Fuel Pressure

[BLOFLY]

Quick question, I've got a 1.4:1 malpassi regulator which I'm going to use on a sonata setup. Should I remove the factory fuel pressure regulator from the end of the sonata fuel rail and just use the malpassi, or should I run them in series(easier) to control fuel pressure???

[Starion VR4]

Remove the original unit, the malpassi is a replacement unit.... :beer

[mrb1]

Quick question, I've got a 1.4:1 malpassi regulator which I'm going to use on a sonata setup. Should I remove the factory fuel pressure regulator from the end of the sonata fuel rail and just use the malpassi, or should I run them in series(easier) to control fuel pressure???

Why are you running the Malpassi regulator are your injectors too small?

[fr335tyl3r]

What is the purpose of a malpassi type rising rate fuel regulator over a standard one?

[WIDEST_1]

not much!! Std pressure reg's are the go.most efi cars need between 280~ 350Kpa fuel pressure. all std pressure regs are rising rate to compensate 4 pressure diffurences via the vac fitting to inlet manafold. They raise pressure 2 compensate for extra manafold presure. malpassi what evers are for people using injectors,pumps,regs ect that are not suited for each other.Each injector is designed to work with a specific fuel pressure range. I can't answer the ? because i don't know what tey are needed 4.

[SpidersWeb]

What is the purpose of a malpassi type rising rate fuel regulator over a standard one?

1. Higher fuel pressure allows the injectors to flow more without replacing them. Of course a fuel toy like an Apexi S-AFC would be needed, or an aftermarket computer.

2. if you upgrade your fuel pump too far beyond factory spec, you also want a stronger fuel pressure regulator.

Rising rate - all FPRs on turbo cars are rising rate. 1psi extra fuel pressure, for every 1psi of boost is normally the go, known as 1:1 rising rate. However another common one is the 1.7:1, which adds more fuel pressure per pound of boost, which is beneficial if your injectors really suck, but most car tuners prefer 1:1 (as its easier for them to work with) and for you just to buy decent injectors (assuming you are running an aftermarket ECU).

Well thats what I gathered. I tend to research weird topics sometimes, and I did a bit of reading on this one, and thats what I learned.

[scum]

your all missing the point. they LOOK cool!

[BLOFLY]

I was going to use the sonata injectors to get it up and running but I decided to buy some VR4 injectors instead.

[Junkers]

I would've thought the sonata injectors would be a bit to small anyway, mayaswell get something decent if your spending up on mpi.

[Cookiemonster]

Nothing wrong with using the standard Sonata FPR. It'll work fine.

Don't use the Sonata injectors though. Way too small.

[BLOFLY]

Multipoint up and running now, using a modded Sonata manifold, VR4 injectors, VN throttlebody, Haltech F9 (fuel only), custom wiring, etc. etc. Took the whole weekend to install plus about 6 weeks previous to do all the fabrication/wiring and chase up every other part needed. Now it starts and idles great and revs up much more freely with heaps crisper response.:D :D :D Big thanks to local Super Cheap, and Bottleshop for making the job much easier :beer as well as the Austarion.

[Fuel]

Nothing wrong with using the standard Sonata FPR. It'll work fine.

Have you tested the fuel pressure on boost using this FPR or when you were using the L300 FPR?

[TOMSUN]

I have the standard Sonata FPR. Running 550cc RX7 injectors

[Fuel]

I have the standard Sonata FPR. Running 550cc RX7 injectors

But your starion doesn't run, so that doesnt mean much.

I am using a standard L300 FPR, but i suspect it is not rising the fuel pressure above 15psi boost...

[TOMSUN]

Good point... But I don't think I'll be needing to go to a rising rate FPR with the bigger injectors.