Subaru Impreza GC8 & RS Forum & Community banner
1 - 8 of 8 Posts

·
Registered
01 2.5rs ej257 block
Joined
·
79 Posts
Discussion Starter · #1 ·
Alright guys well im deep in the process of of build my rs. Before i ask my questions ill list my set up and condensed parts list.

2001 2.5rs

ej257 block
-cp 8:1 compression
-Manley h beam rods
-sti crank
-all balanced

-td02 turbo
-wrx manifold
-wrx up pipe
-ebay down pipe
-HKS carbon cat back
-9x6 aem dry flow filter
-cx racing y-pipe kit
-wrx intercooler
-ebay fpr w/jegs gauge
-Greddy e-manage ultimate


obviously there is a lot more to my build but this is all that pertains to my questions

1) The big question i have is how much boost can i run on stock 280cc injectors with the fuel pressure turned up.

-I know the max ill want to run is about 90psi and i plan to upgrade the injectors when i have the money for them, but can i run stock internal wastegate pressure with the 280cc injectors(which ive heard mixed answers some say its 7psi and other swear its 10psi? if you could help there to that would be great)

2) I know i need the wrx water pump but what exactly do i need to make it all work. For example, will the rs thermostat, plastic 90, and the hose work or do i need the wrx parts, and if so what parts would they be?

THANKS IN ADVANCE FOR THE HELP, charley

FYI: I have search for hours and cant find a clear answer so i will be grateful for links or answers
 

·
Registered
Green 97 OBS
Joined
·
1,840 Posts
1- running up to 90 psi would get you quite a bit of breathing room for the injectors, that's over twice the fuel pressure. I hope you are upgrading your lines if you do that though, that's enough pressure to rupture them if they are old. Leaking fuel is not a good thing in a car. As for the amount of boost, I don't really know. You'd have to see if there is some way to watch your duty cycle of the injectors. If you get over 80 percent then you should definitely look into bigger injectors.

The stock (I'm assuming you mean the WRX TD-04?) turbo wastegate is set at 7 psi. there is a little restrictor pill that is put in the stock pressure line that makes it 10 psi. But the actual actuator is 7 psi.

2- Unless you have the WRX water lines and oil cooler, the WRX water pump won't really gain you anything except two return ports that you need to plug. The impeller isn't much different than the N/A one, I've compared them myself. Run a N/A for less headaches IMHO.
 

·
Registered
99rs-t
Joined
·
79 Posts
i think your going to be using about 90% injctor duty cycle at 7psi..also u are going to need a voltage clamp wit your map past 7psi...get some wrx injectors and a better adjustable fpr...others will chime in for better info...
 

·
Registered
01 2.5rs ej257 block
Joined
·
79 Posts
Discussion Starter · #4 ·
1- running up to 90 psi would get you quite a bit of breathing room for the injectors, that's over twice the fuel pressure. I hope you are upgrading your lines if you do that though, that's enough pressure to rupture them if they are old. Leaking fuel is not a good thing in a car. As for the amount of boost, I don't really know. You'd have to see if there is some way to watch your duty cycle of the injectors. If you get over 80 percent then you should definitely look into bigger injectors.

The stock (I'm assuming you mean the WRX TD-04?) turbo wastegate is set at 7 psi. there is a little restrictor pill that is put in the stock pressure line that makes it 10 psi. But the actual actuator is 7 psi.

2- Unless you have the WRX water lines and oil cooler, the WRX water pump won't really gain you anything except two return ports that you need to plug. The impeller isn't much different than the N/A one, I've compared them myself. Run a N/A for less headaches IMHO.

-is there a way to monitor duty cycle? that would be great if i can. and i had overlooked the fact that i should upgrade fuel lines, ill add that to the list

-yeah im ment the td04 wastegate. 7psi thank you for that

- the only reason id be changing the water pump is to fit the wrx manifold. every thread ive read says that it wont clear. if it does fit i wont swap it out, besides the n/a one i have is like 8000 miles ol

Thank you sir
 

·
Registered
01 2.5rs ej257 block
Joined
·
79 Posts
Discussion Starter · #5 ·
i think your going to be using about 90% injctor duty cycle at 7psi..also u are going to need a voltage clamp wit your map past 7psi...get some wrx injectors and a better adjustable fpr...others will chime in for better info...

is that 90% even with fuel pressure turned way up? im using e-manage to clamp. i plan to upgrade to 565cc but im trying to get the car done and i don't have unlimited funds (been building for a year and half and im getting impatient)
 

·
Registered
Green 97 OBS
Joined
·
1,840 Posts
-is there a way to monitor duty cycle? that would be great if i can. and i had overlooked the fact that i should upgrade fuel lines, ill add that to the list

-yeah im ment the td04 wastegate. 7psi thank you for that

- the only reason id be changing the water pump is to fit the wrx manifold. every thread ive read says that it wont clear. if it does fit i wont swap it out, besides the n/a one i have is like 8000 miles ol

Thank you sir
Oh yeah, forgot about the stock manifold. That's true, the crossover pipe hits. My mistake, sorry.

I do not know if the EMU monitors the duty cycle. I was told my 230s would be plenty for 5 PSI on a RRFPR, so I think your 280s will be ok at 90 psi.
 

·
Registered
01 2.5rs ej257 block
Joined
·
79 Posts
Discussion Starter · #7 ·
Oh yeah, forgot about the stock manifold. That's true, the crossover pipe hits. My mistake, sorry.

I do not know if the EMU monitors the duty cycle. I was told my 230s would be plenty for 5 PSI on a RRFPR, so I think your 280s will be ok at 90 psi.

alright, well i was hoping you were right but oh well :)

hopefully i can run less than 90psi thats the max i want to run

thanks again, charley
 

·
Registered
2000 2.5 RS-T srp sedan
Joined
·
2,732 Posts
with my stock injectors i was get max out of them at 5psi with stock FP and wrx pump.

Might as well toss in Wrx injectors with bigger o rings and call it a day.

I changed my set up and with the 257 bottom end and 14 psi on wrx 440's stock FP I am again maxed out on fuel.
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top