Last I checked, this is not pre-school. Its an internet forum.

Saving about $2 per fill up justifies putting in a low octane gas in a high-output sports cars gas tank? That amount is a drop in the bucket. If you are concerned about $2 saved each time at the gas pump, you bought the wrong car. And that is the point....making the question "does it have to have 91 octane?" a rediculous and stupid question. The S2000 is not a Civic, so buy another car if gas savings is your issue.

 

Only on the B series engine which have high compression ratio also. My friend's D16 before switching to B16 was recommended 87 and above.

My 2000 civic Si with B16 rev to 8000 and its recommended premium only.

As far as the information I gave above, the engine that he got was 12k when he put in his car, he drives hard around town and occasionaly drag it at the light. He is use 87 base on cheapness and he can rebuild himself and that's when he opened up when one of the exhaust valve was leaking (a chip to the valve about a size of your nail that you clipped). We don't think that's the result of the use of 87 but the chamber was not pretty and the knocking he gets every "once in a while" does not help.

I don't know about the "feel no difference" but we tried many times on my sister's mazda 626 automatic, 93 gets about 15 miles more a tank and I think that is a little difference. I never tried it on my Si or my S (I don't want to) so cannot give you guys any of that information.

 

When you buy the car it says.. "Premium Fuel Only" , that isn't a reccomendation. It is there to protect the motor. Do you think Honda will warranty anything that happens to a motor with someone running 87 octane? Maybe if your lucky and know somebody. It's like going to McDonalds, getting a cup of coffee that says HOT.. then pouring it on yourself and saying "Oh Crap, that's hot!!!"
When you start having engine problems and the car doesn't run right.... it is the same principal.. well it says 91+... but who cares about that I'm putting 87 in it. The only possible way your going to not run into as many problems with this is if you drive the car out of VTEC all the time and never switch cam lobes.

Your condensending remarks do nothing to add to this thread either, maybe if your the smart one you would like to go to Honda and tell them that its ok to put a lower grade octane in a car with 11.0:1 compression and they should rethink their degrees. Just because I am a moderator doesn't mean I can't have an opinion and freely express it. The ignorance level is dumbfounding to me that is involved in a simple task as knowing what octane to run in a sports car. Yes, ignorance is an ok word to use since it refers to one's lack of knowledge about a certain subject.

If you would like for me to explain detonation and why it occurs on a lower octane fuel and what the damages that can occur from doing this I will.

 

Technobabble: January 2002
The Octane Game
By Dave Coleman


"On the off chance you're only now trading in your Schwinn 10-speed on a twin-turbo Supra, I guess I should stop here and explain what octane is and how it affects your engine.

When fuel is injected into the cylinder, compressed and ignited, one of two things can happen. It either burns quickly and smoothly, shoving the piston down with a strong, even push, or it explodes all at once, releasing its energy in a sudden burst of heat and pressure. This explosion is called knocking or pinging, and it's something engineers like to call "really bad."

Knock is usually ill timed, occurring early in the combustion cycle when the crank and rod are still straight up or even worse, still trying to complete the compression stroke. As a result, all the energy released slams into the top of the piston without actually turning the crank. When this happens under stressful enough conditions-like, 20-psi of boost in a Miata-you start breaking things. Usually the ring lands; however, if your pistons are strong enough, you might get lucky and blow a head gasket.

Octane, for those of you still on the bike, is the rating of a fuel's ability to not do this. The higher the number, the less likely the fuel is to detonate. What this means to us, of course, is the higher the number, the more boost we can throw at that Miata. High-octane gas isn't just for tuners though. Plenty of stock cars depend on the stuff, including a Celica GT-S with its 11.5:1 compression, or a turbocharged WRX or Volkswagen 1.8T.

These cars rely on high-octane gas to keep from detonating. Feed them 91 octane and they won't start breaking things, because their knock sensors will see it coming and retard the timing, turn down the boost or otherwise reduce your chances of having any fun.

Whose fault is it this time, CARB? The EPA? The CHP? None of the above. This time we're being victimized partly by the oil companies, and partly-this is the one that hurts-by ourselves.

You see, when crude oil is refined into gasoline, the refinery doesn't have all that much control over what comes out. Crude oil is full of all kinds of stuff, and a refinery simply separates it, sorting all the iso-this and hepta-that in order of density. The really heavy stuff, like tar, is near the bottom, while the really light stuff, like butane, is near the top.

Somewhere in the upper ranges of the stack are the components of gasoline. There are between 10 and 15 different blend stocks, each with a different octane rating, which are mixed together to make gasoline.

The crude oil being used and little else determine the amount of each blend stock available for mixing. Generally, if you just dump all the blend stocks into a bucket, you end up with something around 88 or 89 octane. If you're selective and only mix the good stuff, you can make 92, 93 or even 95 octane. But once you take out the good stuff, you're left with crap-something like 85 octane. Then you have to leave enough good stuff in the bucket to bring this pee-water up to at least 87 octane. This limits the amount of 95-octane gas you can make. If you make 93-octane premium instead, you use up less of the high-octane stocks, allowing you to make a higher proportion of premium fuel.

In the Midwest, where an extensive customer base of good old boys in pickup trucks consume vast quantities of 87 octane, demand for premium fuel is low enough to make genuine high-octane premium......."

 

If you've read How Car Engines Work, you know that almost all cars use four-stroke gasoline engines. One of the strokes is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1. (See How Car Engines Work for details.)

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

 

If you're planning to put 70,000 miles on your car = about 300-350 fill ups (if saved average $2 dollars per fill up = $700 saved in 70,000miles). But the question should be "Is premium from shell better than from walmart/racetrac??" I save a $1 or two by filling up at walmart using 93 premium...I also save $15 per oil change at walmart instead at honda. (30 oil change = 75000miles = $450 saved)...Has anything gone wrong...NO!!! i'm passed 75000 miles and still running strong, expecting to go 100K plus. As for tires S02 sucks as hell; it's = expensive as F@ck, last only 10k, dangerous in areas where it's snows, rains (basically everywhere real people live). Assume $750 per tires change (18' rims like mine), i can stick with CHEAPER Falken FK-421 or something like that that Last 30,000+ miles with HALF the cost at $380 for 4 tires. 70000 miles = 8 tires change (S02) = $6000... a saving of $5000+ over Falken FK-421 (70000miles=2 tires change = $760)The falken has AA traction rating, A temp, Zrated for 170Mph+.....Little things COUNTS...That's over $7000 SAVED !!!! This extra money could be used on an ENGINE rebuild + Tranny rebuild+Clutch work+ Radiation+ brakejob+ Axel + paintjob = almost BRAND NEW S2000...Do you think using Shell gasoline/ changing oil at Honda, using name brand tires could do all this for you when the car is at 200,000 miles ???While most people pay $30K plus for a 2003 s2000 two year ago, i paid = $13000 FIXED (the car was vandalized with 5K miles on it)= that's another $20,000 savings...While most people in here still paying for their car till doomsday, i have paid it off on FIRST DAY. People think S2000 is an exotic car, IT'S NOT, it's a super enhanced honda that is MADE to be abused and made it out ok...Don't waste too much money for your car people, it'll die because of abuse before it die because of some gas/oil problems.

 

What about using PREMIUM from SHELL and PREMIUM from Walmart...IS THERE A DIFFERENCE (don't tell me about the detergent level in the gas because EVERY gas needs detergent in them, shell just add more)...

 

87 is fine. There was an article a while back and a senior Honda scientist or something said so. Not saying I would ever put 87 in my car, especially with the turbo comming However if your car is stock then you should have no problems.

 

[QUOTE=FearlessFife,Nov 10 2005, 11:26 AM]Last I checked, this is not pre-school.

 

[QUOTE=Rogazilla,Nov 10 2005, 07:33 PM] As far as the information I gave above, the engine that he got was 12k when he put in his car, he drives hard around town and occasionaly drag it at the light.