ok my setup is 450cc injectors 255 walboro pump and am installing a t25 tubo this weekend and running at 5psi and was told i need to have my idle fuel pressure at 18 to 20 psi i have a fpr but it wont go under 45psi so i was wondering what model the 1:1 is and can i adjust it to 18-25psi i cant find one. the only one i see is from 30 to 70 psi. i am running hella rich right now becasue of the fpr im using now and need to get a new one before monday. thanks

you are going to need a sfmu
like the one from vortech

also are the injectors high or low imp
because most people use 440 injectors
usually the 450cc like the ones from a stock turbo dsm
are low imp and will damage your ecu

but back to the sfmu
injectors are rated 450cc at 40ish psi

now if you have to run at 20psi of fuel pressure to idle correctly
and you are running a 1:1 fpr
you would have to be doing about 20psi of boost to make the injectors spray at their rated pattern

the purpose of larger injectors is to get more fuel not the same amount at insane boost levels
that is where your rising rate sfmu or even the less adjustable fmu comes in

the next thing is
for 5 psi of boost the stock 235cc injectors will work fine

the injectors are low impedance but i have the resister for them i understood the hole psi thing like 12:1 for every one pound of pressure there is 12 psi of fuel so wouldnt i use a smaller disk on the fmu? also my main concern is my idle cause it is insane right now and i eat gas. i have some 390cc injectors i was going to put in place of the 450cc i was just trien to figure out which one i needed to control the fuel pressure so i wouldnt be running rich when driving normal like when i start up the car is crazy and at about 6000rpm itr acts crazy or when i slamn on the gas i just want to get the right thing so i can fix this problem.

i forgot to mention so i should just put the stock injectors back in and hook my stock fpr back up and use the vortech fmu casue i dont have the sfmu. then this should be fine again right . also i plan on putting new internals in after feb and thisa is why i have the 450cc in right now. everyone is confusing me im trien to understand but i got alot of people telling me different things like keep the 450cc and just get the aeromotive fpr but no one tells me a specific one and i keep hearing different psi. im getting lost and confused and just want a straight answer befor this weekend. thanks

Originally posted by ameclipse
i forgot to mention so i should just put the stock injectors back in and hook my stock fpr back up and use the vortech fmu casue i dont have the sfmu. then this should be fine again right . also i plan on putting new internals in after feb and thisa is why i have the 450cc in right now. everyone is confusing me im trien to understand but i got alot of people telling me different things like keep the 450cc and just get the aeromotive fpr but no one tells me a specific one and i keep hearing different psi. im getting lost and confused and just want a straight answer befor this weekend. thanks

okay here it is plain and simple to get rid of your headache and problems.

if your only planning on running 5psi, 450's are way huge overkill for that dood.

heres what to do:

1.take out the 450's, put your stock injectors back in, they are fine for up like 8-10psi.

2.get the 12:1 recal kit for the fmu and just use the fmu for now until you build your motor. you need to use the stock fpr in the there as well with the vortech fmu.

3.when you build your motor up, get the sfmu and then use the 450's with resistor pack.

do this, and you will be fine.

sweet finally an answer. thanks bro im going to switch them out this weekend when i do my turbo. thanks.