I have heard conflicting on this, some say more octane makes more power. Others including a website from the goverment says no benifit from higher octane than your owners manual says. Some say it burns cooler while others say hotter, can anyone clear this up? Thanx.
Higher octane make a difference?
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i know in my motorcycle higher octane created increased carbon. I was actually told by the local shops and Kawasaki NOT to use high octane. I think it was the shop that told me higher octane was for high compression engine.? which my compression ratio is 9.5:1 After i used higher octane for a few thousand miles i heard pinging, so i used seafoam and it all cleared up then after being told to use 87 octane i heard had ping again
Depends!!! Somes cars can handle a wide spectrum of octane rateing and can radicly adjust the valve, ignition and fuel timeing to the fuel being used. My Toyota can run on regular just fine but the owners manual specificly mentions that the engine will make more power with higher octane fuels as the computer will compensate for the octane used. My buick on the other really does not car if it is 87 octne or 110!
I have a 99 Pontiac GTP which if I use 92,93,94 octane at each fill up I CAN notice a difference between each grade and brand, but my compression is 10.5 to 1 so I have to use prem. gas. It seems to like the Sunoco 94 the best. So I would have to say it all depends on the type of car and engine,mods,etc. Just my 2 cents
Criminy! 10.5?!?? How'd you manage that since the highest compression pistons i've seen are Intense's 9.5?
ferb!
So from what I have gathered here unless you have a reason to use high octane it will not make a difference. John and big I can see where it would make a difference if the computer will adjust to compensate for it and make more power. I seen something where generac generators recommened not using higher octane than the manual suggested because of a carbon problem.
Compression ratios are not what they used to be....My Toyota Sienna's engine (year 2002) has a ratio of 10.5:1--this is a minivan! With knock sensors, variable valve timing, etc, the octane equation has a bunch of variables. But in my engine, I do notice a difference in gas mileage between higher and lower octanes. Maybe the bottom line is to follow the octane recommendations....
My old Volvo turbo WITHOUT a knock sensor and a few mods
needs premium and really loves an octane bump (via additives) to take full advantage of the boost.
So yes, "it depends".......
So yes, "it depends".......
So then in a small engine, a car without the need for it and the owners manual says 87 octane am I right that premium would do nothing but waste money?
This topic has been pounded to death in a bunch of motorcycle forums I belong to. Just use what the owners manual says. If you need to use high octane fuel to cure a ping or knock, then there's other issues to be dealt with. I heard on a local radio auto-talk program that less than 10% of vehicles in the US require high octane fuel. Oh, some of the motorcycles today have over 11:1 compression and run fine on regular gas. Just my $.02
A couple of years ago, "Car & Driver" magazine did some dynamometer testing with two or three cars and different octane gasoline. The result was that if the car calls for hi-test and you use low octane, the subsequent power loss and fuel consumption increase matches the savings in the lower cost fuel...a wash. If the car calls for 87 and you use 92, no power gain was apparent--the difference in power was less than the degree of accuracy of the instrumentation on the dyno.
Ken
Ken
I use inexpensive WaWa 87oct in my Volvo & VW. VW calls for a minimum of 89oct, but the car seems to run just fine on 87. I had a Pontiac Bonneville SSEi (supercharged 3.8 V6) that had to have 92oct or better or it ran like absolute ca-ca.
On my 87 Accord, I tried a tank of 93 octane as an experiment...it may have been my imagination, but I felt a slight loss of power with that gas. However, I got slightly higher mileage, but that could easily be a fluke...I never take the MPG of a single tank seriously, I have to look at the one before and after for it to mean anything, and I haven't finished the "after" yet....
On Nissan Sentra GA16DE motor, JDM, the mileage decreases and power appears to be decreased with high octane. Low octane suits this motor fine, as it is set up.
That is 100% correct countryboy.
My 240sx calls for premium and the ecu is programmed to expect this fuel
It will of course, run on 87 octane, but with a noticeable reduction of power primarily because the ignition timing must be retarded to prevent pinging/detonation.
In a different car, say a base model Honda Civic, the engine is not designed, nor is the ecu programmed, to take advantage of high octane fuel and it won't attempt to compensate for the extra octane. So you are wasting money by using it.
Also, the additives in fuel required to raise octane levels have been known to cause more combustion chamber deposits, (as someone mentioned above)
AND, pound for pound, high octane fuel has less energy than low octane fuel. (measured in BTU's per pound) It's a minor difference but the fact is, in a car not designed for high octane fuel, using high octane can actually make less power.
(although it is to small of a difference to be usefully measured)
[ November 14, 2003, 12:52 PM: Message edited by: Aaron ]
My 240sx calls for premium and the ecu is programmed to expect this fuel
It will of course, run on 87 octane, but with a noticeable reduction of power primarily because the ignition timing must be retarded to prevent pinging/detonation.
In a different car, say a base model Honda Civic, the engine is not designed, nor is the ecu programmed, to take advantage of high octane fuel and it won't attempt to compensate for the extra octane. So you are wasting money by using it.
Also, the additives in fuel required to raise octane levels have been known to cause more combustion chamber deposits, (as someone mentioned above)
AND, pound for pound, high octane fuel has less energy than low octane fuel. (measured in BTU's per pound) It's a minor difference but the fact is, in a car not designed for high octane fuel, using high octane can actually make less power.
[ November 14, 2003, 12:52 PM: Message edited by: Aaron ]
Perhaps this is the place to raise a question with premium gas. Remember the Amoco Ultimate TV commercial a few years back showing how clear this 93 octane was and showing a beaker of dark gunk that would be present in regular gas falling over? All the 93 octane gas I have used has been clear, without the amber tint that lower octane grades have--not just Amoco Ultimate, but all of them rated 93.
My old Festiva did not like regular gas in any form, even when it was new (for a period of several years here in the 1980s, it seemed that most 87 octane gas was crap, and even my old Toyota Corolla got to where it didn't like regular). I got 350,000 miles on that car myself, and my brother put on another 50,000. A very experienced, older mechanic who works on everything--especially the older carbureted vehicles that today's techs won't touch--told me that running cleaner premium likely helped with engine longevity. He was amazed that the car had managed so many miles. I remember that unlike my old Toyota, I rarely had to use carb cleaner to clean visible deposits on the Festiva.
I have used nothing but premium, preferably Sunoco or Phillips 66 when I can find it, in my '97 Escort wagon, which I bought new. It now has 232,000 miles on it and the engine has never been apart--original injectors, etc.--though I do use Red Line SI fuel additive regularly as well. Using Red Line oil has obviously helped, but I wonder if premium fuel hasn't helped also.
So after all of this, here's my question. In an engine that has no detrimental effects from running premium, wouldn't the engine benefit long-term from premium? I'm not talking about extra power, which wouldn't apply to most engines anyway. I'm talking about premium being a cleaner fuel than 87 or 89 octane. Not having the gunk that gives the amber tint to regular gas must help an engine long-term. But what do the rest of you say?
My old Festiva did not like regular gas in any form, even when it was new (for a period of several years here in the 1980s, it seemed that most 87 octane gas was crap, and even my old Toyota Corolla got to where it didn't like regular). I got 350,000 miles on that car myself, and my brother put on another 50,000. A very experienced, older mechanic who works on everything--especially the older carbureted vehicles that today's techs won't touch--told me that running cleaner premium likely helped with engine longevity. He was amazed that the car had managed so many miles. I remember that unlike my old Toyota, I rarely had to use carb cleaner to clean visible deposits on the Festiva.
I have used nothing but premium, preferably Sunoco or Phillips 66 when I can find it, in my '97 Escort wagon, which I bought new. It now has 232,000 miles on it and the engine has never been apart--original injectors, etc.--though I do use Red Line SI fuel additive regularly as well. Using Red Line oil has obviously helped, but I wonder if premium fuel hasn't helped also.
So after all of this, here's my question. In an engine that has no detrimental effects from running premium, wouldn't the engine benefit long-term from premium? I'm not talking about extra power, which wouldn't apply to most engines anyway. I'm talking about premium being a cleaner fuel than 87 or 89 octane. Not having the gunk that gives the amber tint to regular gas must help an engine long-term. But what do the rest of you say?
In the past, some gasoline makers put a stronger detergent package into their premium fuel. I believe that is no longer the case, especially in light of the fact that the EPA requires all gasoline to have a minimum level of detergents to help engines maintain a low emission level for many years.
I see no difference in the color of gasolines here. What you saw was probably just a marketing gimmick. The difference between high octane gasoline and low octane is the antiknock resistance.
Ken
I see no difference in the color of gasolines here. What you saw was probably just a marketing gimmick. The difference between high octane gasoline and low octane is the antiknock resistance.
Ken
I think it was BP that I called a few months ago and asked them if there was any difference in the additives between regular and premium, the answer was no.
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