LBZ: Exhaust Question

[Duramax 6.6L]

After removing the converter, stock tune, my truck sitting and idling sounds like a jet air craft waiting to take of. if I give it soft increase in throttle the turbo whistle is amazingly strong. If I do a hard acceleration, it sounds like a jet taking off on the runway.

Is this normal.

On the engine and transmission, there are tags telling the dealer not to take them apart, they must be sent to the factory complete. But that is another question.

 

[Alligator]

Yes, totally normal for LLY-LMM trucks.

 

[Duramax 6.6L]

I have heard other LBZ trucks and none sound like this. With the tags on the motor and trans saying not to disassemble, could that that have something to do with it, does anyone know what GM could have done to he engine and trans that they do not want takin apart.

 

[Alligator]

Where were these tags? Were you just listening to it without exhaust installed, just the sound coming out of the downpipe? I have never seen tags like that around the exhaust...

 

[Duramax 6.6L]

The tags are on the engine block and the side of the trans.

The sound I am talking about is with a full exhaust, straight pipe.

 

[NelsonDiesel]

sound is normal for that type of system. It's the turbbo - it works at idle.

All variable vane turbos do that unless you have a program that turns the vanes down at idle.

EfiLive....

 

[coldLBZ]

Mine has a slight rumble and whistle at idle. At full throttle it sounds awesome, more of a loud shreik. It should be ok, mines been like that for 15 000 miles atleast.

 

[LBZ]

Normal.

 

[Sean8816]

I have heard other LBZ trucks and none sound like this.

Because they were not straight-piped.

 

[LarryJewell]

Because they were not straight-piped.

exactly

 

[Alligator]

The tags are on the engine block and the side of the trans.

The sound I am talking about is with a full exhaust, straight pipe.

Ding, ding, ding. normal.

 

[blackduramax07]

Mine does the exact same thing. Put the exhaust on as soon as I bought the truck. It still catches me off-guard when I hear it. That's a year later.