What did you do to your NBS GMT800 Tahoe/Yukon Today?

[Rocket Man]

Been having some clunks at low speed turns. Decided to re-check torque on the cross member I removed to drop the oil pan. Damn. One side not even hand tight. Torqued em down to spec.

Oops. Shit happens as they say.

 

[BlackedOutHoe]

Been having some clunks at low speed turns. Several weeks ago, I greased everything underneath. Thought that fixed it, but still there. Did some troubleshooting mentally then put it in the air and had my wife make lock to lock turns. No noise. Put it back on the ground and same - no noise. Decided to re-check torque on the cross member I removed to drop the oil pan. Damn. One side not even hand tight. Torqued em down to spec.

Will test drive later, right now, she's parked parallelly to my garage as I have to keep it outside overnight while the hardwood floors get refinished. All furniture in the garage. Doing my best attempts to keep thievery from happening.

I also fought clunk gremlins and narrowed it down to my passenger side LCA bolts that were a little loose. Somewhere to look if the noise is still present.

 

[Dantheman1540]

Gutted the passenger side cat, this time a much easier more professional method. First time welding exhaust and I was surprised how easy it burns. Took a couple trys before I got the settings right so I'll grind it down and make sure theres no leaks.

Felt like a surgeon.

 

[Dantheman1540]

Is there some sort of voodoo that makes exhaust actually flow through a catalytic converter? I couldn't see light through this thing and don't see how the mass amount of air flowing through a 408 would make it.

 

[Tonyrodz]

Gutted the passenger side cat, this time a much easier more professional method. First time welding exhaust and I was surprised how easy it burns. Took a couple trys before I got the settings right so I'll grind it down and make sure theres no leaks.

Felt like a surgeon.View attachment 260042 View attachment 260039 View attachment 260041 View attachment 260040 View attachment 260038

That's a nice job. I need that done on my van.

 

[Dantheman1540]

That's a nice job. I need that done on my van.

I'd say it's easier doing what I did then cutting them out and running a straight pipe. Plus someone that's not a total hack like me could probably do it on the very top and when the truck is on a lift it might still pass a visual emissions inspection.

 

[Rocket Man]

Is there some sort of voodoo that makes exhaust actually flow through a catalytic converter? I couldn't see light through this thing and don't see how the mass amount of air flowing through a 408 would make it.

If you hadn’t mashed it you would be able to see through it. They’re designed to have the most amount of surface area inside the converter in order to help the process but with minimal restriction. I’ve heard that removing the honeycomb material actually decreases flow because instead of going straight through, now it swirls inside the hollow chamber creating a disturbance. Maybe not as much on a bullet style but still would be better to cut them completely out and replace with the same diameter pipe as the rest of the exhaust.

 

[Dantheman1540]

If you hadn’t mashed it you would be able to see through it. They’re designed to have the most amount of surface area inside the converter in order to help the process but with minimal restriction. I’ve heard that removing the honeycomb material actually decreases flow because instead of going straight through, now it swirls inside the hollow chamber creating a disturbance. Maybe not as much on a bullet-style but still would be better to cut them completely out and replace with the same diameter pipe as the rest of the exhaust.

I can't see it causing any noticeable power loss and certainly no more than having the honeycomb in place. Especially since both cats had the honeycomb broken free from the sides of the housing and moving freely. I would imagine it does exactly what exhaust is designed to do in a straight-through muffler. Go slow and have the sound waves bounce around and cancel each other out during idle or low flow conditions. Then under high load, it blasts right past. Would be cool to see someone like engine masters do a test but I have a feeling the difference would be minuscule. Dual 3" is kinda overkill for any NA motor even a big stroker boy.

 

[mattbta]

Oops. Shit happens as they say.

Clunk fixed. Actually kinda embarrassed. Bah!

 

[nglauer]

Finally bought tires and also had to unexpectedly buy a new propane tank for the house ugh. I would of waited on tires if i knew but thats just how life works haha.

Right there with ya. I was getting ready to pull the trigger on a set of emergency lights and Bilstein 5100's... then our front load LG washer flew apart. The month before that I had planned to buy the Westin Elite XD Pushbar... then my wife notified me that our water softener crapped itself... Oh well. I'll slowly add to it as time and money permit.

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