Low Boost Issues on 2004 WRX - Experts help needed here

[Myzkoo]

Alright, dunno were to start but i think i'll start with a mod list, then try to describe my problem and what ive done so far with no gains.

IHI VF34 Turbo
EcuteK tuned ECU
3" downpipe with a racecat followed by a 666 evilpipe catback exhaust.
Aftermarket up-pipe.
255l/h walbro pump.
GFB hybrid BOV
Green cotton panel filter.
1 step colder sparkplugs.

The story is, ive had this car for quite a while and it has always peaked at 1,4 bars of boost and then settled at 1,35 bar. But since like 6 or 7 weeks ago it peaks at only 0,6-0,7 bar of boost? BUT, when i pull the hose from the wastegate acutator i'll hit boost pretty quick, have been very carefull here but have been up to 1,2 bar a few times. Engine runs like normal except for the boost, no misses or what so ever.

Ive done this so far in the order i'll stack em up:

- Changed the boost controll solenoid. No difference here.
- Changed all vac-lines, and yes i put the restrictor pill into the new line, and yes, it the right line to also changed the T at the same point.
- Battery went out over the night (2 times)
- Borrowed the MAF and the MAP-sensor from a friend who is also owning a 2004 WRX. No difference.
- Removed intercooler and checked all hoses and reinstalled.
- Leak tested trough the inlet of the turbo all the way to the intake were the intercooler attaches to the throttlebody (steady 1,5 bar here and no signs of leaks).
- Pressure tested the acutator, seems like it looks good to me, not stuck and open and closes as it should
- Soldered a 12v lightbulb into the wires running to the boost solenoid, had it in front of my eyes while driving and the signal seems ok, light is pulsing.
- Put a clean vac-line directly from the compressorhousing to the acutator (without pill) and boost peaks at 0,3 bar. Had the solenoid still connected but lines were plugged.
- Also tried to do the EcuteK boost map switch to see if that was enabled it the ecu, it was not. (ignition on, full throttle and press rear window heater to on)

Have talked to my EcuTek tuner to and he keeps saying that the ecu has to be ok. Its like 6 hours of traveling to get there so we been trying to solve this over phone.

Im running out of ideas, only thing i have left to do, i think, is to bring the downpipe down to see if the wastegate flap is still there and if its sealing. Will do this next weekend.

Tips and tricks are more than welcome!!

[mycologist]

Bugger, it does seem like you have covered all the bases. ALthough, taking the battery out over night might not have reset it - you need to hold the brakes for a couple of minutes to drain it.

I would log the car it is easier than all what you have done and could tell you a lot more.

[Myzkoo]

Bugger, it does seem like you have covered all the bases. ALthough, taking the battery out over night might not have reset it - you need to hold the brakes for a couple of minutes to drain it.

I would log the car it is easier than all what you have done and could tell you a lot more.

Will do that just to have it done then. Battery was out for 10 hours last time, but if you say so

Thing is that ive got 6 hours of traveling one way with the car to get to my ecutek tuner, where i could log the car.

Also i got no CEL light on.

Im looking at the DeltaDash software right now, maybe its worth it. Then i can log the ecu all by myself.

EcuTek DeltaDash

[Sinister]

Subscribed.

the restrictor pill get cleaned out?

[zax]

subscribed to see the solution to this mystery.

Just out of curiousity, do you see any boost creep when your IWG plumbing is set up normally or does the boost hold at 0.6-0.7 bar through the whole efficiency range of your turbo?

[Myzkoo]

subscribed to see the solution to this mystery.

Just out of curiousity, do you see any boost creep when your IWG plumbing is set up normally or does the boost hold at 0.6-0.7 bar through the whole efficiency range of your turbo?

No, the boost holds at 0.6 bar like it held 1,35 before this problem occured. Peaks at 0,7 now, before it peaked at 1,4.

Have written down a "to-do" list that i will work on this saturday or sunday.

+ Unbolt downpipe and check wastegate flapper
+ Check manifold and up-pipe for leaks

If this is ok, i will probably unbolt the turbo too and bring it on the table for an closer inspection.

Wish i had a replacement wastegate to!

And the restrictor-pill is cleaned. It looked like new, should not be worm out by just sitting in that got damn hose doing its work If it was something that blocked it, it would probably give me higher boost.

[mycologist]

No, the boost holds at 0.6 bar like it held 1,35 before this problem occured. Peaks at 0,7 now, before it peaked at 1,4.

Have written down a "to-do" list that i will work on this saturday or sunday.

+ Unbolt downpipe and check wastegate flapper
+ Check manifold and up-pipe for leaks

If this is ok, i will probably unbolt the turbo too and bring it on the table for an closer inspection.

Wish i had a replacement wastegate to!

And the restrictor-pill is cleaned. It looked like new, should not be worm out by just sitting in that got damn hose doing its work If it was something that blocked it, it would probably give me higher boost.

Datalogging with Romraider:

If it hit 1.2 with the line to the wastegate off then it doesn't sound like the exhaust, turbo, or wastegate flapper.

How about the spring? You mentioned the boost "peaked" at .3 bar with the line straight to the actuator - this should be spring pressure and hold more like .5-.6 (this would throw your BCS off and could account for more than .3 lost).

[Myzkoo]

Datalogging with Romraider:

If it hit 1.2 with the line to the wastegate off then it doesn't sound like the exhaust, turbo, or wastegate flapper.

How about the spring? You mentioned the boost "peaked" at .3 bar with the line straight to the actuator - this should be spring pressure and hold more like .5-.6 (this would throw your BCS off and could account for more than .3 lost).

Alright, yes the boost holds 0.3 bar with the line straight to the acutator, is this to low? I cant find any info on the wastegate, it comes with the VF34 but theres not much info at all on this turbo to find.

Maybe there's someone on this forum reading this (with this turbo-setup) who could just hook up a vac-line on thier car and have a look what it reads on the boostgauge?

Will romradier work with a ecutek'ed ecu? havent looked much into romraider yet.

[mycologist]

Alright, yes the boost holds 0.3 bar with the line straight to the acutator, is this to low? I cant find any info on the wastegate, it comes with the VF34 but theres not much info at all on this turbo to find.

Maybe there's someone on this forum reading this (with this turbo-setup) who could just hook up a vac-line on thier car and have a look what it reads on the boostgauge?

Will romradier work with a ecutek'ed ecu? havent looked much into romraider yet.

It is supposed to be 7 psi - no need for someone to check. If your boost gauge is accurate and is not leaking, then it is too low and it is a problem. It is almost 50% weaker than it should be - that is what balances with the amount the BCS is bleeding off - it will make a difference.

I'm not up on ecutek so IDK.

[Myzkoo]

It is supposed to be 7 psi - no need for someone to check. If your boost gauge is accurate and is not leaking, then it is too low and it is a problem. It is almost 50% weaker than it should be - that is what balances with the amount the BCS is bleeding off - it will make a difference.

I'm not up on ecutek so IDK.

Alright, maybe its possible to make a new bracket to fit a wastegate from a different turbo. Just for testing purposes.. Is 7 psi a standard somehow for internal wastegates?

I mean, if 0,3 bar is what this wastegate is made to hold for (speculating), couldnt the ecu be tuned to somehow work with it with a different pill or something? Can a acutator be worn out?

Im glad to all info that i could possible get before ill put my head under the hood again

Romraider looks good, will send a mail and question if it will work with an ecutek rom (map). almost the same as delta dash i think. But DD is like $300

[mycologist]

Alright, maybe its possible to make a new bracket to fit a wastegate from a different turbo. Just for testing purposes.. Is 7 psi a standard somehow for internal wastegates?

I mean, if 0,3 bar is what this wastegate is made to hold for (speculating), couldnt the ecu be tuned to somehow work with it with a different pill or something? Can a acutator be worn out?

Im glad to all info that i could possible get before ill put my head under the hood again

Romraider looks good, will send a mail and question if it will work with an ecutek rom (map). almost the same as delta dash i think. But DD is like $300

It is just a common pressure used. It is true for both vf-34 and a TD04 (but we can adjust the length of the arm and get a bit more). They range more like 7-8 or 7-9 (like I said, .5-.6). There are upgrades for higher PSI springs for IWG turbos that are intended for higher total boost.

I would replace the actuator. The other options are helper springs and or a larger restrictor pill. Or even a different BCS. Way more challenging than just getting one that works and also is going to keep working. If the spring dropped that much it is on its way out.

[mycologist]

Oh, forge and AVO make aftermarket replacements, or you can scavenge one from a dead turbo. Folks on NASIOC have them laying around I'm sure.

[Myzkoo]

It is just a common pressure used. It is true for both vf-34 and a TD04 (but we can adjust the length of the arm and get a bit more). They range more like 7-8 or 7-9 (like I said, .5-.6). There are upgrades for higher PSI springs for IWG turbos that are intended for higher total boost.

I would replace the actuator. The other options are helper springs and or a larger restrictor pill. Or even a different BCS. Way more challenging than just getting one that works and also is going to keep working. If the spring dropped that much it is on its way out.

Okay, I'll start searching for a wastegate acutator tomorrow then, im located in northern parts of Sweden, Europe, a acutator from NASIOC would be very costly i think local junkyard over here should have them layin around.

So if i connect compressed air to the acutator and start from zero, should i look for a acutator thats tight up to 0.6-0.7 and then just pops up? If its just a spring in there i cant imagine it will pop. Maybe this was a stupid question My feelings says it will open slowly at some point and further more as i increase pressure.

[mycologist]

Okay, I'll start searching for a wastegate acutator tomorrow then, im located in northern parts of Sweden, Europe, a acutator from NASIOC would be very costly i think local junkyard over here should have them layin around.

So if i connect compressed air to the acutator and start from zero, should i look for a acutator thats tight up to 0.6-0.7 and then just pops up? If its just a spring in there i cant imagine it will pop. Maybe this was a stupid question My feelings says it will open slowly at some point and further more as i increase pressure.

Yeah, .5-.6 and it should start to open like you said at the end.

It may not be the only problem but it is a significant problem. Let us know what you figure out & good luck.

[Myzkoo]

Yeah, .5-.6 and it should start to open like you said at the end.

It may not be the only problem but it is a significant problem. Let us know what you figure out & good luck.

Alright, i wll post updates on Saturday. Thanks alot man..