LBZ: Exhaust Question

[speedmetal6.6]

I'm not sure where to post this, when I put my exhaust on I thought it sounded cool for like the first day but at an idle it changes pitch it will grumble for a little bit and then it will change and sound like a spaceheater.I dont know if it is the EGR or some thing mine is not blocked anymore( I've been having some issues latley and took it out incase I had to take it to the dealership for warranty work) any how when I floor it all I hear is the turbo screaming it might sound cool from farther away i've never let anybody drive my truck, but I figured it would have more of that throaty roar not just the sound of forced air and turbo. Do I need to straight pipe it or change mufflers or switch brands or something

 

[LB7Diesel]

The sound pitch your hearing is the vains in the turbo cycling. It's normal.

If you wanted a deep throaty sound, Buy an LB7!!!

 

[the4wheeler]

X2 its your trubo vains cycling to find there range it does this when the motor reaches 140 -150 degrees. ( i think that the first 1/4 mark on the temp gauge usally we are driving when it need to do the cycle and weights untill the engine is idling usually at a stop light or costing off the freeway takes it about 4 seconds to cycle
will also do this at first start up if the engine is above the 140-150 mark siting at idle
of course if you step on the throttle while its in med. cycling it cancels and weights till there is no input and trys agin.

 

[slowlmm]

tht can easly be adjusted with efi if you dont want it to cycle at idle. and you will have a nice low rumble

 

[the4wheeler]

tht can easly be adjusted with efi if you dont want it to cycle at idle. and you will have a nice low rumble

doesn't the ecm need to preform this check in order to know absolute position of the vains?

olny does it once per key on/motor on (asuming the motor gits up to temp.)

yes you can adjust it so the vains are open all the way at idle for rumble effect

 

[WolfLMM]

You can still have the check, but once thats done the commanded vane position can be set lower, to make it sound better.

 

[WolfLMM]

Its called Vane position relearn, and the ecm performs it every time the truck is started.

 

[cdbright]

soooooo, do you turn it off? or do you stop it untill it reaches above idle RPM?
i would like the rumble too

 

[wikdlmm]

its a certain table.. i forget which one but i have it done to mine.. sounds good

 

[stacks04]

it is the max vain tables and once it does the learn it goes back to rumble. also can set your vain tables to make it souinde nicer through and through but you may sacrifice some throttle response.

 

[E.carter]

I'm not sure where to post this, when I put my exhaust on I thought it sounded cool for like the first day but at an idle it changes pitch it will grumble for a little bit and then it will change and sound like a spaceheater.I dont know if it is the EGR or some thing mine is not blocked anymore( I've been having some issues latley and took it out incase I had to take it to the dealership for warranty work) any how when I floor it all I hear is the turbo screaming it might sound cool from farther away i've never let anybody drive my truck, but I figured it would have more of that throaty roar not just the sound of forced air and turbo. Do I need to straight pipe it or change mufflers or switch brands or something

You have lly in your sig but your question is under LBZ exaust? I like the sound of my lbz and yes I do get the same sound your refering to when the vanes, Its seems to happen quite often on mine

 

[lotsofmiles]

and yea even with the vanes open at idle it still does its cycle
sorry.


i edited it out before someone else does.

sorry.

 

[lotsofmiles]

:hug:
all better