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what boost should i run??? supporting mods in sig

getting mods in sig installed tommorrow
 

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Discussion Starter #3
thanks bud, do you think 14 psi would be under taking it.... 16 to 17 sounds good though!!
 

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20psi is good, make sure you got a GM boost control solenoid, and a good tune. and you can run 20psi fine! thats what im running.
 

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20:whoa:
i was going to say 18.5 max
 

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with a good tune 20 is ok. though it is reaching the VF-39's Volumetric Efficiency.

ive been running it for over 8months and this recent Opensource Road tune i just did yielded me at 21.0psi @3800RPM w/ ZERO Knock at 78deg+ weather and at sea level (14.7psi atmos. pressure )

2nd and 3rd gear pulls feel amazing on boost!!!! wish it had a little more down low, but thats ok...if you drive it its powerband the response is freaking awesome!
 

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I have an 07 WRX with the VF43 (much like the VF39) and similiar mods.

At 16.5psi, I dyno'd at 294whp/285wtq.

The boost was raised to 18psi, but not dyno'd. I wanted a bit higher torques #'s.

The thing that is holding me back from going full boost are the stock injectors. They're maxed out at anything past 18psi.

Your injectors for the 2.0 liter should be fine.

If I port my turbo and get 650cc FI, I could boost to 20-21psi and maybe look at 320whp/350wtq with the current setup.

But then I'm still saving for PPG's! :)

EDIT: I realized after posting that we have two different engines (2.0 vs 2.5) so my results may not be a good comparison. sorry...
 

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im running 07 injectors also. and a stock STi fuel pump. on my last tune, i was running a little lean at 19.5psi but we retuned it to 21psi and richened her up a little bit. i dont think i would have gone past 16psi with my stock injectors.

check out XPT Tuning. the owner Braden tuned my car and several of my friends as we know him personally. he is WELL known among the opensource community. and he know his stuff. i dont know what exactly his tuning methods are but its pretty impressive!

XPT tuning has a bunch of "fully Tuned" maps based off of cars he tuned that are specific to mods you have. i believe recently he added Lauch Control to All 02-05WRX.



you have the 2.5l you are going to have some impressive numbers with a good tune especially with the TQ numbers!



for those who doubt my tune and think i am lying, i can Send you my LOGS!
 

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what boost should i run???
Cobbs conservative VF39 map is 18.5psi so I would imagine with a custom tune you could get 19 or 20 w/o a problem. Enjoy!
 

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what boost should i run??? supporting mods in sig

getting mods in sig installed tommorrow
the biggest question that no one has asked that needs to be asked is:

what octane fuel?

good midwest non-Ethanol mix 93 you can run as high as 22-23psi w/o issue on a VF39 IF you are properly tuned & have proper heatsoak prevention/intercooling. You will need a GM BCS or other 3-port solenoid or a MBC to achive that high of boost.

You may or may not have enough fuel w/ the 550cc injector to support that much boost.
 

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ahh yes! Thank you for fixing that!!! i knew it was along the lines of that!!!
 
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