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Mogas and E/PMags

ExtraKatana

Well Known Member
I have successfully run a mix of non-Ethanol Mogas in other O-360's with standard Slicks timed at 25 BTDC and Std 8:5.1 compression pistons. I know there is a relationship between octane and advanced timing, and E/PMags advance further than standard slicks based on RPM and MAP. I have read the PMag manual and understand in bold letters that Emagair has not run these tests.

I have a fairly new airplane with dual PMags / O-360 with 8:5.1 compression.
As Avgas prices continue to rise I'm flirting with the idea of an Avgas/Mogas mix. Based on previous good experiences (lower cost and what appears to be cleaner oil) I would like to run the mix in my current O-360 with Dual PMags.

Has anyone experienced results with Mogas/Mogas-Avgas Mix, Dual E/Pmags and O-360?
 
PMAG's & Mogas

I have successfully run a mix of non-Ethanol Mogas in other O-360's with standard Slicks timed at 25 BTDC and Std 8:5.1 compression pistons. I know there is a relationship between octane and advanced timing, and E/PMags advance further than standard slicks based on RPM and MAP. I have read the PMag manual and understand in bold letters that Emagair has not run these tests.

I have a fairly new airplane with dual PMags / O-360 with 8:5.1 compression.
As Avgas prices continue to rise I'm flirting with the idea of an Avgas/Mogas mix. Based on previous good experiences (lower cost and what appears to be cleaner oil) I would like to run the mix in my current O-360 with Dual PMags.

Has anyone experienced results with Mogas/Mogas-Avgas Mix, Dual E/Pmags and O-360?

My RV-7A is setup with dual PMAGs. I've been running 93 Octane E10 gas for years with no unknown issues. I also have my AUX fuel pump automatically turn ON (like it does in your car) if the fuel pressure at the fuel body goes below a set point (that is higher than the alarm setting). That system uses an independent fuel pressure sensing circuit that turns ON the AUX pump until the sensed pressure is above the set point, plus 10 seconds.It is almost impossible to get a vapor lock if the fuel is ALWAYS under pressure to the engine pump. That system, plus no 90* fittings, and air on the engine fuel pump, is very reliable.
 
that is certainly a +1 for Mogas.
I'm assuming you have injection? StD Compression? PMags timed at TDC?
 
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Its a gas...

I have successfully run a mix of non-Ethanol Mogas in other O-360's with standard Slicks timed at 25 BTDC and Std 8:5.1 compression pistons. I know there is a relationship between octane and advanced timing, and E/PMags advance further than standard slicks based on RPM and MAP. I have read the PMag manual and understand in bold letters that Emagair has not run these tests.

I have a fairly new airplane with dual PMags / O-360 with 8:5.1 compression.
As Avgas prices continue to rise I'm flirting with the idea of an Avgas/Mogas mix. Based on previous good experiences (lower cost and what appears to be cleaner oil) I would like to run the mix in my current O-360 with Dual PMags.

Has anyone experienced results with Mogas/Mogas-Avgas Mix, Dual E/Pmags and O-360?

Tim
I regularly utilize 89 Octane Non Ethanol MoGas in my 0-360J2A. I use a Emag and a Electroair IGN, dual EI with no issues whatsoever. Judicious use of boost pump below 2K' especially on hot days to avoid Vapor Lock, otherwise no worries.

For what it's worth...
:)
Smokey
 
Tim
I regularly utilize 89 Octane Non Ethanol MoGas in my 0-360J2A. I use a Emag and a Electroair IGN, dual EI with no issues whatsoever. Judicious use of boost pump below 2K' especially on hot days to avoid Vapor Lock, otherwise no worries.

For what it's worth...
:)
Smokey

Thanks. Looks like the judicious concern is for vapor lock instead of the timing from the EI. Good news. I plan to do a mix so not even worried about vapor lock. Encouraging news.
 
I recommend 93 octane ethanol free as the only fuel to use other than 100LL. For dual pMags running either this of 100LL I also recommend setting the timing at the base for your engine - 25 degrees BTDC parallel valve and jumper in (so no more than 9 degrees of advance). My study tells me there is no practical gain for running jumper out, but there is some down side.

For angle head engines I recommend a long discussion with the engine provider before running anything other than 100LL.

Carl
 
I recommend 93 octane ethanol free as the only fuel to use other than 100LL. For dual pMags running either this of 100LL I also recommend setting the timing at the base for your engine - 25 degrees BTDC parallel valve and jumper in (so no more than 9 degrees of advance). My study tells me there is no practical gain for running jumper out, but there is some down side.

For angle head engines I recommend a long discussion with the engine provider before running anything other than 100LL.

Carl
Yes, I am running the "A Curve" with the jumper. I failed to mention that. For setting timing, I think the manual states you set the PMags at 0 TDC or slightly retarded from there and it does all advancing.
 
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Here we go again on the Pmag timing curves. Some observations on my io320 E2D. Less advanced curve- slightly higher EGT and slightly Lower CHT. Can not tell any difference in performance. On the other hand at 9500 ft and above it runs smoother at 100 degrees lean of peak on the more advanced curve.
Running 100LL since I have no easy source of unleaded Auto fuel.
 
MoGas AUX Pump Controller

Just in case you guys want to know how I did the controller, Here's all the info. Feel free to copy it.....
 

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Here we go again on the Pmag timing curves. Some observations on my io320 E2D. Less advanced curve- slightly higher EGT and slightly Lower CHT. Can not tell any difference in performance. On the other hand at 9500 ft and above it runs smoother at 100 degrees lean of peak on the more advanced curve.
Running 100LL since I have no easy source of unleaded Auto fuel.

PMags and Mogas was the question. Thanks for the qualified answers.
 
Wow! That's impressive!

Simple timer circuit.. Radio Shack parts, or now, Jameco. I probably have a few circuit boards left (14) from the sample batch I had made.

Here's the schematic with a parts list....
 

Attachments

  • Aux Pump Schematic.jpg
    Aux Pump Schematic.jpg
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