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

Do you believe that vapor lock will remain a problem given a remote fuel
pump and the actual carb located away from the exhaust manifold?
Interesting
that the VW users are reporting problems given their intake and exhaust
configuration. Are these reports from people who use block mounted
mechanical fuel pump?
Vlad

Yes.
If it is a Posa type carb it is a low pressure carb.
If you find a less than 1 psi fuel regulator it is probably a float
bowl.

The only way to use a fuel pump is to fill a header tank.
Then the pressure at the carb is a function of the pitch of the aircraft.
It is also a function of how many right angles you have in the fuel
plumbing.


Check out Great Plains aircraft for more info.
http://www.greatplainsas.com/

Paul Lamar

I don't understand the reasoning behind your comment on not using a fuel
pump. The POSA carb should be able to use a electric fuel pump just as any
other type of carburetor, the only difference is the need to regulate the
pressure down to around 1psi. Also, the regulators I listed earlier can be
adjusted to regulate between 1 and 6psi. Could you post a more specific link
within greatplainsas as that site is rather large and I couldn't find any
information regarding POSA carbs.
Vlad

Good luck finding a less than 1 psi pressure regulator. 12 inches of water is .44 psi.
12 inches of fuel is .35 psi. These carbs are designed to use
that kind of pressure head.

Win or lose let us know how you make out.
http://www.greatplainsas.com/
Send Steve email and ask him where he has the data. Tell him I sent you.

Paul Lamar