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)
11-26-18, 08:39 AM
#181
Nothing to debate here. 91+ in all ISs. No downside. Only upsides.
Whether or not you can use 87 is moot. Don't.
Whether or not you can use 87 is moot. Don't.
11-26-18, 08:44 AM
#182
.
11-26-18, 08:51 AM
#183
You'll get worse fuel mileage using 87 in an engine that optimally runs at 91+. So you'll be spending more long term. This has been beat to death on other forums for other performance sedans. There's engineering level SAE studies on this from long ago.
And even what you were saying is true, if saving $3 per tank is "wasting money," these aren't the cars for you.
11-26-18, 09:02 AM
#184
Nope.
You'll get worse fuel mileage using 87 in an engine that optimally runs at 91+. So you'll be spending more long term. This has been beat to death on other forums for other performance sedans. There's engineering level SAE studies on this from long ago.
And even what you were saying is true, if saving $3 per tank is "wasting money," these aren't the cars for you.
You'll get worse fuel mileage using 87 in an engine that optimally runs at 91+. So you'll be spending more long term. This has been beat to death on other forums for other performance sedans. There's engineering level SAE studies on this from long ago.
And even what you were saying is true, if saving $3 per tank is "wasting money," these aren't the cars for you.
I would encourage everyone that doesn't plan to be spanking their car regularly to try for themselves to see which works best for them. And for those driving their car aggressively on a regular basis, I recommend sticking to 91+ octane.
The following users liked this post:
lexuscanuk (11-27-18)
11-26-18, 09:14 AM
#185
11-26-18, 09:15 AM
#186
11-27-18, 01:11 AM
#187
I am.
My understanding is that this is a place to learn and discuss reality of Lexus cars and how they operate, as well as understand what works, and what doesn't.. What is the point of talking about something without knowing if it is true or not, or without caring about it being true? There is no value in that, as you can't use that anywhere.
Correct! You actually used wrong words that mean a completely different concept.. Accept it and lets move on..
My understanding is that this is a place to learn and discuss reality of Lexus cars and how they operate, as well as understand what works, and what doesn't.. What is the point of talking about something without knowing if it is true or not, or without caring about it being true? There is no value in that, as you can't use that anywhere.
Correct! You actually used wrong words that mean a completely different concept.. Accept it and lets move on..
The following users liked this post:
lexuscanuk (11-27-18)
11-27-18, 01:56 AM
#188
Keeping on topic, I saw someone ask "Scotty Kilmer" (the mechanic from YouTube) whether or not he can use lower than 91 in his 3rd gen IS.. Scotty said yeah, you can run a lower grade of fuel but the horsepower is going to be reduced but besides that the computer will learn to run on the lower fuel. He is a big fan of Toyota and Lexus reliability.
Throwback to when I got my car: My family member was trying to be being nice and put 87 or 89 gas in my car, haha, I was so mad. I could tell the car was driving like ****, throttle response was way worse. I always get 91+.
Throwback to when I got my car: My family member was trying to be being nice and put 87 or 89 gas in my car, haha, I was so mad. I could tell the car was driving like ****, throttle response was way worse. I always get 91+.
11-27-18, 07:09 AM
#189
As long as it does not damage the engine in anyway I would be willing to try running lower octane even if I loose some ponies. The question for me would be... would I have a carbon build up problem or something else down the road since I am planning to keep this car for about 8 years?.
I was so going to try lower octane and see if it was worth the savings/kms but the price of gas just dropped to records low. So I am keeping it premium for now..... or maybe I will try 94 (i put 91)
I was so going to try lower octane and see if it was worth the savings/kms but the price of gas just dropped to records low. So I am keeping it premium for now..... or maybe I will try 94 (i put 91)
11-27-18, 01:21 PM
#190
As long as it does not damage the engine in anyway I would be willing to try running lower octane even if I loose some ponies. The question for me would be... would I have a carbon build up problem or something else down the road since I am planning to keep this car for about 8 years?.
I was so going to try lower octane and see if it was worth the savings/kms but the price of gas just dropped to records low. So I am keeping it premium for now..... or maybe I will try 94 (i put 91)
I was so going to try lower octane and see if it was worth the savings/kms but the price of gas just dropped to records low. So I am keeping it premium for now..... or maybe I will try 94 (i put 91)
It's also my understanding that anything above 91 octane is literally a waste because the ECU will not under any circumstances advance the timing past the 91 octane preset. So you're not going to see any additional hp just using 93/94 unless the 91 you're using normally isn't actually 91. But I think the standards for that sort of thing are pretty strict.
This comes from my friend who is a Lotus tech in STL.
11-27-18, 01:28 PM
#191
It's my understanding that, after the ECU relearns the fuel being used, which is pretty quick, it's going to retard the timing and run with the exact same efficiency that it would with higher octane fuel. This is why there are no disclaimers for areas that 91 isn't available. You are just losing some hp because of the difference in timing, but you shouldn't see any other issues.
It's also my understanding that anything above 91 octane is literally a waste because the ECU will not under any circumstances advance the timing past the 91 octane preset. So you're not going to see any additional hp just using 93/94 unless the 91 you're using normally isn't actually 91. But I think the standards for that sort of thing are pretty strict.
This comes from my friend who is a Lotus tech in STL.
It's also my understanding that anything above 91 octane is literally a waste because the ECU will not under any circumstances advance the timing past the 91 octane preset. So you're not going to see any additional hp just using 93/94 unless the 91 you're using normally isn't actually 91. But I think the standards for that sort of thing are pretty strict.
This comes from my friend who is a Lotus tech in STL.
11-27-18, 01:33 PM
#192
ECU self-adjusts all the time, trying to push the timing further, until it detects the sounds of knocking. Then it retards the timing a bit and then tries again. It balances in that state all the time. So, I think it will/might go over 91 equivalent (in terms of what max achievable timing value corresponds to), given that the geometry of the engine would permit that. But the knocking signal from one of knock sensors (microphones, essensially) is what is used as a feedback loop for the ecu to stop advancing timing any further, and not just some predetermined value in the ECU.
11-27-18, 01:40 PM
#193
It might be mechanical, but I'm betting it's the tune, as is the case with most every car I've encountered. I have a tune for 93 on my Lotus, but originally it would not benefit from the use of 93 at all. I also think that if the use of 93/94 would add hp, one of the tuners would have figured that out by now. I'll ask the tech.
lawyers can take from that guy) ....but there is a lot of money they can extract from those manufacturers tho. That is why manufacturers always appear too conservative.
11-27-18, 02:22 PM
#194
well, tuners do recommend the use of e85 fue (in some cars) which means, they see the difference with higher octane fuels. Also, a tuner (and so does the manufacturer) can extract more hp from their engines at the expense of the reliability. Of course, a tuner does not have to pay for the mistake of pushing the tech too far,since he is a dude/dudess with a computer who wont be tried in the court of law with some class action lawsuit (because there is nothing
lawyers can take from that guy) ....but there is a lot of money they can extract from those manufacturers tho. That is why manufacturers always appear too conservative.
The following users liked this post:
sunamer (11-27-18)
11-28-18, 08:54 AM
#195
drives cars
The tech said he couldn't rule out a few more hp with the use of 93/94, but said that it would be super minimal, and even if you were racing the car you wouldn't notice any performance advantage. So, I guess it's at least possible to add a few ponies with higher octane gas, but the realization of a benefit from it would be an entirely different story.
I have tried running 93 for a few tanks in my car and didn't notice anything different. Low speeds, flooring it, and all of the above felt identical. However I also have the 300 which isn't exactly the go-fast model.
I wouldn't mind putting 93 in there, but sadly it costs enough extra that I don't want to when 91 is technically recommended.
