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Old 07-15-2013, 10:30 PM   #1
mxrath98
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So I bought my sti in April just started being able to drive in may (broke my ankle) but anyway only performance mod I have done was a Perrin CAI and noticed once when I first put it on towards the end of may I was hearing a fluttering sound when boosting. It is only when I am about full throttle right when it reaches 3k rpms a quiet flutter starts and continues till about 3600 to 3700 rpms then goes away and is fine the rest of the way to red line. It only starts happening in third gear and also does in 4th, 5th and 6th. Also it does not seem to lose any power so I am lost as to what it could be and don't want to keep running it if it's surging obviously. Any help would be great I am thinking of taking it to the dealer if I can't figure it out or probably just go to have them check anyway second opinions are always good.
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Old 07-15-2013, 11:57 PM   #2
El tor0
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Do you have the stage 1 map to go with that intake?
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Old 07-16-2013, 12:11 AM   #3
08sedanwrx
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I hope you have an accessport and are running a stg1 map like el toro said. If not, uninstall that intake ASAP until you get a Catback exhaust and cobb accessport. You may as well pick up a downpipe so you can flash stg 2, then install your intake. Its going to have to be AEM or COBBs version of intake to get a free stg1 or stg2 intake map from cobb.

You are probably hearing the intake suck air too, a noise you wouldn't hear with a stock airbox

If you are going to modify your car... I do not suggest taking it to a dealer. They will deny warranty work in a heart beat. Try finding a local tuning shop that specializes in specifically Subaru. You will have the same info, same tools, better info as far as tuning goes, cheaper labor rate. etc.
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Old 07-16-2013, 12:21 AM   #4
The Duke
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It's the Wastegate modulating boost under high load, low rpm.


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Old 07-16-2013, 08:08 AM   #5
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1. Remove the intake unless you have a tune that is specific to the Perrin (COBB OTS is not). Regardless of what Perrin tells you, the intake requires a tune.

2. The noise you are hearing is most likely wastegate flutter and is completely normal. As mentioned before, it is the sound of the wastegate rapidly opening and closing to regulate boost. It was there before, the intake just amplifies the sound... Posting a video would help us confirm as flutter is a very distinct noise.
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Old 07-17-2013, 11:31 AM   #6
CO11WRX
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Quote:
Originally Posted by mxrath98 View Post
So I bought my sti in April just started being able to drive in may (broke my ankle) but anyway only performance mod I have done was a Perrin CAI and noticed once when I first put it on towards the end of may I was hearing a fluttering sound when boosting. It is only when I am about full throttle right when it reaches 3k rpms a quiet flutter starts and continues till about 3600 to 3700 rpms then goes away and is fine the rest of the way to red line. It only starts happening in third gear and also does in 4th, 5th and 6th. Also it does not seem to lose any power so I am lost as to what it could be and don't want to keep running it if it's surging obviously. Any help would be great I am thinking of taking it to the dealer if I can't figure it out or probably just go to have them check anyway second opinions are always good.
Although I have a WRX, I get the same exact noise at the same RPM range/gear. My car is now stage 1 (with Cobb SF intake) but it had the noise even when stock. It became much more noticeable after I installed the intake. I freaked out at first, but from what my tuner and others told me it was wastegate flutter and is fairly common. Like you, I did not notice any power loss and also did not see anything unusual in my AP logs.

Take a look at this video I found. Does it sound similar to the noise you are hearing (its a VF52 turbo in the vid)? EDIT: I added a second video in which you can hear the flutter much more.



Also, +1 for removing the intake until you can get a proper tune. Cobb only has OTS maps for their intake and the AEM, but I do believe Perrin offers a custom map for their intake if you purchase an Accessport from them; at least I think they used to. One of the first things I learned was that almost all modifications to these cars requires proper tuning (one of the few exceptions being a cat-back exhaust).

Last edited by CO11WRX; 07-17-2013 at 06:07 PM. Reason: ADDED SECOND VIDEO WITH BETTER SOUND
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Old 07-17-2013, 07:58 PM   #7
mxrath98
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Alright guys thanks for the info and help. I read a bunch that the Perrin is like the only intake you don't need a tune for but I guess that's not right so I will work on getting a tune/ access port I'm doing a turbo back exhaust in the near future so ill have that soon enough. And ill try to get a video I did set up my gopro in the engine bay right by the intake (only spot I could find to secure it) but you cannot hear the flutter so I will try to get a in car video and see if you can hear it that way
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Old 07-17-2013, 08:01 PM   #8
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Bump!

Last edited by mxrath98; 07-17-2013 at 08:22 PM.
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Old 07-17-2013, 08:09 PM   #9
mxrath98
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Quote:
Originally Posted by CO11WRX View Post

Video Link: http://www.youtube.com/watch?v=zFHFcYpuPrk

Also, +1 for removing the intake until you can get a proper tune. Cobb only has OTS maps for their intake and the AEM, but I do believe Perrin offers a custom map for their intake if you purchase an Accessport from them; at least I think they used to. One of the first things I learned was that almost all modifications to these cars requires proper tuning (one of the few exceptions being a cat-back exhaust).
Doing just what that second video sounds like minus the squeak/cherp sound just more or a air release for mine but thanks for the advice I'm going to work on getting tune and everything as soon as possible. Thanks for info ill check with Perrin if I can get a map from them with the access port
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Old 07-17-2013, 11:57 PM   #10
CO11WRX
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Quote:
Originally Posted by mxrath98 View Post
Doing just what that second video sounds like minus the squeak/cherp sound just more or a air release for mine but thanks for the advice I'm going to work on getting tune and everything as soon as possible. Thanks for info ill check with Perrin if I can get a map from them with the access port
You're welcome. You know, I have been going through Perrin's site and I don't see any mention of an OTS map for their intake. I do see something that says to contact their tech support, so maybe that's the only way to get the map? I remember seeing reviews on their stage 1 map, but maybe they no longer offer it? I guess the best thing to do would be to contact Perrin directly.

I also have another suggestion. I run a Torqued Performance stage 1 map on my car and couldn't be happier. It's 85 bucks and TP will adjust your tune to your specific vehicle if necessary (based on logs you send them). They also offer Open Source maps (so you dont have to spend $500 + on an Accessport). TP actually offers a map specifically for the Perrin intake. This is another route you could go. I've been running their stage 1 map (I have the Cobb SF intake) since December and couldn't be happier. Obviously, a protune would be the best way to go, but I personally did not feel it necessary to spend that much money for a stage 1 tune.

EDIT: sorry, I forgot you have an STI so I believe the tune would be a little more. You would need to contact them directly for more details as you cannot order an STI map directly off their site. It looks like they charge $120 for STI tunes.

here's a link to their site: http://torquedperformance.com/

In the end, I recommend you first get together a basic list of goals for your car (i.e. power goals, mods you want) and then research as much as possible. Once that is done and you have a basic understanding of the modifications you plan to perform, you can start looking for a reputable tuner. Take your list of goals/planned mods to them and see what they recommend (even better, get in touch with a few reputable tuners). Only then should you start buying parts.
This is just my opinion as it is what I did and it seems to have worked well. Hope this helps!

Last edited by CO11WRX; 07-18-2013 at 12:15 AM.
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Old 07-18-2013, 12:12 AM   #11
the suicidal eggroll
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Quote:
Originally Posted by mxrath98 View Post
Alright guys thanks for the info and help. I read a bunch that the Perrin is like the only intake you don't need a tune for but I guess that's not right
They're lying. This has been covered many times on this forum and is old news. Basically their argument is that the stock tune runs rich enough that the ridiculous AFR error their intake introduces (just as bad as every other 08+ intake) won't cause the car to swing lean enough to cause damage. This is just flat out wrong, considering how lean the stock tune runs around the CL/OL region even stock.
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Old 07-18-2013, 07:34 PM   #12
mxrath98
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Quote:
Originally Posted by CO11WRX View Post


here's a link to their site: http://torquedperformance.com/

In the end, I recommend you first get together a basic list of goals for your car (i.e. power goals, mods you want) and then research as much as possible. Once that is done and you have a basic understanding of the modifications you plan to perform, you can start looking for a reputable tuner. Take your list of goals/planned mods to them and see what they recommend (even better, get in touch with a few reputable tuners). Only then should you start buying parts.
This is just my opinion as it is what I did and it seems to have worked well. Hope this helps!
Sweet I will look in to that TP tune and get a hold of some tuners around my area I know of a few I will contact them for my next step.
I also tried getting a vid but it's so quiet my camera doesn't pick it up well at all. But you got the idea you know what I'm talking about so ill say we figured out what it is. Looks like ill be doing some more work in the near future and get it done right!
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