FYI : RB25DET Injector Flow Rates

[EnricoPalazzo]

Standard R33 Rb25det injectors can flow:

pressure cc/min

2.55bar(37.5psi) 370 (standard pressure)

3.05bar(44.8psi) 410

3.55bar(52.2psi) 440

[rb20-calais]

good info

[Guilt-Toy]

so thats how people are getting 400bhp out of stock injectors... 440cc at 52psi.. use 65psi and im sure 400bhp is not impossible.....

[INASNT]

But remember the more you raise the rail pressure and ram more fuel throught the injector you change the spray pattern

[Sydneykid]

But remember the more you raise the rail pressure and ram more fuel throught the injector you change the spray pattern

And you have to leave some headroom in the fuel pump for boost. :headspin:

[Guilt-Toy]

so how much pressure is the best most you can run without changing the spray pattern too much ?

[aqik33]

Around 45psi rail pressure. its a trade off. aftermarket inj. cost tons, raising the rail pressure costs F A. If u had the coin to need 65psi rail pressure u would change the inj anyway.

[Sydneykid]

Around 45psi rail pressure.  its a trade off.  aftermarket inj. cost tons, raising the rail pressure costs F A.  If u had the coin to need 65psi rail pressure u would change the inj anyway.

And since most fuel pumps are rated at 73.5 psi, you would only have 8 psi left for boost. That's not much :wassup:

[Guest RedLineGTR]

Thanks for the info

[Abo Bob]

I've heard that R34 injectors are smaller. Anyone got any info?

Sorry for the minor hijack.

[Sydneykid]

R34 GTT injectors are smaller in size, I haven't detected any significant difference in their flow rate. If anything they seem to flow slightly more than other RB25DET injectors.

[B-Man]

How long will your fuel pump last if you fit a FPR - ie compared to if you didn't fit a FPR ??

A) The same as if you didn't fit the FPR ?

B) Less because you are labouring the Fuel Pump ??

c) More because of some unknown reason ??

I suspect (B)

[Abo Bob]

How come I get 92-94% injector duty quite regularly with 0.85 bar and standard turbo?

One day it hit 100% when i wasn't looking but it seems to have these microsecond spikes like 65% when you've barely touched it.

[4door_Sleeper]

And since most fuel pumps are rated at 73.5 psi, you would only have 8 psi left for boost.  That's not much :wassup:

To get that sort of power I assumed you would already be on boost. Surely an aftermarket rising rate regulator will allow you to maintain a slightly elevated fuel rail pressure and then rise it to 65psi by the time you are on full boost.

I don’t have a problem with using a RRR, but if you are pushing that type of power (and I am assuming you have replaced the turbo, fuel pump, computer, intercooler) then surely the cost of injectors is worthwhile even if it’s just insurance for your motor.

[Sydneykid]

How come I get 92-94% injector duty quite regularly with 0.85 bar and standard turbo?

 

One day it hit 100% when i wasn't looking but it seems to have these microsecond spikes like 65% when you've barely touched it.

Car is running rich?

[Sydneykid]

To get that sort of power I assumed you would already be on boost. Surely an aftermarket rising rate regulator will allow you to maintain a slightly elevated fuel rail pressure and then rise it to 65psi by the time you are on full boost.

Yep, that means full boost is 8.5 psi.

[Abo Bob]

Car is running rich?

You should see my fuel bills! Jeez man. Weird thing is, at the track the exhaust goes brown like it's running lean.

I'm thinking of putting a 2nd hand SAFC in there till I can afford an emanage and a good tune. The ECU I have makes it run so smooth but I think it's just putting way too much fuel in.

[N I B]

Magic1s GTS has 435rwhp on stock injectors and uprated pump,this is the most we have seen sofar on stockers and we have never had any problems at high fuel pressures.

We will fit a bigger pump and see how we go.

This power is in shootout mode.

[INASNT]

Magic1s GTS has 435rwhp on stock injectors and uprated pump,this is the most we have seen sofar on stockers and we have never had any problems at high fuel pressures.

We will fit a bigger pump and see how we go.

This power is in shootout mode.

I see around 80% duty cycle from my 550cc injectors with no FPR and Bosch 044 pump with around 312kw@wheels.

[Sydneykid]

I see around 80% duty cycle from my 550cc injectors with no FPR and Bosch 044 pump with around 312kw@wheels.

That's about right, I have seen around 565 to 570 cc's out of injectors rated at 550 cc's.

So 570 X 80% / 1.34 - 60 = ~300 rwkw

Your 312 rwkw is a pretty good effort.