Octane? By scooter12 (Read 2,793 times)

[scooter12]

My MC-13-250 scooter says 90 octane or higher.. on the gas tank.. I had put 91 octane in it, when new, in 2008.. Since than, put 89 octane because it was cheaper..

Now thinking of it being winter and thinking of 89 octane having 10% ethanol added to it, well ethanol ruins rubber parts and freezes up if seperates and turns to water, well that does not sound real good. So I have been doing some thinking, of switching to 91 octane( 91 octane is premium gas and has no ethanol added to it in Missouri). So this would be harder to freeze up, better on rubber parts, and stop pings..

I use Seafoam too. This helps gas and ethanol from seperating and freezing. Would you switch to 91 octane, if your engine required a higher octane, reasons it might make parts last longer, ect..

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[go4it]

Octane is a flame retardent meaning it causes the the ignition to occure at a higher tempeture. This is needed in high compression engines only. The only value for you to use a higher octane is as you point out if there is no ethanol in it in your area. A lot of people (including dealers) insist on following the 90+ octane rule for Chinese scooters and cycles. But that rating is not a US rating and is actually different. It's not that the Chinese have poorer gas it's the methiod of how they messure the octane. Generally speaking you can take the Chinese rating and subtract 4 points and that is the US rating of the same fuel. So your required 90+ is actually 86+ in US octane ratings.

Bottom line the only value to running higher octane is if there's no ethanol in it. Other then that it has no value to your scooter...and it will not increase your MPG. BTW, in most areas where the temps drop significantly in winter the gas is reformulated to improve engine starting. This is one of the reasons the MPG drop off in winter.

Personally, I'd stay with the 89 octane.

Bob

[scooter12]

As noted on Chevron's Web site, while conventional gasoline can dissolve up to 150 parts per million of water at 70°F, the situation is different for gasoline oxygenated with 10% ethanol. This 90% gasoline/10% ethanol blend can dissolve up to 7,000 ppm of water at 70°F. When this blend is cooled, both the water and some of the ethanol become insoluble. Contacting the blend with more water also draws ethanol from the blend. The result, in both cases, is two layers of liquid, an upper ethanol-deficit gasoline layer and a lower ethanol-rich water layer. This phase separation of the gasoline/ethanol mix lowers the octane number and may cause knocking in an engine, while the engine will not run at all on the ethanol/water layer.


This I copied from web: It shows how 90% petro gas and 10% ethanol mix. Now if this occures, well eventually my engine will not start up. So by placing 100% petro gas in the engine every once in a while will prevent this from happening.. maybe.. And adding 100% petro in the winter might prevent this from occuring.

[niedzwiedz]

I just ride a 50cc and I tried it with all the different grades and never noticed a difference going up hills or an increase in speed.
I had been told about the Ethanol being bad for certain engines, I not really know. But, the Stations I buy from "say" they are 100% no ethanol. Since their price is not any different from other's I see no reason to buy a 10% ethanol whether it does any damage or not.
I do buy the higher Octane 92/91 or sometimes 89. My scooter holds less than 2 gallons so any cost differences may be 20-30 cents.
I like to joke with the people about buying premium, as they buy the cheapest and ask how many miles I get to the gallon.

[scooter12]

lol... Ya, I like telling people around 70 mpg, will do 69 mph on the level ground and faster down hill, all for $1700 including shipping to your home. Well, ethanol is a bad choice we Missourian that have smaller engines that take more compression to run. The ethanol is not bad every once in a while. Can save one money... But continually ethanol can be bad because it seperates in cool weather. I use Seafoam, but that might not be good in 20 below zero weather. Even though I never try to start my scooter when that cold outdoors, the gas/ethanol mixture can't be all that healthy for an engine at such temperatures. Pure 91 octane gas may cost a little more, but may save you headaches when trying to start it. It is 100% petro gasoline.

[Bashan]

Man, I don't know what part of this thread to save for the tech Library! You guys covered about all of the octane debate. Around here you can't get any gas without ethanol. When I bought my Vulcan 1500 in 2000 the manual said don't worry about ethanol, it's made to run on it. After 11 years and 50K miles there has never been a problem related to fuel lines, injectors, etc. So they can make them ethanol compatible if they want to. The guy at the auto store told me that all fuel lines, vac lines, pumps, etc., they sell are ethanol compatible too. Now I don't know if the Chinese are adapting for that or not but if you swap all of your lines with auto store replacements that would take at least those parts off of the table. Rich

[scooter12]

I always hear, China uses a cheaper grade steel.. This maybe true.. If so, well is the rubber parts the sameway.. I don't actually know this. Just information others have suggested about Chinese scooters. Like on Scootdawg Forum, they claim to use Seafoam as a gas additive to stop ethanol from seperating.. Claim it cleans ones gas lines from corrosive ethanol.. I hear, don't add a octane booster because it don't work..

Ethanol evidently will cause a engine to knock and ping, if gets cooler. Missouri gets 20 below zero at times. Chilly. Missouri adds 10% ethanol to gasoline that is 87, 89, and 90 octane gas. They don't add nothing to 91 octane gas- so it is 100% petro gasoline. It is a bit more costly, because of this. So I posed the question in the winter time, is it better to use 91 octane gasoline because it lacks ethanol which could make the engine knock and or ping if live in a area that gets extremely cold? By getting cooler, ethanol looses some octane.

[go4it]

Here's a very good artical on ethenol fuel worth reading. Based on it and a few other articals I've read I have to agree that at the very least a fuel take should be kept topped off if using ethenol. But of course not using it at all in winter is the best idea. At least not in a vehicle that will not consume the fuel quickly.

Bob

www.azbw.com/past_issues/november07/b7_ethenolfuel.php

[speedracer]

I use 89 octane and my 250 54B has 9600 miles on it. Every time I fill it up I put an ounce or two of Seafoam in the gas.

[scooter12]

Ya, I generally use 89 octane..but my scooter sounds a bit rougher than usual.. Starts up fine, but rougher sounding and pinging.. I went ahead and fillup up half a tank with 91 octane gas. The ping noise is now gone. This would raise the octane level and mixing the gas with 100% gasoline would add a higher percentage of gasoline to the ethanol.

I know you live in SC... I was in SC in Columbia watching my son graduate from the army.. Pretty warm there compared to Missouri. Now my scooter slowly stopped pinging because the more powerful gas took a bit to get to the carb..

[jct842]

the only difference I have ever noticed with motorcycle/scooters between hi octane and low is with my 1200cc bandit in the summer the engine was a bit balky at low rpms when using 87. in the summer I did use the good stuff only because there were several real low speed turns on my dirt road and I had more engine control with it. the 3 scooters I have now all have 87 in them and run just fine.

now crapahol is a different problem. for the same price is stupid to buy it. besides the inherent problems like absorbing water it has way less btu's compared to gasoline and gas would still be a better buy at a quarter a gal more.

[scooter12]

Well, I discovered what was pinging.. My center stand has become bent, thus does not fit right. So anyhow, is was metal again metal: the crankcase and centerstand causes a vibration that I had difficulty locating the noise. Thought is might be pinging due to octane and ethanol. Come to findout, it was due to the centerstand, so I will go back to 89 octane with 10% ethanol.

[imnts2]

We are having less and less problems with ethanal. In the late 80 and early 90's I was in Illinois (sort of a corn state) and we were amoungst the first to use a lot of ethanol . I did a lot of custom work on british cars and we had a mess. Overrnight we were loosing diaphrams in fuel fumps and carburators. Even new diaphrams would melt in the stuff. Of course, in a few months , most of the suppliers were providing us with ethanal proff replacement parts and we moved on. The US and Brazil and perhaps Canada are the only nations I know of that now use ethanal fuel. From a marine standpoint, that is a big share of the world market and so expect those people to make enough noise to have some effect either in solving the problem or stopping the expansion. We are seeing more and more fuel injection in outboards and that seems to go a long way to solve the problem. No commonly manufactured automobile is without fuel injection any more. Despite how small our scoot market is, more and more scoots have become more ethanal tolerant via fuel injection. I also think the fuel manufacturers are getting better at the blending because modern fuel seems to work better in my antique string trimmers and chain saws than it did a few years ago. Even my 89 outboard seems to tolerate this years ethanal better than it did a few years ago. Either that or I have gotten better at keeping fresh fuel in it.

The bottom line is - I do not think we have seen anything yet. For the first time in history one nation bought more cars than the US only a few months ago. (China) But China's appetite for gasolene is just gotten a good start. India is not far behind and rapidly growing too. And 3/4 of the world is next. Thinking ahead the next 50 years is almost frightening. It may turn out we were very wise to be early in learning what we are about using corn fed engines.
Happy new year

lefty2

[Deleted]

I always use 93 octane from Shell (V Power) That's because I have a high compression piston.