iv got 450cc DSM injectors. i had them cleaned and rebuilt about 2 years ago. they work great so i didnt want to buy new larger ones. i bought a fpr and was wondering what a safe fuel pressure would be to run? i cant seem to boost more than 5psi because i will go lean. would 60psi be a safe place to start?

 

ttt

 

450cc injector are good for about 300 hp. Unless you are make number close to it or over it I see no reason why you will go lean. I also running the 450cc and I have my fuel pressure at stock between 38-40 psi.

 

i dont think i am making over 300hp. but i do know for sure that my injectors are working at over 100% duty cycle which is why i see the need for my fuel pressure. do you know if i can run 60psi?

btw, i have 50psi fuel pressure at idle beforei hooked up my regulator..how do you have 42psi?

 

bump for a safe fuel pressure to run...

 

I have a walbro 255lph fuel pump so with the stock fuel pressure regulator my fuel pressure is somewhere in the 50s psi. I don't remember exactly. Before I went to tune my car I added my AEM fpr and adjust it back stock fuel pressure. Do you have a aftermarket fuel pump or are you still on the stock fuel pump?

 

i have the walbro 255. yes my fuel pressure is 50psi as well. i used the regulator to get my about 60psi but i want to know how much pressure is safe to use?

 

nobody cranks their fuel pressure on this forum...

 

Two years ago when I was using dsm injectors in my SI, I ran them at 65psi of rail pressure to keep up until I got some rc 750's. They ran like that for about 10k no problems.

 

ya ill keep it at 60 for now..well at least at a pressure that will allow me to run a 90% duty cycle

 

i'm about to do the same to keep my dsm's at a safe duty cycle. don't see why it wouldn't work, y'know?

 

PM a1320honda and ask him what fuel pressure he was running

 

You shouldn't be maxing them @ 5psi boost unless you are tuning to 8:1 AFR or something

60psi is fine

BTW what is your setup (motor, turbo, etc) ?

 

no, im above a 90% duty cycle at 10psi....5psi boost i was fine!!!!!

 

FYI

450cc@50psi = almost 500cc
450cc@60psi = about 540cc

Should be enough to knock your duty cycle down a bit

 

60psi should be fine... I don't see how you're maxing them at 5psi though. My lsvtec had 13psi of boost with a gt35r and they never maxed?

 

Thread from 2007 meng