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Discussion Starter #1
I just bought my 04' Forester with the standard STI stage 2 upgrades. VF43 Turbo etc..

When I put the pedal to the metal I can feel the boost kick in, hear the throaty roar then it cuts back and so does the power as I accelerate.

If I floor it while in 6th gear, the boost fades in and out as I accelerate.

If I put the pedal down 2/3 to 3/4 it doesn't fluctuate but doesn't accelerate as fast.

Only thing that doesn't match the mod package is that it has the stock intake. I am going to replace it with a AEM soon.

SOO...

Is this a tune issue or is it a hardware issue? Do I need a new wastegate manager? or is it the ECU improperly controlling the engine.

Thanks for the Help!!
 

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2004 Subaru FXT MT
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1,853 Posts
What are the engine management mods? Its not tuned right or something mechanically is off (like improper vacuum hose routing or something like that)

Any CEL's?

6 speed swap then? Sounds rather modified to me...Just so the we are clear, stg 2 is stock turbo. VF43 is not stock turbo. A full list of mods would be helpful.

I don't really care for the AEM intakes, and whatever you do, don't short ram it. I really don't understand why people do that. I'm at the point I will simply refuse to tune a short ram...
 

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Ol' Timer
2006 WRX Spec-C 6MT
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6,091 Posts
The AEM has been known to cause MAF issues. SPT is a much better option...

As for the car, Foos, I think he said he has an STi stage 2 build, meaning VFxx turbo + TBE.
Sound like you have yourself a seriously built up car. Find out everything that is done to it, then we can help you figure out what's going on.
Post a photo too, we might recognize it. Not too many 6 speed builds around...

EDIT: Wait, did you end up buying Singing's car? His thread closed, said he sold it, you were the last one interested.
 

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Discussion Starter #5
I believe the car just has a Cobb pre-set. I have a cobb access port and a Clark Turner map that I haven't worked with yet.

I didn't get Bruce's car, that was a fiasco. He still hasn't payed me for my ticket yet!

I bought Juston's (JMP) car, which unbeknown to me was the same situation as Bruce for another guy!

Below is the mod list. Thanks for the help!

STI scoop/Subtle splitter
STI wheels w/almost new Potenzas
Tinted windows
Interior:
Heated seats
05 STI steering wheel, E brake, console trim
Subaru all weather mats/cargo mat
Suspension:
07 wagon struts
STI pink wagon springs
STI control arms
STI sway bars/Kartboy links
STI lateral links
Engine:
STI tmic/vf43/STI ecu/AP v2
Walbro 255 pump
Maddad whisper turbo back
Cobb uppipe
Ported manifolds w/crossover pipe
Drivetrain:
Complete 04 STI 6spd conversion with hubs, axles and Brembos(black calipers) from a 57,000 mile donor car.
Parts that were BRAND NEW with the swap include:
04 Diff
Driveshaft
STI clutch
Starter
Grp N trans and pitch mounts
DBA rotors


The AEM has been known to cause MAF issues. SPT is a much better option...

As for the car, Foos, I think he said he has an STi stage 2 build, meaning VFxx turbo + TBE.
Sound like you have yourself a seriously built up car. Find out everything that is done to it, then we can help you figure out what's going on.
Post a photo too, we might recognize it. Not too many 6 speed builds around...

EDIT: Wait, did you end up buying Singing's car? His thread closed, said he sold it, you were the last one interested.
 

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Discussion Starter #6
With this mod list should I be complete (besides intake) to get 280-300 at the wheels ?

STI tmic/vf43/STI ecu/AP v2
Walbro 255 pump
Maddad whisper turbo back
Cobb uppipe
Ported manifolds w/crossover pipe

Will a STI/ SPT intake for an imprenza fit on the Forester, or do I need a Forester specific.?
 

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Ol' Timer
2006 WRX Spec-C 6MT
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6,091 Posts
Check out the How to go faster than an STi thread.... It should ansewr a lot of questions.

With this mod list should I be complete (besides intake) to get 280-300 at the wheels ?

Will a STI/ SPT intake for an imprenza fit on the Forester, or do I need a Forester specific.?
Yes, that is good for about 300 hp/tq to the wheels. Many have achieved those numbers with the same mods, as long as you get a protune. Are you running the protune now, or the Cobb OTS map? If you're running the Cobb map, definitely switch to the protune map, see if that fixes the boost issues you are seeing. If not, get another tune done to your needs.

As for the intake. The stocker with a good panel filter is good for your goals. If you really want the sound from an aftermarket one, go for SPT. I'm not 100% sure, but it fits 02-07 WRX and STi models, so it should fit the Forester as well.
SPT Intake...on sale!

The EBCS can definitely help dial in the boost for a tune. But if you're not having any problems reaching targets, then I don't see the need for one.


Congrats, you have a very nice ride. :Banane35:
Now enjoy dialing it in to your needs, a tune will go a long way in helping you do that.
 

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Discussion Starter #9
Currently just running a Cobb map. I'm thinking I need a pro-tune tho.

I have a Clark Turner map ( guess you send it to clark and he does the tuning?) Any experience with this?



Check out the How to go faster than an STi thread.... It should ansewr a lot of questions.



Yes, that is good for about 300 hp/tq to the wheels. Many have achieved those numbers with the same mods, as long as you get a protune. Are you running the protune now, or the Cobb OTS map? If you're running the Cobb map, definitely switch to the protune map, see if that fixes the boost issues you are seeing. If not, get another tune done to your needs.

As for the intake. The stocker with a good panel filter is good for your goals. If you really want the sound from an aftermarket one, go for SPT. I'm not 100% sure, but it fits 02-07 WRX and STi models, so it should fit the Forester as well.
SPT Intake...on sale!

The EBCS can definitely help dial in the boost for a tune. But if you're not having any problems reaching targets, then I don't see the need for one.


Congrats, you have a very nice ride. :Banane35:
Now enjoy dialing it in to your needs, a tune will go a long way in helping you do that.
 

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2004 Subaru FXT MT
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1,853 Posts
Currently just running a Cobb map. I'm thinking I need a pro-tune tho.

I have a Clark Turner map ( guess you send it to clark and he does the tuning?) Any experience with this?
I think email tuning is a bad idea. I can see it working if a proper DOE was done and all parameters of the ECU were fully understood by the tuner, but frankly, that just isn't going to happen...

Get tuned live...
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,158 Posts
If I floor it while in 6th gear, the boost fades in and out as I accelerate.
I presume you're using this on a track then...cos if you're on boost in 6th you are travelling well over 80mph+ on an STi !!

Have you had it dyno'd with the current set-up...? That will confirm what boost issues you are having an what (if anything) needs correcting.

Rich
 

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2007 Forester XT Limited
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653 Posts
Before you go out and spend money, save it for a pro-tune and get it up the dyno to see what's what. I would pay for pre-tune inspection too to sort out any mechanical issues since you just got the car.
PS: The only bolt on intake I would use on my car is APS CAI.
 

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Discussion Starter #13
I presume you're using this on a track then...cos if you're on boost in 6th you are travelling well over 80mph+ on an STi !!

Have you had it dyno'd with the current set-up...? That will confirm what boost issues you are having an what (if anything) needs correcting.

Rich
I haven't dyno'd or pro-tuned, I was wondering if I needed to buy something first. My closest tuner is an hour away, and I don't want to pay him any more 100's than I need to.

I don't track race, but I do thoroughly enjoy the 1000's of miles of remote forest service and country roads in WI. Doesn't everyone do 120 on one lane dirt roads with their subie?:rock::rock:
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,158 Posts
I haven't dyno'd or pro-tuned, I was wondering if I needed to buy something first. My closest tuner is an hour away, and I don't want to pay him any more 100's than I need to.
Personally I'm in favour of knowing what's going on before starting on a path, so as to get a base-line. Then you have something to judge your results post-modding/cure against. I don't what rolling roads cos you guys over there, but in the UK it's around £40 for 3 runs, with full printouts, and in my experience the person running the road will give you a (free) opinion as to what's up the car just from the printouts. I would say it's a worthwhile investment for ANY modder.
 
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