Auto Fuel STC for PA32-260

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)

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.

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