Has anyone considered using a POSA style carburetor on their engine? I
recall the older Lake Injector carbs receiving their share of bad press
due
to the sensitivity of the floatless system to head pressure. While this is
a
problem on gravity feed fuel system, using a very low pressure (import
type)
electric fuel pump would eliminate the tuning complications as fuel levels
changed.
To my understanding, here is a list of the core components needed for such
a
system to properly work;

1) Either a AeroCarb (
http://www.aeroconversions.com/products/aerocarb/index.html) or Revmaster
(
http://www.revmasteraviation.com/products/revflow_injector_carburetor/index.htm)
carburetor. Cost is $395 and $330 respectively.

2) Custom intake manifold. I can't really guess a price but since the POSA
style carbs can be mounted as downdraft, sidedraft or updraft, you would
have more design flexibility and potentially save some money.
3) Very low pressure electric fuel pump. Units like the Mr. Gasket 42S (
http://beta.summitracing.com/parts/MRG-42S/,) Professional Products 10701
(
http://beta.summitracing.com/parts/PFS-10701/) and Facet 40105 (
http://www.aircraftspruce.com/catalog/eppages/facetpumps.php) would work
and
keep the costs reletively low at $37, $40 and $32 respectively.

4) Very low pressure fuel regulator such as the Mr. Gasket 9710 (
http://beta.summitracing.com/parts/MRG-9710/) for $26 or Holley 12-804 (
http://beta.summitracing.com/parts/HLY-12-804/) for $28.
This list excludes items such as fuel filters, gascolator, fuel lines,
etc.
due to their universal nature.
Plumbing a carburetor heat system should be easier since the carb can be
mounted in different orientations and much less critical since POSA
carburetors lack venturi.
Vlad

We looked at it for a long long time.
They are very susceptible to vapor lock as the fuel pressure
is down around 1 psi. Even the VW guys don't recommend them any more :)
Go with a float bowl. Float bowl Carbs have it all. Mass airflow sensor,
fuel pressure regulator and fuel injector all rolled up into one :)

Paul Lamar

Vlad,
The POSA was the original slide carb, then came the Aero Carb (copy of the
POSA) and some other carb was further developed by someone leaving Aero Carb
(or so I have been told). The Aero Carb looks good and the flat ground
needle is the way to go IMHO, however no two needles are the same from what
I have read on the internet discussion groups. This is Ok for a single carb
on a single rotor but would need some care in matching the needles in a 2
carb set-up.

Aero Carb recommend 35mm for up to 120hp and 38 mm for up to 160hp - no
venturi.

Revmaster 40mm carb will flow 166cfm at 10"water

Edelbrock recommends 42mm for up to 125hp.
Mukuni recommends 48mm ( 42 venturi) for anything over 120hp

38mm Lectron carbs flows 161cfm at 10" water
40mm 186cfm at 10"water
44 flows 217cfm at 10"water

All carbs without a float bowl require low fuel boost pump.

Can't remember all the different carbs and their venturi sizes, but appears
a venturi does two things- increases inlet speed and acts at a restrictor at
some point.

It was a fun exercise I didn't find anything that was exactly what I wanted,
so started making my own- and still not finished.
George (down under)