Turbo/boost Issues

[tomistoogood]

Hello guys, as the titles says i'm a bit unsure to what my turbo is meant to be performing like.

Ive had my s3 for around 4 months now and ever since ive driven it i thought it was quite sluggish i assumed that was down to the weight of the car. Ive installed a boost gauge to try and figure out what was going on but i am still unsure.
the turbo kicks in around 2.5-3k revs at about 5k rpm the boost is at 0.4bar/ 6psi and when i hit the top end it raises to 0.7bar/11psi but the climb seems slow these readings are in 3rd gear in 2nd they are even lower.

my question is does this sound correct or is the boost supposed to be 11psi when the pedal and inlet are fully open?

thanks for any replies

 

[tomistoogood]

i also forgot the mention the previous owner had it mapped and then unmapped, would a bad map ever have this effect on a turbo?

 

[bobby_southward]

Just from experience, have you checked the diverter valve (DV)? the original ones can go bad with them being plastic. when I first got mine it would pull, then dip, then pull, then dip etc etc. I swapped it out for a forge 007p made from billet aluminum, and it's a serviceable part unlike the original.
Also had mine remaped after fitting a new turbo, but then lost a key so took it to an audi dealership where they had to plug it in to recode the new and old key's, in doing so they "updated" the car's software and reset the mapping to factory settings which played havoc with the car, and it drove terrible, so i'm only guessing that a bad ecu map would make a difference, if it's all standard a quick trip to your local dealers and a plug in to update the car should sort it out.

do you have any warning lights showing on the dash? any mod's etc....

 

[Stuart B]

6psi is actuator pressure, maybe the N75 is broken?

 

[badger5]

12-14psi is std levels.
usual fault code checks and vcds logs may assist you getting to the issue, or book it in to somewhere who knows these things and can check, log, dyno etc etc

 

[ayfreetee]

You can check your dv by, pushing the plunger up to the top with a screwdriver handle, put your finger over the small vacuum inlet, then release the plunger, it should stay up, causing suction on your finger, when you let it off it will drop down, if not, the diaphragm is split, get a replacement Bosch item.