium. Not bad. Filled up immediately. 40 cents per gallon is hard to justify when the vehicle runs just as good on 87 or 89 the way I drive it. Just my 2 cents worth. I do use premium probably 50% of the time
03-31-10, 07:20 AM
#30
Lexus Champion
You guys are lucky. Premium (93 octane) in my area is mostly 40 cents more than regular (87 octane). I was fortunate yesterday I happened upon a Shell station 25 plus miles away that was only 27 cents more for premium. Not bad. Filled up immediately. 40 cents per gallon is hard to justify when the vehicle runs just as good on 87 or 89 the way I drive it. Just my 2 cents worth. I do use premium probably 50% of the time
