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Discussion Starter #1
Hi guys

i am getting my r33 gtr mildly upgraded. But i am in 2 minds about getting injectors for my car. Question is..will i need injectors at the power level i am chasing. 400 rwhp.

here are my mods:

internally stock r33 gtr with:

-garrett 2860 -7's
-pfc (non djetro)
-nismo intank direct replacment fuel pump
-slightly thicker fmic than stock
-2.5in front pipes, to 3 and 1/4 in cat back. hiflowed cat.
-stock dumps
-stock injectors

. car hasnt been tuned yet cause theres too many different answers for power outputs on stock injectors.
 

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Discussion Starter #4
i heard this from someone but dont quote me on it.

apparently the r32 gtr's make less power than the r33 gtr's with stock injectors due to a different base line fuel pressure?? or something to do with the stock fpr??
 

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Discussion Starter #5 (Edited)
i dont want to have to change injectors for another reason. Down here in Aus they are very strict on power laws and modifications. Im going with a stealthy setup.

For an extra 20whp should i just get a nismo fuel pressure reg?


And i have another question?

Would i need to port my exhaust manifolds with the -7's?


some say yes and others say its a waste of money.

i will never run boost past 18 psi on a stock motor anyway.
 

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Discussion Starter #7
looks like i am going to see what the stock injectors produce as safely as possible.

if it does 380 rwhp il leave it. After all it is an internally stock motor. :)
 

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im running 472bhp (393 athe wheels) with stock injectors on my r32 gtr.im running 1.1 bar with gt2860-5s i do have a tomei adjustable regulater.i wudnt push the boost any higher with stock injectors.Im running well over 90percent duty at this boost
 

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easy way to calc how large injectors you should have is

HP x K
-------- = Fuel flow (cc per minute)
C

Where hp = maximum horsepower, K 4,6 for naturally aspirated engines, or 5,6 for turbo/superchargrd engines, and C= numbers of cylinders

400x 5,6
-------- = 373,33333...fuel flow (cc per minute
6

373cc is what a 6 cylinder, 400 hp gtr needs every minute per cylinder

TF x 100
Injector static flow(cc per minute)= ----------
N x M


Where TF = theoretical flow, N = number of injectors per cylinder , and M=
injector duty cycle

Best duty cycle is somewhere between 60-80%

TF= 373
N= 1
M= we take 70% for now

373 x 100
----------- = 532 cc/min
1 x 70

So you can buy 500cc injector or 600cc you get lower duty cycle on the 600cc
 
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