oh and i already have a greddy front mount and walbro 255

 

Throw whatever the t25 will give em...15psi or so. I wouldn't upgrade to anything bigger w/out bigger injectors because they are pretty much maxed when the stock turbo is maxed.

 

i would do 15 as well

the t25 wont hold 15 though it will drop off

 

I would only go about 13-14.....

 

really depends on tuning, but no point going past 15lbs since the stock T25 is past it's efficiency range. Some people will suggest not boosting past 12lbs on stock injectors, which seems to be the normal threashold people are willing to go to.

 

ive heard people claiming 18 psi on t25 or so but id only push around 14 to be safe

 

yup. I boosted the bitch to 22psi................open wastegate.............then it blew 3 secs later.

 

^ it must have been -20 degrees outside because at 60 degrees with no wastegate signal (max boost) the turbo wouldnt go past 16psi. It spiked to 17, maybe 18, but fell to 16 and slowly died to 12-13 by redline. Nothing blew, but it did run very lean (egt went very high, very fast haha)

I wouldnt go past 14psi, that a good, safe boost and is still in the turbo effciency.

 

ive dropped a wastegate line off before and it hit 22 on my t25g

 

stock injectors can handle alot more then u think, as long as u dont go lean.

everyone with an sr should have a wideband.

 

I will ONLY answer this becuase most of you got it wrong.

Also, i cant believe how many kidss are answering this question that has been answered 100's of times when i first joined this site YEARS AGO and most likely 100's of times before that!!

The stock injectors will handle what the t25 dishes out (15ish PSI) BUT your MAFS bottoms out anything above 12psi. That being said... when you go above 12 psi, your car runs pig rich at a 10:1 ratio under WOT becuase of the safeguard the ECU does to protect from detonation when the MAFS bottoms out. If you have a catalytic converter... it will glow red hot and get clogged within time as well with this a/f ratio.:smacked49

 

Only way stock injectors will handle more is if you raise fuel pressure. With the Walbro and Stock FPR its already at 50-55psi so i wouldnt push it higher than that anyways. They max around 250-260whp tuned. When i say max, i mean in the 90% duty cycle area. People have pushed higher duty cycles (100+%) and gotten more power but its pushing your luck.

 

how do you get higher than 100% duty cycle?

 

Im not exactly sure how, but I remember my friend logging his LS1 and he hit like 120% duty cycle!

 

well since 100% duty cycle means the injector is on all of the time, its improbable that he was actually getting 120% maybe he was logging in 4 cylinder mode or something

 

BoostedVR4 did well over 100% Duty Cycle on 370cc injectors @ 18psi from a T28. Logged with his AEM EMS.

 

that doesnt make sense to me....so the injectors are open 120% of the time?

so some space time continuum equation is going on here? im confused

 

you can get 100% + duty cycle if you bump up your fuel pressure. If 100% duty cycle is measured at 35psi of fuel pressure, running 45-50 psi of pressure at 100% duty cycle will end up being calculated as over 100%.

If that makes sense.

 

o....yea that makes sense... i just wouldnt think they would factor that into the duty cycle....i mean, duty cycle is how much time the injectors are open....not how much time they are open along with fuel pressure

or am i wrong

or did you not understand me

 

The fuel computer calculates duty cycle % based off of a combination of Air Flow, Injector Cycle, and A/F. So basically if you're pushing a ton of air, and keeping a good A/F at a higher boost than the injectors should be able to handle under normal fuel pressure, the computer will be tricked into showing 120% duty cycle. Actually the injectors are running 100% cuty cycle, but they're flowing 120%, so thats what the computer will display.

Its funky and weird but thats how it seems to be

 

I've decided to stick with the stock injectors for now with a few mods just to see what I can get out of it. here's my setup (waiting to be installed and tuned) and i was just wondering what numbers i should expect from a professional tune, also i've been thinking about replacing/upgrading the wg actuator but i'm not sure if it'd be necessary/beneficial.

Engine:
S13 SR20DET Redtop (installed)
Koyo Radiator (installed)
VSPL FMIC (installed)
Walboro 255lph Fuel Pump (installed)
Enjuku Racing Hotpipe (installed)
Greddy BOV (installed)
Circuit Sport DP w/ elbow (pending)
Circuit Sport 3" Catback Exhaust (installed)
Test /Cat delete (installed)
Apex'i power intake filter (installed)
Apex'i S-AFC Neo (pending)
Apex'i AVC-R @ 12psi (pending)

 

I was boosting .9 bar on my 15 turbo with gtr pump and stock injectors.

 

i boosted 22psi on s370cc's walbro pump and stock t25. turbo only lasted 3 months with daily driving

 

why boost so high on a T25? they're past efficiency after 15psi

 

Your very lucky to not blow the engine boosting 22psi on the T25. It might be a little turbo but thats way outa the effeciency and with that high of pressure its alot of extremely hot air, the pistons definitly arent liking the detonation you most likely put them through.

 

get a good boost controller and stay around 12-13psi. unless you got a lot of $$ and dont care.

 

PS

I blew my engine at 17 psi becuase of OEM fuel pump wiring not being able to carry the voltage needed to the walbro.

60 amp relay, 30 amp fuse, and 12 guage wire that is wired directly to the battery fixes it.

 

Now i could be wrong, but im sure ive heard somewhere that the stock fuel pump in the s13 is a 2 speed pump. The ecu increases the voltage to the factory pump at high load/rpm to increase the fuel flow. Weh you swap the pump out you need to do something to the wires to make it run at the high speed all the time. That might explain why your voltage was low.

 

I hardwired my Fuel Pump too a while back when i relized the AFR would get leaner as the revs increased. Cheap and easy to do.

 

The only two speed pump that Nissan had was in the 300zx TT.