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Old 03-09-2008, 01:00 AM
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Low octane fuel or High octane fuel??

Hey guys, what can be a difference between using low or high octane fuel??, on a DA 5O, I have always use low octane fuel, I would like to try high octane is there really a diffence?, what are pros and cont?.

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Old 03-09-2008, 01:01 AM
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Re: Low octane fuel or High octane fuel??

Here in Mexico, low octane fuel is 87 and high octane fuel is 92...
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Old 03-09-2008, 01:25 AM
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Re: Low octane fuel or High octane fuel??

Hi Benji,

Here in Aust we have Regular which is 91, Premium which is 95 & Ultimate which is 98.
I started using 98 in my ZDZ & it ran great. I then thought i would try 95 & re tach it.
The 95 was slightly better than the 98 (50-100 or so revs give or take)
I put this down to the fact the ign timing as it was set was more suited to the 95 fuel than the 98. As i have no accurate way of setting the timing except for trial and error i left things as they were & ran 95. It starts well, runs well & performs well.
I could possibly get more power by advancing the ign and richening the mixture, but at what expense.
No harm in trying it. It wont hurt anything, but tach it now then re-tach it with the new fuel to see what is better.
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Old 03-09-2008, 07:14 AM
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Re: Low octane fuel or High octane fuel??

I've tried 87,89, and 91 in my DA-50. It appeared to me like it ran best on 87. That is also what DA recommends, they must know something.
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Old 03-09-2008, 07:24 AM
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Re: Low octane fuel or High octane fuel??

Exactly, DA recommends 87 octane for all of their engines.
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Old 03-09-2008, 07:42 AM
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Re: Low octane fuel or High octane fuel??

The octane rating that is recommended for any motor is based on the compression ratio of that motor. The higher the compression the higher the octane necessary to prevent detonation. If you run high octane fuel in a motor that recommends 87 you may not notice any difference other that the costs. But if you run 87 in a motor that requires high octane fuel you run the risk of the fuel igniting to early and can damage your engine.
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Old 03-09-2008, 08:29 AM
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Re: Low octane fuel or High octane fuel??

Quote:
Originally Posted by Shoe View Post
Exactly, DA recommends 87 octane for all of their engines.
I have a 100 and a 150 the 100 directions say use low octane and the 150 directions say use mid to high octane.
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Old 03-09-2008, 08:41 AM
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Re: Low octane fuel or High octane fuel??

I run 87octane in my DA100,, you gain NO performance advantages running 89 or 92 or anything higher,
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Old 03-09-2008, 08:59 AM
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Re: Low octane fuel or High octane fuel??

I run 93 octane in my DA 150 like DA says. I just follow the rules whether it makes a difference or not.
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Old 03-09-2008, 09:03 AM
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Re: Low octane fuel or High octane fuel??

My DL-50 is low compresion ratio so i run 87 octane. My ZDZ 80 is a higher compresion engine i believe 11:1 so i run 93 octane.
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Old 03-09-2008, 04:08 PM
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Re: Low octane fuel or High octane fuel??

I've always run high-test (92 or so) in my ZDZ, because that's what they recommend, and regular in the DA-150.

The higher the octane, the slower the fuel burns. An engine with more compression running low-octane fuel will risk detonating the fuel before the spark plug fires, causing damage to the engine. Higher octane is for higher compression because it burns more slowly.

So raising the octane level on an engine that runs fine on regular fuel will make it burn slower than it needs to. It's more expensive, and you will notice no performance increase, perhaps even a decrease.

The idea that running higher octane than normal gives you a performance boost is false.
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Old 03-09-2008, 05:41 PM
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Re: Low octane fuel or High octane fuel??

Quote:
Originally Posted by Artie Johnston View Post
I have a 100 and a 150 the 100 directions say use low octane and the 150 directions say use mid to high octane.
Yes, that's exactly why I called DA. Our DA-150 manual says to use "mid to high octane." I asked them to put an octane NUMBER on that recommendation. They said to use 87 octane on all of their engines.
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Old 03-09-2008, 07:10 PM
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Re: Low octane fuel or High octane fuel??

Quote:
Originally Posted by Shoe View Post
Yes, that's exactly why I called DA. Our DA-150 manual says to use "mid to high octane." I asked them to put an octane NUMBER on that recommendation. They said to use 87 octane on all of their engines.
Wow, thats fantastic.I'm glad to know they say to do one thing and put in writing something else.What is up with that!!!!!
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Old 03-11-2008, 06:11 PM
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Re: Low octane fuel or High octane fuel??

Welp, I guess in some parts of the country, or world, 87 IS considered mid to high octane.
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Old 03-11-2008, 06:29 PM
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Re: Low octane fuel or High octane fuel??

In the 150 manual it does state to run mid to high octain. This manual was writen back in the late 1990's and will be corrected on the next printing run. 87 to 89 octane gas is what is reccomended for all of are engines however a slightly higher octane may be needed when running tuned pipes. Sorry for any confusion in the manual.
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