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MOGAS Use With FI Engines

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gmcjetpilot(at)yahoo.com
Guest

Posted: Tue Jul 04, 2006 1:39 am Post subject: MOGAS Use With FI Engines

ANY CAR GAS OR MO GAS HAS LOWER VAPOR 

PRESSURE AND IS SUBJECT TO VAPOR LOCK.

   

  JUST A NOTE: MO gas is what you can buy out of a pump 

at the airport, MO gas for Motor Gas. Auto Fuel, is what you 

get at the corner gas station. MO Gas is like 86 octane. 

   

  If you need 91 octane you need to get premium from the 

corner gas station. The problem is your plane is at the 

airport. (not much price difference from premium to 100LL)



  So to use Auto fuel in your plane you are faced with the 

hassle of hauling fuel to the plane. This can be a huge 

hassle, dangerous and illegal. At most airports and with  

state highway laws (hazardous material transport) a NO 

NO. You are just not going to be hauling eight 5 Gal jerry 

cans around or 55 gal barrels with gas easily. I can see 

all the cheapskates thinking of the cost savings they 

will get. In fact the  saving is small if impractical for 

91 octane engines. If you have a low compression engine 

that can run on MO gas than sure there is some advantage. 

   

  HOWEVER A RV tight cowl is NOT ideal for MO gas 

operations.

   

  Also price of MO Gas is not that much less than 100LL or 

can you even get MO gas widely. Some times MO gas cost 

more than 100LL. So you might be taking abut $4.00/hr 

savings for all the hassle.

   

  Fuel Injection has nothing to do with it, it is compression 

ratio. All the original STC's where for low compression 

engines that where made for like 80 octane.

   

  There are premium gas STC's for Lyc 320/360's with the 

8.5:1 CR, which needs 91 octane, but not all planes can  

pass the test and get a STC, even after much effort.

   

  A 150HP O320 is a low octane engine, a O235 is  NOT.

   

  The INSTALLATION is critical. When a STC for auto 

fuel is given it is for the installation as well as the engine. 

   

  YES I know we are experimental but you can't ignore 

physics. I recall airplane like the older Mooney's 

with the O360 can't get a STC for premium auto fuel 

because of vapor lock. Like RV's the Mooney have 

very tight cowls. Don't compare the Piper with a huge 

cowl and a RV with a very tight cowl and exhaust pipes 

snaking all around near fuel lines.

   

   

  The overall issue is you will not get AUTO GAS with out 

all the hamburger helper and modified fuel like alcohol 

and ethanol. I remember in Washington state, in the 

winter they went to an alcohol blend fuel. My gas 

milage went in the crapper. That is the other issue. 

Car gas is NOT CONSISTANT. It varies widely by

region, session and testing is a  hassle.

   

   

  If you do go auto fuel insulate and heat shield EVER 

part of the fuel system and add a vapor return line 

even for Carb engines.

   

   

   

  >From:  "Tracy Crook" <lors01(at)msn.com (lors01(at)msn.com)>

 	  Quote: 	
		  

My RX-8 rotary (10 : 1 CR) powered RV-4 runs best and 

gets best fuel economy on 87 octane. I burn 100LL in a 

pinch but plug life is greatly reduced.

  
	


Automotive and aircraft engines are two differnt things. RX8 

cars strictly call for premium and use 2 qts of oil between 

oil changes, and also get terriable gas millage. I know you 

are a rotary expert Tracy but a water cooled car engine 

piston or rotary is not an aircooled aircraft engine. 

  

My Lyc plug life is 1000 hour plus on 100LL.

   

  I am not picking on you Tracy but you  have to take 

the good with the bad. Good, you can use auto fuel; 

Bad, your engine is noisier, heavier and burns way 

more fuel than a Lycoming for equivalent performance.

   

   

   

  >Best experts I've read say that almost all aircraft engines 

 	  Quote: 	
		  would work fine on 91 octane mogas.

  
	


Most aircraft engines where certified for 91, like 320 (160HP) 

and 360 (180 hp) Lycoming. So that is a no brainer,  The 

problem is the MO gas you can buy at the airport is way 

less than 91 octane, like 80/86.

   

  If you want premium AUTO fuel you have to haul. And the 

idea of having your own tank, even on your own property 

is likely to be illegal in most states.

  

We may get a 91UL or 95UL in the near future. Basically I

believe 100LL without the lead.

   

   

  

 	  Quote: 	
		  equipped with knock sensors  to adjust timing appropriately. 

This would be a simple and inexpensive thing to do if the 

FAA were not involved.  

   
	


  The FAA has nothing to do with it.

  

Aircraft engines can not use automotive knock sensor, which 

are basically little microphones. An air cooled engine with out 

water jackets can not use them due to mechanical noise. 

When I say noise I DON'T mean what you hear, like thru the 

exhaust pipe but mechanical valve noise. 

   

  Now combustion chamber pressure probes would work in 

maximizing timing and improving economy of a Lyc, but 

that is very expensive and not needed. Lyc's work at such 

a narrow RPM/Power band you don't need fancy electronics 

to make it work. You do need a trained pilot who knows 

what the red knob is for.

   

  Most (not all) aircraft  engines will work with premium AUTO 

FUEL or the  new 91UL that MAY BE coming down the road. 

I say may be because it might not happen. There are some 

high end piston aircraft engines that will not work with less 

than 100LL.  

   

  BTW Rotaries are of course the loudest engine you can 

put on a plane. Of course there are no valves.

   

  We are again talking water cooled verse aircooled. You 

would think that would give a fuel edge to the rotary but 

in fact the rotary burn more fuel than a Lyc.

   

  You can talk all the ECU tweaking the basic design of 

the rotary will never allow the same spacific fuel 

consumption. The RX8 gets 5 mpg less than equivalent 

220hp sport cars, BOTH City and Highway. Even the 

Nissan Z car with almost 100 hp more gets the same 

milage as the RX8 Mazda. (about 20% less fuel econ)

   

  Do you think Mazda tuned their ECU for best EPA milage 

for  the gas milage sticker test? Sure. 

  

So when talking about the advantage of burning auto 

fuel, talk about the higher fuel burn and oil usage. 

Also mixing oil into the fuel tank is a pain, or if you   

use an oil injector instead, it's more weight.

   

   

   

  >We will still be saddled with the expensive idiocy of a 

 	  Quote: 	
		  separate distribution system for our fuel due to the growing 

mandates to use ethanol which requires 1.3 gallons of fossil 

fuel to produce 1 gallon of the moonshine.  

Are we stupid or what?  

  
	


Well we are not to be political, but where is the presidential 

primaries held? (Iowa?) Where do they grow the most corn 

and what is ethanol made of? (corn?)

  

That is the problem alternative fuel availability Auto GAs and 

Mo gas, with out alcohol or ethanol is getting hard to get.

    

  We can expect that 91UL aviation gas will come down the 

road. IT already has in Europe. For now all we have 100LL.



  		Want to be your own boss? Learn how on [url=http://us.rd.yahoo.com/evt=41244/*http://smallbusiness.yahoo.com/r-index] Yahoo! Small Business.[/url]

jmsears(at)adelphia.net
Guest

Posted: Tue Jul 04, 2006 3:40 am Post subject: MOGAS Use With FI Engines

 	  Quote: 	
		  > ANY CAR GAS OR MO GAS HAS LOWER VAPOR

PRESSURE AND IS SUBJECT TO VAPOR LOCK.<<
	




Actually, I think you'll discover that it's the other way around.  Per a 

note from Mr. Heathco, the vapor pressure in 100LL is very low.  Winter 

blend auto fuel has a fairly high vapor pressure, when compared to the other 

blends.  Winter blend is more apt to cause vapor locking when the temps rise 

to more comfortable levels.  I see the results when springlike weather 

approaches before the fuel is converted to summer blend.



 	  Quote: 	
		  > JUST A NOTE: MO gas is what you can buy out of a pump

at the airport, MO gas for Motor Gas. Auto Fuel, is what you
	


get at the corner gas station. MO Gas is like 86 octane. <<



Well, that's news to me.  Most of us, if not almost all of us, consider auto 

gas and mogas to be the same thing with different nicknames.  I consider any 

gas sold at an airport to be avgas, unless it's clearly mogas (auto gas).



 	  Quote: 	
		  > If you need 91 octane you need to get premium from the

corner gas station. The problem is your plane is at the
	


airport. (not much price difference from premium to 100LL)<<



Well, we seem to have some of this statement correct.  Yep, I consider 91 

antiknock to be premium fuel.  I do buy my auto gas from the local gas 

station.  However, I find that over a dollar a gallon savings to be 

substantial when I use more than eight gallons per hour of it.  Now, if I 

were buying my auto fuel from the local airport, I know it would cost more 

than what I can purchase at the local gas station; but, I've never paid as 

much as 100LL for it, at any airport I've purchased it from.



 	  Quote: 	
		  > So to use Auto fuel in your plane you are faced with the hassle of 

> hauling fuel to the plane. This can be a huge hassle, dangerous and 

> illegal. At most airports and with  state highway laws (hazardous 

> material transport) a NO NO. You are just not going to be hauling eight 5 

> Gal jerry cans around or 55 gal barrels with gas easily. <<


	


Boy, I'd sure like to see that enforced!  Just about every person who has to 

mow his yard has gas cans to go get gas for the mower.  Of course, one must 

not forget that we ferry gas in every vehicle that uses it.  All of my 

vehicles use gas and carry it in their tanks.  Does that mean I'm illegal? 

I don't think so.



Granted, hauling gas for my airplane is a little bit of a hassle.  I'm so 

happy that I can use a cheaper fuel that I'm willing to put up with the 

hassle.  As for the danger, there is some; but, there's danger in driving to 

the airport.  With today's drivers, it's like running a gauntlet to get to 

the airport.  Compared to that, hauling gas in cans is nothing.



 	  Quote: 	
		  > I can see all the cheapskates thinking of the cost savings they

will get. In fact the saving is small if impractical for 91 octane engines. 
	


If you have a low compression engine that can run on MO gas than sure there 

is some advantage. <<



Let's see.  Premium gas is just under $3.00 per gallon, here.  Avgas is 

between $4 and $4.50, roughly, around here.  That's upwards of half as much 

more per gallon.  I don't know about the rest of you guys; but, that's 

pretty substantial to me.



As for being a cheapskate, I like to consider myself frugal.  It's from 

being frugal that many of us are able to afford the expenses of aviation, in 

the first place.  Many of us aren't rich and famous, like you must be; so, 

any savings helps to keep us flying.  If I had to pay for 100LL all the 

time, I'd have to give up flying my own airplane.



Why is it that this guy sounds like a fixed base operator who hates it when 

we don't buy avgas?  He sounds a lot like some of the ones I've dealt with. 





 	  Quote: 	
		  >HOWEVER A RV tight cowl is NOT ideal for MO gas

operations.<<
	




The AA-5A Cheetah I owned had a tight cowl, as well as my RV-6A that I fly, 

now.  Both run just fine on mogas.  Another thing.  I always thought that a 

tight cowl enhances air flow that keeps things cooler.  Keeping things cool 

is what makes using auto gas work better.  Am I mistaken?



 	  Quote: 	
		  > Also price of MO Gas is not that much less than 100LL or

can you even get MO gas widely. Some times MO gas cost
	


more than 100LL. So you might be taking abut $4.00/hr

savings for all the hassle.<<



In my little bitty airplane, I'm saving about $10+ per hour.  Do the math. 

I save over a dollar a gallon on the fuel.  In fact, it's over $1.50, right 

now.  I use at least 8gph.  When I'm on a trip, I use 100LL unless I can 

find auto fuel that's pretty fresh at the airport.



Last year, for the very first time I've seen, there was a spike in auto gas 

that pushed it up to the price of 100LL.  The FBO still had some 100LL at a 

lower price.  The price of auto gas was within a penny of the 100LL.  I 

bought 100LL.



 	  Quote: 	
		  > Fuel Injection has nothing to do with it, it is compression

ratio. All the original STC's where for low compression engines that where 
	


made for like 80 octane.<<



Haven't you read any of the thread?  Use of mogas has every bit to do with 

fuel injection, fuel flows, compression ratios, etc.



 	  Quote: 	
		  > There are premium gas STC's for Lyc 320/360's with the

8.5:1 CR, which needs 91 octane, but not all planes can
	


pass the test and get a STC, even after much effort.<<



With a proper fuel system, it can be done.  We aren't restricted to the fuel 

systems used on certified aircraft.  We can use what works.



 	  Quote: 	
		   A 150HP O320 is a low octane engine, a O235 is NOT.


	


Yes.



 	  Quote: 	
		   The INSTALLATION is critical. When a STC for auto

 fuel is given it is for the installation as well as the engine.


	


Yes; but, we aren't required to have STCs for our experimentals; so, the STC 

is really a moot point.  The testing used to create the STC is not, though. 

That testing has given us a jump start for setting up fuel systems that will 

work for us.



 	  Quote: 	
		  > YES I know we are experimental but you can't ignore

physics. I recall airplane like the older Mooney's with the O360 can't get a 
	


STC for premium auto fuel because of vapor lock. Like RV's the Mooney have 

very tight cowls. Don't compare the Piper with a huge cowl and a RV with a 

very tight cowl and exhaust pipes

snaking all around near fuel lines.<<



If the airplanes in question had proper return systems, they may have passed 

muster.  I have a friend who is flying a wood wing Mooney and can't use auto 

gas.  He told me some of the later models can use it.  All Mooneys have 

tight cowls; so, why can some use it and other's not?  Fuel system changes.



 	  Quote: 	
		  > The overall issue is you will not get AUTO GAS with out

all the hamburger helper and modified fuel like alcohol and ethanol. I 
	


remember in Washington state, in the winter they went to an alcohol blend 

fuel. My gas milage went in the crapper. That is the other issue.

Car gas is NOT CoNSISTANT. It varies widely by region, session and testing 

is a hassle.<<



That's right.  Auto gas is not for all of us because some states, or cities, 

require alcohol.  However, many of us aren't in those states that are hell 

bent on making us use alcohol enhanced fuels.  If one is wary of the fuel, a 

simple test can be done to catch the use of alcohol.



 	  Quote: 	
		  > If you do go auto fuel insulate and heat shield EVER part of the fuel 

> system and add a vapor return line even for Carb engines.<<


	


Oh?  I'm sure glad you told me.  I've been flying on auto gas for 20 years 

and don't have every part of my fuel system insulated.  I do insulate the 

lines with firesleeve and do put blast tubes to the pump.  That's it.  My 

Cheetah didn't even have the blast tubes.



Now, I must admit that's it's good to have insulation, blast tubes, etc. to 

make things work better; but, my experience has shown me that most of the 

vapor locks I've encountered have been during fast turnarounds.  I've always 

been able to clear the vapor locks, easily.  I don't have return lines. 

However, each fuel system is different.  Some do require them.



Folks, I don't want to cut down any contributor to the RV-list; but, Mr. 

gmcjetpilot has gotten some bad information from somewhere.  He reminds me 

of the fixed base operators who used to try to get me off of auto gas.  Hey, 

they were losing my fuel business; so, I could see why they were interested 

in my giving it up.  My trying to get some of the other customers on auto 

gas didn't set well with them, either.  



My suggestion to Mr. gmcjetpilot is that he continues to run his aircraft 

engines on avgas or jet fuel, whichever is appropriate.  I'll continue to 

use auto gas in my airplanes and will try to win over every other aircraft 

owner I can.  The tiny bit of hassle I have to endure is well worth the 

savings I've accumulated in the 20 years I've used it.  I hope I can 

convince many others to join me.



BTW, I wonder what Mr. gmcjetpilot will do when the FAA approves 82UL, or 

some other auto gas fuel, to replace 100LL.   Now, that may happen. 

Goodness knows we've proved it works.



Jim Sears in KY

do not archive

aerobubba(at)earthlink.ne
Guest

Posted: Tue Jul 04, 2006 6:53 am Post subject: MOGAS Use With FI Engines

Hi All-



It's been a bunch of years since I followed this aspect of the industry, so

please pardon my ignorance.  I'd like some clarification from those of you

(Charlie?) who've done the research on this issue.  The Lyc manual for my

8.7:1 IO-360-A1B6D specifies 100/130 fuel.  It also refers to S.I. 1070,

which says the engine was certificated for 100/130 but that 100LL or 100

are the commercial designations to be used.  The SI further states "The

chart showing specified and alternate fuels that can be safely used in no

instance permits use of fuels of lower grade than that which is specified.

Also, it is not permissible in any instance to use automotive fuel in

aircraft engines, regardless of octane or advertised features because of

the corrosive effect of its chlorine content and because of vapor lock that

could result due to its high vapor pressure. Any fuel used in Lycoming

engines must conform with Specifications ASTM-D910 or MIL-G-5572F."  



Last things first- if one were to test / verify the vapor pressure of the

locally available mogas, and only use fuel with a Ried vapor pressure less

than 7, wouldn't that essentially preclude vapor lock problems?



Does the chlorine mentioned only corrode / swell fuel system seals, or are

there other effects?  



If one tank held avgas for non-cruise ops, and the other held mogas for sub

75% cruise ops, wouldn't knock be a non-issue?  Or would some sort of knock

sensor still be appropriate?



Is there any news on the status of the efforts to keep 91 octane alcohol

free?



Thanks in advance, guys!



glen matejcek

aerobubba(at)earthlink.net

chaztuna(at)adelphia.net
Guest

Posted: Tue Jul 04, 2006 10:26 am Post subject: MOGAS Use With FI Engines

At 10:52 AM 7/4/2006, you wrote:

  	  Quote: 	
		  --> RV-List message posted by: "glen matejcek" <aerobubba(at)earthlink.net>



 Hi All-



 It's been a bunch of years since I followed this aspect of the industry, so

 please pardon my ignorance.  I'd like some clarification from those of you

 (Charlie?) who've done the research on this issue.  The Lyc manual for my

 8.7:1 IO-360-A1B6D specifies 100/130 fuel.  It also refers to S.I. 1070,

 which says the engine was certificated for 100/130 but that 100LL or 100

 are the commercial designations to be used.  The SI further states "The

 chart showing specified and alternate fuels that can be safely used in no

 instance permits use of fuels of lower grade than that which is specified.

 Also, it is not permissible in any instance to use automotive fuel in

 aircraft engines, regardless of octane or advertised features because of

 the corrosive effect of its chlorine content and because of vapor lock that

 could result due to its high vapor pressure. Any fuel used in Lycoming

 engines must conform with Specifications ASTM-D910 or MIL-G-5572F."  



 Last things first- if one were to test / verify the vapor pressure of the

 locally available mogas, and only use fuel with a Ried vapor pressure less

 than 7, wouldn't that essentially preclude vapor lock problems?



 Does the chlorine mentioned only corrode / swell fuel system seals, or are

 there other effects?  



 If one tank held avgas for non-cruise ops, and the other held mogas for sub

 75% cruise ops, wouldn't knock be a non-issue?  Or would some sort of knock

 sensor still be appropriate?



 Is there any news on the status of the efforts to keep 91 octane alcohol

 free?



 Thanks in advance, guys!



 glen matejcek

 aerobubba(at)earthlink.net 	


 Glen,

  No one related to obtaining STCs for use of auto fuel in aircraft recommends it's use in engines with greater than 8.5 to 1 compression ratios. Even though the Lycoming angle valve engines are only 0.2 points higher, they have a totally different combustion chamber design. That said, I do know of RV owners using auto fuel in these engines with no modification. I would expect that their detonation margins are reduced to less than what Lycoming would like. Another option would be to operate on a mixture of 100LL and premium auto fuel. On refueling away from home base, this will occur anyway.

  Testing the Reid Vapor Pressure of all auto fuel you use, (as well as testing for alcohol) would be extremely wise. Modification of your fuel system to include a Continental style vapor return system would also be wise with this engine.  As mentioned by another lister, knock sensors are not practical for air cooled engines.

  The addition of ethanol to auto fuel is a regional issue at present.  The issue of chemicals used in auto fuels that are not used in aviation fuels has been dealt with in recent years. Re-read my last post regarding this.

 Charlie Kuss

panamared3(at)brier.net
Guest

Posted: Tue Jul 04, 2006 1:44 pm Post subject: MOGAS Use With FI Engines

Wow!!!

  

 Are you some sort of lobbist for the 100LL fuel  industry.  You have convinced me, I won't even use mogas  in  my tractor after this warning.  100LL for everything!!

  

 Bob

 [quote]   ---

rocketbob(at)gmail.com
Guest

Posted: Tue Jul 04, 2006 1:44 pm Post subject: MOGAS Use With FI Engines

Guys I have been running over four years and 500+ hours on a mix of 25% 100LL, 75% 87 octane no-alcohol unleaded which I purchase from the local farm bureau.  Never had any trouble, other than the stains it makes on the paint.  No signs of detonation or elevated temperatures.  Typically as a flatlander I rarely go above 7500ft and have flown many times where the OAT was 95 deg. F.  At the moment my fuel costs are $31.98/hr, and if I go 100% 100LL its $40.00/hr, for a savings of $8.02/hour. (based on 10gph, 87 octane at $2.93/gal and 100LL at $4.00/gal.).  I typically fly 10 hours a month, for a net savings of  $80.20 a month, $962.40/year.  It's worth the hassle!



Regards,

Bob Japundza

RV-6 O-360 C/S flying 700+ hours, F1 under const.

gmcjetpilot(at)yahoo.com
Guest

Posted: Wed Jul 05, 2006 4:54 am Post subject: MOGAS Use With FI Engines

 	  Quote: 	
		  posted by: "Jim Sears" <jmsears(at)adelphia.net (jmsears(at)adelphia.net)>

  > Oh? I'm sure glad you told me.  I've been flying on 
	


 	  Quote: 	
		   auto gas for 20 years and don't have every part of 

 my fuel system insulated.  I do insulate the lines with 

 firesleeve and do put blast tubes to the pump.That's 

 it. My Cheetah didn't even have the blast tubes.Jim 

 Sears in KY

   
	


  Jim:

  

Thanks for the very detailed response, I learned a 

lot. You clearly have way more experience with Auto 

Gas in planes than I. However you miss quote or 

miss read a few things. No need to repeat 

everything, but let me address a few things.

   

  

I think you gloss over and paint a very rosy picture 

that may be less than typical. I think your fuel 

savings is at the extreme MAX of what is possible.  

In the real world it's  much less, but first.......

   

  

First let be say the most important thing is Auto gas 

in planes CAN cause loss of power, engine failure. 

That is the main reason for NOT using it.

   

   

  The important thing to remember 160, 180 and 200 

HP Lycomings need premium Auto gas and that is 

NOT available for purchase right out of an airport pump.

   

   

One better consider the facts of hauling fuel around 

to fill your plane from the corner gas station: Hassle, 

legality, safety and lack of availability away from 

home.

   

  

The price savings if you HAUL YOUR own gas can 

be good, especially IF you can use 80/87 octane. 

However if you buy from the airport if avail, the price 

diff between AVgas and MOgas is often measured in 

dimes not dollars. Any one can do a search for gas 

prices nation  wide.

   

   

  Avgas  avg $4.28  min $2.90  max $7.05

  

Mogas (auto)  avg $3.17  min $1.75  max $5.10

  

Premium (auto)  avg $3.35  min $x.xx  max $x.xx 

   

  

As you can see price varies;  100LL can 

be CHEAPER than AUTO GAS! 

   

  Yes you can play games and that the Low of 

one and the high of another and go WOW, look 

at that. The real world and Murphy's law says 

the savings will be much smaller. IF you just 

look at average you can see you will may be 

save $1.00 on average. That is about $8.00/hr on 

my plane. 

   

  OK, that is great, about 100 hrs a year that is $800. 

   

  However 1/2 of my flying is X-C and I likely could not 

get premium auto gas, so that savings is $400, but 

than again I might find some $3.00  AVgas.

   

  That $400 will cost me the hassle of hauling and 

storing fuel. Add the worry of Vapor Lock.... no thanks.



  If you need premium, again check the price of 

premium auto gas (from the corner station) & AVgas. 

Premium Autogas can be over $3.00/gal. AVgas 

in the low-mid $3-$4 range. Not the $1.50 you say. I 

believe you but not everyone lives in Kentucky, which 

has the lowest car gas price nation wide. Good 

for you Mr. Smug. You have a very provincial and 

narrow focus, other (most) states, savings not so great.

  

If you are going to go around the patch in KY than 

haul your own gas might work. Travel cross country 

and buy MOgas at the airport, the price difference is 

not that great. ANY ONE can verify that for themselves. 

   

  If your engine was certified for 91/96 octane you need to 

get Premium and you will not fine that in a X-C  flight. If 

you price premium Vs. AVgas the price is again in 

dimes not dollars. 

  

Again this is easy to look up on the web. Assume 50 

cent savings per gal and 8 gal an hr burn, $ 4.00. 

Say it is double that, $8.00. Is it worth it to flame out 

your engine on a hot day takeoff? Will that gas 

savings rebuild your airplane you just Ball'ed up in 

the corn field (if you are lucky).

  

Good for you that you live in a state that does not 

require Alcohol or Ethanol. It is widely known that 

your days are numbered. The good old Fed Gov will 

force that down our / your throat sooner than later.

 

I am glad your RV-6A is working well. However a 

Grumman Cheetah is a BIG cowl compared, and the 

exhaust pipes do not snake and wrap around the 

Carb like they do on a RV. I do know that.

  

To quote Lycoming why not to use Auto fuel: 

ENGINE FAILURE.

   

  Yea I  know Lycoming does not know anything.

   

  Yea I know you have done it and live a charmed life 

and nothing ever will go bad because of your 

experience in Kentucky. Vapor Lock is a REAL 

issue. Please don't gloss that over, that is 

disingenuous and not forthright. 

  

Pouring your OWN gas into your plane is NOT 

allowed at most Muni Airports. Even large gas 

tanks on personal property are regulated and 

restricted by law.

   

  Also there is a big difference in one 5 gal gas can 

and a 55 gal barrel or ten (5) gal jugs. Check out Haz 

material laws for your state, I know. Just because you 

can get away with it, may not be a good reason to do it. 

  

I am sure gas station attendants will question you filling 

your 10 jugs that are more than a car fill-up by a factor 

of 3 or 4.  Handling Gas is not without danger.

   

  No thanks,  and your reward for all the effort is worry if

you will lose power on takeoff or climb on a hot day.

  

Yes there are hotter places than Kentucky. 

   

  Thanks for the info but I think you have been somewhat 

lucky. I know experimentals don't need STC btw and 

said that. However you gloss over the fact some planes 

can not get a STC. Than you correctly state we can 

learn from STC's. Well Take the HINT. RV's are very 

tight cowls and have little in common with a Grumman.

   

  I am not saying don't do Auto gas but at least know what 

you are getting into and the real RISK! That is all.

   

  Cheers George M



  		Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls.  Great rates starting at 1¢/min.

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Jul 05, 2006 6:15 am Post subject: MOGAS Use With FI Engines

I've tried to stay out of this food fight, but want to make a few comments.  I've been using Auto fuel in my Pitts (modified O-360-A4A with high lift cam) and PS-5 (modified too for increased fuel flow) pressure carburetor for 26 years now.  In Florida.  With no electrical system.  It really likes hi-test (92 or 93) but will run on 87 if the engine doesn't get hot like when doing heavy akro.

 George appears to be in the anti auto fuel camp and I'm on the other side.  I'm not going to convince George (or anyone else) that they should switch to auto fuel.  If they want to, great, and if they want to use a strictly 100LL diet, that's great too.  My only complaint is that George makes statements without any FACTS to back them up.  Like Jim, I've used auto fuel in my Grumman too.  For years.  The only gripe I have with Auto fuel is that it coats the inside of the sight gauges with a red film over time, and I have to disassemble them to clean them.  Like Jim, I find that the benefits outweigh the hassle of carting fuel to the airport. The benefits have all been discussed here already so I won't repeat them.  For me, the purchase cost is lower, and then I can remove the federal excise tax when I file for my federal taxes.  Legally.

 Just my two pennies worth. YMMV and the best you can do with this disagreement is to agree to disagree and move on.  If you're interested in using auto fuel, do your own research.  I know, it'll take some time, but best to get the facts separated from urban legend.  Learn what typically creates vapor lock and how to ameliorate the contributing factors.  All I ask is that you approach the fuel dilemma with an open mind and do your fueling safely.  And do your own research.  There are experts out there, and they may, or may not, be listening on these lists.

 Linn

 gmcjetpilot(at)yahoo.com (gmcjetpilot(at)yahoo.com) wrote:

  	  Quote: 	
		     >posted by: "Jim Sears" <jmsears(at)adelphia.net (jmsears(at)adelphia.net)>

      > Oh? I'm sure glad you told me.  I've been flying on 

 > auto gas for 20 years and don't have every part of 

 > my fuel system insulated.  I do insulate the lines with 

 > firesleeve and do put blast tubes to the pump.That's 

 > it. My Cheetah didn't even have the blast tubes.Jim 

 > Sears in KY

      Jim:

 Thanks for the very detailed response, I learned a 

 lot. You clearly have way more experience with Auto 

 Gas in planes than I. However you miss quote or 

 miss read a few things. No need to repeat 

 everything, but let me address a few things.

 I think you gloss over and paint a very rosy picture 

 that may be less than typical. I think your fuel 

 savings is at the extreme MAX of what is possible.  

 In the real world it's  much less, but first.......

 First let be say the most important thing is Auto gas 

 in planes CAN cause loss of power, engine failure. 

 That is the main reason for NOT using it.

      The important thing to remember 160, 180 and 200 

 HP Lycomings need premium Auto gas and that is 

 NOT available for purchase right out of an airport pump.

 One better consider the facts of hauling fuel around 

 to fill your plane from the corner gas station: Hassle, 

 legality, safety and lack of availability away from 

 home.

 The price savings if you HAUL YOUR own gas can 

 be good, especially IF you can use 80/87 octane. 

 However if you buy from the airport if avail, the price 

 diff between AVgas and MOgas is often measured in 

 dimes not dollars. Any one can do a search for gas 

 prices nation  wide.

      Avgas  avg $4.28  min $2.90  max $7.05

 Mogas (auto)  avg $3.17  min $1.75  max $5.10

 Premium (auto)  avg $3.35  min $x.xx  max $x.xx 

 As you can see price varies;  100LL can 

 be CHEAPER than AUTO GAS! 

      Yes you can play games and that the Low of 

 one and the high of another and go WOW, look 

 at that. The real world and Murphy's law says 

 the savings will be much smaller. IF you just 

 look at average you can see you will may be 

 save $1.00 on average. That is about $8.00/hr on 

 my plane. 

      OK, that is great, about 100 hrs a year that is $800. 

      However 1/2 of my flying is X-C and I likely could not 

 get premium auto gas, so that savings is $400, but 

 than again I might find some $3.00  AVgas.

      That $400 will cost me the hassle of hauling and 

 storing fuel. Add the worry of Vapor Lock.... no thanks.

      If you need premium, again check the price of 

 premium auto gas (from the corner station) & AVgas. 

 Premium Autogas can be over $3.00/gal. AVgas 

 in the low-mid $3-$4 range. Not the $1.50 you say. I 

 believe you but not everyone lives in Kentucky, which 

 has the lowest car gas price nation wide. Good 

 for you Mr. Smug. You have a very provincial and 

 narrow focus, other (most) states, savings not so great.

 If you are going to go around the patch in KY than 

 haul your own gas might work. Travel cross country 

 and buy MOgas at the airport, the price difference is 

 not that great. ANY ONE can verify that for themselves. 

      If your engine was certified for 91/96 octane you need to 

 get Premium and you will not fine that in a X-C  flight. If 

 you price premium Vs. AVgas the price is again in 

 dimes not dollars. 

 Again this is easy to look up on the web. Assume 50 

 cent savings per gal and 8 gal an hr burn, $ 4.00. 

 Say it is double that, $8.00. Is it worth it to flame out 

 your engine on a hot day takeoff? Will that gas 

 savings rebuild your airplane you just Ball'ed up in 

 the corn field (if you are lucky).

 Good for you that you live in a state that does not 

 require Alcohol or Ethanol. It is widely known that 

 your days are numbered. The good old Fed Gov will 

 force that down our / your throat sooner than later.

 I am glad your RV-6A is working well. However a 

 Grumman Cheetah is a BIG cowl compared, and the 

 exhaust pipes do not snake and wrap around the 

 Carb like they do on a RV. I do know that.

 To quote Lycoming why not to use Auto fuel: 

 ENGINE FAILURE.

      Yea I  know Lycoming does not know anything.

      Yea I know you have done it and live a charmed life 

 and nothing ever will go bad because of your 

 experience in Kentucky. Vapor Lock is a REAL 

 issue. Please don't gloss that over, that is 

 disingenuous and not forthright. 

 Pouring your OWN gas into your plane is NOT 

 allowed at most Muni Airports. Even large gas 

 tanks on personal property are regulated and 

 restricted by law.

      Also there is a big difference in one 5 gal gas can 

 and a 55 gal barrel or ten (5) gal jugs. Check out Haz 

 material laws for your state, I know. Just because you 

 can get away with it, may not be a good reason to do it. 

 I am sure gas station attendants will question you filling 

 your 10 jugs that are more than a car fill-up by a factor 

 of 3 or 4.  Handling Gas is not without danger.

      No thanks,  and your reward for all the effort is worry if

 you will lose power on takeoff or climb on a hot day.

 Yes there are hotter places than Kentucky. 

      Thanks for the info but I think you have been somewhat 

 lucky. I know experimentals don't need STC btw and 

 said that. However you gloss over the fact some planes 

 can not get a STC. Than you correctly state we can 

 learn from STC's. Well Take the HINT. RV's are very 

 tight cowls and have little in common with a Grumman.

      I am not saying don't do Auto gas but at least know what 

 you are getting into and the real RISK! That is all.

      Cheers George M

  		   Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls.   [url=http://us.rd.yahoo.com/mail_us/taglines/postman7/*http://us.rd.yahoo.com/evt=39666/*http://messenger.yahoo.com] Great rates starting at 1¢/min. [/url]

sportav8r(at)aol.com
Guest

Posted: Wed Jul 05, 2006 6:49 am Post subject: MOGAS Use With FI Engines

Linn-

  

 I'm a bigtime mogas user and one of the guys who hauls premium mogas home to the hangar by the hundred-gallon tankload.  I have been filing for a rebate on the ~15 cents/gallon state road tax for years, but was unaware you could get back the federal tax as well, which should be quite substantial.  How do I go about doing that?

  

 Thanks.

  

 -Stormy 

 

--

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Jul 05, 2006 8:29 am Post subject: MOGAS Use With FI Engines

sportav8r(at)aol.com (sportav8r(at)aol.com) wrote:

  	  Quote: 	
		            Linn-

      

     I'm a bigtime mogas user and one of the guys who hauls premium mogas home to the hangar by the hundred-gallon tankload.  I have been filing for a rebate on the ~15 cents/gallon state road tax for years, but was unaware you could get back the federal tax as well, which should be quite substantial.  How do I go about doing that?

      

     Thanks.

      

     -Stormy 

  

   

 	
 There's a federal form you file with your taxes.  Try 4136 .... go to http://www.irs.gov/ and search for 4136

 Linn

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Jul 05, 2006 8:29 am Post subject: MOGAS Use With FI Engines

sportav8r(at)aol.com (sportav8r(at)aol.com) wrote:

  	  Quote: 	
		            Linn-

      

     I'm a bigtime mogas user and one of the guys who hauls premium mogas home to the hangar by the hundred-gallon tankload.  I have been filing for a rebate on the ~15 cents/gallon state road tax for years, but was unaware you could get back the federal tax as well, which should be quite substantial.  How do I go about doing that?

      

     Thanks.

      

     -Stormy 

  

   

 	
 There's a federal form you file with your taxes.  Try 4136 .... go to http://www.irs.gov/ and search for 4136

 Linn

rv7(at)b4.ca
Guest

Posted: Wed Jul 05, 2006 8:55 am Post subject: MOGAS Use With FI Engines

On 9:32:12 2006-07-05 linn Walters <pitts_pilot(at)bellsouth.net> wrote:

 	  Quote: 	
		   There's a federal form you file with your taxes.  Try 4136 .... go to

 http://www.irs.gov/ and search for 4136


	


Direct link:



http://www.irs.gov/pub/irs-pdf/f4136.pdf



-Rob

Jerry Cochran

Joined: 10 Jan 2006
Posts: 111
Location: Wilsonville, OR

Posted: Wed Jul 05, 2006 10:02 am Post subject: MOGAS Use With FI Engines

George  (aka gmcjetpilot),

  

 Cheapskates? Puhleeze!!!

  

 With due respect, not all of us are highly paid Boeing drivers such as  yourself  ... As soon as my XP-IO360 flies (soon, very soon...), I fully  intend to save myself 4.05-2.93=1.12/gal x 8.5=9.52x150hrs/yr= $1428. That is  enough to entirely offset the cost of insurance each year. I think that is  significant. 

  

 Hauling it to the airport? No problem for anyone with a pickup. Aux  transfer tanks of any config like the farmers use to fuel their tractors,  combines, etc. are available all over the country complete with hoses/pumps.  Totally legal, BTW... Or, in my case the  1994 F-150 with dual tanks,  and 50 gal capacity, a bit of creative plumbing will get the job done  nicely. 

  

 According to my engine manual, Superior not only allows the use of 91 oct,  but encourages it, FWIW...

  

 Methanol? Easy as pie to test for. Alcohol-free mogas has been available  year round outside our metro area. (KPDX). However, if the politicians have  their way, may not continue... 

  

 Illegal to have a tank on your own property? Tell it to my local fire  marshall who issues the permits to anyone with an acre of ground for "farm use"  of course... Obviously George, you are not a country boy...  hoho...

  

 Cheers,

 Jerry Cochran

 Wilsonville, OR

  

  

  	  Quote: 	
		     Time: 02:39:28 AM PST US

From:    <gmcjetpilot(at)yahoo.com>

Subject: Re: MOGAS Use With FI    Engines 



ANY CAR GAS OR MO GAS HAS LOWER VAPOR 

PRESSURE AND IS    SUBJECT TO VAPOR LOCK.

   

  JUST A NOTE: MO gas is what    you can buy out of a pump 

at the airport, MO gas for Motor Gas. Auto Fuel,    is what you 

get at the corner gas station. MO Gas is like 86 octane.    

   

  If you need 91 octane you need to get premium from    the 

corner gas station. The problem is your plane is at the 

airport.    (not much price difference from premium to 100LL)



  So to use Auto    fuel in your plane you are faced with the 

hassle of hauling fuel to the    plane. This can be a huge 

hassle, dangerous and illegal. At most airports    and with  

state highway laws (hazardous material transport) a NO    

NO. You are just not going to be hauling eight 5 Gal jerry 

cans around    or 55 gal barrels with gas easily. I can see 

all the cheapskates thinking    of the cost savings they 

will get. In fact the saving is small if    impractical for 

91 octane engines. If you have a low compression engine    

that can run on MO gas than sure there is some advantage. 

      

  HOWEVER A RV tight cowl is NOT ideal for MO gas    

operations.

   

  Also price of MO Gas is not that    much less than 100LL or 

can you even get MO gas widely. Some times MO gas    cost 

more than 100LL. So you might be taking abut $4.00/hr 

savings for    all the hassle.

   

  Fuel Injection has nothing to do    with it, it is compression 

ratio. All the original STC's where for low    compression 

engines that where made for like 80 octane.

      

  There are premium gas STC's for Lyc 320/360's with the 

8.5:1    CR, which needs 91 octane, but not all planes can  

pass the test and    get a STC, even after much effort.

   

  A 150HP O320 is    a low octane engine, a O235 is NOT.

   

  The    INSTALLATION is critical. When a STC for auto 

fuel is given it is for the    installation as well as the engine. 

   

  YES I know we    are experimental but you can't ignore 

physics. I recall airplane like the    older Mooney's 

with the O360 can't get a STC for premium auto fuel    

because of vapor lock. Like RV's the Mooney have 

very tight cowls.    Don't compare the Piper with a huge 

cowl and a RV with a very tight cowl    and exhaust pipes 

snaking all around near fuel lines.

      

   

  The overall issue is you will not get AUTO GAS    with out 

all the hamburger helper and modified fuel like alcohol 

and    ethanol. I remember in Washington state, in the 

winter they went to an    alcohol blend fuel. My gas 

milage went in the crapper. That is the other    issue. 

Car gas is NOT CONSISTANT. It varies widely by

region, session    and testing is a hassle.

   

   

  If you do    go auto fuel insulate and heat shield EVER 

part of the fuel system and add    a vapor return line 

even for Carb engines.

      

   

   

  >From:  "Tracy Crook"    <lors01(at)msn.com>

 	  Quote: 	
		  

My RX-8 rotary (10 : 1 CR) powered RV-4    runs best and 

gets best fuel economy on 87 octane. I burn 100LL in a    

pinch but plug life is greatly reduced.


	


Automotive and aircraft    engines are two differnt things. RX8 

cars strictly call for premium and    use 2 qts of oil between 

oil changes, and also get terriable gas millage.    I know you 

are a rotary expert Tracy but a water cooled car engine    

piston or rotary is not an aircooled aircraft engine. 



My Lyc plug    life is 1000 hour plus on 100LL.

   

  I am not picking    on you Tracy but you have to take 

the good with the bad. Good, you can use    auto fuel; 

Bad, your engine is noisier, heavier and burns way 

more    fuel than a Lycoming for equivalent performance.

      

   

   

  >Best experts I've read say    that almost all aircraft engines 

 	  Quote: 	
		  would work fine on 91 octane    mogas.


	


Most aircraft engines where certified for 91, like 320 (160HP)    

and 360 (180 hp) Lycoming. So that is a no brainer,  The 

problem    is the MO gas you can buy at the airport is way 

less than 91 octane, like    80/86.

   

  If you want premium AUTO fuel you have to    haul. And the 

idea of having your own tank, even on your own property    

is likely to be illegal in most states.



   <snip>

sisson(at)consolidated.ne
Guest

Posted: Wed Jul 05, 2006 11:28 am Post subject: MOGAS Use With FI Engines

linn Walters wrote:

  	  Quote: 	
		                   I've tried to stay out of this food fight, but want to make a few comments.   I've been using Auto fuel in my Pitts (modified O-360-A4A with high lift  cam) and PS-5 (modified too for increased fuel flow) pressure carburetor for 26 years now.  In Florida.  With no electrical system.  It really likes hi-test (92 or 93) but will run on 87 if the engine doesn't get hot like when doing heavy akro.

  

  George appears to be in the anti auto fuel camp and I'm on the other side.   I'm not going to convince George (or anyone else) that they should switch  to auto fuel.  If they want to, great, and if they want to use a strictly  100LL diet, that's great too.   	
 

 

 I snipped the rest of  Linn's posting.

 

 

 Hello Linn, long time no see.

 

 Well me and my Pitts also used auto fuel.  I used it when the  stations up here were selling No Alcohol premium. It did not have a steady diet of Auto fuel. I used it when it was convenient.  And as you and I know, we turned  the Pitts engines up to 32 or 3300 very regularly.

 

 Mine is a bendix fuel injected 180, converted from a carbureted engine. It has no mods except for Total Seal Rings. I flew it for 20 years with no electric starter. Hot starts were learned and it was not a real problem even at contests, to get a "hot start hand prop" . I now have that engine on the RV with a starter. ( I love electric starters)

 

 I don't burn auto fuel any more because they don't sell it here without alcohol. It would probably do just fine with the ethanol  and I have used it on very limited occasions with no known problems. Had I used it regularly, I may have found problems. Dunno.....

 

 One thing one must always remember ( you and I know this) is that 100 LL is not immune to vapor lock. When I first finished the Pitts back in 81, I used 100 LL all the time and paid  about $1.55 a gallon.  For those who are not familiar, the S1S Pitts is not tightly cowled. There is plenty of room in the cowl and plenty of clearance.     But,  I had on going problems with the fuel getting hot and getting temporary engine bobbles after  powering back for awhile as in a spin or snap roll.  I also got a predictable bobble on take off almost every time after a long taxi out...     Then after "browning my shorts" a few times, I solved the problem with wrapped lines and air blown on the fuel pump and gascolator. Then I saw a factory airplane, I think a Piper, which had air blown all over its fuel  components,  (pump and gascolator). So 100 LL fuel is not the complete answer to hot fuel problems as evidence shows from all the fuel pump air shrouds used on Type Certificated planes.  I never had a problem when there was a steady flow of fuel going through the system.  

 

 The whole point is, builders should stand back and look at their fuel systems and think about it. Wrap the lines, blow some air here and there where a component may heat up and pay some attention to routing because 100 LL can vapor lock and/or develop air bubbles in the fuel lines, even at lower altitudes. It just behaves a little better in more critical conditions.

 

 These are opinions which I should keep to myself.  I am pleading fifth ammendment for errors in grammer.

 

   And by the way, We have space to camp here on the airport 3LF, courtesy car, and restaurants and motels are all close. Just something to think about for your trip to or from Oshkosh.  Today, our 100 LL is selling for $3.55 , It will probably be somewhat higher by Oshkosh. On our way home from Hondo, Texas Fly-in, we bought gas at Salem, Mo for $3.05.   Check AirNav for current pricing. We keep AirNav up to date, Don't know about Salem, MO..

 

 Phil in Illinois             RV 6        N181RV

 

 Do not archive

pcowper(at)webtv.net (Pet
Guest

Posted: Wed Jul 05, 2006 6:30 pm Post subject: MOGAS Use With FI Engines

Does anyone know what the Research Octane + Motor Octane divided by 2

would equal for 100LL Aviation Gasoline?  (R+M / 2)



The highest the R+M / 2 current pump sticker would have ever been for

the 103 octane premium (Union 76 Super & Chevron white pump) would be

about 96.



Pete Cowper

Union Oil Company of California 1972-84

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