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  #1  
Old 12-06-2019, 08:55 AM
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avrojockey avrojockey is offline
 
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Location: Appleton, WI
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Default Auto Fuel and EMag

O-320 parallel valve with 8.5:1 pistons running mostly non-ethanol 91oct pump gas. My regiment involves one tank auto and one tank 100LL. I take-off and climb out on 100LL, cruise and descent on auto (normally 1hr flight), and switch back to 100LL for landing. All this, from my reasoning, give me better margin regarding detonation and vapor lock in critical flight phases.

I'm just about to install my first Emag and wondering if I need to retard the A curve slightly using the "clocking" method.

I'm guessing using the above technique I could get away with the B curve, but not sure if I should take any chances on pump gas considering the potential risk of accidentally taking off on auto fuel tank. Given this scenario should I stick with the standard A or do I need to retard even further?
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  #2  
Old 12-06-2019, 10:15 AM
dougmattson dougmattson is offline
 
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Location: Dike Iowa
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Default

I have the exact same setup. I am using standard a curve timed at tdc. It seems to be working fine.
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  #3  
Old 12-06-2019, 10:31 AM
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N941WR N941WR is offline
 
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We have found that regarding the P-mags by 1.4?, you will see a drop in CHT's and a slight increase in TAS.

The reason is that it moves the A curve (jumper in) timing from 26.6? to 25.? for takeoff and from 25.0? in cruise to 23.6?.

While you can clock them, it is best to do it programmatically with either the EICAD program or an EICommander.
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  #4  
Old 12-07-2019, 01:02 PM
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avrojockey avrojockey is offline
 
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Location: Appleton, WI
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Default

Quote:
Originally Posted by N941WR View Post
We have found that regarding the P-mags by 1.4?, you will see a drop in CHT's and a slight increase in TAS.

The reason is that it moves the A curve (jumper in) timing from 26.6? to 25.? for takeoff and from 25.0? in cruise to 23.6?.

While you can clock them, it is best to do it programmatically with either the EICAD program or an EICommander.
Is this on an O-360? If so, how does this correlate to a 320 considering the stroke is different. Does anyone know if this matters considering the same compression ratio of 8.5:1?
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