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Location:
Newcastle, Australia
Registered:
March 2005
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Fuel Pressure Regulators
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Fri, 29 July 2005 00:52
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Hi guys, I need a fuel pressure regulator for my 1JZ now that I have a Walbro 255lph fuel pump.
I've been advised against Malpassi, and directed towards Aeromotive and SX instead. I assume they are rising rate?
I know nothing about fuel pressure regulators, I've just been told to get one that is dual diaphragm and rising rate.
Sard is another brand I have been looking at, are they any good? If so, what model Sard FPR should I get?
I can get Sard ones for around $200 on eBay, but no luck with the other 2 brands.
Any idea who stocks these cheaply?
Thanks in advance 
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Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 01:00
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I have also "heard" that the Malpassi rising rate regs are unreliable. But three cars with them and boost ranging from 13psi to 24psi I have not seen a problem yet. Nearly 3 years of use on one of the cars.
The other ones you are looking at are meant to be quite good.
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Location:
Brisbane
Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 01:14
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| Ribfeast wrote on Fri, 29 July 2005 10:52 |
Hi guys, I need a fuel pressure regulator for my 1JZ now that I have a Walbro 255lph fuel pump.
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No you don't. RRFPR's are used when you put a turbo on a non-turbo engine and you're too cheap to get a proper ECU. Your engine is already built for forced induction so you don't need any such bodginess.
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Location:
Perth
Registered:
October 2003
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 01:53
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Yeah you don't need a new regulator unless you plan to increase rail fuel pressure.
Which you don't need to do with stock turbos.
The stock regulator is fine, I run a Bosch 044 with mine.
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Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 02:21
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RRFPR's are used when you put a turbo on a non-turbo engine and you're too cheap to get a proper ECU.
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I am quite happy to be wrong or confused (and probably am  ) but EFI cars have fuel pressure regulators and forced induction EFI vehicles use 1:1 rising rate regulators? So regardless of the ECU a forced induction vehicle will always have a rising rate reg. Some notes below explain a little......
This was taken from http://www.mcbrooms.com/volvo/injcalcs/injcalcs.ht m
EFI systems used in charge-air applications work under a different set of operating parameters than those found in normally aspirated systems. Not only is the ECU typically programmed to dump more fuel during wide-open-throttle (WOT) conditions, due to the need for a richer air/fuel mix under boost, but the fuel system's rail pressure must successfully counteract the elevated pressures that occur in the intake system. The latter is accomplished by means of a fuel pressure regulator. A stock fuel pressure regulator is set to increase fuel system pressure by the same amount that boost pressure increases. Thus, if a system is running 8 psi of boost, fuel rail pressure will have increased by 8 psi, but only while the system is actually experiencing this additional boost pressure. The reason for this is simple -- in order to maintain the same flow rate through the injectors, the pressure across the injector (aka the delta p) must remain the same. So, if intake pressure has increased 8 psi, then fuel system pressure must also increase by 8 psi.
My Malpassi fuel reg is rising rate 1:1 so does the job of a factory unit, I fail to see how this is bodgy?. I belive it is easy to set the baseline fuel pressure with this type of unit which is probably handy when your car is nothing like factory specs.
In Ribfeasts case though you guys are probably right, he does not need any such device if his only change is to his fuel pump.
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Location:
Newcastle, Australia
Registered:
March 2005
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Registered:
May 2002
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Location:
Brisbane
Registered:
May 2002
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Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 02:42
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Rising-rate FPR's on the other hand have a ratio like 2:1, which means if the manifold pressure increases by X the fuel pressure increases by X * 2.
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Forgive my Friday stupidity 
It's always good to get these things clear in your cloudy head 
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Location:
Newcastle, Australia
Registered:
March 2005
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 03:07
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Excellent, thanks guys, looks like I'll be sticking with the stock FPR for now
I guess I'll need a fuel cut defender to stop fuel cut, especially after I raise the boost? It won't lean out or anything I hope? I don't know nearly enough about turbo motors as I'd like
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Location:
Brisbane
Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 03:11
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Yes it will lean out if you go too far past 1 bar. The fuel cut is there for a very good reason in the case of the 1JZ. Going past 1 bar with the stock turbos is asking for trouble anyway.
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I supported Toymods
Location:
Sutho/Hills NSW
Registered:
September 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 03:17
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mines using the stock FPR
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Location:
Newcastle, Australia
Registered:
March 2005
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 03:57
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The stockies will handle the boost no worries once the twin dump pipes are on, as the heat at 15+ PSI is what kills them. The dumps take that away.
My main fear is just leaning out at high boost etc. 1 bar is 14.7PSI AFAIK, and 15 PSI is roughly what I will be running anyway, so leaning out hopefully won't be a problem?
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Location:
Brisbane
Registered:
May 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 04:37
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If you definitely max out at 15psi (ie the turbos never spike) that will be fine. The factory tune on the 1JZ is very rich so that gives you a bit of headroom.
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Location:
sunny coast, qld
Registered:
October 2002
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 05:08
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The other day 1jz747 told me that a couple of 1j cressidas he knows of had issues with the standard FPR and advised me to get an aftermarket one. I just got a 1:1 Malapassi so I am assuming this is the same as the factory one.
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Location:
Newcastle, Australia
Registered:
March 2005
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Re: Fuel Pressure Regulators
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Fri, 29 July 2005 07:15
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Was yours rising rate? I assume so The age of the stock FPR is the main issue, plus it will be pulling a lot more HP than stock, so the Malpassi or a Sard might be the go (or SX etc depending on price).
What are some good online aussie stores that sell these upgrades?
Thanks guys
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Location:
sunny coast, qld
Registered:
October 2002
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Re: Fuel Pressure Regulators
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Sat, 30 July 2005 00:42
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Mine is 1:1 so that rises 1psi fuel pressure for every psi of boost. I think this is the same as the stock one. I agree with you though about the age of the stock one. I figure that it is better to be safe than sorry.
I got mine from horsepowerinabox.com for $220 delivered.
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Location:
Newcastle, Australia
Registered:
March 2005
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Re: Fuel Pressure Regulators
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Sat, 30 July 2005 10:26
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Awesome, thanks mate
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Location:
Osama's hideout
Registered:
February 2003
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Re: Fuel Pressure Regulators
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Tue, 02 August 2005 00:24
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FPR necessary?
is it necessary to drink my own urine, no, but its sterile and i like the taste.
back 4 or 5 years ago when about 5 of us were running 1j's with twin pipes putting out around 200 to 230 rwkw, some of us had trouble with the stock FPR, we all preferred to be safe than sorry, a FPR for $160 at the time was cheaper than grenading a motor and forking out $1000 for an engine and the fuck around of changing it.
btw i dont drink my own urine.
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