DIY_EFI Digest V4 #436

[Pedro Haynes]

>
>
>With the list in digest mode it seems the mail has really slowed down.
Anyway,
>I'd appreciate if someone has a solution for this minor inconvenience. I
have
>finally managed to get my Fiat 850, with the MR2 supercharger on it,
running.
>Currently its using the original carby in a blow through configuration (the
>setup is crap, but will have to do for the time being). With the whole
carby
>being pressurised there is enough fuel pressure in the electric pump to
make the
>car idle, however I'm sure as the pressure builds up the fuel pump runs out
of
>steam. What is the solution?
The problem here is as the boost builds it forces the fuel back in the tank.
If you raise the fuel pressure to a level where it will run the car during
full boost the carb will flood at low boost. What you need is a rising rate
regulator. The other problem, which may arise, is the fuel pump not being
able to have the mass flow needed or the pressure so you may need to gang
more than one pump. Also the brass float will indeed collapse
>
>Do you use a high pressure efi pump with a 0.5bar regulator, vacuum/boost
>compensated to the inlet manifold, so the fuel pressure is always 0.5bar
above
>boost level ?
>
>What about the float. The carby currently uses a soldered brass float, will
it
>be strong enough to withstand say 20psi of boost ? Or will I need to fill
it
>with something non collapsible ?
>
>What about the needle and seat, will there be any problems here ?
>
>Might sound logical, but I'm a bit out of my depths here and so appreciate
any