Gas Engines Questions or comments about gas engines can be posted here

Super Unleaded Gas = Loss of Performance?

Reply
Old 01-23-2013, 10:29 AM
  #51
MTK
 
Join Date: May 2004
Location: Whippany, NJ
Posts: 5,386
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: rmh

For those who never tried it - - the accumulation of water inside an alky fueled engine can be extreme- and in actual practice these engines -not run dry then saturated with a water displacing oil - easily rust the bearings.
At the flying fields -it is easy to tell which fliers don't keep water out of their engines - -you can hear the bearings as they run.
Yet another reason to use a gas with no alcohol. Avgas for melenty of pop, no stench, stable over time and now,look ma, no rust....Itdoesn't seem to bother the carb innards either, as some have suggested. I took anDLE55carb apart (on the shelf for1 1/2years after fairly hard running for about 1 season) to check the rubber....rubber parts appeared the same as rubber in a new and unused 55 carb. And bearings are silky smooth on the shelf.

But avgas does result in a couple hundred rpm loss over premium autogas at full revs, in an OS GT33. But since I practically never fly it at full revs, it doesn't matter at all in my application.

It seems to me thatsome people on these threads in the engine forum are poopoo'ing avgas but have never really tried it.....
MTK is offline  
Reply With Quote
Old 01-23-2013, 10:45 AM
  #52
rstearman
 
Join Date: Dec 2001
Location: puyallup, WA
Posts: 122
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Hi TimBle

At a recent conference the speaker’s term used was Phase Out. He stated that fuels with ethanol phases out quicker and should be used within a matter of weeks. He did not go in to detail as to what happens with the fuel.

At my place of work we stopped using fuels with ethanol a couple of years ago due to issues with our small gas engines not running properly. They ran rough, had to choke them longer than normal, and often they just would not start at all. We made the switch to ethanol free fuel and ever since we made the change we have had zero problems. This is the fuel we are using now:
http://www.vpracingfuels.com/sef-94.html

Personally I think SEF is overpriced for home use but not for the equipment we use it in at work.

For home use I buy ethanol free pump gas. There are websites to help find ethanol free gas pump, one is: http://pure-gas.org

Here are some reason I do not use fuel with ethanol besides the before mention reason.

Here in the Pacific Northwest in the winter we have a lot of moisture around. In the air, on the ground, in our fuel tanks, it’s everywhere. With my Honda mower I often I find water sitting in the bottom of fuel tank. So if I had used say E10 fuel in the Honda mower, the ethanol would have absorbed water and then at some point made its way in to the engine. This phase separated fuel could then sit in the bottom of the float bowl and start corroding away destroying the carburetor, or just sit in the bottom of the fuel tank corroding the tank.

Another reason is when the phase separated fuel runs through a two stroke engine a mixture of ethanol and water with no gasoline and no lubricating oil will be ran through the engine.

Another is ethanol can dissolve varnish and gum deposits that have previously formed inside fuel storage cans or engines, and the deposit can plug small opens in the carburetor.


The cost of ethanol free fuel is only about 20 cents more a gallon. So that is a dollar more for five gallons.

Okay here is my math test:

My planes have 16 oz fuel tanks,
5 gallon is 640oz
640oz divided by 16 =40.
$1 in extra cost for the good stuff divided by 40 = .025



So if my math is right, the cost is two and a half cents more per tank for the Ethanol free fuel.

2.5 CENTS

I think I will spurge and spend the extra cash on ethanol free fuel.


Oh more thing. I rather eat a corn feed cow than a corn feed chevy.
rstearman is offline  
Reply With Quote
Old 01-23-2013, 10:57 AM
  #53
rstearman
 
Join Date: Dec 2001
Location: puyallup, WA
Posts: 122
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Image of a carburetor damaged from corrosion http://www.stihlusa.com/WebContent/C...uretor-200.png[img][/img]
rstearman is offline  
Reply With Quote
Old 01-23-2013, 11:24 AM
  #54
av8tor1977
 
av8tor1977's Avatar
 
Join Date: May 2003
Location: Tucson, AZ
Posts: 6,966
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: rstearman

Image of a carburetor damaged from corrosion http://www.stihlusa.com/WebContent/C...uretor-200.png[img][/img]
I wanted to try to see what they wrote in the article that the photo came from, but couldn't access it. Why is Stihl so stingy with their tech info? Scratch that, I know; it is so that you (theoretically) have to take your equipment to them to service. If they weren't such great engines I wouldn't use them just because of that. However, I use Bowman rings, Boca bearings and seals, make my own gaskets, and certainly don't need a mechanic's service guide to instruct me, so "to H e l l" with them! Their parts are priced so high nobody could afford them anyway!

Anyway, is there a way to access the gasoline-guide-carburetor file?

Thanks,
AV8TOR
av8tor1977 is offline  
Reply With Quote
Old 01-23-2013, 12:37 PM
  #55
rstearman
 
Join Date: Dec 2001
Location: puyallup, WA
Posts: 122
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Hi av8tor1977

Here the link to Stihl's "Gasoline Guidelines for STIHL Outdoor Power Equipment" http://www.stihlusa.com/information/...wer-equipment/
rstearman is offline  
Reply With Quote
Old 01-23-2013, 12:59 PM
  #56
rmh
 
rmh's Avatar
 
Join Date: Dec 2001
Location: , UT
Posts: 12,630
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: MTK


Quote:
ORIGINAL: rmh

For those who never tried it - - the accumulation of water inside an alky fueled engine can be extreme- and in actual practice these engines -not run dry then saturated with a water displacing oil - easily rust the bearings.
At the flying fields -it is easy to tell which fliers don't keep water out of their engines - -you can hear the bearings as they run.
Yet another reason to use a gas with no alcohol. Avgas for me: plenty of pop, no stench, stable over time and now, look ma, no rust....It doesn't seem to bother the carb innards either, as some have suggested. I took an DLE55 carb apart (on the shelf for 1 1/2 years after fairly hard running for about 1 season) to check the rubber....rubber parts appeared the same as rubber in a new and unused 55 carb. And bearings are silky smooth on the shelf.

But avgas does result in a couple hundred rpm loss over premium autogas at full revs, in an OS GT33. But since I practically never fly it at full revs, it doesn't matter at all in my application.

It seems to me that some people on these threads in the engine forum are poopoo'ing avgas but have never really tried it.....
Avgas is fine -for what you want.
I was always after maxed power setups - so I used the gas which burned the fastest without causing a preignition -OR detonation- and 87 was fine -all things considered - I hate alky /gas fuels - and the government clowns who believe adding alky to gas for autos are dead wrong about it's benifits. Ethanol is not desirable for auto fuel- costwise or anyotherwise -except for as a race fuel.
rmh is offline  
Reply With Quote
Old 01-23-2013, 07:51 PM
  #57
av8tor1977
 
av8tor1977's Avatar
 
Join Date: May 2003
Location: Tucson, AZ
Posts: 6,966
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: rstearman

Hi av8tor1977

Here the link to Stihl's ''Gasoline Guidelines for STIHL Outdoor Power Equipment'' http://www.stihlusa.com/information/...wer-equipment/
Thanks for the link. Interesting reading.

Take care,
AV8TOR
av8tor1977 is offline  
Reply With Quote
Old 01-24-2013, 09:30 AM
  #58
tkg
 
Join Date: Jan 2002
Location: Riverton, WY
Posts: 3,114
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

FWIW, I spent the better part of a day running a Sachs based 3.2 (52cc) on Regular gas , Colman Fuel and Av gas. Basic results were reg gas gave the most power and ran coolest. Av gas had reduced power and hotter temps. WalMart "Coleman" fuel was in the middle.
IMHO stick with no Alky regular.
tkg is offline  
Reply With Quote
Old 01-24-2013, 10:44 AM
  #59
pe reivers
 
Join Date: Jan 2002
Location: Arcen, , NETHERLANDS
Posts: 6,571
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Terry, did you care to adjust ignition timing? Results might well have been different.
Hmmm.. yes Avgas is lead composed, so may be slower burning. Too bad you don't have access to leadfree 95 PON fuel.

pe reivers is offline  
Reply With Quote
Old 01-24-2013, 10:34 PM
  #60
choihjin
 
Join Date: Feb 2008
Location: Daegu, SOUTH KOREA
Posts: 54
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Hi
One more additon to ON debating.
In Korea all gasoline has some of MTBE , no ethanol at all. The ON numbers are based on RON, so slightly higer ON than in USA. They keep the aromatic contents less than the required in US regulation.
These days Korean oil companies export a lot of gasoline and petroleum prodcuts to other countries, it's the most exporting item than electronis, so they keep the quality as high as to secure competitiveness. I just got these informations from a friend of mine who worked as a plant manager and retired now in an major oil company. Still do I have to worry about the phase separation gas/MTBE?
choihjin is offline  
Reply With Quote
Old 01-25-2013, 07:58 AM
  #61
tkg
 
Join Date: Jan 2002
Location: Riverton, WY
Posts: 3,114
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Yes timing was adjusted when I switched from reg to av gas. No repeatable difference. I did see a higher flash rpm, but it only would last 5-10 sec, before the rpm would drop to a stable number. Timing was returned to normal for the balance of the test.
TKG
Quote:
ORIGINAL: pe reivers

Terry, did you care to adjust ignition timing? Results might well have been different.
Hmmm.. yes Avgas is lead composed, so may be slower burning. Too bad you don't have access to leadfree 95 PON fuel.

tkg is offline  
Reply With Quote
Old 01-25-2013, 08:03 AM
  #62
w8ye
Moderator
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,531
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: choihjin

Hi
One more additon to ON debating.
In Korea all gasoline has some of MTBE , no ethanol at all. The ON numbers are based on RON, so slightly higer ON than in USA. They keep the aromatic contents less than the required in US regulation.
These days Korean oil companies export a lot of gasoline and petroleum prodcuts to other countries, it's the most exporting item than electronis, so they keep the quality as high as to secure competitiveness. I just got these informations from a friend of mine who worked as a plant manager and retired now in an major oil company. Still do I have to worry about the phase separation gas/MTBE?
NO

w8ye is offline  
Reply With Quote
Old 01-25-2013, 09:34 AM
  #63
TimBle
 
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

My comments in Red
Quote:
ORIGINAL: rstearman

Hi TimBle

At a recent conference the speaker’s term used was Phase Out. He stated that fuels with ethanol phases out quicker and should be used within a matter of weeks. He did not go in to detail as to what happens with the fuel. Even though it was used at a conference does not make it the right term. Phase separation is the right term but as long as we understand what we're talking about lets not make an issue of it ok?

At my place of work we stopped using fuels with ethanol a couple of years ago due to issues with our small gas engines not running properly. They ran rough, had to choke them longer than normal, and often they just would not start at all. We made the switch to ethanol free fuel and ever since we made the change we have had zero problems. This is the fuel we are using now:
http://www.vpracingfuels.com/sef-94.html
The problems you describe are well documented as storage and handling issues


Personally I think SEF is overpriced for home use but not for the equipment we use it in at work.

For home use I buy ethanol free pump gas. There are websites to help find ethanol free gas pump, one is: http://pure-gas.org

Here are some reason I do not use fuel with ethanol besides the before mention reason.

Here in the Pacific Northwest in the winter we have a lot of moisture around. In the air, on the ground, in our fuel tanks, it’s everywhere. With my Honda mower I often I find water sitting in the bottom of fuel tank. So if I had used say E10 fuel in the Honda mower, the ethanol would have absorbed water and then at some point made its way in to the engine. This phase separated fuel could then sit in the bottom of the float bowl and start corroding away destroying the carburetor, or just sit in the bottom of the fuel tank corroding the tank.

Another reason is when the phase separated fuel runs through a two stroke engine a mixture of ethanol and water with no gasoline and no lubricating oil will be ran through the engine.

Another is ethanol can dissolve varnish and gum deposits that have previously formed inside fuel storage cans or engines, and the deposit can plug small opens in the carburetor.


The cost of ethanol free fuel is only about 20 cents more a gallon. So that is a dollar more for five gallons.

Okay here is my math test:

My planes have 16 oz fuel tanks,
5 gallon is 640oz
640oz divided by 16 =40.
$1 in extra cost for the good stuff divided by 40 = .025



So if my math is right, the cost is two and a half cents more per tank for the Ethanol free fuel.

2.5 CENTS

I think I will spurge and spend the extra cash on ethanol free fuel.


Oh more thing. I rather eat a corn feed cow than a corn feed chevy.

Its your choice
TimBle is offline  
Reply With Quote
Old 01-25-2013, 03:01 PM
  #64
pe reivers
 
Join Date: Jan 2002
Location: Arcen, , NETHERLANDS
Posts: 6,571
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

I checked my trusted Blair book on Avgas.
A Yamaha racing engine, trapped compression of 11:1 and BMEP of 10.5 @11500 rpm had the ignition timing at a mere 20° BTDC using the 100 PON fuel. Slow burning? Based on what??
pe reivers is offline  
Reply With Quote
Old 01-25-2013, 03:23 PM
  #65
TimBle
 
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

sorry Pe, why directed at me, I've never said Avgas was slow burning. I have always maintained it will burn fast since it mostly iso paraffins in the C7 and C8 range. TEL slows it down a bit but its still faster burning than any piston aviation engine can exploit. 
ISo Paraffins are fully exploited in F1 engines 
TimBle is offline  
Reply With Quote
Old 01-25-2013, 04:08 PM
  #66
tkg
 
Join Date: Jan 2002
Location: Riverton, WY
Posts: 3,114
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Major point of confusion in this type of discusion. octane has NOTHING to do with flame speed. The hydrocarbon mix n the fuel determines flame speed.
tkg is offline  
Reply With Quote
Old 01-26-2013, 03:43 AM
  #67
pe reivers
 
Join Date: Jan 2002
Location: Arcen, , NETHERLANDS
Posts: 6,571
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: TimBle

sorry Pe, why directed at me, I've never said Avgas was slow burning. I have always maintained it will burn fast since it mostly iso paraffins in the C7 and C8 range. TEL slows it down a bit but its still faster burning than any piston aviation engine can exploit.
ISo Paraffins are fully exploited in F1 engines
Sorry Tim,
It was not directed at you, but just a general remark due to hard factual data I found in Blair's book. I cannot prevent the "in answer to" if I make a new post right below yours.

pe reivers is offline  
Reply With Quote
Old 01-28-2013, 06:10 AM
  #68
TimBle
 
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?


Quote:
ORIGINAL: tkg

Major point of confusion in this type of discusion. octane has NOTHING to do with flame speed. The hydrocarbon mix n the fuel determines flame speed.

Exactly. I've been saying that for long time but dogma's are hard to let go off.


Pe, thanks for clearing that up.
TimBle is offline  
Reply With Quote
Old 01-28-2013, 10:48 PM
  #69
Ernie Misner
 
Ernie Misner's Avatar
 
Join Date: Jul 2002
Location: Tacoma, WA
Posts: 5,024
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Some of the boat racing guys with the Zenoah 20 something cc engines are running Coleman fuel which is very low octane, like 55? and they run it with excellent and race winning results. (without adding any octane boosters)

How can they get away with that when we can't with the airplane engines?
Ernie Misner is offline  
Reply With Quote
Old 01-28-2013, 11:54 PM
  #70
TimBle
 
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

high rpm, low compression ratio, fast burning fuel
TimBle is offline  
Reply With Quote
Old 01-29-2013, 10:20 AM
  #71
Ernie Misner
 
Ernie Misner's Avatar
 
Join Date: Jul 2002
Location: Tacoma, WA
Posts: 5,024
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Makes sense also because the boat and car guys aren't turning large diameter props at low rpms. No grunt needed.
Ernie Misner is offline  
Reply With Quote
Old 01-30-2013, 03:17 PM
  #72
captinjohn
 
Join Date: Jan 2002
Location: Hesperia Michigan, MI
Posts: 12,874
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Earnie, how far do live from the Valley View Flying site? Regards, Capt,n
captinjohn is offline  
Reply With Quote
Old 01-30-2013, 09:30 PM
  #73
Ernie Misner
 
Ernie Misner's Avatar
 
Join Date: Jul 2002
Location: Tacoma, WA
Posts: 5,024
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Super Unleaded Gas = Loss of Performance?

Hello Capt'n. From here I live it's about 35 minutes or so to the Valley View RC store. And it's about the same drive to the MRRCS field where most of us fly around here. Here's a link John. It's a great field with Mt. Rainier so close it looks like you could touch it. They have a nice paved runway and clubhouse. A roof over most of the tables and electricity to each table now.

http://www.mrrcs.org/home

Best Regards to you, Ernie
Ernie Misner is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 01:27 PM.