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Old 28-06-2012, 09:46 PM
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Default 04 STi technical info needed...

Just spent some time googling this stuff but came up pretty short. Hoping you guys can fill in some blanks...

Assuming the 04 STi has factory electronic boost control... is this handled by the ECU or some other ancillary controller?

As above, if it's controlled via the ECU, can boost be easily adjusted during a retune (reflash) of the ECU? Can peak pressure and gain be adjusted? (assuming using Verso or the like)

Does anyone know what the minimum wastegate actuator pressure is? or "gate pressure" if one was to bypass the factory ebc?

What is the general consensus on maximum safe boost on a VF35 if stock boost is 1.1 bar / 16 psi? ...and can the factory motor handle it given sufficient supporting mods?

Are the stock injectors pink? what CC are they? and can they become a limiting factor when modifying even when retaining the factory VF35 turbo?

Does this model STi have forged pistons/internals? ...Does anyone know the factory static compression ratio?

Thanks in advance.
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Old 28-06-2012, 10:10 PM
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1. It is controlled by the ECU.

2. It can be adjusted via a reflash. It is not adjusted by peak and gain like a electronic boost controller. It is adjusted by directly controlling the duty cycle of the boost solenoid.

3. 9psi

4. Safety is found in the tune not the amount of boost you are running... to a point. You can piss in 20psi.

5. pink top feeds = 565cc @ OEM fuel pressure. They wont hold you back on the stock vf35. But consider upgrading the standard fuel pump. Good cheap insurance. These injectors can also be decapped up to 816cc

6. Forged pistons can be found in all 2002-2005 STI EJ207 motors. That would be a yes in your model. I think OEM compression ratio is 8.5:1 or 8.7:1. CBF Googling it.
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Old 28-06-2012, 10:29 PM
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awesome, thanks man.
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Old 28-06-2012, 10:37 PM
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A couple more if you dont mind...

On partial throttle, when coming on boost is it normal to hear compressor surge? (fluttering / choofing) ...I dont think it surges when WOT though. Could this be due to the ebc duty cycle being set too high?

Do these cars use a MAP sensor, AFM or both?

Do they have a factory BOV? ...if so, is it recirculated back into the intake and does it become a problem at higher boost pressures?
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Old 28-06-2012, 11:15 PM
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Quote:
Originally Posted by Todd View Post
A couple more if you dont mind...

On partial throttle, when coming on boost is it normal to hear compressor surge?
Could be wastegate flutter. As far as I know it regulates boost pressure so you dont break anything. You'll generally hear the flutter sound if you've taken out the intake silencer.
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Old 28-06-2012, 11:32 PM
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Both Map and AFM.

Factory recirc valve will be effective up to 1.7-1.8 bar
Quote:
Originally Posted by Todd View Post
A couple more if you dont mind...

Do these cars use a MAP sensor, AFM or both?

Do they have a factory BOV? ...if so, is it recirculated back into the intake and does it become a problem at higher boost pressures?
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  #7  
Old 29-06-2012, 05:20 AM
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Quote:
Originally Posted by mao View Post
Both Map and AFM.

Factory recirc valve will be effective up to 1.7-1.8 bar
Factory bov will begin to bypass around 1.2 bar+, but can be modified to sustain much higher pressures without bypassing.
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