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Author Topic: Turbo fuel pressure regulator  (Read 1053 times)

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Offline Ian Northeast

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Turbo fuel pressure regulator
« on: February 29, 2020, 01:40:42 PM »
Hi experts,

I have been running a FAST efi system for some years with no issues or problems. The fuel pressure regulator has a take off from the inlet manifold which I assume supplies a vacuum. I don't fully understand why it needs one unless it affects the pressure dependant on demand.

However I have recently fitted a turbo and so that raises the question if the regulator is expecting a vacuum what happens when it gets positive pressure and is this something I need to worry about or will it work fine?

Ian

Offline datadoc

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Re: Turbo fuel pressure regulator
« Reply #1 on: February 29, 2020, 02:22:11 PM »
The fuel pressure regulator is designed to keep a constant pressure differential across the injector. So you will need to be concerned when you add a turbo. I would also think you need to make sure your fuel pump can supply the pressure needed to keep up with your boost pressure. Then there would be the question of the injectors flow rate.

Offline Ian Northeast

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Re: Turbo fuel pressure regulator
« Reply #2 on: February 29, 2020, 02:56:49 PM »
Okay, it's good to hear i'm right to ask the question.
I have uprated both the fuel pumps and injectors to match the turbo.
The obvious question is what, if anything, do I need to do with the regulator?

Offline datadoc

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Re: Turbo fuel pressure regulator
« Reply #3 on: February 29, 2020, 03:50:53 PM »
The system will need a regulator so I would contact Fast and see if your current regulator is up to the task of your new configuration. Depending on your boost pressure your new system will require the flows for a engine up to 3 times your NA config.

Offline maj

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Re: Turbo fuel pressure regulator
« Reply #4 on: February 29, 2020, 07:38:43 PM »
As Datadoc said the regulator keeps the pressure differential between the fuel in the rail and manifold pressure constant , weather in vac or under pressure the regulator should maintain a constant effective pressure

EG 43 psi at key on should give you 73 psi at 30 psi manifold pressure (constant 43 psi differential)
and therefor you need to test your pump is capable of the required volume at that pressure

Offline Stainless1

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Re: Turbo fuel pressure regulator
« Reply #5 on: February 29, 2020, 08:11:46 PM »
This is basically a start over on the dyno sort of thing... that  will help you know if your components are up to the challenge and your EFI is set up correctly.  A lean setup with the turbo can be disaster.
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.