high octane or low octane?

[brookliner7]

Some goobs out west here at the track are saying that low octane is better for making more power with NA setups.
Is that true? sounds kinda ghey, but since it is less refined, it could kinda make sense.
Is high octane gas just safer, less detonation and pinging?
I know if you're running boost or juice, you definanlty want the high octance, but if you're racing NA, is lower better? Ialways run 91 octane, and use octane boosters when skaweezing.
thx

chris
Ls Vtec EG Civic Coupe
B18B/B18C1
CTR cams
ITR DC 4/1 header
Skunk2 harness, mugen specs
GSR tranny and axles
ACT street/strip clutch
NOS wet single point injection

[accordy2g]

higher octane is safer reducing the chance of detonation and pinging. Its a cleaner gas also. I really dont know if lower octane is better for all motor but i would think they are just cheap <img src="http://www.clubhonda.com/infopop/emoticons/icon_wink.gif" alt="Wink" width="15" height="15"><!--graemlin:;)-->

----------------------------------
Resurrected '00 Accord
JDM H22a LSD
Stay Tuned!!! <img src="http://www.clubhonda.com/infopop/emoticons/icon_wink.gif" alt="Wink" width="15" height="15"><!--graemlin:;)-->

[19civic99]

No they are wrong. With N/A your compression is that much higher and you want a higher Octane gas to make sure all the mixture is burnt, and since a higher octane gas burns better...MmMmmm its common sence. <img src="http://www.clubhonda.com/infopop/emoticons/icon_cool.gif" alt="Cool" width="15" height="15"><!--graemlin::cool:-->

______________________________
2004 Rally Blue WRX
HKS Up-pipe, HKS 3 inch Down-pipe, HKS Carbon-ti catback, Turbo XS RFL-BOV..More to come! *IN PAIN AT THIS TIME*<img src="http://www.clubhonda.com/infopop/emoticons/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin::(-->


1999 Civic DX Coupe
JDM B18C powered.... 14.1 @ 106MPH... *SOLD* I will never forget you my Friend... <img src="http://www.clubhonda.com/infopop/emoticons/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin::(-->

"RWD Club"-Honerary member
FORMER --"Civic DX"-member 0001
http://www.clubhonda.com/images/ubbicons/canada.gif
<<QUOTE OF THE WEEK AWARD>>
Joad's CRX Holland Quotes- "Can you do me a favor and get on your damn knees and suck my salty caribbean balls?"

[itr206]

you guys are forgetting the biggest reason why higher octanes are used.. . .
more octance reguardless of compression allows for higher and higher igntion advance without detonation or ping. which in turn equals more power.

-01 Itr
10 SEC STREET CAR IN THE WORKS
-02 EP SI
-89 240SX FAST BACK
. . . BRINGING THE PAIN. . .
www.G-ForcePerformance.net (http://www.G-ForcePerformance.net)
http://www.imagestation.com/picture/sraid65/pee8ae51e7c0e5525a099e052d0646fd7/fbf6e583.jpg

[19civic99]

"and you want a higher Octane gas to make sure all the mixture is burnt" By- ME!


thats what i ment!

______________________________
2004 Rally Blue WRX
HKS Up-pipe, HKS 3 inch Down-pipe, HKS Carbon-ti catback, Turbo XS RFL-BOV..More to come! *IN PAIN AT THIS TIME*<img src="http://www.clubhonda.com/infopop/emoticons/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin::(-->


1999 Civic DX Coupe
JDM B18C powered.... 14.1 @ 106MPH... *SOLD* I will never forget you my Friend... <img src="http://www.clubhonda.com/infopop/emoticons/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin::(-->

"RWD Club"-Honerary member
FORMER --"Civic DX"-member 0001
http://www.clubhonda.com/images/ubbicons/canada.gif
<<QUOTE OF THE WEEK AWARD>>
Joad's CRX Holland Quotes- "Can you do me a favor and get on your damn knees and suck my salty caribbean balls?"

[brookliner7]

kool,
i'll tell them they're all full of schick when i see them again.

chris
Ls Vtec EG Civic Coupe
B18B/B18C1
CTR cams
ITR DC 4/1 header
Skunk2 harness, mugen specs
GSR tranny and axles
ACT street/strip clutch
NOS wet single point injection

[BSeRiEsHaTcH69]

lower octance gas burns better of course, because its made easier to burn and less resistant to knock, hence anti-knock rating. higher octane gas is what itr said, n/a and boosted cars use it so that when the a/f mixture comes in and the piston comes up sometimes on high compression engines or boosted the fuel will burn before being ignited (basically like a diesel runs, no sparkies).
Joe

93 Si with B16a Turbo
COMING SOON
RICE PATROL OFFICER 0001
------------------------------
AlmightySi: he's lucky i dont go out there and smack the sh!t outta him
AlmightySi: fu*kin keyboard gangsta

AlmightySi: dude the girl didnt want to come over no more i was like damn dont worry he dont care.

[www.crazyaudiosystems.com]

im with 19civic99 <img src="http://www.clubhonda.com/infopop/emoticons/icon_wink.gif" alt="Wink" width="15" height="15"><!--graemlin:;)-->

www.crazyaudiosystems.com (http://www.crazyaudiosystems.com)
http://www.imagestation.com/picture/sraid95/p74e36aad643bb5c93f41ae624df9b00b/fa2abb0d.jpg

[candymanjl]

from what I've read the octane rating is the rating of the fuel's ability to resist detonation, and in my experience my cars have run better and gotten better milage so I always get the higher octane.

_____________
stolen, but not forgotten - 2002 CBR954RR Red / Black (http://www.clubhonda.com/6/ubb.x?a=tpc&s=316602881&f=4676013852&m=5526017752), B16A Turbo CRX (http://www.clubhonda.com/images/nopipimps/DCP_1112.jpg) http://www.clubhonda.com/images/ubbicons/headshot.gif

[Joad]

What they are saying is not necesarily correct. The octane rating strictly defines resistance to preignition in fuels for spark-ignition engines. Higher octane ratings simply indicate a greater resistance to knock, and comparing this to NA setups, they would have much more friction, asuming that they cary out a higher compression ratio, so lower octane levels making more power wouldn't really make sense!

______________________________

1991 Honda CRX SiR

[BSeRiEsHaTcH69]

dude thats exactly what i said! higher octance will make more power because you can obviously bump compression and timing without risking pre-ignition.
Joe

93 Si with B16a Turbo
COMING SOON
RICE PATROL OFFICER 0001
------------------------------
AlmightySi: he's lucky i dont go out there and smack the sh!t outta him
AlmightySi: fu*kin keyboard gangsta

AlmightySi: dude the girl didnt want to come over no more i was like damn dont worry he dont care.

[badta00]

Early in the evolution of automobiles, engines, and gasoline, engine “knock”, “pinging”, became a problem. It is also referred to as “detonation”, “pre-ignition”, “spark knock”, “valve noise”, and other terms, misnomers or not.

If the gasoline in an engine burns (combusts) prematurely (in terms of mere milliseconds), or combusts spontaneously, or too rapidly, or too violently, it is inferior combustion, and makes a pinging or rattling noise from the engine, usually when accelerating. Severe pinging can quickly destroy an engine. Chronic mild pinging can eventually result in serious damage to an engine. A sturdy engine can withstand occasional light pinging, though maybe with slightly accelerated wear on certain parts. When any pinging occurs, efficiency and power are reduced, and fuel consumption is increased. Put simply, pinging is not good.

In the 1920s, gasoline companies began offering a new, improved, and slightly more expensive type of gasoline that resisted pinging, knock. The new gasoline contained an “anti-knock” additive, a chemical called tetraethyl lead, “TEL”, that actually made gasoline slightly “reluctant” to burn, which helped to remedy inferior combustion, “pinging”. The more TEL that was added to gasoline, the more knock-resistant the gasoline became. The manufacturer of TEL, who supplied it to the gasoline companies, was the Ethyl Corporation. Gasoline that contained the most TEL, that (thus) was the most knock resistant, was widely referred to as “ethyl”. Into the 1960s, drivers who preferred that premium type of gasoline told “service station attendants” to “fill it with ethyl”.

But the TEL anti-knock additive in gasoline caused engines to emit in their exhaust tiny amounts of lead, which pollutes the air, and which cannot be controlled by automobile emissions-control systems because lead damages them. So, TEL was phased out during the 1970s and was replaced by other anti-knock additives. Of course, at gas stations in recent decades, gasoline that is more knock-resistant is referred to, not as “ethyl”, but as “premium”.

A gasoline’s knock resistance can be measured in the laboratory, and the gasoline is assigned a numerical value that is referred to as its “knock rating”, or “octane number”. The more resistant a gasoline is to knock, the higher its octane number. Today, octane numbers at gas stations range, roughly, from 85 to 95.

Of course, it is particularly catastrophic if an aircraft engine fails. So, “premium”-type aviation gasoline (“avgas”, for piston-engined aircraft) has an octane number of around 115. Too, many racing cars use avgas or special super-high-octane racing gasoline. Whether or how higher octane makes them go faster is a complicated matter that I will not go into here, but it certainly helps to increase the probability that the engine will finish the race. Of course, some types of racing cars do not use gasoline. For example, Indy cars use methanol (wood alcohol), which is weird stuff. For example, it is extremely corrosive to engine parts. But methanol is water soluble, which makes extinguishing fires easier, and it has excellent natural anti-knock properties.

It might surprise some people that, in jet aircraft fuel, high octane is not desirable, and jet fuel would have a low octane rating. Jet fuel and diesel fuel, which are similar, feature, not an octane rating, but a “cetane” rating, which is the opposite of an octane rating. Jet fuel would run very poorly, if at all, in a gasoline engine, and would quickly ping it to destruction. Jet fuel would not make a gasoline engine “really take off”. Conversely, high-octane gasoline would run poorly, if at all, in a jet engine. I do not know anything about rocket fuel.

There are several myths about engine pinging and gasoline octane. One myth is that the pinging noise is from “the valves rattling in the engine”.

Another myth is that higher octane gasoline “burns hotter”. For example, it is not an old “wive’s tale”, but, rather, a common “husband’s tale”, that if you put premium gasoline into a lawn mower, or into a low performance car like a decades-old VW Beetle, you will “burn up the engine”. News reporters often excitedly describe some blazing inferno as “burning furiously!, like it was fueled by high-octane gasoline!”. In reality, higher octane gasoline not only is slightly more “reluctant” to burn, but actually has a slightly lower energy content. Technically, it is perfectly sensible to run premium gasoline in a lawn mower or an old Beetle. Technically, it would be more correct to exclaim that some blazing inferno was “burning furiously!, like it was fueled by low-octane, regular-grade gasoline.....the cheap stuff!”. But, you can’t let facts throw cold water on a hot news story! That’s why they call them “stories”.

Automobile manufacturers like to suggest, especially regarding their economy models, that the cars are “designed to operate on” regular-grade fuel, which is a carefully worded statement, and a true statement, and which portrays the cars as economical to operate. But, more than a few car owners have observed that “it might have been designed to operate on regular-grade fuel, and the engine does operate on regular-grade fuel, but it pings, so I have to use premium”. Of course, the phrase “designed to operate on” remains true.

In recent decades, a few “consumer advocates” have persuaded a few consumers that premium gasoline is “a ripoff, that is sold simply to make more money for oil companies”. In my years as an auto mechanic I have seen several engines that were consumed because their owners refused to be “ripped off” by premium gasoline. The engines pinged to death. Those consumers spent more money, and all at once, for major engine repairs, than the total additional money that they would have spent, and pennies at a time, on premium gasoline. Pinging can cause, for example, “blown” head gaskets, damaged heads, damaged pistons, damaged cylinder bores, “blown” engines, etc.

Some people who own cars with engines that ping on regular-grade gasoline use it anyway, but they buy premium every other fill-up, or every third fill-up, or once a month, or whatever. They believe that octane has a residual beneficial effect that gives the engine some ongoing protection, to get it through the lean times. It does not.

One old story was that if you put moth balls in a car’s gas tank it would keep the engine from pinging. The story had a basis in fact. Moth balls contained a chemical that has a powerful anti-knock effect. I have seen moth-balled gasoline tested in the laboratory for its octane rating. The moth balls would dissolve in the gas tank and become an anti-knock additive. The trick was to put enough moth balls into the tank to increase the octane enough to prevent pinging. Modern moth balls do not contain that chemical and will not stop engine pinging.

Each piston-type gasoline engine has some minimum octane requirement, below which it will ping. Ping and octane requirement are a function of engine design, manufacturing tolerances, engine condition, specific engine part malfunctions, and certain engine adjustments. If your car’s engine does not ping, you do not need to buy higher octane gasoline. If it does ping, then, first, have a mechanic check it and make any necessary repairs or adjustments. Then, in my opinion, if it pings at all, or if you do not know whether your engine pings (because, for example, your hearing is fading, like mine), or if you just like to be on the safe side, you should routinely use premium gasoline. There are no harmful effects on an engine of using higher octane gasoline than the engine needs.


by:Marlyn Kerman

[badta00]

All modern gasoline manufactures add the same amount of detergents and cleaners to all their grades. The difference comes down to the manufacture not the grade of gasoline. "Oxygenated gasoline" is a mixture of conventional gasoline and one or more combustible liquids which contain oxygen ("oxygenates"). At present, the most common oxygenates are ethanol and MTBE (Methyl Tertiary Butyl Ether). The government requires gasoline to be oxygenated during the winter in areas that have a carbon monoxide pollution problem (cold weather and atmospheric inversions worsen carbon monoxide pollution). Oxygenated gasoline helps engines run leaner, which helps engines, particularly older engines, produce less carbon monoxide.
Which would not be good for a car trying to prevent spark knock.
The higher the Octane the harder it is for a fuel to ignite so running a higher than needed octane can hurt performance. But running a lower octane than needed can damage an engine.


Oxygenated gasoline reduces fuel economy an average of 2%-3% because oxygenates contain less energy than non-oxygenated gasoline. Oxygenated gasoline will perform satisfactorily in most later-model engines. However, some manufacturers expressed concerns about its use in older engines. The owner's manual is the most authoritative source of information about the fuel requirements of your equipment. If your equipment is older and the manual does not mention oxygenated gasoline, consult an authorized dealer.

[candymanjl]

lol, "Methyl Tertiary Butyl Ether", say that 5 times really quick :D

good write up there TA :cool:

[wreckless]

thanks T/A, i was starting to foam at the mouth again. great write up!! but to make this post worth something more than a post count number......

what you pointed out about jet fuel is true.... kinda.

it's like this, jet engines are like piston engines in that they rely on the compression of air (air/fuel mix in most piston engines) to make the conditions right for fuel ignition or combustion (whichever you like) but un like the common automobile engine the jet engine relys on stages of compression. this is how it works guys (and this will be very crude so you won't get lost):
air comes into the inlet and past a stage of guide vanes (most bigger high bypass jets like the ones seen on airliners, forgo the first set of vanes) these guide vanes "turn" or change the direction of the air so the first stage of fan blades can pick up more air. the air is "scooped and thrown" back to the next set of guide vanes. a set of vanes and fan section is called a stage. each consecutive stage not only turns the air onto itself more, but also, the radial space shrinks. by the last stage (on say a F-15 motor) the same amount of air that was pick up by the first stage in squeezed into the last. the volume of the last stage is aporx. 1/16 the size of the first. combine this with the fact that while it's been getting squeezed it's been getting folded over itself in every stage. this air is hot and very compressed.

just like gasoline there are grades to jet fuel. the air force now uses JP8+100. the "+100" is like detergent rating for jet fuel, except it has "low smoke" additives and the like. jet fuel is, for the most part, a mix of gasoline and kerosine. it has a high flash point (i can personaly account for this) because of the compression and heat it must be subjeted to. indeed you may have heard jet fuel likend to desiel, but it's "come a long way baby". there may be some high bypass turbofan engines out there that use a lower flash point type fuel but they aren't fast and they are really just glorified turbo props so who cares?

also, roket fuel is kinda like all the other combustion engines. but instead of taking O2 from the air and burning it, it brings its own to the party. most of the time in liquid form. this oxygen concentrate or oxidiser is mixed with fuel (i suppose you could call it rocket fuel) and is usually ignited in the combustion chamber ( what you might call the exaust cone). some rockets use a fuel that ignites itself when exposed to an oxidiser. then theres solid rockets.... it's called a bottle rocket, you guys have been playing with them for years, you get the idea.


again, thanks for the great post. i feel it is sticky worthy