What injector size??

[s13dan]

Well sounds dumb but i need help with my new setup... im using a GT25r with .86 A/R and have all supporting mods Z32 fmic 3inch piping 255 ect ect. but i really dont know what size injector to use im hoping damn close 400hp at around 20-22psi, im thinking 660cc but i dont what to run the duty cycle crazy.so maybe bigger?but 660 are very large as is so... anyone with experience with simular setups have any ideas??

[caall99]

740cc to be safe with that horsepower, i wouldn't run 400hp out of a gt25r, i don't even know if its possible. but at 20-22 psi its close to end of its efficiency, i.e. becomes very inefficient.

[SochBAT]

You'd be able to reach 400 on 555ccs. I usually go by flowrate as HP cap, ie 370 is good up to 300, safely, 550s are good to 500 blah blah blah. But safely boosting that high on the injectors is beyond me.

[statik]

Originally Posted by sochbat

You'd be able to reach 400 on 555ccs. I usually go by flowrate as HP cap, ie 370 is good up to 300, safely, 550s are good to 500 blah blah blah. But safely boosting that high on the injectors is beyond me.

i guess your talking flywheel?

370 = 250whp
440 = 300whp
550 = 350whp

thats pretty much avg around these boards, you should be safe with 650's at 400whp

[NemeGuero]

yah the turbo might be stressin' a little hard to make that much power.. t3/t4 is better for your range and yah.. 500ish injectors would be ok

[fliprayzin240sx]

Im running 740cc with GT2871R and i doubt ill break 400whp with this setup. Then agian i need to dyno to see and fine tune enthalphy's rom tune with my safc.

[Mike Wazowski]

Enthalpy stated this formula in the past for 4 cylinders engines

XXXcc injectors * 0.666666666 = wheel horsepower

e.g. 370cc * 0.66666666 = 247rwhp
e.g. 480cc * 0.66666666 = 320rwhp
e.g. 550cc * 0.66666666 = 367rwhp
e.g. 555cc * 0.66666666 = 370rwhp
e.g. 600cc * 0.66666666 = 400rwhp
e.g. 620cc * 0.66666666 = 413rwhp
e.g. 650cc * 0.66666666 = 433rwhp
e.g. 660cc * 0.66666666 = 440rwhp
e.g. 680cc * 0.66666666 = 453rwhp
e.g. 700cc * 0.66666666 = 467rwhp
e.g. 720cc * 0.66666666 = 480rwhp
e.g. 740cc * 0.66666666 = 493rwhp
e.g. 750cc * 0.66666666 = 500rwhp
e.g. 800cc * 0.66666666 = 533rwhp
e.g. 850cc * 0.66666666 = 567rwhp
e.g. 900cc * 0.66666666 = 600rwhp
e.g. 950cc * 0.66666666 = 633rwhp
e.g. 1000cc * 0.66666666 = 667rwhp

Keep in mind that injectors don't always flow what they are rated. The only real way to tell is to get them tested. I had my SARD 850cc injectors tested by Dave at DeatschWerks (http://www.deatschwerks.com), a sponsor on this site. The results were that they were indeed 850cc injectors and that they were very closely matched.

Victor