subaru fuel tank questions

For my fuel system im going to use the subaru internals (swirl pot and pump) grafted into my tank because I dont want an external pump or to pay out for a swirl pot.

It all looks good but Preliminary examination of the scoob tank shows there are 2 pressure relief valves.......well thats what I believe they are rather than breathers?

Does the subaru run a pressurised tank?
if so why?
what happens if i dont use this pressurised system - bearing in mind im using subaru internals.?

richbaker78 wrote:For my fuel system im going to use the subaru internals (swirl pot and pump) grafted into my tank because I dont want an external pump or to pay out for a swirl pot.

It all looks good but Preliminary examination of the scoob tank shows there are 2 pressure relief valves.......well thats what I believe they are rather than breathers?

Does the subaru run a pressurised tank?
if so why?
what happens if i dont use this pressurised system - bearing in mind im using subaru internals.?

I don't know subies specifically, but most modern cars run a sealed tank with some means to test the integrity of the system. For example some cars actually have pressure sensors and vacuum lines and valves to the tank to temporarily lower the tank pressure to check for leaks. If a leak is detected the CEL light illuminates. That's why the first think a mechanic checks for a CEL light is the fuel cap!

George

Can you have a look at these pressure valves and see how much pressure the release at. I would imagine the kombi tank could handle a small pressure.

This slight pressure may even be used to assist / prime the pump ???? maybe.

Personally I would prefer to modify the system to incorporate this pressure, this way you can be asured of a fully sealed system. Remember to use the Suby petrol cap aswell.

just thouht i should give everyone a bit of a warning from my personal experance (ej20t manx)
i put a swirl pot with internall pump under my main tank
this was gravity feed
i put a breather/equlizer from swirl pot to top of main tank
i put the fuel return line from the injectors into the bottom of the main tank
then went for a drive
the tank very quickly (in a couple of k`s) blow up like a balloon
so i relized i needed to put a breather in my filler neck as well
this fixed the problem
i think i was very lucky it didn`t split at the seems
back to having fun now hotdog

hmm interesting this - ive put this on some scoob forums too but not a single answer!! so thanks to all you for your replies....i think i will probably use them if I cant find out more info - however I would prefer not to as its more work to fit them than not. ill check the pressure rating.