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Discussion Starter · #1 ·
If you have a 04, you need a fuel pump for anything above STG2 off the shelf..... period...

I'm running intake/catless tbe/prodrive solenoid/ported manifolds/injen crosspipe and with a 22psi midrange / 16.5psi redline boost curve i was seeing 11.7-11.8:1 in some spots in the 5000s and 11.4:1 at redline, after installing the pump and logging again, it's ~10.0:1 at 5000 and 10.5:1 at redline, richer acrossed the board

to make matters more interesting, 2005 cars don't seem to have this issue, any 05 car i log on a custom tune has considerably more headroom in the fuel system, probably equal to what i'm seeing with a upgraded pump in the 04, this probably applies to 06/07 too but i can't prove it

bottom line, when scott says here that custom tuned sti's NEED a fuel pump and people disagree... he's 50% right, it appears the 05s get away without it, but he's seen enough 04s to warrant it

cliff notes: map wasn't changed but with the same atmospheric conditions, same fuel and the same idcs... the afrs have changed .5-.75 point from 4000+rpm and lemme tell ya, when yer 10.0:1 at 5000rpm it sucks... to be corrected tommorow and dragged soon
 

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why would it apply to the 04 and 06/07's that's kinda of random. And the 05' guys get away without a problem.
 

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Not sure the validity of the claim.... my 05' was told the fuel pump was not cutting it for a stage 2 Protune.
 

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he probably means 05+
 

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Discussion Starter · #6 ·
yeah i'm saying i assume 06/07 are fine as well but haven't touched enough of them
 

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Interesting. Was datalog done via Street Tuner and a wide band?
 

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Discussion Starter · #9 ·
Probably varies acrossed all years, but the 05s i've had my hands on personally do fine with tons of airflow and stock pump/injectors, my 04 and some others however ran very high idc's and couldn't satisfy the requested afr 5000+ on the stock fuel pump, protuner/wideband/ecuexplorer are being used for comparisons
 

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Possibly early 05's got a version of the 04's pump.
 

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most likely, halfway through subaru changed a few little things on the 05's...i have the later date ones..
early 05 = metal coolant tank
late 05 = black plastic tank
 

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Its pretty much hit or miss on any car. This has been debated over and over as some people wonder why with identical setups one person runs a 90% idc and the other over 100%. i.e. the only time I have personally seen over 98% idc's was on an OTS map running a very rich 10:1 ratio and 15psi at redline. Ive tuned a couple of 04's that don't have problems w/ extreme idc's and on a pretty conservative safe tune. It is a good idea so that in the case you do need one, you do not waste dyno/tuning time swapping it out but it varies. Wolf tested this out already as well, and conclued that it did not do anything for his idc's.
 

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VSGTS14 said:
most likely, halfway through subaru changed a few little things on the 05's...i have the later date ones..
early 05 = metal coolant tank
late 05 = black plastic tank
Here's a curveball for the group on here.

My car was built in March 2005. (Just checked the door plate). It has the black plastic tank and needed a fuel pump. :) (The reason I thought it was a late build was because my buddy's 05 STi was built in October 04--He too has a black plastic tank).
 

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Discussion Starter · #15 ·
well my fuelling is definately under control where it wasn't possible before, this may be the case for others on a protune... now i'm fighting to keep to get it out of 10.5:1 5000-7000 @ 99% idc
 

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Eh :)

Keep in mind that you are running 23psi on spoolup and going to 16.5psi @ redline. Not many people are doing that ... .. well, actually, I don't know anyone else doing that - lol. From what I recall in your logs, you are still running 22psi into the 5000rpm range on the stock turbo.

Good to hear you have the issue ironed out and can hit the AFRs you want :)

t
 

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Wow, I don't even run that much on alky. Well at least not on street mode ;)
 

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twiSTies said:
Here's a curveball for the group on here.

My car was built in March 2005. (Just checked the door plate). It has the black plastic tank and needed a fuel pump. :) (The reason I thought it was a late build was because my buddy's 05 STi was built in October 04--He too has a black plastic tank).
I believe mine was one of the earlier 05's, I have the metal coolant tank (not sure of the benefit of the plastic one) and I needed a fuel pump.
 
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