Gasoline 112

[Amma351]

So my buddy has a nice muscle car packs around 350 horsies and he bought some gasoline that has 112 octane. The question is could my stock 1.8 mx3 handle that much octane or I would do some serious damage. I only intend to use it once/twice to race my buddy's corrado.( I know i cant beat it but at least to come closer would be great!)

[babyblueMX3]

where did he got that??

[Amma351]

There is some place in St. Catharines i forgot the name best fuel or something. 15 bux a galon i believe. But my friend said he felt a huge gain in speed.... although you can smell the gas all around the car. Sooooo flamable!! It almost like NOS lol.

[Nd4SpdSe]

Theres a small garage about 2min from home that i drive by everyday, they sell it too, never looked into it...

[koreanmx-er]

here in minnesota theres a gas station thats sells 111 octane for $4.59 a gallon i think thats a steal compared to the guy above paying 3 times that for one more octane level , i tried it once but i had already had about a 1/4of a gallon of regular in and i only put in 3 gallons , there was a somewhat noticable change that i could tell in the azz dyno , but in the long run i dont think i'll be using it to go race

[guyaverage]

But my friend said he felt a huge gain in speed.... although you can smell the gas all around the car. Sooooo flamable!! It almost like NOS lol.

Geez Louise, where to start....huge gain in speed? Not unless he was running huge boost or huge spark advance. If he really got a huge increase in power or speed, he had something FUBAR'd even BEFORE he put in the high octane.

Sooo flamable? Try LESSSSSS flamable. Octane ratings are a measure of a fuels ability to resist detonation, or combustion BEFORE the ignition spark. Thats it. Its NOT a measurement of how 'powerful' a fuel is, its not a measurement of heat content, its not an engine performance indicator. If you are running high octane in an engine that doesnt have a knock sensor, and it isnt knocking or detonating on regular pump 91-93 octance, then putting in even higher octane fuel will NOT increase power. As a matter of fact, it will increase EGT's (due to slower burning), cause catalyst overheating (because fuel is still burning as it enters the exhaust), and cause slight DECREASES in power (because its burning in the exhaust stroke, and not in the power stroke where the energy is harnessed by the piston). Use the LOWEST octane rating your engine can handle without detonation based on how much compression it has and where you have the ignition timed at.

<small>[ July 21, 2004, 01:54 PM: Message edited by: guyaverage ]</small>

[killerpickle]

ooh.. sticky this The ever-debated topic of octane vs performance...

[IanL]

Originally posted by guyaverage:
Not unless he was running huge boost or huge spark advance.... Octane ratings are a measure of a fuels ability to resist detonation, or combustion BEFORE the ignition spark. Thats it. Its NOT a measurement of how 'powerful' a fuel is, its not a measurement of heat content, its not an engine performance indicator.

Its amazing how many butt dynos are fooled by higher octane fuel. The only performance improvement available from using a higher octane than your engine needs is to the Oil Companies share prices.

[papa roached]

you only need high octaine with high boost, high compression apps, the rest your just throwing out your tailpipe

[Redhouse]

Octane is C8H18, meaning it's a chain of eight carbon atoms and 18 hydrogens. Unlike other combinations of carbon and hydrogen (such as butane, pentane, hexane and heptane - 4, 5, 6 and 7 carbon atoms respectively), octane handles compression very well.

Your engine has four strokes - intake, compression, combustion and exhaust. On the intake stroke the piston goes down and the air-fuel mixture is let in through the intake valves. On the compression stroke, the one we're concerned with, the piston moves up and compresses the air-fuel mixture. During combustion, the spark plug ignites the mixture, producing the combustion (or power) stroke which moves the piston down forcefully, and finally we have the exhaust stroke when the piston moves back up to push the spent gases out.

The reason octane is important is because engines can produce more power if they have higher compression ratios. A 10:1 compression ratio means that the engine compresses the volume of air it sucks in - say X, into a volume on tenth that size. The problem is that when air compresses, it increases in pressure and this heats it up. A low octane gasoline is prone to spontaneously ignite prematurely in a high compression engine, which causes damage. If the gasoline ignites too soon, the power of the burning gas and air mixture will push down on the piston as it's still compressing, losing you power and over-heating the piston (as well as valves, head, and cylinder walls), eventually leading to catastrophic engine failure. This is known as pre-detonation, pre-ignition or "knock".

With a high octane rating, engines can run with higher compression.

You may be asking yourself why turbocharged or supercharged engines with low compression (sometimes as low as 8:1) would need high octane gasoline. The reason is because turbocharging and supercharging compresses the air even before it reaches the engine proper, meaning it's already very hot when it enters the cylinder.

In summary: higher octane gasoline allows engineers to design engines that have more power. However, that doesn't mean that an engine designed for regular gas will gain power just because you added high octane gasoline.

[fry_81]

if you want to race someone, dont put higher than recommended octane levels. our engines were designed to perform best with normal pump gas. unless of course you have engine mods, if its a stock engine, putting that high of octane in will just make it perform like garbage.

[mitmaks]

kid dont waste your money unless you got stroked engine with 12.5:1 compression ratio forget about it, of course you can go and try it, hey its not my money for all i care...

[RoundTop]

Actually, in the 1996 MX-3 GS manual it states to use 90 octane gas or higher

[mrspanky79]

Greg Ridout well put

[IanL]

This says it all.