View Poll Results: OCTANE - Which gas do you put in your 3IS
I always use 91 or higher.
259
91.20%
I sometimes use 89 or 87.
3
1.06%
I always use 89.
6
2.11%
I always use 87.
16
5.63%
Voters: 284. You may not vote on this poll
OCTANE - Which gas do you put in your 3IS and why?(merged threads)
12-06-18, 10:54 AM
#211
ok, my 2 canadian cents. I filled up with regular gas on Sunday Dec 2 from empty (gas light was lit up). Cost of regular at the time was like 98 center per liter (records low now a days). I did a quick calculation and if I was to buy premium at that time I would have spent 9 dollars more.
Let me say that I drive mostly highway for work and I typically fill up every 4-5 days. My style of driving is not aggressive at all but on occasions I step on the gas (rare).
I think i feel that there is a very slight power loss but not a lot. Could be on my mind but the car feels slight heavy. It does not feel sluggish tho or unrefined.
Fuel economy from computer I see that it is the same or even slightly less? but not much. I still have some gas left (I worked from home Monday and Today) so its looking pretty good.
Thats my experiment. It would be good to see/ask the 2nd gen people. Maybe some of them have a longer test on this or maybe even the ones that are running 87 for years can tell us if they run into any problems relating to putting regular vs premium.
Let me say that I drive mostly highway for work and I typically fill up every 4-5 days. My style of driving is not aggressive at all but on occasions I step on the gas (rare).
I think i feel that there is a very slight power loss but not a lot. Could be on my mind but the car feels slight heavy. It does not feel sluggish tho or unrefined.
Fuel economy from computer I see that it is the same or even slightly less? but not much. I still have some gas left (I worked from home Monday and Today) so its looking pretty good.
Thats my experiment. It would be good to see/ask the 2nd gen people. Maybe some of them have a longer test on this or maybe even the ones that are running 87 for years can tell us if they run into any problems relating to putting regular vs premium.
Last edited by sunamer; 12-06-18 at 11:15 AM.
12-07-18, 04:40 AM
#212
ya, so we experiencing similar but my mpg seems same (or maybe slight better) Are you still running with regular? I am still debating and I just filled up with regular again!. Its so taboo even to mention this at the forum tho because of all the Haters lol. I am reading forums now to see if there are long term effects on this. I am fine with slight power loss, I am fine with same mpg (at least for my small test). I am fine if reduces motor life if it means will run up to 250,000 kms only without problems. It would be good to find a good amount of people that have does this test before rather than "its fine, no problems" and/or "you bought a luxury car, what is another 10 15 bux per fill up"
12-07-18, 05:22 AM
#213
ya, so we experiencing similar but my mpg seems same (or maybe slight better) Are you still running with regular? I am still debating and I just filled up with regular again!. Its so taboo even to mention this at the forum tho because of all the Haters lol. I am reading forums now to see if there are long term effects on this. I am fine with slight power loss, I am fine with same mpg (at least for my small test). I am fine if reduces motor life if it means will run up to 250,000 kms only without problems. It would be good to find a good amount of people that have does this test before rather than "its fine, no problems" and/or "you bought a luxury car, what is another 10 15 bux per fill up"
I did notice two things that I did not like after I switched fuel (apart from the decrease in power and snappiness of the throttle response) - exhaust and/or induction note are noticeably less pronounced with 87 E0, than they were with 91 E0. Besides, the engine itself started to sound a bit different, probably due to different maps that ECU is running now.
I will probably also test 87 E10 to see what that does, because the price difference of 2.42 vs 2.72 (e0 87 vs e0 91) would not justify worse mpg, acceleration and the retardation in the sound department for me. E10 87 costs 2.12 and that might be closer to justifying the switch. But, I think I will most likely be running 91 after that.
87 will likely cause more carbone deposits on the piston heads long term, as the temperature of the combustion will be lower which may cause more buildup on the spark plugs and maybe exhaust valves.
But I can see why people would switch - sound difference aside, it is still a fun car to drive even on 87.
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lexuscanuk (12-07-18)
12-07-18, 08:35 AM
#214
drives cars
E0 87 has that much of a premium over E10 87? That is odd. At Quiktrip there's only a 10 cent difference between E0 91 and E10 91. Though, at Costco, the 91 octane gas is still cheaper than the E0 87 you have listed...
Btw, we both live in the KC metro, so my comparisons are valid.
Interesting findings. No idea why the sound would be (noticeably) different.
Btw, we both live in the KC metro, so my comparisons are valid.
Interesting findings. No idea why the sound would be (noticeably) different.
12-07-18, 08:52 AM
#215
E0 87 has that much of a premium over E10 87? That is odd. At Quiktrip there's only a 10 cent difference between E0 91 and E10 91. Though, at Costco, the 91 octane gas is still cheaper than the E0 87 you have listed...
Btw, we both live in the KC metro, so my comparisons are valid.
Interesting findings. No idea why the sound would be (noticeably) different.
Btw, we both live in the KC metro, so my comparisons are valid.
Interesting findings. No idea why the sound would be (noticeably) different.
Last edited by sunamer; 12-07-18 at 10:05 AM.
12-07-18, 12:12 PM
#216
Anyone in a 93 octane area ever mix 93 and 87? 50/50 mix would average out to 90. Higher than midgrade of 89 and 1 point lower than the requirement of 91. I've thought about doing that for long distance trips where you're mostly maintaining throttle and not much load
12-07-18, 12:41 PM
#217
you can get the same effect by getting 1 gallon of 87 for every 3 gallons of 91. Honestly, from what I have seen when driving with 87, you will be just fine in the higher gears even on straight 87, especially when you simply sit the same speed for hours. The engine noises I mentioned come on only at 3500 or higher rpms.
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Former5SFE (12-10-18)
12-08-18, 10:59 AM
#218
Driver School Candidate
Why is this even a question? Just put what the manufacturer recommends. If people do otherwise, is it to pinch pennies? And at this coin for car, why do people even do that? It'll save a few bucks... it's like the age old oil questions on BMW forums: just use what the manufacturer recommends.
04-27-20, 10:42 AM
#219
87 Octane Regular fuel in Lexus IS200T?
So i was filling up, I clicked 91 as my octane, and it put 87 (regular gas) into my car. On the sticker, it does state premium fuel only. Should I be good?
04-27-20, 10:56 AM
#220
Pole Position
Yeah you’ll be fine just try to avoid driving your car hard until you’re able to put 91 or higher back in. Take it easy. An alternative is to put octane booster in too. Either way you’ll be fine as long as you’re not doing it often.
04-27-20, 11:17 AM
#221
Thanks so much! That's what I needed to hear haha. Also I read in the manual which stated e. "If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91)." Should I run till my tank is almost empty before filling back up with premium fuel?
04-27-20, 11:32 AM
#222
Pole Position
Thanks so much! That's what I needed to hear haha. Also I read in the manual which stated e. "If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91)." Should I run till my tank is almost empty before filling back up with premium fuel?
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yayeeeet (04-27-20)
04-27-20, 05:00 PM
#223
get an octane booster from an auto parts store
04-27-20, 08:17 PM
#224
The entire time I've had my IS I've also had another car which ran 87. One time I accidentally filled with 87 on the IS, my last couple fillups were with the other car and it was just muscle memory.
I walked right into the gas station and spent a few dollars on octane booster. Not that I was worried about it, but why not.
I walked right into the gas station and spent a few dollars on octane booster. Not that I was worried about it, but why not.
04-27-20, 08:19 PM
#225
Did this with my RC once, I got a check engine light but luckily I didn't fill up a lot. I burned a few gallons and refueled with 91 and I was good. I cleared the CEL and was good to go.