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Old 01-12-2013, 12:40 PM   #1
xaaronex
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Default Boosting 15.x after Perrin turbo inlet

Is this normal? I have an 04 STi where boost is supposedly ~14.5 stock and after this install, I peaked at 15.8. The inlet hose is the only mod aside from a cat back and removed intake silencer. I replaced the OEM inlet due to a torn boot.

It is also around 40-50 degrees outside if that matters that much.
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Old 01-12-2013, 01:53 PM   #2
424wrx
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if the old one was torn i think you answered your own question. boost can differ up to 1-2 psi.
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Old 01-12-2013, 01:53 PM   #3
424wrx
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im running 22 psi. dont worry man.
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Old 01-12-2013, 01:55 PM   #4
holyjoetart
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You could always do a leak test and make sure nothing is wrong. I doubt anything is wrong. When I was tuned for 18 psi, I would hit 20 or 21 when it got cold out.
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Old 01-12-2013, 02:34 PM   #5
xaaronex
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i'm not worried about damaging anything, i'm just super anal about my car and had planned to keep this as stock as possible... that didn't last long haha

thank you for the replies. i may do a leak test soon to be safe. a few of the fittings that were supplied were questionable. two of them i couldn't get to sit flush for the life of me, but i doubt that they are leaking seeing as how tight they are.
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Old 01-13-2013, 07:27 AM   #6
dingobite
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Id myself guess the air flow is so different and its not really a leak those inlets let alot of air in compared to the stock inlet.

id say needs tune.
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Old 01-13-2013, 05:54 PM   #7
HinshawWRX
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Quote:
Originally Posted by 424wrx View Post
im running 22 psi. dont worry man.
He's wondering why he's now boosting over stock levels, not how much boost an inlet will take.
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Old 01-13-2013, 09:41 PM   #8
xaaronex
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Quote:
Originally Posted by dingobite View Post
Id myself guess the air flow is so different and its not really a leak those inlets let alot of air in compared to the stock inlet.

id say needs tune.
i definitely want a tune even with the little stuff i have done. hopefully in the spring/summer time but from the crazy amount of researching i've done, i've found that i will be alright with it as is until then.
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Old 01-20-2013, 10:56 PM   #9
jaboyd
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Default boost

Your boost will increase with colder temps and freer flowing air via the Perrin vs stk air tube. The level of boost is no sweat for the engine but if your boost remains higher than normal it would be good to take a data log using an AP or get a tune. For reference, Cobb stage 2 map goes to 17.5 psi and most tuners will run stock motors with conservative tunes in the 18 psi range wo/any problems.
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Old 01-21-2013, 12:40 PM   #10
Clark Turner
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Dont worry. This is normal. The perrin hose has less presssure Drop and flows more air. I have tested stock and aftermarket hoses for drop over the years. You can run the test yourself by hooking a Vac/boost gauge to the inlet pipe it self. Then boost the car and you will see the heavy vacuum in the inlet. As much as -12 PSI with a large bolt on turbo with a silicone turbo inlet pipe.

C
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Old 01-21-2013, 04:08 PM   #11
Zackbo
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The early Perrin inlets would actually collapse under the vacuum.
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Old 01-21-2013, 04:22 PM   #12
Clark Turner
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many years ago. Not an issue now.

C
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Old 01-23-2013, 09:32 PM   #13
roadtrip1098
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With the intake silencer delete there is a tad more airflow going in, this would be enough to allow boost over 15 psi on a stock tune. Don't worry, I ran 19 psi on my WRX for about 60,000 miles before I traded it in. Stock internals and fuel system, never had an issue.
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