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Old 08-06-2020, 06:12 PM   #1
NicMonte
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Default Overboost 02wrx

I’m tuned for 20lbs. I am overboosting to 25lbs for a split second on the logs. Literally just a split second does not hold.

Obviously concerned... what would cause this? And is it of concern if it’s just for a split second?

Manifold Absolute pressure:

At 20lbs at 37.319seconds before- 34.19
At 24.73lbs at 37.393seconds later-34.23

Then at 37.415 it’s back to 20lbs then tapering etc. Very brief overboost, no check engine lights AFR remains 11.14 throughout boosting.

Thankyou.
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Last edited by NicMonte; 08-06-2020 at 09:11 PM.
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Old 08-08-2020, 04:07 AM   #2
subaru_gc8
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what gear? can you do a log?
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Old 08-08-2020, 02:02 PM   #3
NicMonte
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Old 08-08-2020, 02:04 PM   #4
NicMonte
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Default Overboost 02wrx

Believe this was 3rd or fourth. I’m thinking electrical? MAP sensor is brand new. 3port is brand new.

It’s at 4038 rpm on the second photo.
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Old 08-08-2020, 02:47 PM   #5
subaru_gc8
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Quote:
Originally Posted by NicMonte View Post
Believe this was 3rd or fourth. I'm thinking electrical? MAP sensor is brand new. 3port is brand new.

It's at 4038 rpm on the second photo.
you gotta give us more info, its hard to take a shot in the dark fi you dont let us know mods what trans what gear your pull was in ect. if your not sure, why dont you talke to your tuner about whats going on,
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Old 08-08-2020, 11:40 PM   #6
NicMonte
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Vf48
Pinks
Cobb3port, DP, MAP Sensor
Tgv deletes
Invidia UP
MishimotoTMIC
Walbro255
Jdm205 swapped
Stock5speed(217k miles)Have a 4.44rearLSD waiting to go in.

Tuner has suggested cleaning terminals, and the boost is not real. Logs show as much as i know. stock map was just replaced with the Cobb because of this issue(not the tuners issue, but my own, seeing that boost) He suggested the MAP sensor may be faulty, so I replaced with the Cobb(and obviously tuned for it) and it is still happening.

Reaching out here for some insight and or if anyone has experienced this, as I couldn’t find a forum to compare, to what I’m experiencing. Thus my post.
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Old 08-08-2020, 11:57 PM   #7
subaru_gc8
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Quote:
Originally Posted by NicMonte View Post
Vf48
Pinks
Cobb3port, DP, MAP Sensor
Tgv deletes
Invidia UP
MishimotoTMIC
Walbro255
Jdm205 swapped
Stock5speed(217k miles)Have a 4.44rearLSD waiting to go in.

Tuner has suggested cleaning terminals, and the boost is not real. Logs show as much as i know. stock map was just replaced with the Cobb because of this issue(not the tuners issue, but my own, seeing that boost) He suggested the MAP sensor may be faulty, so I replaced with the Cobb(and obviously tuned for it) and it is still happening. your afr are a little rich too

Reaching out here for some insight and or if anyone has experienced this, as I couldn't find a forum to compare, to what I'm experiencing. Thus my post.
uhh I dont think you can just use a cobb map sensor as they read different if you are tuned on the stock stuff you need to stay with the stock stuff... your tuner saying it could be a gake reading is like taking a shot in the dark do you have a boost gauge? if you do compare the 2 if not.. yeah I guess you can just take what he is saying... but yeah not sure he can say that without any proof. but thats me.

so your car shouldt be overboosting unless he is trying to ramp the boost up really quick, some tuners do this but the problem that comes along with that is the overboosting issue.
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Old 08-09-2020, 01:20 AM   #8
NicMonte
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Cobb map sensor is tuned for. Replaced the Oem one due to the same reasons.
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Old 08-12-2020, 10:56 PM   #9
serrilion
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Stuck waste gate? Also I would agree with the overboosting question? Could also be good fuel but not the same fuel the car was tuned with? just some ideas

As for the map sensor could check the voltage readings see if they are in Manufactures specs another idea
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Old 08-13-2020, 09:40 PM   #10
NicMonte
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This has occurred on the Stock map sensor W/ td04.
And now occurring on the vf48 w/ Cobb map sensor.

I want to say electrical, but obviously could be dead wrong. When this occurs, nothing happens, it’s just a blimp on the accessport.

I might change the alternator, and see if that fixes the issue. I have a theory that there is an electrical boost, and it so happens to be popping up on the Map sensor.

This is a jdm motor, and I kept the alternator on the jdm motor that came with it, and used that. So Ill swap over my old one and see if that fixes the issue.

But I might be dead wrong.

I trust the tuner I’m working with, and he recommended replacing the old map sensor. I bought the Cobb one, because, why not?

This weekend I’ll swap the alternator, and do a pull and take a log. Fingers crossed.
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Old 08-15-2020, 08:17 PM   #11
FujiSwede
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Double check your vacuum line routing on your 3 port.
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