There seems to be a lot of evidence that if your compression ratio is 8.5:1 or less and you use 92 octane fuel you will be ok. If you are worried, you can retard the base timing by a few degrees (say, 22-23 instead of 25 BTDC).
What evidence?
I've been running 87 mogas for almost 1000 hours now, O-360 std. comp. and an Electroair/mag setup.
Where have you read this? I follow E/P-mags fairly closely and haven't don't recall seeing a thread on this?...Most of what I have read previously before i heard of pmags was DON't run mogas in this type engine for a variety of reasons.
... thanks
Where have you read this? I follow E/P-mags fairly closely and haven't don't recall seeing a thread on this?
What base timing setting are you using? Do you ever run lean of peak?
Most of the "evidence" seems to be theoretical, with one or two people having reported detonation under certain circumstances. With carburated engines it is harder to flow match, so running lean of peak stands a greater risk of detonation in one cylinder - but that too seems to depend on the airplane.
There is a good bit of difference between the installation of the E/P-mags and Laser system. The E/P-mag installation is simple as they just plug in like a mag, wires run, and they are timed. The difference between the two is the P-mag has an internal generator that allows the unit to power itself, if your electrical system goes out. The Laser is a bit more complex in its installation as you have to mount a brain box, coil packs, and trigger. Most people run one Laser and one traditional mag, just incase their ship?s electrical system dies. That or they have an extra battery wired in just to power their ignitions. The functional operation of these units is about the same.Keep in mind that I know little or nothing about this issue. Here are several issues that I have questions about:
1. What are the differences among the various installations? P/mag, E/mag, Lasar, etc. That has been touched on here briefly, but mainly quotes like "I have this or a combo of that, etc."
Fueling (not the type of fuel) has little to do with the ignition. The need for a fuel return line has to do with the type of fueling system you run. A carb does not need a fuel return line and neither do some FI systems.2. Do you have to have a fuel return for auto fuel or does an 0-320 D1A with pmags just fly away with mogas? without fuel injection - with just a carb?
See this thread.3. Lycoming says no auto fuel in 8:50:1 ratio compression engines.
4. What other changes are needed, different hardware or fuel lines or gaskets or changes to the standard Vans fuel pump, etc.?[/url]
None, if you stay away from ethanol. Because we are running parts (fuel pumps & carbs/FI mostly) that are approved by the FAA, they have parts in them that may deteriorate over time with exposure to ethanol. Do your research before running ethanol, call the EAA and ask them about it, etc. Frank is having good luck running ethanol laced mogas in his RV and I expect you will hear from him.
The best info on the E/P-mags is here in the EI section of this forum. You will have to search for it, but it is there. Also, down load the manual from the Emag web page, that explains the installation and operation of their systems....Thank you for taking an interest in my questions and would appreciate any reference material you could provide links to. Since my last post I have found a couple of articles regarding LASAR. But other than suppliers websites, that's about it. thanks
Full disclosure: I am an E/P-mag bigot. Do your research, they have had problems in the past but but based on what I have heard, those problems are in the past and there have been no new issues for almost two years.
Stock timing, 25 deg. I have a timing advance meter, and at the altitudes I usually fly it stays at 25-26 deg. Carb setup so I can't consistently run LOP. When leaned I usually run 8.5 GPH on 87 mogas.
RocketBob,
Do you run mogas w/ ethanol? If you do, what modification is necessary for your carb to make it compatible with ethanol?
Thanks,
Robin Hou