Austarion

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???

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

BLOFLY wrote: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?

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

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.

fr335tyl3r wrote: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.

your all missing the point. they LOOK cool!

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

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

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

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

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.

Cookiemonster wrote: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?

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

TOMSUN wrote: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...

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