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Discussion Starter #1
Not sure if target or peak boost is the correct term, but what is the peak boost that I should hit w/ Cobb stg 2 map? Isn't it ~14.5 psi?

Any idea how long it should take for the ECU to "re-learn" before I can expect to hit peak boost? I previously had to adjust my waste gate actuator arm 4 full turns before I saw the stg 1 target (peak?) boost of ~12.5 psi.

I was hearing a lot of waste gate flutter after installing my Stromung divorced waste gate DP, so I am wondering if I am going to have to do some more adjusting to the waste gate actuator arm.

Thanks
 

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I am having a similar problem w/ my 05 FXT. The first day I did the stage 2 reflash, it actually felt slower! It was hitting 12.7 max boost according to the A/P. A few hundred miles later, it got as high as 13.5. After researching online, seems the stage 2 target boost for WRXs is 15.8 +- 0.5; dono if the same applies for the FXTs.
 

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Discussion Starter #3
sonny said:
I am having a similar problem w/ my 05 FXT. The first day I did the stage 2 reflash, it actually felt slower! It was hitting 12.7 max boost according to the A/P. A few hundred miles later, it got as high as 13.5. After researching online, seems the stage 2 target boost for WRXs is 15.8 +- 0.5; dono if the same applies for the FXTs.
Well, others said it is 13.5 psi and I called Cobb and they confirmed it is 13.5 psi. I am still not hitting 13.5. I did some tari racing logs, and only hit 12.6. I am getting a lot of waste gate fluter w/ the new DP though. I think I heard an exhaust leak recently too. I just haven't taken the time to check the torque on the up-pipe/dp bolts again.
 

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fxtacy said:
I am getting a lot of waste gate fluter w/ the new DP though. I think I heard an exhaust leak recently too. I just haven't taken the time to check the torque on the up-pipe/dp bolts again.
there is your answer... WG flutter = lost boost...
 

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fxtacy said:
Well, others said it is 13.5 psi and I called Cobb and they confirmed it is 13.5 psi. I am still not hitting 13.5. I did some tari racing logs, and only hit 12.6. I am getting a lot of waste gate fluter w/ the new DP though. I think I heard an exhaust leak recently too. I just haven't taken the time to check the torque on the up-pipe/dp bolts again.
Really? really!? Spoke to a cobb rep and he said 15.8 +- 0.5 was the target boost. Alright, so here is a noob a$$ question. What are the symptoms of wastegate flutter?
 

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Discussion Starter #7
DanzBorin said:
there is your answer... WG flutter = lost boost...
Rob... I know.. just need to take the time to adjust the waste gate acutator arm again. Bummer part is I already adjusted it 4 full turns when I wasn't hitting target boost of stg1. Now I will have to adjust it more now that there is less back pressure w/ the DP. :(
 

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fxtacy said:
Rob... I know.. just need to take the time to adjust the waste gate acutator arm again. Bummer part is I already adjusted it 4 full turns when I wasn't hitting target boost of stg1. Now I will have to adjust it more now that there is less back pressure w/ the DP. :(
I feel you... I've been putting mine off for a year... :lol:

mainly because i don't have a boost gauge... :(
 

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Northwest Tan said:
Unfortunately, the actuator adjustment can end up being temporary since the ecu will eventually wise up to your efforts and fix your fix.
wastegate flutter isn't caused or controlled by the ECU... it's the fact that the spring cannot hold the wg shut... adjusting the arm preloads the spring to help combat the flutter...
 

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DanzBorin said:
wastegate flutter isn't caused or controlled by the ECU... it's the fact that the spring cannot hold the wg shut... adjusting the arm preloads the spring to help combat the flutter...
i see... so why does wastegate flutter comeback? why do i have less wastegate flutter after a protune without touching the wastegate?
 

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Northwest Tan said:
i see... so why does wastegate flutter comeback? why do i have less wastegate flutter after a protune without touching the wastegate?
wastegate flutter may come back due to the spring wearing, or perhaps increased flow due to any # of changes...

from what I understand it's pressure change from putting a large bellmouth on there that causes the door to be "sucked" open...

best way to fix it would be a new spring, but for all the PITA it would be, you'd be better off just getting a new turbo and be done with it...
 

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DanzBorin said:
wastegate flutter may come back due to the spring wearing, or perhaps increased flow due to any # of changes...

from what I understand it's pressure change from putting a large bellmouth on there that causes the door to be "sucked" open...

best way to fix it would be a new spring, but for all the PITA it would be, you'd be better off just getting a new turbo and be done with it...
PITA for new spring? Please elaborate......

I hate elves, gnomes on the other hand...not so much
 

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GatorXT said:
PITA for new spring? Please elaborate......

I hate elves, gnomes on the other hand...not so much
i believe you have to remove the turbo... if I'm wrong, let me know, but i don't think it's an "easy" job to replace a wastegate spring...
 
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