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Old 09-14-2021, 08:11 PM   #1
josh13wrx
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Default 2020 STI inly 13lbs of boost

Hey everyone,
So I've searched and searched through numerous threads and websites but can't get to the bottom of why i can't get past 13lbs of boost. This issue began after tuning for the following mods.

- Delicious tuning Flex fuel kit Mk2 with Fuel Pressure sensor kit
- Delicious tuning GR Stumble fix kit
- Cobb 1050x
- Cobb AP V3
- Cobb EBCS
- AEM fuel pump
- AEM Inline wideband
- Cobb SF intake
- 3in catted Dp
- Perrin Catback

Tune is being done by Eric at torqued performance. He mentioned the logs show a possible boost leak. I've searched all boost/ vacuum lines and haven't found any issues. I even did a boost leak test at 20psi and no boost leaks. I've been at it for a week now and am completely stumped. Any help is appreciated. Thanks in advance!
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Old 09-14-2021, 08:15 PM   #2
djoye
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Checked and re-checked that the EBCS is plumbed correctly and connected to the correct ports and removed the restrictor pill from the stock boost lines if still using those?
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Old 09-14-2021, 08:19 PM   #3
josh13wrx
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Quote:
Originally Posted by djoye View Post
Checked and re-checked that the EBCS is plumbed correctly and connected to the correct ports and removed the restrictor pill from the stock boost lines if still using those?
Yes tripled checked EBCS lines and restrictor pill is also removed
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Old 09-14-2021, 08:25 PM   #4
josh13wrx
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Old 09-14-2021, 09:41 PM   #5
K3rm1tth3fr0g
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Perhaps a bad map sensor...
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Old 09-14-2021, 09:56 PM   #6
josh13wrx
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Quote:
Originally Posted by K3rm1tth3fr0g View Post
Perhaps a bad map sensor...

Wouldn稚 the drivability of the car be affected more than just the lack of boost? The car drives fine just doesn稚 get past 13lbs of boost.
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Old 09-15-2021, 08:26 AM   #7
SuperPete
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I had issue when my inlet pipe was collapsing right before the turbo inlet, been tracking that for weeks until I put go pro in the engine bay and saw it myself, so try quizzing that hose by hand closest to the turbo, if you can move that, its your problem.
Also, make sure your EBC connected correct.
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Old 09-15-2021, 10:13 AM   #8
josh13wrx
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I値l look into the turbo inlet issue. Boost controller is plumbed properly so I can rule that out
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Old 09-15-2021, 10:45 AM   #9
horsePOOGAS
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Eric is a great tuner and was the tuner of my car. I had an issue that turned out to be a boost leak. I could only find it by using a smoke tester. For me it was my intake runners on the driver side.

But a smoke tester is a really helpful tool and can come in handy down the road if any other problems arise. I bought mine off of Amazon. If you do get one - spend the coin on a decent one with an inline fuse.
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Old 09-15-2021, 11:01 AM   #10
K3rm1tth3fr0g
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Quote:
Originally Posted by horsePOOGAS View Post
Eric is a great tuner and was the tuner of my car. I had an issue that turned out to be a boost leak. I could only find it by using a smoke tester. For me it was my intake runners on the driver side.

But a smoke tester is a really helpful tool and can come in handy down the road if any other problems arise. I bought mine off of Amazon. If you do get one - spend the coin on a decent one with an inline fuse.
He already boost leak tested - he said that in the first post
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Old 09-15-2021, 11:15 AM   #11
josh13wrx
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Eric is great. This is the second Subaru he tunes for me. So I知 not second guessing his knowledge or tuning abilities. Thanks for the advice tho. Keep the ideas coming. I知 hoping someone can take a look at the log I posted and help me rule out a couple things.
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Old 09-15-2021, 12:18 PM   #12
benflynn
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Unhook the wastegate hose and see where she ends up, hopefully oberboost will catch it.
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Old 09-15-2021, 12:19 PM   #13
benflynn
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If it was a boost leak then the turbo is living way outside its flowmap
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Old 09-15-2021, 12:40 PM   #14
Stretch18
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Do you know what your target boost levels are? You actually do get up to 16 psi, but not until close to 5,000 rpms. You can monitor TD Boost Error on the AP to see if you are off target.

Are you at elevation? Your boost pressure - absolute pressure is in the 13s. At sea level, 0 psi of boost is 14.7 psi absolute pressure. If that's not accounted for, that could be your issue...
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Old 09-15-2021, 01:27 PM   #15
josh13wrx
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Quote:
Originally Posted by Stretch18 View Post
Do you know what your target boost levels are? You actually do get up to 16 psi, but not until close to 5,000 rpms. You can monitor TD Boost Error on the AP to see if you are off target.

Are you at elevation? Your boost pressure - absolute pressure is in the 13s. At sea level, 0 psi of boost is 14.7 psi absolute pressure. If that's not accounted for, that could be your issue...

Target boost is about 20psi. I知 at 2,655 feet above sea level. I値l monitor boost error. The 16 pounds I get seems like creep but I知 not 100% sure.
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Old 09-18-2021, 06:26 PM   #16
josh13wrx
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Default 2020 STI inly 13lbs of boost

Ok I did a boost leak test again but this time at the throttle body instead of the inlet. No audible leaks holds 20 psi and slowly comes down after about a second or so. No hissing. I知 running out of ideas. Maybe a bad EBCS?
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Old 09-18-2021, 08:05 PM   #17
SuperPete
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you have OEM of aftermarket boost controller?
Take vacuum hoses from boost controller, all of them and check them for cuts, leaks holes, once I had hose with crack in it, that was a mess.
Intake turbo inlet, OEM of aftermarket?
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Old 09-18-2021, 08:06 PM   #18
josh13wrx
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Quote:
Originally Posted by SuperPete View Post
you have OEM of aftermarket boost controller?
Take vacuum hoses from boost controller, all of them and check them for cuts, leaks holes, once I had hose with crack in it, that was a mess.
Intake turbo inlet, OEM of aftermarket?

Cobb 3 port boost controller
Oem inlet. All brand new vacuum hoses.
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Old 09-18-2021, 08:19 PM   #19
SuperPete
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unplug boost controller, get two wires and try testing boost controller by connecting to the battery, if should click when you apply power,
you can also try blowing it in to it where turbo connects, when its OFF no air should pass, when you apply power air should pass, so if you have compressor set it to 10-20 PSI and by putting power to it it will open waist gate
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Old 09-18-2021, 08:24 PM   #20
josh13wrx
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Quote:
Originally Posted by SuperPete View Post
unplug boost controller, get two wires and try testing boost controller by connecting to the battery, if should click when you apply power,
you can also try blowing it in to it where turbo connects, when its OFF no air should pass, when you apply power air should pass, so if you have compressor set it to 10-20 PSI and by putting power to it it will open waist gate

Tried that as well and the boost controller does click as it supposed to when hooked up to a 9v battery. Thanks for the quick reply.
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Old 09-18-2021, 08:33 PM   #21
SuperPete
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I looked at your log really quick, your waist gate is at 50-60%, with stock turbo it should be around 70-80%
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Old 09-18-2021, 08:37 PM   #22
josh13wrx
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Quote:
Originally Posted by SuperPete View Post
I looked at your log really quick, your waist gate is at 50-60%, with stock turbo it should be around 70-80%

Pardon my ignorance but what could be causing that? The tune is from a reputable tuner and he has halted the tuning process because he believes the lack of boost issue is not from the tune but from a leak or some mechanical issue.
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Old 09-18-2021, 08:44 PM   #23
SuperPete
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just ask him to crank WG up by 10% across the bend just for heck of it as test only, for one pull test and see if anything changes.
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Old 09-18-2021, 08:46 PM   #24
josh13wrx
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Quote:
Originally Posted by SuperPete View Post
just ask him to crank WG up by 10% across the bend just for heck of it as test only, for one pull test and see if anything changes.

Ok I値l see what he says
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Old 09-18-2021, 11:45 PM   #25
josh13wrx
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Something just came to mind but I don稚 have time to check tonight. Could it be the cat in the downpipe is bad. It痴 an aftermarket 3in downpipe from Rev9. Probably not the highest quality cat but can this be a possibility? I知 just grabbing at straws here haha
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