How to get my 650ccs to work as 550ccs via fuel pressure?

[xpl2007]

I know stock sr20det fuel pressure is 43.5 with vacume off. How would i make my 650cc work like 550cc?
Lower fuel pressure? If so how and what formula?
Tweak SAFC II? Dont want to tune with SAFC II just yet, would like to start at fuel pressure..
thanks

[DOOK]

buy the correct injectors

[B Love]

It doesnt matter you are jeff. jeff doesnt use 550cc injectors only 650 and above because he is jeff

[cdlong]

it's 36.8 psi if you want to go that route, but at lower pressures you might start to have problems with atomization and spray pattern. use what ever you're using to tune for 550cc injectors and change it to 650. or just take ltd's advice.

[xpl2007]

Thanks!
Thanks B Love... lol
With 550 there is little to no tune I have 650cc .. Mines ECU Stage 3 takes care of it..
How did you figure out 36.8?

Just looked at my paper work from the 650cc injectors and they are flowing at: 652,635,635,652..
It says 43.5 psi would be 643cc
40 psi 617cc
35 psi 577cc
30 psi 534cc

Ill do 40 or little less maybe... Then SAFC II Tune for now thanks. Always safe on 100 octane!

[NiSmOKnIghTsRBS14]

sell the 650s and buy 550. good luck

[s13coupedrfter]

Pressure does not equal volume and like cdlong said you will has atomization and spray problems

[xpl2007]

I got the print out and it says it safe to do so??? Ill call them.

[xpl2007]

Nismo 550 injectors run at 615 so im good at 40psi it dosnt affect the spray as much any lower will idles and runs fine. Just called and talked with DeatschWerks...