Auto Fuel STC for PA32-260

[Bruce McFadden]

I'm getting really tired really fast of paying $3.30/gal for AvGas,

I'm considering buying the STC to use MoGas in my aircraft. Does anyone
have the STC and use auto gas. Do you have any comments, warnings or
anything else on the subjuct.

Thanks in advance.


Bruce McFadden Birmingham, AL
PA32-260 N5594J

[[email protected]]

Bruce
I've used mogas for so many years I've forgotten when I started. Use
the supreme and you should have no problems. I don't know the tech
reasons or the difference in heat generated on the valves, but as a
precautionary measure, I kept the mixture just a little on the rich
side for power applications. Never had a single problem that could be
attributed to the use of mogas. Used it in both low horsepower, and up
to the 300hp in ag aircraft.
I HAVE heard of guys who tried to go the cheap gas route and had
premature engine failures or overhauls with valve problems. In the long
run they ended up paying a lot more for their pecuniary efforts.

[Jay Honeck]

> I've used mogas for so many years I've forgotten when I started. Use
> the supreme and you should have no problems. I don't know the tech
> reasons or the difference in heat generated on the valves, but as a
> precautionary measure, I kept the mixture just a little on the rich
> side for power applications. Never had a single problem that could be
> attributed to the use of mogas. Used it in both low horsepower, and up
> to the 300hp in ag aircraft.
> I HAVE heard of guys who tried to go the cheap gas route and had
> premature engine failures or overhauls with valve problems. In the long
> run they ended up paying a lot more for their pecuniary efforts.

Using premium car gas (92 octane or higher) is completely unnecessary, if
you've got the STC.

Our old engines were designed to run perfectly on 80 octane fuel. 87 - 89
octane regular unleaded car gas is perfect for them.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Gig Giacona]

"Jay Honeck" > wrote in message
news:KrVCd.620164$wV.262033@attbi_s54...
>> I've used mogas for so many years I've forgotten when I started. Use
>> the supreme and you should have no problems. I don't know the tech
>> reasons or the difference in heat generated on the valves, but as a
>> precautionary measure, I kept the mixture just a little on the rich
>> side for power applications. Never had a single problem that could be
>> attributed to the use of mogas. Used it in both low horsepower, and up
>> to the 300hp in ag aircraft.
>> I HAVE heard of guys who tried to go the cheap gas route and had
>> premature engine failures or overhauls with valve problems. In the long
>> run they ended up paying a lot more for their pecuniary efforts.
>
> Using premium car gas (92 octane or higher) is completely unnecessary, if
> you've got the STC.
>
> Our old engines were designed to run perfectly on 80 octane fuel. 87 -
> 89 octane regular unleaded car gas is perfect for them.
> --

I've never really had any dealings with an mogas STC. Do they acctually do
anything to your engine or do they just change the stickers.

[Jay Honeck]

> I've never really had any dealings with an mogas STC. Do they acctually do
> anything to your engine or do they just change the stickers.

With most aircraft, it's a paperwork change -- period.

In some aircraft (some O-360 powered Cherokees, for example) you have to add
a supplemental fuel pump.

Both my Warrior and my Pathfinder came with the STC. In both cases, it was
a paperwork "upgrade"...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Gary]

Well if most aircraft piston engines will work fine on regular unleaded pump
gas then why even bother with avgas?.
And holy smokes if you guy are paying $3.30/gal in the states then up here
in Canada we are paying $12+/gal (4 liters=1 us gal) and for what?. Avgas up
here is all 100LL so the 97 octane pemium at your local Petro-Can should
work!.

Unless there is some additive or screening proccess to make the aviation
fuel cleaner or less resistant to altitude related problems I see no reason
why pump gas can't be used.

However!, one thing I am forgetting here is the bureaucratic process that
most goverments like to play, If the government is making a good dollar by
holding us hostage on one particular thing, they are not likely to give it
up!. They seem to like to play the saftey trump card and tell us it is for
our own good.


"Bruce McFadden" > wrote in message
...
> I'm getting really tired really fast of paying $3.30/gal for AvGas,
>
> I'm considering buying the STC to use MoGas in my aircraft. Does anyone
> have the STC and use auto gas. Do you have any comments, warnings or
> anything else on the subjuct.
>
> Thanks in advance.
>
>
> Bruce McFadden Birmingham, AL
> PA32-260 N5594J
>

[[email protected]]

Jay Honeck wrote:
>
> Using premium car gas (92 octane or higher) is completely
unnecessary, if
> you've got the STC.
>
> Our old engines were designed to run perfectly on 80 octane fuel.
87 - 89
> octane regular unleaded car gas is perfect for them.

Not exactly true. Some STCs require the use of 91 octane (or better)
autogas. There's a good reason for it, too. It all comes down to the
piston's compression ratio. Some of the older engines were designed
with a higher compression ratio and required the old 91/96 octane
avgas. The lyc. O-320 (160 hp version) and O-360 are two examples.
Your pathfinder uses the 235 hp low compression version of the the
O-540. The higher hp versions (250, 260, etc...) have a higher
compression ratio and require the use of high octane fuel.

If you use lower octane fuel in an engine designed for higher octane
fuel, you run a serious risk of detonation. This will eventually
result in bad things happening, like blowing a hole in the piston or
cracking the cylinder head.
John Galban=====>N4BQ (PA28-180, with a high octane autofuel STC)

[Jay Honeck]

> Not exactly true. Some STCs require the use of 91 octane (or better)
> autogas.

Very true. You've got to read the fine print in the STC. (Although, as I
understand it, there are very few STCs that actually specify "premium" car
gas.)

> Your pathfinder uses the 235 hp low compression version of the the
> O-540. The higher hp versions (250, 260, etc...) have a higher
> compression ratio and require the use of high octane fuel.

Right. Which makes me wonder why they don't simply come out with an STC
that specifies the use of higher octane auto gas (as in the example, above),
rather than simply not having a mogas STC for the high-compression O-540.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Stefan]

Jay Honeck wrote:

> Right. Which makes me wonder why they don't simply come out with an STC
> that specifies the use of higher octane auto gas (as in the example, above),
> rather than simply not having a mogas STC for the high-compression O-540.

There is more about avgas than just the name. Lower vapour pressure,
lead, generally stricter specifications, and certainly a lot more that I
don't know.

Stefan

[G.R. Patterson III]

Jay Honeck wrote:
>
> Right. Which makes me wonder why they don't simply come out with an STC
> that specifies the use of higher octane auto gas (as in the example, above),
> rather than simply not having a mogas STC for the high-compression O-540.

Didn't we just go through a discussion (in which you took part) to the effect
that there *is* an STC for the engine? It's the airframe under discussion that
lacks an STC.

George Patterson
The desire for safety stands against every great and noble enterprise.

[[email protected]]

G.R. Patterson III wrote:
> Jay Honeck wrote:
> >
> > Right. Which makes me wonder why they don't simply come out with
an STC
> > that specifies the use of higher octane auto gas (as in the
example, above),
> > rather than simply not having a mogas STC for the high-compression
O-540.
>
> Didn't we just go through a discussion (in which you took part) to
the effect
> that there *is* an STC for the engine? It's the airframe under
discussion that
> lacks an STC.
>

That's true. In addition to detonation margins, the STC holder also
has to test for fuel flow characteristics. Petersen's web site points
out that most gravity feed fuel systems don't have a problem there, but
those requiring a pump system have varying results. As a result, some
STCs like the one for my PA28 with an O-360, require pump and fuel
system modifications in order to qualify. Other airframes could
probably be STCed in a similar way, but there may not be enough of a
perceived market for development to be cost effective. An example
might be the Grumman Tiger. It's siblings, the Cheetah and Traveller,
both qualify for autofuel STCs, but the Tiger didn't perform well
enough in the fuel flow tests (180 hp = higher flow requirement) to
pass them without modification. The market for the mod is fairly
small, so the auto fuel STC was not pursued for that engine/airframe
combination.

John Galban=====>N4BQ (PA28-180)

[Jose]

> It's the airframe under
> discussion that
> lacks an STC.

How does the fuel know what airframe its engine is attached to?

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

[steve.t]

Well, I have the MOGAS STC on my PA28-180. I had the engine rebuilt by
PenYan Aero and they will dishonor the warranty if MOGAS is used (per
the paperwork with my engine).

In talking with a few A&P/IA types, I found that 100LL contains more
TEL (Tetra Ethyl Lead) than I thought. And they tell me that this TEL
lubricates the valves.

Meanwhile I wrote PennYan Aero and asked the specific issues with
MOGAS, they've never replied (been over 2 months now).
Later,
Steve.T
PP ASEL/Instrument