View Poll Results: What kind of gas do you use?
91
546
41.65%
92
68
5.19%
93
612
46.68%
I'll put anything in there CHEAP!
85
6.48%
Voters: 1311. You may not vote on this poll
The mother of all 2IS gas discussions. Premium or Mid-grade (merged threads)
01-24-14, 04:13 PM
#992
I use premium on my IS350 but we ONLY use Regular on my wife's 2014 RX350 (because that what Lexus recommended)
01-27-14, 07:05 PM
#994
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Cost per mile as a decider
I did a study some years ago to determine the cost per mile using low octane and high octane fuels. The cost per mile for that v8 car was so fractionally close using either fuel. The car went further with the higher octane than with the lower. Try it out. See what happens for you.
Oh, did you know that the fuel is not injected when you down shift instead of braking. Be gentle on the tranny when doing this. We pick up 4-6 mpg by doing this with an LS430 and a ES300. Such fun watching the mpg spool up going down a long hill or mountain or an exit ramp.
Oh, did you know that the fuel is not injected when you down shift instead of braking. Be gentle on the tranny when doing this. We pick up 4-6 mpg by doing this with an LS430 and a ES300. Such fun watching the mpg spool up going down a long hill or mountain or an exit ramp.
07-28-15, 08:54 PM
#996
I don't get this, it's simple physics, there are 2 major variables that decide whether or not you should run 87, or higher octane gas. It's all about the static compression ratio and the timing advance. Since it's hard to know what amount of timing advance is occurring and at what times, reading the compression ratio figures is the most important thing, and the 2IS is DEFINITELY in the realm of using 91 or even higher; most mid-level performing cars these days have compression ratios in the 10:1-11:1 range and usually do run better on 89/91. The 2IS has compression ratios very close to 12:1, to be honest, I am surprised they run well on 91 
As far as the timing advance, at which I alluded to earlier, when you are pushing high horsepower numbers per cc, it is fairly well assumed that there is a lot of timing advance and variable valve timing schemes at work to squeeze so much power out of the engine, so while it's no Honda CBR10000RR engine (putting out almost 200hp/L) it is a fairly power dense engine and should be treated to a fuel that will help it perform the way it was intended.
For me, the stress alone of catching my IS350 knocking/pining literally scares me into putting premium into the car every time. I have driven and replaced engines in older Lexus/Acura/Infiniti products and even though they ALL have knock sensors and subroutines for pulling timing they are NOT perfect and over time you will likely cause damage. Speaking of that, I used to see it ALL THE TIME with Acura Legends, #1 cause of engine failure, pinging causing herniation of the fire ring on the headgasket. Perhaps not a lot of you have had to see an engine blown up by detonation (broken ring lands, fractured con rods, damaged pistons, head gasket failures, block cracks). These are just terrible jobs to have to do, if you can even afford them, plus the thought of having to rip out an engine that should have been good for hundreds of thousands of miles b/c you continually put the wrong gas in it is just heartbreaking.
General rule, anything with a compression ratio in the 9:1 range is probably "ok" to run 87, 10:1-11:1 MIGHT be ok with 89, higher than that, 91 or higher, always. You lose MPG by forcing the computer to pull timing on anything lower, so you are not really saving yourself anything in the long run.
Now my most refined and distilled form of hatred applies to dealers of high end performance cars that stock their fleet with 87. I have had quite a few engines pinging on test drives b/c of this and it pisses me off to no end, but I digress.
As far as the timing advance, at which I alluded to earlier, when you are pushing high horsepower numbers per cc, it is fairly well assumed that there is a lot of timing advance and variable valve timing schemes at work to squeeze so much power out of the engine, so while it's no Honda CBR10000RR engine (putting out almost 200hp/L) it is a fairly power dense engine and should be treated to a fuel that will help it perform the way it was intended.
For me, the stress alone of catching my IS350 knocking/pining literally scares me into putting premium into the car every time. I have driven and replaced engines in older Lexus/Acura/Infiniti products and even though they ALL have knock sensors and subroutines for pulling timing they are NOT perfect and over time you will likely cause damage. Speaking of that, I used to see it ALL THE TIME with Acura Legends, #1 cause of engine failure, pinging causing herniation of the fire ring on the headgasket. Perhaps not a lot of you have had to see an engine blown up by detonation (broken ring lands, fractured con rods, damaged pistons, head gasket failures, block cracks). These are just terrible jobs to have to do, if you can even afford them, plus the thought of having to rip out an engine that should have been good for hundreds of thousands of miles b/c you continually put the wrong gas in it is just heartbreaking.
General rule, anything with a compression ratio in the 9:1 range is probably "ok" to run 87, 10:1-11:1 MIGHT be ok with 89, higher than that, 91 or higher, always. You lose MPG by forcing the computer to pull timing on anything lower, so you are not really saving yourself anything in the long run.
Now my most refined and distilled form of hatred applies to dealers of high end performance cars that stock their fleet with 87. I have had quite a few engines pinging on test drives b/c of this and it pisses me off to no end, but I digress.
Last edited by soloist3; 03-31-16 at 09:27 PM.
07-29-15, 07:00 PM
#997
I don't get this, it's simple physics, there are 2 major variables that decide whether or not you should run 87, or higher octane gas. It's all about the static compression ratio and the timing advance. Since it's hard to know what amount of timing advance is occurring and at what times, reading the compression ratio figures is the most important thing, and the 2IS is DEFINITELY in the realm of using 91 or even higher; most mid-level performing cars these days have compression ratios in the 10:1-11:1 range and usually do run better on 89/91. The 2IS has compression ratios very close to 12:1, to be honest, I am surprised they run well on 91
As far as the timing advance, at which I alluded to earlier, when you are pushing high horsepower numbers per cc, it is fairly well assumed that there is a lot of timing advance and variable valve timing schemes at work to squeeze so much power out of the engine, so while it's no Honda CBR10000RR engine (putting out almost 2hp/cc) it is a fairly power dense engine and should be treated to a fuel that will help it perform the way it was intended.
For me, the stress alone of catching my IS350 knocking/pining literally scares me into putting premium into the car every time. I have driven and replaced engines in older Lexus/Acura/Infiniti products and even though they ALL have knock sensors and subroutines for pulling timing they are NOT perfect and over time you will likely cause damage. Speaking of that, I used to see it ALL THE TIME with Acura Legends, #1 cause of engine failure, pinging causing herniation of the fire ring on the headgasket. Perhaps not a lot of you have had to see an engine blown up by detonation (broken ring lands, fractured con rods, damaged pistons, head gasket failures, block cracks). These are just terrible jobs to have to do, if you can even afford them, plus the thought of having to rip out an engine that should have been good for hundreds of thousands of miles b/c you continually put the wrong gas in it is just be heartbreaking.
General rule, anything with a compression ratio in the 9:1 range is probably "ok" to run 87, 10:1-11:1 MIGHT be ok with 89, higher than that, 91 or higher, always. You lose MPG by forcing the computer to pull timing on anything lower, so you are not really saving yourself anything in the long run.
Now my most refined and distilled form of hatred applies to dealers of high end performance cars that stock their fleet with 87. I have had quite a few engines pinging on test drives b/c of this and it pisses me off to no end, but I digress.
As far as the timing advance, at which I alluded to earlier, when you are pushing high horsepower numbers per cc, it is fairly well assumed that there is a lot of timing advance and variable valve timing schemes at work to squeeze so much power out of the engine, so while it's no Honda CBR10000RR engine (putting out almost 2hp/cc) it is a fairly power dense engine and should be treated to a fuel that will help it perform the way it was intended.
For me, the stress alone of catching my IS350 knocking/pining literally scares me into putting premium into the car every time. I have driven and replaced engines in older Lexus/Acura/Infiniti products and even though they ALL have knock sensors and subroutines for pulling timing they are NOT perfect and over time you will likely cause damage. Speaking of that, I used to see it ALL THE TIME with Acura Legends, #1 cause of engine failure, pinging causing herniation of the fire ring on the headgasket. Perhaps not a lot of you have had to see an engine blown up by detonation (broken ring lands, fractured con rods, damaged pistons, head gasket failures, block cracks). These are just terrible jobs to have to do, if you can even afford them, plus the thought of having to rip out an engine that should have been good for hundreds of thousands of miles b/c you continually put the wrong gas in it is just be heartbreaking.
General rule, anything with a compression ratio in the 9:1 range is probably "ok" to run 87, 10:1-11:1 MIGHT be ok with 89, higher than that, 91 or higher, always. You lose MPG by forcing the computer to pull timing on anything lower, so you are not really saving yourself anything in the long run.
Now my most refined and distilled form of hatred applies to dealers of high end performance cars that stock their fleet with 87. I have had quite a few engines pinging on test drives b/c of this and it pisses me off to no end, but I digress.
07-29-15, 08:58 PM
#998
I've been running ethanol free 91 since I got the car, that being said I have a family friend who owns a 2006 IS250 with 150k miles whose run nothing but regular since he got it brand new and the only major issue he's had was the carbon buildup problem, and says he averages 22 MPG.
01-19-16, 01:25 PM
#999
Regular vs Premium - I've read many posts
Before I start, if you're only value-add to this thread is
"If you can afford a Lexus, why won't you pay the extra money for premium??"
DO NOT POST. I don't want to hear your feedback, it is useless and adds absolutely no value to the conversation......
This is a serious question and I have done a fair amount of research on this topic. I am looking for a technical response from someone who is very knowledgeable of the 4GR-FSE and understands its limitations, strengths, weaknesses etc.
The reason why I am asking is because I don't feel like paying an excess of $1 per gallon of gasoline for premium fuels when a barrel of oil has hit rock bottom prices, it's a matter of principle and the price difference between premium and regular is ridiculous......
Here are two articles I came across that discuss the A/F mixture and the dual GDI/Port injection system.
http://www.cnet.com/roadshow/news/wh...s-of-car-tech/
http://wardsauto.com/news-analysis/t...ofold-strategy
With those technical aspects considered, and the fact that the engine contains anti-knock sensors as well...is it feasible to run 87 octane for a 2011 IS250 AWD with the 4GR-FSE engine? Can the stock engine mapping of this car determine knock prior to detonation and correct the A/F ratio on a dynamic and real time basis? What is the risk of pre-detonation if 87 is used (percentage of time would help here)?
"If you can afford a Lexus, why won't you pay the extra money for premium??"
DO NOT POST. I don't want to hear your feedback, it is useless and adds absolutely no value to the conversation......
This is a serious question and I have done a fair amount of research on this topic. I am looking for a technical response from someone who is very knowledgeable of the 4GR-FSE and understands its limitations, strengths, weaknesses etc.
The reason why I am asking is because I don't feel like paying an excess of $1 per gallon of gasoline for premium fuels when a barrel of oil has hit rock bottom prices, it's a matter of principle and the price difference between premium and regular is ridiculous......
Here are two articles I came across that discuss the A/F mixture and the dual GDI/Port injection system.
http://www.cnet.com/roadshow/news/wh...s-of-car-tech/
http://wardsauto.com/news-analysis/t...ofold-strategy
With those technical aspects considered, and the fact that the engine contains anti-knock sensors as well...is it feasible to run 87 octane for a 2011 IS250 AWD with the 4GR-FSE engine? Can the stock engine mapping of this car determine knock prior to detonation and correct the A/F ratio on a dynamic and real time basis? What is the risk of pre-detonation if 87 is used (percentage of time would help here)?
01-19-16, 01:38 PM
#1002
I have searched, there is no substance in any of those articles discussing the technical merits of running regular vs premium on the 4GR-FSE platform. It is specific to that engine because of the anti-knock sensing and the dual fuel injection system..the engine platforms prior the the GR-FSE did not have that kind of technology.
01-19-16, 01:42 PM
#1003
I have searched, there is no substance in any of those articles discussing the technical merits of running regular vs premium on the 4GR-FSE platform. It is specific to that engine because of the anti-knock sensing and the dual fuel injection system..the engine platforms prior the the GR-FSE did not have that kind of technology.
01-19-16, 02:07 PM
#1004
01-19-16, 02:11 PM
#1005
I have searched, there is no substance in any of those articles discussing the technical merits of running regular vs premium on the 4GR-FSE platform. It is specific to that engine because of the anti-knock sensing and the dual fuel injection system..the engine platforms prior the the GR-FSE did not have that kind of technology.
Jeff