Who is using what in there atv 87 or 92 octane and why? Is there a difference? Have you noticed one if so?

 

Run 92 or 93 oct gast in your quad. You can run 87 but it will run a little better on the better gas. It should own cost you about 40cents each more. You do not need to run race gas or octane boost if you have a utulity quad. Make sure that you don't buy any gas that has water in it. I have been told that the ones that say 10% men.added don't use. Because, after the quad sit's the 10% is a type of water and it will cloug up the main jet.

 

Check your owner's manual. If it says that you only need 87 Octane, then don't run anything higher than that. It is just more expensive to pay for premium, and it won't make any performance difference, unless your engine was made for it. Usually only higher performance engines will need to use 93 Octane fuel (ie turbo, or supercharged cars for example.). But if your quad knocks with 87 octane, then you should probably run 93 octane gasoline.

 

The lower the octane in fuel the easier it burns,so you will get better milage with the higher octane but better performace with the lower.

 

Less performance w/higher grade feul? That's a new one on me. I run 100+ octane because I have a higher compression ratio from my mods, 12:1 wiseco piston. Run 87 if your engine doesn't knock but you will get a little more mileage and performance w/ a higher octane.

 

Let me see if I can give the rundown on octane. I think most of what I have to say has already been said in one form or another.

Regular Unleaded = Fuel burns faster, on stock quads you can actually see better performance, easier to cause detonation in the engine, creates more carbon deposits.

Mid-Grade = Fuel burns a little slower, less carbon deposits, not as easy to detonate.

High Grade = Even slower burning, cleanest of pump gas. The higher number doesn't exactly mean high performance, just means its cleaner and resists detonation for vehicles that may have a problem with it, i.e. super, turbo charged cars, older cars with worn parts, things such as these.

Then you have your race fuels and what not, for high compression engines. I'm not really sure, but my guess that the gas is really good at resisting detonation which would occur due to the higher compression, that would compress the air/fuel mixture much quicker which would then make it easier to detonate.

Hopefully this helps someone out. I personally run the regular unleaded in my Quad because it would have no use for Supreme. On the other hand my car gets supreme because of the mods on it. Just read your owners manual, it will tell you.

 

Personally, I have tried both and found that my quad runs much better with higher octane. There is a reason for that, and I will have to wait til hubby is around to give the answer. In the meantime, try both and see what you like better.

 

The higher octane fuels do burn much slower, but the higher the octane, the faster it flows. If you go to really high octane plan to rejet your carb.
To bluehonda4x4, the higher octane fuels do make more power. The reason this happens is because of the reason that you explained, they burn slower. The reason the slower burning fuel makes more power is because it chases the piston farther down the cylinder. The "explosion" so to speak, is "pushing" on the piston for a longer period of time.
Oh by the way, detination has to do mostly with timing. Detination is basically firing at the wrong time. The sprark is supposed to fire when the piston has reached TDC and starts back down the cylinder. Detonation happens when the spark fires as the piston is on its way up on the exaust stroke(that's an exaggeration so you get the idea). But really, the rod has to be at the right angle on the way down before you can put pressure on it, if the fuel ignites too soon, or too late, you have detination.
Hope that helped, a little!

 

Maybe some minor clarification is in order with the ever present Octane discussion.

First, you will see NO IMPROVEMENT IN PERFORMANCE if your engine is designed to run on 87 octane fuel and you run a higher octane fuel, period.

I don't care what anyone says. If you don't have the compression ratio to support the need for high octane fuel, why waste your money?


Second, higher octane fuel has a higher heat of vaporization rate, i.e. it takes a higher temperature to turn it into a vapor which can, in turn make it much more difficult to start on really cold days.

Low octane fuel is no more conducive to carbon deposits/varnish than a high octane fuel. It all comes down to the way you use/abuse/care for your machine plus the quality of fuel from where you pumped it.

Third, detonation is uncontrolled combustion. If you are detonating fuel inside your engine, you are destroying it. Detonation usually occurs in older vehicles because of carbon desposits that form on the tops of the pistons or the top of the combustion chamber, a hot spot develops and as soon as the fuel/air mix enters the combustion chamber it ignites, uncontrollably.

Racer18J, your analogy that high octane fuel makes more power because it burns slower is incorrect. It doesn't chase the piston down farther. Given a certain amount of camshaft lift/duration plus the exhaust stroke of the engine, the spent gases are often pushed OUT of the cylinder before they completely combust. Because high octane fuel resists detonation better than low octane fuel, you can run accordingly higher compression ratios. It's the compression stroke that determines how much potential you have, plus how much fuel/air you can cram into the engine during the intake stroke. Ignition systems, on high performance machines generally fires a few degrees BEFORE TDC, not AT TDC which would be a performance robber since the time the flame front propogates outward, the piston has already begun it's travel downward. Ideally, you want the combustion gases to begin their expansion as the piston is coming up to TDC and the maximum expansion occurs right as the piston stops and begins it's downward travel.

2fiftyX, you are correct, with your mods you will see a performance improvment since you are using a fuel thats much less volatile than what I use in my quad, 87 Octane fuel. You have to use high octane fuel or else you'd have an expensive pile of damaged parts. I've repaired many engines where the guy installs all these high dollar parts only to run lower octane fuel.

The only fuel enhancements I use is drygas. Since the quads often sit for a week or more outside in my garage the fuel tends to absorb a bit of moisture.


I hope THAT clears up some of the misconceptions floating around about Octane.


Phil

 

If you read this far you might as well see the rest.

Octane numbers can be very confusing due to several different terminology's used in discussions. I will try to clear up some common
misunderstandings and define some of the variousterms used when discussing octane quality.

Octane:
The octane quality of a gasoline is its ability to resist detonation, a form of abnormal combustion. Detonation occurs when the air-fuel mixture reaches a temperature and/or pressure at which it can no longer keep from self igniting. Two types of abnormal combustion are common:
The first is detonation as previously mentioned and the other is preignition. Detonation occurs after the spark plug has ignited the air-fuel
mixture and the flame front is moving smoothly across the combustion chamber. If, during this burning process, the unburned air-fuel
mixture reaches a temperature and/or pressure at which it is no longer stable, it burns very rapidly causing a new flame front to collide
with the one that originated at the spark plug. Maximum pressure in the cylinder occurs before the piston reaches top dead center (TDC)
and that pressure try's to push the piston down before it is ready to go down. Piston burning and rod bearing damage are the result.

Preignition is the other bad actor and is usually started by a hot spot in the combustion chamber which causes the mixture to ignite before the plug fires. Under wide open throttle conditions,
preignition will destroy pistons in seconds.

Research Octane Number (RON)
RON is determined in a single cylinder variable compression ratio engine that operates at 600 rpm with a 125 degree inlet air temperature at standard barometric pressure. Spark advance is fixed at 13 degrees btdc. In a real world engine, RON is necessary to satisfy part throttle knock problems. A good quality racing gasoline has a RON in the range of 110 to 115. The difference in the spread of RON is not very important to racing engines. The test and hardware were originally developed in 1931. The hardware was revised in 1946 with procedural changes made until the late 1960's.

Motor Octane Number (MON)
MON is determined in a single cylinder engine similar to the RON engine with a few changes that make operating conditions more severe and therefore the octane numbers are lower. The MON engine runs at 900 rpm with a 300 degree mixture temperature.Spark advance varies with compression ratio. In a real world engine, MON is necessary to satisfy octane demands at wide open throttle. This is a very important number for racing engines since they spend a high percentage of their lives under high speed and high load conditions. Racing engines cannot afford to be short on octane
quality, since detonation or preignition will quickly reduce a racing engine to junk.
The motor octane appetite of an engine with 13:1 compression ratio and a four inch bore varies with operating conditions but is normally around 101. Good quality racing gasolines have MON in the
range of 100 to 115. If your engine requires a 101 MON, it is of no value to use a gasoline that has a 115 MON. To cover yourself for extreme conditions, it is wise to have an octane cushion but THERE IS NO ADVANTAGE TO USING A VERY HIGH OCTANE QUALITY PRODUCT IF YOU DO NOT NEED IT.

R+M)/2
This is the average of RON and MON. It is sometimes referred to as the aki or anti-knock index. By law this number must be posted
on the dispensing pump at retail outlets in most states. It is the most commonly used octane reference today. It was developed about
20 years ago as a compromise between RON and MON for advertising purposes and also to keep from confusing the consumer with too many different terms.