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Old 06-13-2011, 01:12 PM   #1
jacky599r
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Default Back to Stock (with a couple of problems)

Hi Guys:

I have since returned to stock hardware less exhaust and a cold air intake. Further, I've also gotten my ECU flashed with a stock ROM. However, the car still behaves weird. On boost, part throttle or WOT, there seems to be a fluttering sound coming from the right side of the engine compartment. Also, the transition between boost and off boost isn't a smooth one.

May i know what could be the probable causes?

Jacky
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Old 06-13-2011, 01:15 PM   #2
sc00ter
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Assuming you mean that you left the CAI and exhaust on the car, my guess would be that the CAI with the stock tune is causing this issue.

Also, is your downpipe stock?
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Old 06-13-2011, 01:39 PM   #3
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You need stock parts to run a stock map.

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Old 06-13-2011, 02:28 PM   #4
2Fast4U1DAY
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Quote:
Originally Posted by jacky599r
Hi Guys:

I have since returned to stock hardware less exhaust and a cold air intake. Further, I've also gotten my ECU flashed with a stock ROM. However, the car still behaves weird. On boost, part throttle or WOT, there seems to be a fluttering sound coming from the right side of the engine compartment. Also, the transition between boost and off boost isn't a smooth one.

May i know what could be the probable causes?

Jacky
The fluttering is probably your wastegate trying to regulate boost this is normal.

The transition you are speaking of is probably the Closed Loop/ Open Loop fueling transition which as far as I know has never been smooth in the turbo Subaru's in their stock form.

Last edited by 2Fast4U1DAY; 06-13-2011 at 10:01 PM.
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Old 06-13-2011, 03:08 PM   #5
Midevil
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You need to take the CAI off and replace with a stock intake system. CBE should be fine regardless.
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Old 06-13-2011, 03:13 PM   #6
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Quote:
Originally Posted by 2Fast4U1DAY View Post
The fluttering is probably your wastegate trying to regulate boost this is normal.
Agreed
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Old 06-13-2011, 06:58 PM   #7
IA Performance
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if the fluttering changes pitch from when the exhaust is cold to hot then you may have a leak at one of the pre turbo gaskets, most likely one of the 2 on the up-pipe. As others have also mentioned, there will be some wastegate door chatter sounds with an aftermarket downpipe. The bell mouth downpipes have some of the loudest chatter.

Stephen
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Old 06-13-2011, 07:40 PM   #8
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you should prob get tuned for all those bolt ons. by exhaust do you mean tbe or cbe?
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Old 06-13-2011, 10:28 PM   #9
jacky599r
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Thanks for the prompt replies.
Well, my downpipe is stock and exhaust would be CBE (Fujitsubo). As for the transition, its really bad, I'm talking about "stages" of lag and punch between 2.5krpm to about 4.5krpm; it gets pretty jittery.
Is the wastegate supposed to sound like that? I remember i have the same intake,20g and a forge bpv and it did not make that kinda sound.
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Old 06-13-2011, 11:38 PM   #10
IA Performance
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I'm leaning towards a mechanical issue versus wastegate door flutter given the stock DP. Stock DPs tend to make zero noise. Air leaks on the pressure side of the turbo will make noise, as will leaks between the turbo outlet and intake valves (throughout IC and intake manifold). Time to start with a boost leak test. A vacuum leak will create A/F issues that could result in the jittery sensation you feel.
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Old 06-14-2011, 06:15 AM   #11
2Fast4U1DAY
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Quote:
Originally Posted by IA Performance
I'm leaning towards a mechanical issue versus wastegate door flutter given the stock DP. Stock DPs tend to make zero noise. Air leaks on the pressure side of the turbo will make noise, as will leaks between the turbo outlet and intake valves (throughout IC and intake manifold). Time to start with a boost leak test. A vacuum leak will create A/F issues that could result in the jittery sensation you feel.
I disagree with your first statement. My 06 flutters ALOT. Stock turbo, stock DP, stock tune, all new gaskets, and no leaks.

Vacuum leaks will also cause the engine to Idle rough.
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Old 06-14-2011, 05:40 PM   #12
IA Performance
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You are entitled to disagree, I too own a 2006, it is actually my 3rd one, and did not have a note worthy flutter noise from the wastegate. This was on a WRX, STi, and again with a WRX. All with Stock downpipes. I later changed to a bellmouth which brought in some flutter/chatter from the wastegate.
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Old 06-14-2011, 05:46 PM   #13
IA Performance
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Check to make sure there are no leaks between the MAF and the turbo inlet. Sometimes the o-ring around the MAF fails, especially if an intake has been put on the car. If this leaks you may end up with similar symptoms.
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Old 06-14-2011, 08:03 PM   #14
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Quote:
Originally Posted by IA Performance View Post
You are entitled to disagree, I too own a 2006, it is actually my 3rd one, and did not have a note worthy flutter noise from the wastegate. This was on a WRX, STi, and again with a WRX. All with Stock downpipes. I later changed to a bellmouth which brought in some flutter/chatter from the wastegate.
Did you have a CAI on any of these? My '08 went from dead quiet to flutter city after installing an AEM CAI. The flutter should sound consistent if you're accelerating at a relatively constant rate, and should not be present at lower boost levels. Is this the case?

Finally, by flashing back to the stock ROM do you mean that you have a stock-like map or that you unmarried an AP? If some one sent you a "stock" map, is there a chance that it actually wasn't?
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Old 03-09-2014, 11:55 AM   #15
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Does the fluttering sound sound like a chattering either? Like rapidly tapping a coin on a hardwood table?
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Old 03-09-2014, 12:00 PM   #16
Raven999
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I ask because I have this issue with mine, and I know turbo systems well enough to understand leaks and or cracks in turbocharged exhaust systems may or will cause chattering sounds. I own an 07 STi sedan, stock. (New project car and daily driver) and due to the rough winter that thankfully recently ended here in Spokane Washington, I feel my cars insides have taken much of a beating as well.
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