Sticky:Gas Mileage / Octane to use threads

blkonblkcpe · 10-08-07, 11:25 AM

blkonblkcpe · 10-09-07, 07:27 AM

Hey, you guys must love all those mileage and octane threads all the time, WTF?

Speak up, lets get this stickied!

4cruizn · 10-09-07, 11:57 AM

We see these repeats all too often.

blkonblkcpe · 10-10-07, 08:10 AM

What kind of fuel do you use in your legend, is premium really necessary?

93LegendSedan · 10-10-07, 12:01 PM

Hey guys, new guy here, I was wondering what type of fuel is best for my Legend?

Should I use premium only?

The Crowing · 10-10-07, 12:16 PM

Octane rating won't harm or help your car either way. You will be fine to use either type in. (This is where someone asks why)

Why? Becuase all octane does is tweak the point of ignition for the air/fuel mixture.

Familiar with the R+M/2 method? In short, this is the method that gives the octane ratings based on a scale of 0 to 100.
On one end, 0, there is heptane, the other end, 100, being octane. Heptane will detonate under the slightest pressure. Octane you can compress to the point of hydrolocking and it will not detonate. The way the rating is determined is based on two tests: the MON (Motor Octane Number) and RON (Research Octane Method) your M and R, respectively. Test consists of a one cylinder engine that the lab will run at 900 RPM with an intake air temperature of 300 degrees F. Timing advance will be from 19-26 degrees. The lab will vary the compression of the engine as it's running looking for the engine to start knocking. Say they get the knock meter to read 20. The next step is to shut down the engine, then run it again with a known standard rating of gas, ISO-Octane at a 100 rating. The lab knows at what point the ISO will knock at, so they compare this to the 20 reading they got from the gas they are testing to get their first number, usually around 85 (The M in the equation). The perform the same setup again (using the Research Method), this time the engine running at 600 RPM with an intake air temp of 100 degrees F and an advance of 13 degrees. This produces a second number, usually around 93 (the R in the equation). R+M/2 = OCT ---> 93+85/2=89, so an 89 octane rated fuel.

So what's the point? The different octane ratings tell you how much the gas can be squeezed before it ignites, so a lower number is closer to heptane and will ignite sooner than a higher number, closer to octane, which has to be squeezed harder to get to ignite. Your engine's knock sensors will read the way the fuel is being ignited and adjust the ignition timing to suit. In cars that do not have knock sensors, you'll hear the knocking or pinging, as the engine won't compensate for it.

MYTH: Higher octane give me better gas milage
FACT: Using lower octane rated fuel in a car that is designed for higher octane AND HAS KNOCK SENSORS will seem like it's getting worse gas milage because the lower octane fuel will make the car retard it's timing to compensate. This translates to less milage, as you are going to push the pedal a little farther to get the same effect.

This brings us to

MYTH: I get more power with high octane
FACT: Same as above, really. When you use the proper octane rated fuel for your car, your car will be running at optimum timing and delivery, etc, seeming like a boost in power you're just not pushing the pedal as far to get the same performance as a lower octane. It's not the gas thats causing the lag, it's the computer, and you.

This said, it doesn't matter one bit which octane you use, as far as harming the car goes. Make sense?

blkonblkcpe · 10-12-07, 08:37 AM

One last try to get this thread stickied!

JZ_ · 10-12-07, 12:04 PM

You got my vote John.... You stopped one thread already. Its true. Any other questions, Just look below your damn gas needle... What does it say???? Notice it says, "Premium Unleaded ONLY!!!!!"

Feuerstoss · 10-12-07, 02:05 PM

+1 for sticky. This'll answer a lot of questions from the new guys, I think.

The Crowing · 10-12-07, 02:29 PM

If anyone has any other questions on fuel or aditives, just ask. I can amswer em.

To that, I'll add info on octane boosters, fuel cleaners, etc.

Monkey Pee. Basically all this stuff is. 90% of octane boosters are pretty much alcohol. Alcohol will contain more oxygen than fuel, yes, but it's very harmful to fuel system components. It has a battery acid on clothing effect on the components. Many states (Minnesota being one of them) already add around 10% alcohol to all their fuels, so going overboard and adding more can really mess stuff up. Fuel cleaners work the same, just in a slightly smaller dose. They are mostly alcohol with some detergents to basically eat away contaminents and the such. Me, personally, the only thing I trust is Seafoam, which contains no alcohol. Unsure about a product? Read the ingrediants. If there isnt any, it's most likely a monkey pee product (alcohol based).

How about fuel stabilizers? While not monkey pee, they really aren't necessary anymore, with today's cars. These products "stabilize" the fuel (now ask yourself, what is "unstable" fuel and what would cause that?) and draw out moisture. Most fuel systems are pressurized and your EVAP systems will purge the tank, lines, etc of air and moisture. Adding Iso-Heet or what have you can mess the car's fuel schedule and can hinder performance. On small engines or really old cars, it's a good thing to use as they do not posses the technology that modern cars have.

JZ_ · 10-14-07, 08:37 PM

We also need to sticky the damn radio code... I see those just as much

kotetu · 06-16-08, 09:17 PM

I adjusted my suspension and tire pressure before my last fill up and changed my brake pads. This tank drove 423.4 miles on 15.135 gallons of 89 octane; just about 28mpg. 12% improvement over my prior average of 25mpg.

DevanTheDude · 06-16-08, 09:39 PM

Quote:

Originally Posted by JZ_

What does it say???? Notice it says, "Premium Unleaded ONLY!!!!!"

It's funny when people believe everything they read.

*stevieray* · 06-17-08, 01:48 PM

Ask and ye shall receive. Stuck.

RLbuddy96 · 06-19-08, 07:11 PM

Quote:

Originally Posted by JZ_

You got my vote John.... You stopped one thread already. Its true. Any other questions, Just look below your damn gas needle... What does it say???? Notice it says, "Premium Unleaded ONLY!!!!!"

lol

10-08-07, 11:25 AM	#1 (permalink)
blkonblkcpe RALPHS HANDS ARE CLEAN! Join Date: Jan 2006 Location: Minnesota Posts: 10,000 Car 1: 91 LS Black window trim EDM/Hids Remus 2 1/2 cat back Headers stage 3 ecu Car 2: ,Red tails, Type 2 Car 3: 6 speed, EDM spoiler iTrader: (35)	Sticky:Gas Mileage / Octane to use threads Come on, every week, some noob asks one of these questions, PLEEEEEEEEEEZE make this a sticky! FIRST READ, THEN IF YOU DIDN'T GET THE ANSWER, SEARCH Mileage! GAS milege? - The Acura Legend & Acura RL Forum what octane do you put in your legend? - Page 3 - The Acura Legend & Acura RL Forum Gas Mileage question...again - The Acura Legend & Acura RL Forum Gas mileage - The Acura Legend & Acura RL Forum About MPG - The Acura Legend & Acura RL Forum Everyone Post Your Avg. Gas Mileage #'s - The Acura Legend & Acura RL Forum OCTANE: Gas Mileage - The Acura Legend & Acura RL Forum what octane do you put in your legend? - Page 3 - The Acura Legend & Acura RL Forum super unleaded fuel - The Acura Legend & Acura RL Forum unleaded or premium - The Acura Legend & Acura RL Forum __________________ It's obvious they're both BAD for America! DEMOCRACY IS TWO WOLVES AND A LAMB VOTING ON WHAT TO HAVE FOR LUNCH. LIBERTY IS A WELL ARMED LAMB CONTESTING THE VOTE. Last edited by stevieray : 06-17-08 at 02:01 PM.

10-09-07, 07:27 AM	#2 (permalink)
blkonblkcpe RALPHS HANDS ARE CLEAN! Join Date: Jan 2006 Location: Minnesota Posts: 10,000 Car 1: 91 LS Black window trim EDM/Hids Remus 2 1/2 cat back Headers stage 3 ecu Car 2: ,Red tails, Type 2 Car 3: 6 speed, EDM spoiler iTrader: (35)	Hey, you guys must love all those mileage and octane threads all the time, WTF? Speak up, lets get this stickied! __________________ It's obvious they're both BAD for America! DEMOCRACY IS TWO WOLVES AND A LAMB VOTING ON WHAT TO HAVE FOR LUNCH. LIBERTY IS A WELL ARMED LAMB CONTESTING THE VOTE.

10-09-07, 11:57 AM	#3 (permalink)
4cruizn Road Trip King Join Date: Mar 2003 Location: Phoenix, AZ Posts: 4,489 Car 1: 1994 LS coupe 6-spd Car 2: 1994 GS sedan 6-spd iTrader: (15)	We see these repeats all too often. __________________ Facebook Me

10-10-07, 08:10 AM	#4 (permalink)
blkonblkcpe RALPHS HANDS ARE CLEAN! Join Date: Jan 2006 Location: Minnesota Posts: 10,000 Car 1: 91 LS Black window trim EDM/Hids Remus 2 1/2 cat back Headers stage 3 ecu Car 2: ,Red tails, Type 2 Car 3: 6 speed, EDM spoiler iTrader: (35)	What kind of fuel do you use in your legend, is premium really necessary? __________________ It's obvious they're both BAD for America! DEMOCRACY IS TWO WOLVES AND A LAMB VOTING ON WHAT TO HAVE FOR LUNCH. LIBERTY IS A WELL ARMED LAMB CONTESTING THE VOTE.

10-10-07, 12:01 PM	#5 (permalink)
93LegendSedan Goodbye Yankee Stadium Join Date: May 2005 Location: Over the Hills and Far Away Posts: 6,497 Car 1: 1993 Legend Sedan Car 2: 2002 LS430 Car 3: 2008 Highlander iTrader: (20)	Hey guys, new guy here, I was wondering what type of fuel is best for my Legend? Should I use premium only? __________________

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10-10-07, 12:16 PM	#6 (permalink)
The Crowing Banned Join Date: Jun 2006 Location: :p Posts: 2,268 Car 1: 1991 Legend Coupe LS Car 2: 1968 Jaguar XK-E Car 3: 1990 L Sedan iTrader: (12)	Octane rating won't harm or help your car either way. You will be fine to use either type in. (This is where someone asks why) Why? Becuase all octane does is tweak the point of ignition for the air/fuel mixture. Familiar with the R+M/2 method? In short, this is the method that gives the octane ratings based on a scale of 0 to 100. On one end, 0, there is heptane, the other end, 100, being octane. Heptane will detonate under the slightest pressure. Octane you can compress to the point of hydrolocking and it will not detonate. The way the rating is determined is based on two tests: the MON (Motor Octane Number) and RON (Research Octane Method) your M and R, respectively. Test consists of a one cylinder engine that the lab will run at 900 RPM with an intake air temperature of 300 degrees F. Timing advance will be from 19-26 degrees. The lab will vary the compression of the engine as it's running looking for the engine to start knocking. Say they get the knock meter to read 20. The next step is to shut down the engine, then run it again with a known standard rating of gas, ISO-Octane at a 100 rating. The lab knows at what point the ISO will knock at, so they compare this to the 20 reading they got from the gas they are testing to get their first number, usually around 85 (The M in the equation). The perform the same setup again (using the Research Method), this time the engine running at 600 RPM with an intake air temp of 100 degrees F and an advance of 13 degrees. This produces a second number, usually around 93 (the R in the equation). R+M/2 = OCT ---> 93+85/2=89, so an 89 octane rated fuel. So what's the point? The different octane ratings tell you how much the gas can be squeezed before it ignites, so a lower number is closer to heptane and will ignite sooner than a higher number, closer to octane, which has to be squeezed harder to get to ignite. Your engine's knock sensors will read the way the fuel is being ignited and adjust the ignition timing to suit. In cars that do not have knock sensors, you'll hear the knocking or pinging, as the engine won't compensate for it. MYTH: Higher octane give me better gas milage FACT: Using lower octane rated fuel in a car that is designed for higher octane AND HAS KNOCK SENSORS will seem like it's getting worse gas milage because the lower octane fuel will make the car retard it's timing to compensate. This translates to less milage, as you are going to push the pedal a little farther to get the same effect. This brings us to MYTH: I get more power with high octane FACT: Same as above, really. When you use the proper octane rated fuel for your car, your car will be running at optimum timing and delivery, etc, seeming like a boost in power you're just not pushing the pedal as far to get the same performance as a lower octane. It's not the gas thats causing the lag, it's the computer, and you. This said, it doesn't matter one bit which octane you use, as far as harming the car goes. Make sense? Last edited by The Crowing : 10-10-07 at 12:41 PM.

10-12-07, 08:37 AM	#7 (permalink)
blkonblkcpe RALPHS HANDS ARE CLEAN! Join Date: Jan 2006 Location: Minnesota Posts: 10,000 Car 1: 91 LS Black window trim EDM/Hids Remus 2 1/2 cat back Headers stage 3 ecu Car 2: ,Red tails, Type 2 Car 3: 6 speed, EDM spoiler iTrader: (35)	One last try to get this thread stickied! __________________ It's obvious they're both BAD for America! DEMOCRACY IS TWO WOLVES AND A LAMB VOTING ON WHAT TO HAVE FOR LUNCH. LIBERTY IS A WELL ARMED LAMB CONTESTING THE VOTE.

10-12-07, 12:04 PM	#8 (permalink)
JZ_ B anned (SIKE!!!) Join Date: Jan 2007 Location: SoCal Posts: 2,139 Car 1: 03 G35 Coupe Car 2: 98 Accord EX Car 3: 95 Legend SE iTrader: (5)	You got my vote John.... You stopped one thread already. Its true. Any other questions, Just look below your damn gas needle... What does it say???? Notice it says, "Premium Unleaded ONLY!!!!!" __________________ Someone stole maracura91's new wheels one day after he bought them. (10/09/2008) This link will search for "Nitto" + "C2" + "Racing Hart" on all of craigslist for the last 24 hours. Click it to help him find his wheels!

10-12-07, 02:05 PM	#9 (permalink)
Feuerstoss Autobahn-ed. Join Date: Aug 2006 Location: Co. Springs, CO Posts: 599 Car 1: 1991 L Coupe 5MT iTrader: (2)	+1 for sticky. This'll answer a lot of questions from the new guys, I think. __________________ 1991 L Coupe 5-speed: 109K and still ticking. Mods: '93-'95 Type I gauges, Alpine Type S 6.5" speakers all-around, '97 TL CD/tape HU, Manual woodgrain console. Future mods:6-disc changer, CAI.

10-12-07, 02:29 PM	#10 (permalink)
The Crowing Banned Join Date: Jun 2006 Location: :p Posts: 2,268 Car 1: 1991 Legend Coupe LS Car 2: 1968 Jaguar XK-E Car 3: 1990 L Sedan iTrader: (12)	If anyone has any other questions on fuel or aditives, just ask. I can amswer em. To that, I'll add info on octane boosters, fuel cleaners, etc. Monkey Pee. Basically all this stuff is. 90% of octane boosters are pretty much alcohol. Alcohol will contain more oxygen than fuel, yes, but it's very harmful to fuel system components. It has a battery acid on clothing effect on the components. Many states (Minnesota being one of them) already add around 10% alcohol to all their fuels, so going overboard and adding more can really mess stuff up. Fuel cleaners work the same, just in a slightly smaller dose. They are mostly alcohol with some detergents to basically eat away contaminents and the such. Me, personally, the only thing I trust is Seafoam, which contains no alcohol. Unsure about a product? Read the ingrediants. If there isnt any, it's most likely a monkey pee product (alcohol based). How about fuel stabilizers? While not monkey pee, they really aren't necessary anymore, with today's cars. These products "stabilize" the fuel (now ask yourself, what is "unstable" fuel and what would cause that?) and draw out moisture. Most fuel systems are pressurized and your EVAP systems will purge the tank, lines, etc of air and moisture. Adding Iso-Heet or what have you can mess the car's fuel schedule and can hinder performance. On small engines or really old cars, it's a good thing to use as they do not posses the technology that modern cars have.

10-14-07, 08:37 PM	#11 (permalink)
JZ_ B anned (SIKE!!!) Join Date: Jan 2007 Location: SoCal Posts: 2,139 Car 1: 03 G35 Coupe Car 2: 98 Accord EX Car 3: 95 Legend SE iTrader: (5)	We also need to sticky the damn radio code... I see those just as much __________________ Someone stole maracura91's new wheels one day after he bought them. (10/09/2008) This link will search for "Nitto" + "C2" + "Racing Hart" on all of craigslist for the last 24 hours. Click it to help him find his wheels!

06-16-08, 09:17 PM	#12 (permalink)
kotetu 33mpg 6spd Coupe Join Date: Nov 2005 Location: Los Angeles Posts: 3,544 Car 1: 95 LS Coupe 6spd Car 2: 94 L Cpe 6spd - sold Car 3: 98 Prelude - sold iTrader: (13)	I adjusted my suspension and tire pressure before my last fill up and changed my brake pads. This tank drove 423.4 miles on 15.135 gallons of 89 octane; just about 28mpg. 12% improvement over my prior average of 25mpg. __________________ Someone stole maracura91's new wheels one day after he bought them. (10/09/2008) This link will search for "Nitto" + "C2" + "Racing Hart" on all of craigslist for the last 24 hours. Click it to help him find his wheels! maracura91's thread Inflation is your friend! I mean really, who doesn't want to own a $100,000 car? Last edited by kotetu : 06-17-08 at 02:25 PM.

06-17-08, 01:48 PM	#14 (permalink)
stevieray Swollen Member Join Date: Jan 2002 Location: Franklin, TN Posts: 7,545 Car 1: '95 LS Coupe Car 2: '91 LS Coupe Car 3: '89 Prelude Si iTrader: (13)	Ask and ye shall receive. Stuck. __________________ *"King of Kleen"* "Know this. Being able to purchase a Legend and being able to afford a Legend are two separate things. Realize nothing post-purchase is cheap." - LegendGS

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