Octane
Thread Starter
Driver
Joined: Dec 2010
Posts: 129
Likes: 1
From: CA
Octane
Hi, family!
There is another question for you.
Of course when i put 91 grade gas i get more performance than 87 grade. Also i know that if i can use 91 it is mean that my lexus rx300 (2000) engine built for this grade.
But my question is: Higher octane grade mean more power,pressure,temperature in engine, so logically higher grade wear and burn engine more and faster?
There is another question for you.
Of course when i put 91 grade gas i get more performance than 87 grade. Also i know that if i can use 91 it is mean that my lexus rx300 (2000) engine built for this grade.
But my question is: Higher octane grade mean more power,pressure,temperature in engine, so logically higher grade wear and burn engine more and faster?
Lexus Test Driver
Joined: Sep 2007
Posts: 1,239
Likes: 15
From: Ontario
Octane rating is resistance to knocking.
Engines with higher compression ratio or force induction usually require fuel with higher octane rating.
But it does not mean the engine will wear faster provided the owner following proper procedures and maintenance schedule.
Engines with higher compression ratio or force induction usually require fuel with higher octane rating.
But it does not mean the engine will wear faster provided the owner following proper procedures and maintenance schedule.
Like BDSL said, octane in is the resistance to knocking or detonation. In a way you could say octane is a tool used to compensate for more compression or boost. Higher the octane the more resistance to ignite; therefore allowing more head room to make more power, not by running higher octane but more compression or boost.
In general, you are not going to make more power by using higher than the recommended octane in a motor that requires regular.
In general, you are not going to make more power by using higher than the recommended octane in a motor that requires regular.
If a car requires 87 octane, running 91 octane will not increase horsepower and performance.
If a car requires 91 octane, running 87 octane will adversely effect performance. The engine will knock and ping.
Using 91 in a car that requires 87 will not increase engine wear at all. All you are doing is wasting money. Engines are designed to run on a specific octane, running a higher octane is pointless.
If a car requires 91 octane, running 87 octane will adversely effect performance. The engine will knock and ping.
Using 91 in a car that requires 87 will not increase engine wear at all. All you are doing is wasting money. Engines are designed to run on a specific octane, running a higher octane is pointless.
and honestly, making good clean power is not harmful to the engine in any way...
your engine (most any engine, really) can easily make much more hp than they came with and still last a very very long time...
it is actually more harmful to run a lesser octane rating in an engine that was designed for a higher octane rating, as it can cause it to knock... knock is what kills engines (aside from lack of oil, etc). the good thing is that the ECM in a car is smart enough to hear the knock from the knock sensor, so that it retards timing in an attempt to save the engine from the poor quality fuel you used...
less timing = less power
your engine (most any engine, really) can easily make much more hp than they came with and still last a very very long time...
it is actually more harmful to run a lesser octane rating in an engine that was designed for a higher octane rating, as it can cause it to knock... knock is what kills engines (aside from lack of oil, etc). the good thing is that the ECM in a car is smart enough to hear the knock from the knock sensor, so that it retards timing in an attempt to save the engine from the poor quality fuel you used...
less timing = less power
CL Community Team
Joined: Apr 2004
Posts: 17,338
Likes: 213
From: Miami, Florida
Having run my RX300 for 9 years now, I even used to throw in octane boosters and the like at my track back in Mexico (to demonstrate to others) and I guarantee that you would not see any noticeable improvement in the 1/4 mile times (i.e., even .1 seconds which would be statistically significant). There's a lot of postings about this on the Net.
At high altitude back in Mexico City, I would have used 87 octane but for the fact that it had a much higher sulfur quantity at the time (unlike U.S. gasolines) and I had other issues with the quality.
In addition, I haven't had the sometimes complex electronic mechanical issues that other people with RX300s talk of on occasion in our RX forum despite running premium for 99% of the time I have had my RX300 (even doing also the insane modifications I have).
At high altitude back in Mexico City, I would have used 87 octane but for the fact that it had a much higher sulfur quantity at the time (unlike U.S. gasolines) and I had other issues with the quality.
In addition, I haven't had the sometimes complex electronic mechanical issues that other people with RX300s talk of on occasion in our RX forum despite running premium for 99% of the time I have had my RX300 (even doing also the insane modifications I have).
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CL Community Team
Joined: Apr 2004
Posts: 17,338
Likes: 213
From: Miami, Florida
It was one of the few ways I had to demonstrate to people down there about differences in octane. I would find a lot of people at my track using very expensive racing gas or octane boosters and not having the vehicle (and necessary modifications to get any type of benefit).
Had the unleaded been of better quality and lower sulfur rating, I would have used the 87 octane at altitude (like 8000 feet there). There's nothing quite like U.S. gasoline.
Had the unleaded been of better quality and lower sulfur rating, I would have used the 87 octane at altitude (like 8000 feet there). There's nothing quite like U.S. gasoline.
Lexus Champion
Joined: May 2002
Posts: 2,781
Likes: 6
From: Georgia
I recommend whatever gasoline the manufacturer required for your car. If your car required 91 octane then use the 91 octane. You only save $1-$2 per tank when using lower octane.
A good clean burning gasoline is good for your engine and prolong the life of the A/F and O2 sensors.
A good clean burning gasoline is good for your engine and prolong the life of the A/F and O2 sensors.
It was one of the few ways I had to demonstrate to people down there about differences in octane. I would find a lot of people at my track using very expensive racing gas or octane boosters and not having the vehicle (and necessary modifications to get any type of benefit).
Had the unleaded been of better quality and lower sulfur rating, I would have used the 87 octane at altitude (like 8000 feet there). There's nothing quite like U.S. gasoline.
Had the unleaded been of better quality and lower sulfur rating, I would have used the 87 octane at altitude (like 8000 feet there). There's nothing quite like U.S. gasoline.
which essentially means high compression ratio built motor, or turbocharged well above 15 psi, closer to 30 even, or even running quite a bit of ignition advance!
My car loved C16 with 28 psi of boost and no retarded timing! Thats 117 octane MON, and it doesn't even have an RON number (which is usually 7-10 points higher than MON)!
If this stuff was rated the same way fuel you buy from the pump was rated, it would most likely be 122 octane! yeeeeehaw!!!!
Lexus Champion
Joined: Feb 2001
Posts: 2,851
Likes: 4
From: Arkansas
Most of the time, you could run 87 octane and not notice a difference in either performance or gas mileage. Knock is not all that likely to occur in part throttle use. But high load, high temp situations make detonation more likely. Even in your 2000 RX, the ECU reacts so quickly to the knock sensors that timing will be retarded before you ever hear knock. At which point, your WOT isn't delivering all the performance that you'd expect.
So, you really won't harm your engine with the less expensive juice but there will be circumstances when it's not giving you everything you expect! Unfortunately, those also will (at least some of the time) occur when you most need everybody at work in the engine room.
So, you really won't harm your engine with the less expensive juice but there will be circumstances when it's not giving you everything you expect! Unfortunately, those also will (at least some of the time) occur when you most need everybody at work in the engine room.
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