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)
11-24-18, 07:57 AM
#166
drives cars
Again, it depends on how you use the car. I'm certain there are a lot of IS owners out there that just wanted a sporty look to their luxury car, and never drive the car hard. The guys you see commenting on this forum are only a few percent of the IS drivers out there. As to why the manufacturer suggests 91 octane, that's simply a gas mileage thing. The higher the octane, the slower the burn, and consequently the more efficient the car runs, giving you the best gas mileage possible on a TERRIBLE gas mileage car...even when driven normally.
You should always use 91 or above unless it is not available.
11-24-18, 08:01 AM
#167
Again, it depends on how you use the car. I'm certain there are a lot of IS owners out there that just wanted a sporty look to their luxury car, and never drive the car hard. The guys you see commenting on this forum are only a few percent of the IS drivers out there. As to why the manufacturer suggests 91 octane, that's simply a gas mileage thing. The higher the octane, the slower the burn, and consequently the more efficient the car runs, giving you the best gas mileage possible on a TERRIBLE gas mileage car...even when driven normally.
11-24-18, 08:26 AM
#168
11-24-18, 08:44 AM
#169
That's not what I'm saying. Read it again. The ECU will simply pull timing if the car is driven hard with 87 octane. No damage will result.
You want a suggestion to use something different? How about that it's cheaper? If you're not getting a noticeable performance improvement, why not save some money? No reason.
You want a suggestion to use something different? How about that it's cheaper? If you're not getting a noticeable performance improvement, why not save some money? No reason.
11-24-18, 08:47 AM
#170
No sir, I use 93 in all my cars. All I'm saying is that for those that don't drive the car hard, and want to save a little money (in the long run a significant amount of money), the 87 octane will be just fine.
11-24-18, 08:54 AM
#171
And I never said they wouldn't be fine running 87. I said if you want the performance and fuel economy that the car is supposed to give, use the manufacturers recommended 91+.
11-24-18, 08:55 AM
#172
And I agree with that statement. What I don't agree with is most IS owners actually using the performance the car is supposed to give, and for those drivers 87 octane is a better choice because it saves them money.
11-24-18, 01:46 PM
#173
Also depends on your state what your maximum octane will be. In California we only really have 91 octane max. Really the difference only amounts to $1-$2 per tank between 89 and 91.
11-24-18, 03:39 PM
#174
drives cars
Select premium unleaded gasoline with an octane rating of 91 (Research Octane Number 96) or higher required for optimum engine performance. If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91). Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking and significantly reduced performance. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline.
Also,
11-24-18, 03:45 PM
#175
The manual recommends use of 91 octane or higher, and it specifically says to refuel with 91 as soon as possible after using anything else. So I strongly disagree that 87 is a better choice for anyone.
This is from page 537 of the manual, which can be found here: https://drivers.lexus.com/t3Portal/d...f/OM53D18U.pdf
This is from page 537 of the manual, which can be found here: https://drivers.lexus.com/t3Portal/d...f/OM53D18U.pdf
Look, Toyota is just doing a little CYA, the car isn't going to knock with 87 octane, it'll pull timing instead. Even if you were driving the car really hard it wouldn't knock with 87, it'd just pull more timing. Neither though, is my point. My point, is that it depends on how you drive the car if you'd even notice a difference. ** NEWS FLASH ** Not everyone that owns an IS is on this forum or drives the car hard...or would even notice a difference running the car on 87 octane. You can believe that, or not, doesn't matter to me.
Last edited by VisualEcho; 11-24-18 at 04:11 PM.
11-24-18, 04:10 PM
#176
OK, so I can clear this up real quick now.
I have a good friend that works as a tech at a Lexus dealership in St Louis. I've asked him about the use of 87 octane, and will quote him below.
"We put regular in the cars here. I’ve never heard detonation caused by what gas is used, only be mechanical problems or timing issues. And it’s been years since I’ve heard that."
So, believe the manual if you want, no issue there. However, knowing modern cars, and their ECU capabilities, and the quality of the Toyota product, what the tech says is most likely the truth, and what the manual says is most likely a CYA (cover your ***).
I have a good friend that works as a tech at a Lexus dealership in St Louis. I've asked him about the use of 87 octane, and will quote him below.
"We put regular in the cars here. I’ve never heard detonation caused by what gas is used, only be mechanical problems or timing issues. And it’s been years since I’ve heard that."
So, believe the manual if you want, no issue there. However, knowing modern cars, and their ECU capabilities, and the quality of the Toyota product, what the tech says is most likely the truth, and what the manual says is most likely a CYA (cover your ***).
11-24-18, 09:52 PM
#177
Forum Administrator
iTrader: (2)
https://www.clublexus.com/forums/is-...-is-forum.html
Last edited by DaveGS4; 11-24-18 at 09:57 PM.
11-25-18, 08:41 AM
#178
Driver School Candidate
The ECU will quickly adjust to any octane, not allow detonation.
Lower octane will reduce performance at sea level for the heavy footed.
I live at 4750' altitude where performance is not limited by octane.
Lower octane will reduce performance at sea level for the heavy footed.
I live at 4750' altitude where performance is not limited by octane.
11-26-18, 06:05 AM
#179
Again, it depends on how you use the car. I'm certain there are a lot of IS owners out there that just wanted a sporty look to their luxury car, and never drive the car hard. The guys you see commenting on this forum are only a few percent of the IS drivers out there. As to why the manufacturer suggests 91 octane, that's simply a gas mileage thing. The higher the octane, the slower the burn, and consequently the more efficient the car runs, giving you the best gas mileage possible on a TERRIBLE gas mileage car...even when driven normally.
Last edited by sunamer; 11-26-18 at 06:12 AM.
11-26-18, 06:15 AM
#180
This place is worse than the S2000 board!
We aren't trying to prove the physics of ignition here, but simply show that using a lower octane fuel than the manufacturer suggests will NOT result in detonation, which has been confirmed by a Lexus tech. If you don't want to believe that, then don't.
And I actually wrote "slower the burn" when I meant "later the ignition."