premium octane fuel? 87 vs 91?
CL Community Team
Joined: Apr 2004
Posts: 17,331
Likes: 210
From: Miami, Florida
i was under the impression that since it was the "after the cat 02 sensor" it had no bearing on fuel mixture or performance. the sensor i had changed was the one farthest down the line. ie,, after the cat, (the one under the drivers seat and inline the exhause before/near the resonator i think) would that sensor have any effect on exhaust odor? i thought that one was only emissions related. i was told by the lexus dealer that the sensor in question would not affect gas mileage or anything but would only prevent emission inspecion passing for my state/locality. the only code i had was p0136.
it does make sense that different gas blends could cause different odors.
there is ONE thing i can add to the octane discussion. my rx has a lot more "kick" with the higher octane gas. thats all i have to say about that.. lol
it does make sense that different gas blends could cause different odors.
there is ONE thing i can add to the octane discussion. my rx has a lot more "kick" with the higher octane gas. thats all i have to say about that.. lol
I've always noticed more kick with the higher octane.
Lexus Champion
Joined: Aug 2007
Posts: 4,507
Likes: 38
From: Bethlehem Twsp. Pennsylvania
i was under the impression that since it was the "after the cat 02 sensor" it had no bearing on fuel mixture or performance. the sensor i had changed was the one farthest down the line. ie,, after the cat, (the one under the drivers seat and inline the exhause before/near the resonator i think) would that sensor have any effect on exhaust odor? i thought that one was only emissions related. i was told by the lexus dealer that the sensor in question would not affect gas mileage or anything but would only prevent emission inspecion passing for my state/locality. the only code i had was p0136.
it does make sense that different gas blends could cause different odors.
there is ONE thing i can add to the octane discussion. my rx has a lot more "kick" with the higher octane gas. thats all i have to say about that.. lol
it does make sense that different gas blends could cause different odors.
there is ONE thing i can add to the octane discussion. my rx has a lot more "kick" with the higher octane gas. thats all i have to say about that.. lol
What`s nice about that o2 sensor is it hardly ever goes bad.It`s the final link in the exhaust emissions.
Last edited by lexus114; Apr 22, 2009 at 07:20 AM.
Lexus Champion
Joined: Aug 2007
Posts: 4,507
Likes: 38
From: Bethlehem Twsp. Pennsylvania
summer regular unleaded
Okay,I tried another experiment last week.I noticed last summer when I put 87 octane in the RX,that when it adjusted itself the millage jumped from .5 to 1.5 mpg. (and this is not only going by the computer)also the power is almost just as good. So I decided to try this again last week,sure enough the millage jumped from 19.6 to 20.5 and has very good power/throttle response.I can`t figure this out for the life of me how this is possible,especially during warm weather.Now here is the catch!! as soon as the winter blend of fuel comes out,it`s all over....millage drops big time,power goes along with it.Needles to say,I`m glad I can at least save money during the summer month`s. 
CL Community Team
Joined: Apr 2004
Posts: 17,331
Likes: 210
From: Miami, Florida
Okay,I tried another experiment last week.I noticed last summer when I put 87 octane in the RX,that when it adjusted itself the millage jumped from .5 to 1.5 mpg. (and this is not only going by the computer)also the power is almost just as good. So I decided to try this again last week,sure enough the millage jumped from 19.6 to 20.5 and has very good power/throttle response.I can`t figure this out for the life of me how this is possible,especially during warm weather.Now here is the catch!! as soon as the winter blend of fuel comes out,it`s all over....millage drops big time,power goes along with it.Needles to say,I`m glad I can at least save money during the summer month`s.
CL Community Team
Joined: Apr 2004
Posts: 17,331
Likes: 210
From: Miami, Florida
Driving habits I find are never the same when going from one octane to another. When I've used lower octane, I drive less aggressively than I would with higher octane, the pickup isn't there.
I tried this out the last few weeks, keeping my driving habits the same. I have been filling up with cheap Costco gas...premium cause it so cheap. I switched back to my Shell 87. The car ran a little better. So for the last 3 weeks I put in Shell 93. After about 2 tanks fulls and on the 3rd I noticed the engine was a lot smoother. And I got a little over 1 mpg better gas mileage with it.
Driver
Joined: Jun 2002
Posts: 188
Likes: 5
From: usa
It wont be a waste if you can afford high octane. 87 will run the engine, but is it better than 91? of course not. Either one wont ruin the engine. It is just that 87 does not do beyond keeping the engine running.
Drink fountain water or drink ice cold bottle water, both will keep you from dehydration, but I surely like the ice cold bottle water.
Drink fountain water or drink ice cold bottle water, both will keep you from dehydration, but I surely like the ice cold bottle water.
Lead Lap
Joined: Mar 2006
Posts: 4,189
Likes: 16
From: NY/NJ
For what it's worth... running premium on my vehicle since 37K (now 125K) didn't matter much to my coil packs. I know they're not really related, but I had another one go and I figured might as well replace the remaining four since I had the first two replaced not too long ago.
$1090...
my wallet feel so much lighter now.
$1090...
my wallet feel so much lighter now.
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