How/why?

Yeah i was pretty drunk last night when i wrote that. but yeah question above still applies.

I'd have to say you are more likely to get boost spikes and for short moments run more boost. It will hit its target boost a bit quicker which will cause it to overshoot as the ECU isn't ready to control the WG.

Just a guess.

boost cuts at 17psi so there isnt really much room to push it up, especially with a manual boost controller as they spike like hell, even with a ebc there aint much room, buy a decent ecu get it tuned and set it at about 17-18psi..if your running the standard td04, any higher it will just run out of puff.

very insteresting article that explains boost spike on wrx's when breathin mods are performed

http://autospeed.com/cms/A_1836/arti...popularArticle

TD04 starts to get lame at 22 odd psi.

As others have said, using a manual boost controller to just wind up boost is a silly old idea now. With the relative cheapness of ECU's and tuning which will yield safer, better (and more) power (using dyno's to measure the actual benefits, AFR's etc), why risk causing expensive engine damage by winding in more boost because someone on a forum said 'Pfft, 20psi is the magic number mate!'

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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR]

boost spike?

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Funny looking German Subaru

Yeah Chee don't you know, like you throw on a zorst thats and extra 1 psi, throw in a new pod thats an extra 2 psi, before you know You are running 25psi safely cause you have removed all the restrictions!

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- White 'Bug Eye' STi -