To MOGAS or not to MOGAS

[Vev]

Good point Qwerty … you’re correct, but it does depend… hope that clears things up for you J?

 

Jack

 

 

[Guest Qwerty]

Oh, OK Jack, thanks for the clarification.

 

 

[Guest watto]

I did have an experience with BP ultimate when I developed a fuel tank leak after a tank of it and although it cannot be proven that the fuel caused the leak I am a bit suspect of the BP product.

 

When I spoke to Shell about the VPOWER they did say that it had no ethanol and they are required to state that it did at the bowser, I will be getting some tomorrow and will test it and post the result.

 

 

[Vev]

Hi Watto,

 

 

Not sure about where (aircraft, car, motocycle ???) you got a fuel leak when you used BP Ultimate …. May I offer you a possible answer as to why?

 

 

In the main, BP Ultimate is lower in aromatics than the Shell and Caltex perfomance fuels, which can cause seals/O rings to shrink and leak, particularly if you have been using higher aromatic fuels and make an abrupt switch.

 

In some instances, you need to manage the switch more slowly to allow seals to adjust to the change in aromatics content…. The fuel companies do this all the time and blend up or down the aromatic content to minimise fuel leaks, particularly with diesel fuels.

 

 

However in support of lower aromatic fuels (BP Ultimate), these are much more compatible with avgas (which have even lower aromatics) and burn cleaner than higher aromatic fuels. A simple test is to run both fuels (BP/Shell) separately and you will see a high soot deposit in your exhaust pipe from the higher aromatics fuels (Vpower) as they don’t burn as cleanly.

 

 

Personally I prefer Ultimate as its high octane (98/99 RON) is an outcome of a better refinery process and not from boosting octane with cheaper, poorer burning, hydrocarbons.

 

 

Of course you use what best suits your needs, but hope this helps?

 

 

Cheers

 

Jack

 

 

[Guest watto]

Wento to get some Vpower and out of stock, popular little mover.

 

 

[wizzard1964]

what will happen when all fuel has ethanol in it? what will it do?

 

 

[Vev]

G'day Wizzard,

 

I think ethanol in Avgas is a long way off (if ever) as it not considered a viable replacement on technical grounds, nor is there likely to be global agreement around a standard spec.

 

Mogas is a different story … E10 in 91 ULP is becoming more prevalent in some states (NSW) and less so in other states. The jury is still out as there just simply not enough of the stuff to blend off into 91ULP and meet 100% of the consumption.

 

Performance Mogas, > 95 Ron, is less likely to be affected with ethanol blends….. In the main the major oil companies have resisted ethanol blends as it undermines the product positioning of better fuel economy, cleaner combustion etc.

 

To answer your question, ethanol plays havoc with plastics (including fibre glass) by softening the materials, it is hydroscopic and absorbs water from air, you have to burn twice as much to get the same energy value and it leaves carbonised deposits owing to poorer combustion. Lastly is has a very high latent heat of evaporation and acts a bit like a refrigerant gas which will chill the induction air and potentially increase carb icing problems.

 

Bottom line ... never use any ethanol fuels in an aircraft.

 

Cheers

 

Jack

 

 

[wizzard1964]

.....

 

I heard (from some expert on the radio) that the only time its worth using an ethanol blend in your car is if it is at least 3c a litre cheaper, due to the fact that you burn more. I have been using it for a few years and found no ill effect on my car. probably 70,000 kms using an ethanol based mix probably 80% of the time.

 

Recently I have chosen the unblended stuff unless nothing else is available (some independents only have blended for the entire range) or if it was CHEAP..

 

 

[Vev]

Hi Wizard,

 

 

E10 should be cheaper as it doesn’t attract the excise tax components as it does on unbelnded fuels; although your fuel consumption will go up… it’s your call if you use ethanol in your car, albeit I wouldn’t use a drop in any of my toys. You will find that all of the major oil companies (independents should too) will label at the pump if the fuel contains ethanol.

 

 

However don’t be lulled into believing it’s ok for your ac because you haven’t had a problem in your car … it is not technically suitable for aircraft engines and it WILL expose you to potential fatal consequences.

 

 

Cheers

 

Jack

 

 

[Dieselten]

Ran a couple of hundred litres of BP Ultimate in my J160C just before the 500-hourly to see if it would clean out some of the lead deposits. It might have cleaned out a little bit, but when I hauled the heads off there was still a lot of yellow lead-oxide deposits on the piston-crown and around the head. To see any real benefit, you'd need to run exclusively on mogas for several hundred hours. I never tried Vortex 98 or V-power (or its pre-decessor, Optimax).

 

My biggest issue with BP Ultimate was carburettor-ice. The engine was very prone to ice as soon as it started and needed several minutes running at about 2000RPM with carb -heat on before it would deliver full power for takeoff. This was so severe I decided to revert to Avgas after the 500-hourly, and have run on Avgas ever since.

 

My conclusion is you can use any 98-octane RON mogas successfully in the 2.2 litre Jab engine, but keep carburettor-ice uppermost in you mind if the temperature is close to the dew-point and the relative humidity is anything above about 40%. Be prepared to spend several minutes ground-running at 200RPM to heat up the muffler so the carb-heat actually works and removes the ice before you try to take off. I actually printed out a carburettor-ice probability chart and laminated it so it can sit in the right-door pocket for ready reference.

 

Once in the air the engine ran beautifully on mogas, never missed a beat and gave smooth power with temps and pressures all in the green. The carby-ice thing was my only problem, and it was a significant one, especially in winter with low ambient temperatures and high relative humidity.

 

 

[zodiac3813]

Hi, I've been running my 2200 (LSA-55) on BP ultimate for about 100 hours: it starts and runs well, with no fuel-related problems... plugs are clean and all temps where they should be. Jim.

 

 

[Sloper]

l have orded my bits and have my plane planning formulated.

 

The engine l have orded wont like running on 100LL all the time so its premium unleaded.

 

BP Ultimate is my first choice, it is garanteed to be of a particuler standard.

 

Two of my cars have fuel issue's for modern feuls, both at opposite ends of the spectrum.

 

The 1940 chev with low compression and would run on anything in the past will only run properly on premium unleaded or fuels with a alchol blend.

 

The Vk Grp3 has a fun engine ;) and only likes premium, which is expected. :)

 

The plane l am about to start building will be set up to run alchol fuels, wheather l use or am force to use is another question, but at least thats done.

 

Also remember Premium fuesl cant be stored as long.

 

regards Bruce

 

 

[Guest Maj Millard]

The carb icing that deisilton mentions is a rusult I would suggest, of the particular engine/carb set up, as opposed to being related to the unleaded premium. This is mre apt to happen with a cold engine after start-up or if there is significant supended water in the fuel. I have run unleaded premium in my 912s for hundred of hours without any apparent carb icing, although I do apply carb heat regulary as required on descent etc.

 

The fact that icing occures on the ground as mentioned, tells me definitly that there is a systems fault.

 

A lot of carb icing can be best described as 'fuel ice' where a system that is already running a very low carb inlet temp, is pushed into the icing area by the rapid evaporation effect of the fuel itself, as it leaves the carb bowl and enters the intake manifold via the main jet.

 

In this case a carb inlet temp sensor on the dash can be a life saver particulary if icing happens on the ground prior to take off................................Maj...

 

 

[Sloper]

Fuel Injection solves a lot of icing problems. ;)

 

regards Bruce

 

 

[facthunter]

Don't like running cold.

 

The later fuels do not vapourise as easily as avgas and the older blends because they use some aromatics with very high boiling points. This means that you have to enrichen or warm the charge to keep the engine happy, if it uses a carburetter. Injection, which is what virtually ALL modern vehicles have is not affected, because the injectors operate under pressure. It may not be icing that is the cause, but poor vapourisation. Nev

 

 

[Jack Tyler]

E10 Fuels

 

Yet another interesting discussion about fuels, which seems to be near the top of most plane owners' lists of worries.

 

At the moment, I'm writing this from the Land of E10 Fuel - Florida, USA. This state (and others) have mandated E10 fuel and, even for cars the effects are noticeable. The mileage in our Honda Civic EX dropped 10% (33 to 30 mpg) once we had to shift to E10 fuel, so the '3% price difference' mentioned above is a bit low, IME.

 

Experimental owners of all stripes have been very worried about the disappearance of non-Ethanol fuel supplies for some time here, and reports of leaking fuel tanks, failed fuel lines and such are, I'm told by a builder-pilot friend of mine here, not uncommon. There is a helpful website offering a USA-wide non-Ethanol fuel data base - Ethanol-free gas stations in the U.S. and Canada - for just this reason.

 

We're fairly new to the Brisbane area but, so far, I haven't noticed these high-RON rated fuels at the local pumps. Presumably, only specialty vendors offer the fuels being discussed here. I must say: I'm very impressed you can find 98+ rated fuel. The highest mogas RON rating commonly available in Florida is 93...and even that is not available at all fuel pumps.

 

Jack

 

 

[Vev]

Hi Jack,

 

You are spot on in terms of fuel consumption increase using E10, although it should be more like a 5% change ... the energy value of ethanol is close to half of mogas and therefore you need to burn almost twice as much to get the same energy value.

 

The actual octane rating on the pumps in Australia is measured differently to the US. Aust report the RON number and the US uses what is called the AKI (Anti-knock index) which is the average of the RON & MON (R+M)/2.... in reality AKI 93 in Florida is the same as RON 98 in Australia. You will find that 98 is available from just about all the major oil companies.

 

Cheers

 

Vev

 

 

[Jack Tyler]

Vev, thanks for that. I now have to adjust my thinking about octane ratings along with monitoring my Oz Slang Dictionary and the exchange rate... <g>

 

Jack

 

 

[dazza 38]

Today Tonight, tommorrow night are doing a story on theives putting water and other products in Service Stations tanks.Destroying engines.Might be a good story to watch.

 

 

[Vev]

G'day Jack T,

 

Strewth cobber, to learn the lingo will be a mongrel for a septic ... you will sound like a galah for a while but you'll be apples in the end. To give you the drum, head past the black stump and do some jackaroo yakka .. no raw prawns out there mate and you'll pick up dinkum stuff.

 

Hooroo

 

Vev