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Old 06-30-2010, 03:57 AM   #1
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Default Fine tune your engine according to weather and nitro changes

Here is a guide to fine tune your engine according to weather and nitro changes

http://www.myrcbox.com/?p=3899
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Old 06-30-2010, 08:46 PM   #2
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Old 06-30-2010, 09:48 PM   #3
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Thank You.
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Old 07-01-2010, 05:36 AM   #4
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Hmmm... If I go to a higher oil content the fuel will be thicker so I have to richen the main needle.....
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Old 07-01-2010, 08:25 AM   #5
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Originally Posted by Roelof View Post
Hmmm... If I go to a higher oil content the fuel will be thicker so I have to richen the main needle.....
generally its rule of thumb with all two stroke engines( dirt bike, watercraft, etc. etc.), the higher the oil to gas mixture content is the more of a lean mixture your engine will see. from premixed to nitro engines always richen up a tad if bumping up oil content
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Old 07-01-2010, 08:45 AM   #6
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Hmmm... If I go to a higher oil content the fuel will be thicker so I have to richen the main needle.....
It isn't really because your fuel is thicker................it's because if you increase the percentage of oil content, you must reduce the percentage of something else in your "fuel". Alcohol is the actual fuel in your "fuel".

30% nitro + 10% oil + 60% alcohol = 100%
30% nitro + 12% oil + 58% alcohol = 100%
in the above example the 12% oil mixture would have approx. 3% less alcohol.
Your engine would run leaner. (because of the reduction in alcohol)
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Old 07-01-2010, 10:35 AM   #7
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Nitro and methanol are like water, they have a very low viscocity. Oil has compared with nitro and methanol a very high viscocity and is determing the viscocity of the fuel.

Going from 10% to 12% oil contant is a change of 20%, going down from 60% to 58% is just a 3% change. Believe me, more oil content (taken from the same brand/type fuel) will raise the viscocity and a richer setting is needed to get the same strengt of flow with the fuel.

Beside that, tuning an engine must always be done on a feeling regarding the temperature, smoke, sound and visable performance. For starters it is wrong to show such a list, they just do what the list says but can not messure/feel all factors shown in the list so they can go to lean....
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Old 07-01-2010, 12:05 PM   #8
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Quote:
Originally Posted by motomatt View Post
It isn't really because your fuel is thicker................it's because if you increase the percentage of oil content, you must reduce the percentage of something else in your "fuel". Alcohol is the actual fuel in your "fuel".

30% nitro + 10% oil + 60% alcohol = 100%
30% nitro + 12% oil + 58% alcohol = 100%
in the above example the 12% oil mixture would have approx. 3% less alcohol.
Your engine would run leaner. (because of the reduction in alcohol)
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Originally Posted by Roelof View Post
Nitro and methanol are like water, they have a very low viscocity. Oil has compared with nitro and methanol a very high viscocity and is determing the viscocity of the fuel.

Going from 10% to 12% oil contant is a change of 20%, going down from 60% to 58% is just a 3% change. Believe me, more oil content (taken from the same brand/type fuel) will raise the viscocity and a richer setting is needed to get the same strengt of flow with the fuel.

Beside that, tuning an engine must always be done on a feeling regarding the temperature, smoke, sound and visable performance. For starters it is wrong to show such a list, they just do what the list says but can not messure/feel all factors shown in the list so they can go to lean....
So your both in agreement that higher oil content requires a richer needle setting right? Your just in disagreement on which aspect has a greater affect...

1. because there's less fuel % you need to richen it up to get the same fuel/air mixture
2. because the fuel is thicker its harder to pump the fuel through the motor.
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Old 07-01-2010, 12:09 PM   #9
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Quote:
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Going from 10% to 12% oil contant is a change of 20%, going down from 60% to 58% is just a 3% change.
I was following you until this point. Isn't going from a 10% to 12% oil a 2% change?
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Old 07-01-2010, 12:52 PM   #10
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I was following you until this point. Isn't going from a 10% to 12% oil a 2% change?
Yes. if you say the 10% part of the fuel is 100% oil then you go to 120%....
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Old 07-01-2010, 01:00 PM   #11
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just turn the needles until it runs good and temps are reasonable......... eeeeeeeeeeeeasyyyyyyyyyyyy
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Old 07-01-2010, 01:14 PM   #12
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Old 07-01-2010, 02:21 PM   #13
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I have contacted few engines gurus and manufacturers and they have told me that when we use higher oil percentage, we should RICHEN UP the settings a little bit. I have corrected the post.

Sorry for the inconvenience it may have caused
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Old 07-01-2010, 06:19 PM   #14
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I have contacted few engines gurus and manufacturers and they have told me that when we use higher oil percentage, we should RICHEN UP the settings a little bit. I have corrected the post.

Sorry for the inconvenience it may have caused
Yep, that is correct. The issue is the higher oil content reduces the amount of methanol in the fuel. Methanol vaporizes in the combustion chamber at a relatively low temperature and when it does so it has a heat wicking effect which cools the combustion chamber. This means that the operating temperature of the engine is reduced so you can lean the engine out for additional power/run time. An additional benefit of the increase in methanol content (in addition to the reduction in combustion chamber temperature mentioned above) that is not often talked about is that methanol has a really high effective octane rating or anti knock index give you the ability to safely run a lower deck height hence increasing your engines compression ratio with less likelyhood of pre-detonation.

Regards,

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Old 07-02-2010, 10:27 AM   #15
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Originally Posted by Werks View Post
Yep, that is correct. The issue is the higher oil content reduces the amount of methanol in the fuel. Methanol vaporizes in the combustion chamber at a relatively low temperature and when it does so it has a heat wicking effect which cools the combustion chamber. This means that the operating temperature of the engine is reduced so you can lean the engine out for additional power/run time. An additional benefit of the increase in methanol content (in addition to the reduction in combustion chamber temperature mentioned above) that is not often talked about is that methanol has a really high effective octane rating or anti knock index give you the ability to safely run a lower deck height hence increasing your engines compression ratio with less likelyhood of pre-detonation.

Regards,

Ron

Thanks for the explanations...
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