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Location:
Hawthorn, Vic
Registered:
March 2005
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Fuel Pressures and Injectors
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Tue, 22 November 2005 05:11
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Hi Guys,
Just wondering what the stock fuel pressures are for a 2jz-gte, along with stock pump flow rates as well is the fuel pressure regulator. Ill take a stab, and guess most of the 2jz in the country are JDM, thus being 440cc???
Reason for all this, is that I'm currently researching to try and get the best pump/injector/regulator combo for my upgrade.
Thinking of going around 660cc or 720cc's, with a Bosch 044 pump.
Talking to people at work, they seem to think only 1 pump will be necessary for 720cc injectors.
The 044 supplying 5bar, with 200l/h flow, i guess will need to be regulated to 3 or 4 bar, which increases the flow somewhat.
All of Bosch's injector rating are in g/min with a specified operating pressure. So thus, I need to convert this to a cc flow rate. Any idea on how to do this?
And thus, knowing the stock fuel pressure from the pump, and regulator flow, can decide what needs to be purchased. ill assume the fuel rail wont need to be upgraded???
So yeah, if anyone can make sense of my rambling any help would be appreciated!
Cheers!
[Updated on: Wed, 23 November 2005 22:25]
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Wed, 23 November 2005 01:12
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any ideas???? anyone??? 
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Location:
Perth
Registered:
October 2003
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Wed, 23 November 2005 01:48
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1 gallon/min = 3785.412 cm^3/min
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Wed, 23 November 2005 02:15
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ok, slight problem, injectors are gram per min.
not gallon/min
sorry 
so whats the standard weight of 98ron??
ill assume thats what they want???
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Location:
Sydney
Registered:
February 2003
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Wed, 23 November 2005 04:29
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cool.
shame that site doesnt have any of the bosch motorsport injectors.... oh well...
doing some short calcualtions,
Accoriding to here,
Petrol at 60 F is 737.22 kg/cu.m
Thus, at 4C, it equated to .737 g/mL
Working that, it eqautes that 1gm of Petrol results in 1.36mL
So, if an injector say is rated at 185 g/min, it would parse 251.6ml /min or 15.096l/hr.
The injector then, would be rated at 251cc's, correct?
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Wed, 23 November 2005 21:46
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alrighty.
thanks to norbs found out that the stock fuel pressure regulator is set to about 32psi,which is about 2.45bar.
also calculated 660cc injectors are what im after.
only 'slight' issue im still converned about, is that the injectors are rated@ 660cc, so at full rate, they will inject a total of 3960cc's of petrol, which equates to ~237L/hr.
Fuel pump delivers only 200l/hr. But, since the fuel pump is 200L/hr @ 5bar, where as the injectors inject 237
L/hr at 2.7bar, im guessing as the pump is pumping at higher pressure, the pressure ofset increases the flow rate? or will i see a loss in fuel pressure??? and thus require a secondary fuel pump??
UPDATE
talking to some fuel guys, it seems that flow rates have to be met. which means either, getting 2 pumps to make up the loss, or getting a single pump that can supply the desired rate. So off to make some phone calls to see what i can find. Ive been told to look at supercharged VS commo pumps and injectors.
Keep you updated
[Updated on: Wed, 23 November 2005 23:15]
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: 2JZ Fuel Pressures/ g.min to cc conversion
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Thu, 24 November 2005 03:43
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are the injectors rated at 100% duty or 80% duty?
what rail pressure are they rated at?
typical rail pressures are around 40psi.. a nice figure rounded to work from..
what a fuel pump CAN do, and what it does do depends on the pressure regulator.
the regulator controls the pressure the pump is putting out by resistance. so if your reg is set to 2.7bar, the pump puts out 2.7bar. at lower than 5bar, it will flow more. the flow graphs should be easily available for the 044
what boost will you run?
assuming you run 1.5bar, and rail pressure is 2.7, then total rail pressuire is 4.2.. so what does the 044 pump at 4.2bar?
what about 2 walbro pumps, they can be had cheaply and there are high pressure versions (check the flow graphs first)...
they are about 220L/hr at 2.7bar, but maybe 150L at 60-70psi
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 05:19
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I wouldnt expect you are never gonna get 100% duty cycle out of your fuel injectors...
And as has been said check the pump maps coz pressure vs flow is never linear.
The rating is usually the flow acheived at max reccommended pressure. Going over 5 bar would probably result in a radpid flow drop off, conversly dropping the operating pressure could increase flow a lot more than you might expect.
Corollas, unless you have a RRFPR how does boost affect the pressure of the system? I guess the 2J has one stock? How did you calculate 4.2 bar or did you get this figure from spec on the factory FPR?
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 05:21
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ok...
i can see 1.5 + 2.7 = 4.2
How is this operating fuel pressure?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 06:47
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I understand the principal of RRFPR's but i didnt beleive that the manner in which they regulate system pressure was as straightforward as;
FP = factory setting + boost
Furthermore, what FPR does a factory 2JZ-GTE have? Norbie has obviously told Viper that it is about 32psi. If it was a RR variety I wouldnt expect Norbie would ommit this detail? So although im interested in how you have derived this rule, i dont see that it applies does it?
Just an idea, but you could buy/make a simple transformer that will step up the voltage supply to the Bosch a lil bit. You would just get more go out of what you have...
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 06:50
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| mic* wrote on Thu, 24 November 2005 16:19 |
Corollas, unless you have a RRFPR how does boost affect the pressure of the system? I guess the 2J has one stock? How did you calculate 4.2 bar or did you get this figure from spec on the factory FPR?
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normal pressure reference fuel pressure regulators will increase fuel pressure as a 1:1 ratio of the reference pressure.
rising rate fuel pressure regulators are called that because the rate at which the fuel pressure increases is greater than the boost reference pressure, ie 1.5:1, 2:1 etc.
a RRFPR increases fuel faster, and you run into fuel pump problems sooner. since injectors are designed for a certain range of pressure, you should keep the pressure differential across them close to their design.
a higher differential, as with RRFPR, gives higher flow for same PW.. to a point.. and the only time they are warranted is when you are trying to richen the fuel curve of a stock setup using stock ECU which has MAP sensor, after you decrease intake flow path resistance....
or so i think  .... in all other situations, you are better off using a 1:1 FPR so that you always have the same pressure differential across the injector, and then you have a better idea of what a given increase in PW will do to fuel flow..
maybe
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 06:53
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oh, and as far as i know, most stock FPR's as 1:1 ratio. there is no need for a rising rate regualtor when you have the option of changing the tuning by programmable means.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 06:59
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| oldcorollas wrote on Thu, 24 November 2005 17:53 |
oh, and as far as i know, most stock FPR's as 1:1 ratio. there is no need for a rising rate regualtor when you have the option of changing the tuning by programmable means.
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This makes very good sense. You are a wealth of knowledge.
Excuse my ignorance, i still have much to learn but i aint the kinda person you need to tell shit to twice.
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 07:00
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Meaning, i appreciate the education and its not wasted finger movement. Thanx
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 07:20
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| mic* wrote on Thu, 24 November 2005 18:00 |
Meaning, i appreciate the education and its not wasted finger movement. Thanx
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 heh heh
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 07:22
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hmm.... interesting...
ill get the 044 flow rates from work tomorrow.
see what it sais..
as for the injectors... most of the ones ive been looking at operate at around 2.7-3psi (optimum), well short of the 5bar.
ill post up the graph tomorrow.
thanks for all the regulator info. ill just go with the stock one, privided the injectors like running on 32psi. worst comes to worst, buy a new one 
arg... so much shit... bloody hell!
modding the 044 would be interesting... im sure its been done...
ba, ill see what i can find 2morrow
also ring around for walbro pumps... and maybe a pair of smaller bosch ones
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: Fuel Pressures and Injectors
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Thu, 24 November 2005 22:47
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right, bit of google'ing and i came up with this
the graph is abit iffy to read, but yeah... flow rate does change quite abit. at say,3 bar, it flows almost 300l/hr
and using another fuel pump calculator , an 044 pump should be enough to cover what im after. and if not, well ill just run another pump, or overvolt it.
hope this helps other out there who were as confused as i was at the beggining of all this.
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Fri, 25 November 2005 03:38
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bah...
overvolt it anyway. There's always current to spare...
It'll be fun.
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Location:
Hawthorn, Vic
Registered:
March 2005
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Re: Fuel Pressures and Injectors
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Fri, 25 November 2005 03:43
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hah, yeah.
ive decided to go for 2 fuel pumps instead.
instead of the 044 (5bar @ 200l/hr), im gona get 2x 910 (5bar @ 130l/hr)
that way i still get the 5 bar, but at 260l/hr or so flow.
tiny bit cheaper aswell getting 2 pumps, and added security if one fails, i can limp home. extra hassle with piping, but seeing as i intend on runnign new pipes, no biggie
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Location:
Brisbane
Registered:
July 2005
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Re: Fuel Pressures and Injectors
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Fri, 25 November 2005 04:00
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Cool,
I would probably try to put a checkvalve in the fuel line after each pump, but before you tee them together. That way if one does fail, the other will still fuel the system (limp mode), not just pump back into your tank through the other rooted pump (broken down mode)...
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