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Discussion Starter #1 (Edited)
I recently had my power fc on my 32gtr installed and mapped. Im still running the stock injectors and now wished i replaced them before i had it remapped as under full load i see between 90 - 95% injector duty being used.

Im looking at getting some 550 injectors are there any that anyone can recommend as ive seen a few diffrent makes or will all the ones suitable for the rb26 be ok?

Once i have fitted them and an uprated fuel pump i have been advised to have the fuelling checked/tweaked, was wondering whether i would be able to have it mapped to 1.3Bar with the standard headgasket running rebuilt steel turbos or is that a bit risky?

Thanks in advance
 

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Should be ok with stock gasket as long as you have enough fuel, most people change the gasket to drop the static compression ratio. Sard injectors are good .

Also remember that the pfc will need a remap again once fitted
 

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Discussion Starter #3
thanks for the advice, i knew i would need a remap and thought it would be good if i could get them to map it to 1.3Bar so it makes the expensive no so hard to bear with that little bit of extra go :)

Injectors wise i was thinking 550's as my car will prob never see more than 500 flywheel bhp, but was wondering if theres any negative effect of having for examples 700's?

thanks
 

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turboshed said:
Injectors wise i was thinking 550's as my car will prob never see more than 500 flywheel bhp, but was wondering if theres any negative effect of having for examples 700's?

Years ago, when fuel management sucked, then the ECU's had problems controlling bigger injectors. Now days though, there is not a problem controlling bigger injectors.

Its not like putting a bigger carb on a car. An injector you can have very precise control.

When I up grade a GT-R, I dont waste time with a 550 injector. Stock, 700 cc, then 1000 cc.
 

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what boost level were you pushing with the stock injectors at 95% duty cycle?

Didn't someone slag and slander Sard injectors on this board recently? They seem nice enough to me but what do I know, I'm just a ****** browsing parts catalogs...:p
 

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I fitted 550 denso's black with purple collars. They didn't fit too well, i had emery them to death to get them in! Easier than sending them back to Japan. Don't know if this is common practice or if I had a duff set? They also clatter like hell, sounds like the followers have drained down!

Injector sizing

"As a rough guide to power output, take the injector flow in cc/min and divide by 5 then multiply by the number of injectors."

Example: 550cc/min divide by 5 = 110 x 6 injectors = 660bhp

Thats obviously at 100% think 80% is ideal? = 528 bhp
 

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Thacker said:
I fitted 550 denso's black with purple collars. They didn't fit too well, i had emery them to death to get them in! Easier than sending them back to Japan. Don't know if this is common practice or if I had a duff set? They also clatter like hell, sounds like the followers have drained down!
What part didn't fit ? The top or the bottom ? Did you try a different o ring ?

They shouldn't be any noiser than the stockers. Sounds like you might need a spacer between the rail and the head.

What Denso part number ?
 

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Physically didn't fit into the fuel rail even without the o rings. The surface finish was quite poor. Used emery paper to clean them up and they eventually fitted. Brought them from Nengun listed as "HKS 550cc top fed injectors (black) 1402 - RZ001" I still have the box's somewhere think that has the denso part number on it? They work fine now and do seem to be quietening down. You could actually hear them inside the car!
 
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