turbo noise???

[bigzim1321]

I don't know if this is in the right place or not so mods, feel free to move. Ok, I found this video of an lbz w/straight pipes. What is the noise when idling back down that kind of sounds like a turbo but with a more high pitched sound? video link (may have to turn speakers up to hear): http://www.youtube.com/watch?v=XQfHdwwOcsk

[Big Angry]

I think more than anything it is crappy sound quality. It's the VVT turbo, it's just his camera is not picking up the sound accurately, so it sounds really different.

[bigzim1321]

thats what i was thinking. thanks for clearin that up

[Tank]

Quick correction, it's a VGT turbo, stands for variable geometry. I think that is a little of the sound quality, however it could be the turbo, some straight piped big rigs and even some cummins you will be able the hear the high pitch whistle of the turbo at idle and it wont be a stable whistle either it will raise and lower as the motor goes around.

[Big Angry]

Originally Posted by Tank

Quick correction, it's a VGT turbo, stands for variable geometry. I think that is a little of the sound quality, however it could be the turbo, some straight piped big rigs and even some cummins you will be able the hear the high pitch whistle of the turbo at idle and it wont be a stable whistle either it will raise and lower as the motor goes around.

Quicker correction, it's the same thing. tomato/tomato. Variable Geometry is the same as variable vane. Uses the positon or "geometry" of the vanes to control boost and spool up, instead of a wastegate.
The sound changes as the vanes change position, one second it hisses like a mofo (I have no cat/muffler) and then it rumbles something like a big block.

[Tank]

It is, I just don'e hear that near as much. And yes they do sound bada$$.

[Big Angry]

Originally Posted by Tank

It is, I just don'e hear that near as much. And yes they do sound bada$$.

[duratothemax]

Originally Posted by Big Angry

Quicker correction, it's the same thing. tomato/tomato. Variable Geometry is the same as variable vane. Uses the positon or "geometry" of the vanes to control boost and spool up, instead of a wastegate.
The sound changes as the vanes change position, one second it hisses like a mofo (I have no cat/muffler) and then it rumbles something like a big block.

yeah at idle the ECM initially cycles the vanes from 100% to 0% back to ~80% when it runs its standard diagnostics on the vane pos sensor and actuator. Then from time to time it will still cycle the vanes at idle to find the proper position to build back (drive) pressure to get the EGR working at idle.

its the 100% turbo that makes the LLY's sound like they do. On my truck you can not tell the difference between it and an LB7 by sound.