What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[RooTBeeRthe1st]

My resonator delete didn't make any difference that I could tell. depending on your muffler, you might not have any annoying noises in the cabin. Just a muscular growl when on the throttle.

With the full stock exhaust, deleting the resonator literally doesn't do anything in the vehicle as far as sound or anything.
Aftermarket mufflers however, it can make a huge difference.

 

[iamdub]

With the full stock exhaust, deleting the resonator literally doesn't do anything in the vehicle as far as sound or anything.
Aftermarket mufflers however, it can make a huge difference.

I see how this makes sense. The resonator "cleans up" specific frequencies left over after the stock muffler. So, it would be less effective being bombarded with louder and different frequencies being passed by an aftermarket muffler. I'd like to see comparison vids of a factory resonator temporarily clamped to the exit of an aftermarket exhaust system, before the tip is installed.

 

[George B]

What section in the tech2 do yall use to watch for knock and spark ret@rd?

Have some rattling getting on the highway but it comes and goes. I see no spark knock when looking at the ignition data in my log file.

Maybe its something else making noise. I have heard it before but it has been a while.

 

[Doubeleive]

What section in the tech2 do yall use to watch for knock and spark ret@rd?

Have some rattling getting on the highway but it comes and goes. I see no spark knock when looking at the ignition data in my log file.

Maybe its something else making noise. I have heard it before but it has been a while.

sometimes it's the exhaust pipe, there is a spot where it clamps together on the passenger side I think it's between the front and rear passenger seat, mine was rattling there under specific rpms tightening it up did not help so the muffler shop put a couple tiny tacks on it. That section is unbolted and removed to get the transmission out which is why they only put a couple tacks so it could be ground off if the trans has to come out.

otherwise all that kind of data should be in the engine live data I have only gone in there to see if I was getting any misfire, watch fuel trims and monitor oil temperature

 

[gooffeyguy]

Also check all your exhaust manifold bolts. It may just be a very slight, tiny leak happening under certain conditions

 

[George B]

sometimes it's the exhaust pipe, there is a spot where it clamps together on the passenger side I think it's between the front and rear passenger seat, mine was rattling there under specific rpms tightening it up did not help so the muffler shop put a couple tiny tacks on it. That section is unbolted and removed to get the transmission out which is why they only put a couple tacks so it could be ground off if the trans has to come out.

otherwise all that kind of data should be in the engine live data I have only gone in there to see if I was getting any misfire, watch fuel trims and monitor oil temperature

Also check all your exhaust manifold bolts. It may just be a very slight, tiny leak happening under certain conditions

Thanks guys. Same thoughts I had. I will check the bolts. I have all ARP bolts in the manifolds so that isn’t scary to me now.

 

[Sparksalot]

Drove it to a hot rod show. Won a toolbox and a SnapOn pie iron in the auction. Saw a few cool hot rods.

 

[RooTBeeRthe1st]

I see how this makes sense. The resonator "cleans up" specific frequencies left over after the stock muffler. So, it would be less effective being bombarded with louder and different frequencies being passed by an aftermarket muffler. I'd like to see comparison vids of a factory resonator temporarily clamped to the exit of an aftermarket exhaust system, before the tip is installed.

My 3.5" stock style catback.
A Walker School bus muffler and universal resonator.
Just the muffler, and then holding the resonator up to get a rough idea.

I have since welded the resonator on in front of the muffler because I hate seeing that big turd hanging out behind the back tire on the factory exhaust.


Been running this exhaust for just over a year now.

 

[RooTBeeRthe1st]

What section in the tech2 do yall use to watch for knock and spark ret@rd?

Have some rattling getting on the highway but it comes and goes. I see no spark knock when looking at the ignition data in my log file.

Maybe its something else making noise. I have heard it before but it has been a while.

Belt tentioner?

 

[George B]

Belt tentioner?

Hmm… it has about 30k on it.