I recently took my 2008 cobalt SS with GM stage 1 to the dealer in for service. My problem is when I hit full boost, I hear a fluttering noise as if air is escaping but still holds full boost. So the dealer went over my car and tested for boost leaks and said everything's fine and asked if I had an aftermarket tune because "it boosted 23 PSI" and "with Gm stage 1 it should not boost over 20 PSI" and stock is 15 PSI. I tried to explain to them that in different weather conditions it will boost over 20 PSI and they told me I am wrong. Any info on what the problem could be and on GM stage I tune would be helpful so I could print this out and show it to them. Thank you!

 

Not too sure what to tell you but im trifecta tuned to 23psi and i see 25psi spikes all the time.

 

Tell those retards that it can hit as high as 25 in the right conditions, I have seen it on my car w/GMS1 that I installed and flashed myself. Say if they want to argue it so much they can send in your calibration numbers to GM, they will match exactly, and then they can fix your car.

Check the MAP and TMAP sensors and make sure they are snug and the o-rings aren't damaged. You may be getting a small wastegate flutter at high boost.

 

tell em to suck some bawls

 

If these gm mechanics are gonna be working on our cars they should atleast know about boosted engines

 

ur tune is fine, the mechs are idiots. tell them to put there machine on it and they will see its the gms1 tune. as for the surging, that is true compresser surge, that could be a bad turbo. but not sure, if u could get a vid of what its doing that would be helpful.

is it like this?

‪True Compressor Surge‬‏ - YouTube

 

Yes it sounds like that not as loud. After driving around a while in boost it goes away then I can Let it idle awhile and get in boost again and the sound comes back. Seems like when the Turbo gets hot the sound goes away when it cools it comes back.

 

Sounds like your BPV isn't opening for one reason or another. Tell them to check that.

 

bpv shouldnt be opening during boost, its not his bpv, that is the turbo itself, or the tune is messed up.

 

After the dealer having my car for six days they called today and said they are ordering me a new turbo. I guess it must of been compressor surge.

 

I personally would be VERY pissed off if i purchased GMS1 over priced kit and then have GM service techs tell you , that you are wrong when you say you have it.