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Old 10-02-2008 | 01:11 PM
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carrellh
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From: Garland, TX
Default RE: Fuel Change?

ORIGINAL: Warnberg
Will I notice a difference in the way the engine runs from 10% nitro to 15% nitro?
Many engines turn more RPM (with the same prop) with 15% nitro versus 10%. From what I have seen, the OS four stroke will probably show a bigger increase than the OS two stroke. There are engines with compression ratios too high for 15% but they are not made by OS.


Will it idle better with 15% nitro?
Some do, some do not. If the idle mixture is really right, for the fuel being used, the OS engines seem to idle well regardless of nitro percentage.


Are there any benefits or drawback's to switching fuels?
Benefits
- potentially more power and performance

Drawbacks
- 15% costs more than 10%.
- Fuel economy often decreases as nitro percentage increases. If tank size is marginal this may be a concern.


From what I can tell both types of fuel will run fine in both engines... am I incorrect in that assumption?
OS Two strokes and four strokes list 10% and 15% nitro as acceptable and they recommend 18% oil. My brother and I have two and four stroke engines from multiple manufacturers. We use the same fuel (15% nitro, 18% oil) in everything.