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When do u need a Fuel Pressure Regulator

B-Man

By B-Man,
in Engines & Forced Induction

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B-Man Grand Master

B-Man

Posted
Posted

I've had a few mods done to my R33 GTS-t - - And now the fuel pressure is playing silly buggers - First I noticed it was leaning out slightly on high boost , so we hooked up a fuel pressure guage whilst on the dyno. Seems that fuel pressure drops when boost comes on hard - The guys tell me that I need a new fuel pressure regulator.

(My injectors are stock hi-flowed to 610ccs)

Now I don't know a lot about these things...... So I'm looking for some help and guidence.....

I understand that a fuel pressure regulator must 'regulate' the fuel pressure to the fuel rail (der)?? Now I don't think my stock FPR is shagged - and they are going to put a new 1:1 (what ever that ratio means) in this week..

How does a FPR work ? Why would I need a new one ? What does the 1:1 ratio mean ? I think u can get 2:1 ones, and also progresive rate one?? Whats that about ??

My guys say that my ECU will needs re-mapping after the new FPR goes in - I guess this is because the higher fuel pressure behind the big injectors will mean I'll be running way rich and they may have to lean it out some ??

Can anyone give me a "Fuel Pressure Regulator for Dummies" explanation ?? Also whats a good FPR ?? I hear Malpessi are good ??

Thanks in advance,

Clint32 Mentor

Clint32

Posted
Posted

If your injectors are big enough i would be looking toward the pump as the cause of the lean off in the top end. All the reg does is regulate the pressure, and more pressure will obviously mean more fuel, if you have 610cc injectors they should be plenty at stock pressure. If the pump cant keep up the pressure will drop no matter what reg you have.

benm Grand Master

benm

Posted
Posted

Alittle off topic but like Brendan here im also learning.....

What size are the standard R33 GTS-T injectors and is their like a certain rwkw (or figure) they can handle before needing to be upgraded ?

MRK25T Experienced

MRK25T

Posted
Posted

I'm also in the market for a fuel system upgrade.

Can someone tell me where I can get (cheap):

1. a Bosch 044 Motorsport in tank fuel pump

2. a SARD adjustable fuel pressure regulator (or maybe pete's one?)

If possible let me know what sort of money id be up for.

Do I need anything else such as pipes, hose clamps etc?

Currently have FMIC, full exhaust, high flow turbo, EBC.

Mark

Steve Grand Master

Steve

Posted
Posted

Brendanf,

Fuel pressure regs work by maintaining fuel pressure at above plenum pressure, any excess fuel is returned via the return line - if its running lean, your pump isnt keeping up.

For example, a standard pressure regulator may keep fuel pressure at 36psi, with an adjustable, you can dial in the desired fuel pressure. A rising rate is a bit different, they adjust the pressure up as plenum pressure rises. for example if the pressure at 0lbs (in the plenum) is 36 psi (fuel rail), at 2 psi (plenum)it may be 39psi (fuel rail), at 4psi (plenum) it may be 44psi - etc. these are arbitary figures only for demonstration, not real figures. Hope you understand what I mean.

If you do want to get an adjustable fuel pressure regulator, I believe Nismo do one which can be picked up new for $250. However in your instance, a decent fuel pump should be fine - a adjustable reg will only be of use to you if you are trying to get a bit more out of your injectors.

Macka, megalla's site states R33 stockies at 370cc and whatsisname has gotten 257rwkw with them - so you still got a bit of room.

MRK25T Experienced

MRK25T

Posted
Posted

I've been quoted today for the following:

In tank pump (600hp) $380

Rising rate fuel pressure regulator $200

To have it installed $850 or $800 cash.

Am I getting the correct gear at the right price? What questions should I ask my mechanic?

Regards,

Mark

Guest Miles B

Guest Miles B

Posted
Posted

Check out the more well known Supra tuning houses....

I've only ever read good things about Dusty who owns MVP Motorsports in Florida.

http://www.mvpmotorsports.com

Titan (from memory they were good too, but do yourself a favour and read a whole bunch of reviews before you send $200+ overseas to anyone) have it a little cheaper

http://www.titanmotorsports.com

Airmail will probably cost you 30 to 50 bucks, and take 1 to 2 weeks tops. Sea mail will cost about half, but can take up to 10 weeks at times. Both places also sell excellent regulators.

Didn't you say you already have a big fuel pump? Why are you looking at replacing it?

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