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converting to fuel injection compatible with E10

deej

deej

Well Known Member
I've been thinking about converting the O320-E2D 150hp Lyc I have in the Glastar to fuel injection. I'm trying to make sense out of the various things I've read about fuel injection, and would like to get some feedback from the group. Yes, it is a Glastar versus an RV, but many of the same principles apply, and there is a wealth of knowledge in this group. :)

I've heard that you get a little more power out of the engine with FI. This apparently has something to do with a carb using about 1/2 inch of inlet air pressure simply in the way that a carb works, so there is 1/2 inch less manifold pressure, thus slightly reduced power. Truth, or fiction?

I've read that you get slightly better gas mileage, with some people reporting up to 1 gal per hour less using FI versus a carb, related to being able to run LOP and also because the FI balances out the fuel to each cylinder. Truth, or fiction?

Airflow Performance FM-150 claims to be compatible with mogas using 10% ethanol (E10). They also offer the FM-100 unit which is also compatible with E10, and offers a recirculating purge valve option. Anyone have any experience using these FI systems?
http://www.airflowperformance.com/html/site_html.html

I am having a hard time finding information on just how much of a PITA it might be to convert from carb to FI, and exactly what parts I'd need to do it. In addition to the FI unit itself, I'd also have to replace the mechanical fuel pump with either a mechanical or electrical high pressure pump, but I'm not sure what else I might need. My air intake is the standard huge NACA scoop on the right side of the cowling. Can I still use this, and the associated air intake hoses to go to the FI unit, or would I have to rework the cowling in some manner?

If I went with one of these FI systems, the only thing left that may not be
compatible with mogas is the mechanical fuel pump. There is an
electrical fuel pump option which is quite expensive, but not having an
electrically redundant electrical system I'd be hesitant to use this option:
http://www.flyefii.com/add_components/BPM/BPM.htm

Has anyone converted from carb to FI and can offer some insight?

Any concerns combining an FI unit and a P-mag (replacing the right mag)?

Just trying to learn about all this, and ultimately aiming for an 87 octane E10 compatible fuel system if at all possible.

Also, if anyone has any information with regards to making a carb and/or
low pressure mechanical fuel pump compatible with mogas containing
ethanol, I'd like to hear from you.

Thanks,

-Dj
 
FI conversion

Probably a waste of time and money IMHO unless you are planning to replace the whole engine.

Just went thru this with my 6A.

Besides engine parts, add a high pressure boost pump,remove the sump, modify cowl as needed, change out fuel pressure gage/sender, perhaps modify air filters and intake system, engine controls change and re-rig.

Why not just enjoy what you have?
 
Vern said:
Besides engine parts, add a high pressure boost pump,remove the sump, modify cowl as needed, change out fuel pressure gage/sender, perhaps modify air filters and intake system, engine controls change and re-rig.
Click to expand...

Hi Vern,
What engine parts did you have to change out (besides the carb to FI)?

What modifications did you have to make to the sump? I was under the impression that the FI unit bolted to the same place as the carb with no modification needed to the sump.

What cowl modifications did you make?


Vern said:
Why not just enjoy what you have?
Click to expand...

Avgas at the local airport - $6.08 per gal
E10 at the local gas station - $3.43 per gal
Basic Economics - Pricele$$

In addition to the obvious price differences, I am trying to find out if there are other advantages, such as increased power, better fuel economy, etc. That's the primary reason why I started this thread... :)

-Dj
 
JDRhodes said:
You can probably run E10 in a carbed 150HP O-320 as-is.
Click to expand...

Hi Jeff,
There are a lot of postings on VAF about the carb not being compatible with E10. If I could somehow get the carb rebuilt to be compatible with E10, I'd definitely consider that option.
 
The reality is that a carburator will make a little more power than FI, but only under the strictest conditions (on a test bed), which will never be seen in an airplane or even in your car.
FI is not hampered with having to combine fuel and air, and hand operated mixture control is far more precise as well. FI will deliver better fuel consumption, and even improve oil comsumption.
As to E10, we have operated two engines on the stuff, one with 540 hrs, and the second past TBO more than 700 hrs, and both engines performed well.
Both are carburated. My own has FI, and it too runs fine with no ill effects.
As to running a P mag with a regular mag, it would be negating the more positive quality of the P mag. One with the more desirable variable timing and high spark, the P, and the other with fixed, and weaker and short duration spark 120 year old magneto.
 
I switched a superior 0-360 to FI. I bought a used bendix servo and spider/nozzles from a salvage yard, and sent it to Don at airflow. He set it up to run on ethanol for me. I also got a hi pressure pump from him(same that vans sells).

All in all, I replaced the carb with the servo(a spacer about 1" thick is needed between the sump and servo), replaced the mech pump with the HP one, and installed the fuel spider and plumbing.

I have run up to 60% (60% E98, 40% 100LL) ethanol with no problems. Keep working with Don, he will treat you good.
 
I've recently been introduced to the Rotec TBI (http://www.rotectbi.com/), which is E10 compatible. It is almost a bolt-on replacement for my current carb setup, and much easier for me to install than a full FI system. It will bolt up to the engine and my intake plenum in place of the carb, but I'll have to re-do either the mixture or the throttle cable due to the different physical location of them on the TBI unit versus the carb. The cost is $799, and people seem to be having great success with them, including some posts here on VAF.

It will work off the gravity feed fuel system in the Glastar, although I will be installing an electric boost pump for takeoff.

From my perspective, this seems like the easiest and cheapest way to get to a fully compatible E10 fuel system from where I am now.

-Dj
 
Fiberglass fuel tank issues

DJ,
AFP uses Flourosilicone rubber parts in all their FI products. This rubber compound is designed for both ethanol and the various additives used in unleaded auto fuels. That said, there are issues with ethanol attacking components of the fiberglass resin used in the fuel tanks of "glass" airplanes. I am pasting one such below. It is from the Marine Manufacturers Association. I live in SE Florida. The marine industry is very big here. Lots of complaints of problems using E10 fuel in vehicles with fiberglass fuel tanks. The local marinas now all carry unleaded fuel WITHOUT ethanol. See below.
Charlie

The Negative Affects of Ethanol on Recreational Boat Fuel Systems

The National Marine Manufacturers Association (NMMA) opposes the use of marine fuels that contain greater than 10% ethanol content by volume. This position is based on safety and durability concerns and supported by many well documented studies.

According to state boating registrations, there are over 12 million recreational boats in the United States. Boat builders utilize five types of materials to fabricate fuel tanks. These are aluminum, steel, cross-link polyethylene, high density polyethylene and fiberglass. For a rough estimate of today?s numbers, there are approximately four million boats that have aluminum fuel tanks; approximately seven million have steel or polyethylene tanks, and less than one million have fiberglass tanks. The data clearly indicates that the increased use of ethanol in gasoline has raised safety and durability issues for aluminum and fiberglass fuel tanks.

Aluminum Fuel Tanks

In the case of aluminum tanks, aluminum is a highly conductive metal that relies on an oxide layer for its corrosion protection properties. Low levels of ethanol, such as E10 (10%), are usually not a problem in aluminum tanks because the oxide layer provides a good measure of protection. The problem occurs when the ethanol content is increased.

There are two mechanisms that occur with ethanol. Both mechanisms are a result of the hydroscopic property of ethanol, meaning it absorbs water. The more ethanol in the fuel, the more water there will be in the fuel tank. Water not only causes the tank to corrode, it also causes the corrosion particles to clog fuel filters, fuel systems, and damage engine components. The corrosion rate can be accelerated under a number of conditions if other contaminating metals are present such as copper which may be picked up from brass fittings or as a low level contaminant in the aluminum alloy. Chloride, which is a chemical found in salt water, will also accelerate corrosion. In the long term, corrosion can perforate the aluminum to produce leaks that would cause fuel to spill into the bilge and end up in the environment. In the worse case it could cause a fire and/or explosion hazard. Boat fuel tanks are often located under the deck next to the engine where the operator might not be aware of a leak until it was too late. .

The second mechanism that can occurs with the increased use of ethanol based fuel in aluminum tanks is galvanic corrosion. Gasoline fuel is not conductive, but the presence of ethanol or ethanol and water will conduct electricity. The galvanic process that occurs to aluminum trim tabs, stern drives, shaft couplings, etc. will occur within the aluminum fuel tank. Boat builders are able to protect exterior aluminum boat equipment with sacrificial anodes known as zincs. Sacrificial anodes are not a feasible option for the interior of a fuel tank.



Fiberglass Fuel Tanks

NMMA is in the early stage of evaluating the effects that ethanol in gasoline has on fiberglass tanks. Boat U.S., the boater advocacy association, recently issue a consumer alert reporting that owners of older yachts have experienced leaking fiberglass fuel tanks. There have also been reports of heavy black deposits on the intake valves of marine engines resulting in bent push rods, pistons and valves. Some of the preliminary analysis conducted by an independent lab found the deposits to be di-iso octyl phalate, a chemical found in the resin, gel coat and filler used to make fiberglass fuel tanks.

An initial theory is that when ethanol is introduced to the fuel tank the very small ethanol molecules diffuse into pores between the resin where they dissolve the unreacted phalates. Since the phalates are in solution they are able to pass through the fuel line filters. These phalates have exceptionally high temperature stability and remain intact when the fuel evaporates in the carburetor or undergo only partial decomposition in the combustion chamber thus creating the heavy black deposits on the engine?s intake valves.

Unlike aluminum, NMMA has yet to identify the effect that ethanol in fuel has on the tanks integrity or even the root cause of dissolved phalates. The theory is that it is being caused by ethanol and we know that ethanol dissolves phalates, but more testing is currently being conducted.

Conclusion

As stated in the opening paragraph, the NMMA has serious safety and durability concerns with the incremental increase in ethanol content in gasoline motor fuel. The majority of marine engines in use today are open loop systems that are designed, engineered and calibrated at the factory to operate with fuel containing either 10% MTBE or ethanol. Changing the fuel that these engines were designed, engineered and calibrated for will negatively effect driveability, exhaust and evaporative emissions, and potentially damage the components.

While these issues are significant, the boaters have a far more serious issue. The available data indicates that aluminum and fiberglass fuel tanks and Butyl rubber fuel hoses that are currently being used will fail if the ethanol content is increased to 20%. That is not an emissions issue; it is not a driveability or durability issue. It is an issue that needs to be taken far more seriously. It is a threat to the health and safety of the boaters in your state.
 
chaskuss said:
That said, there are issues with ethanol attacking components of the fiberglass resin used in the fuel tanks of "glass" airplanes.
Click to expand...

Hi Charlie,
Thank you for the information. The Glastar has aluminum tanks, so they should be fine with E10.

-Dj
 
Off the sauce...

Hi Charlie,

Excellent post on Ethanol. One thing to add, I too live in FL and buy ethanol free fuel from a local station from this site: http://pure-gas.org/
The owner said the highest octane he can get in FL now is 90 previously 93. My 150HP RVX loves it, cleaner plugs and inside parts than 100LL. I do use Marvel occasionally and CD3.
Question: How does ethanol affect slosh. My RV4 tanks were sloshed per the plans in 89' when I built it. Even though slosh is now a bad word, it is still very well attached inside my RV4 tanks 20 years later. It was applied properly and has been running mostly MoGas some of that E10 all these years. No worries so far. Your thoughts?

Smokey
 
just curious what CD3 is?

been running car gas,MMO, mix with 100LL in carbed o-360 for years now.
the engine likes it, my wallet likes it, my back doesnt like it.
 
chaskuss said:
DJ,


snip.....Gasoline fuel is not conductive, but the presence of ethanol or ethanol and water will conduct electricity.....
Click to expand...

I would like to add to this, that this is not exactly correct.

Ethanol and water mixtures are NOT CONDUCTIVE...if they are pure with no ionic content.

In other words is there are no salts or metal ions released into the mix they will not conduct very well and they will not produce corrosion. However, salt does find its way in there and then you have a component of water in with the ethanol, and some salts, and it is THAT mixture that will corode your tank.

Water will be part of any ethanol mix. It just sticks to it. Not in massive volumes but because of the -OH group on the ethanol the water dipole will will stick to it like a magnet.

in other words....

No matter what you do you will get a bit of water in your fuel but it won't be in a blob, it will be disolved but its there. Add a bit of salt from normal sea spray conditins and over time the two will do their thing. It means priming the inside of your fuel tank if your going to have ethanol as part of your fuel mix.... and don't ask me what that will do to the fuel I have no idea.
 
I once had an in flight fuel tank failure on a c-150 while I was flying by myself with only 30 hours (yup, didn't even have my ticket.)

When I removed it you could poke a screwdriver right through the bottom of it. The nearest I could tell was that the previous owner ran mogas in it, and at that time ethanol was required to be in the fuel during the winter months. I think that the water that was suspended in the tank combined with some other junk and that caused the corrosion.

Anyway, I had the tanks patched and welded up, then flew it another 80 hours before I sold it.

I'm not that interested in flying with ethanol in my tanks. Hopefully we will retain enough freedom to put good fuel in our airplanes without pumping a bunch of lead through them.

schu
 
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