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

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
26,209
Reaction score
39,279
Location
Stockton, Ca.
Darn, I was hoping you were going to say you had the BB tune and it passed no problem.
according to them it should, next time around I will find out for sure sometime in early 2025, unless it's been 2 years already then it would be around march of next year
 

RooTBeeRthe1st

Full Access Member
Joined
Jul 11, 2018
Posts
1,087
Reaction score
2,470
according to them it should, next time around I will find out for sure sometime in early 2025, unless it's been 2 years already then it would be around march of next year

Unless they look at more stuff or look deeper in CA, I never had a problem passing with my rear O2 codes turned off. All readiness monitors set just fine.
Supposedly a year or two ago, they started checking that you have a stock tune or at least one that was made smog legal like the one I have from Whipple.

When I had to get smog last year, I was just going to leave my HP tune on it just to see, but I actually ran out of time and so I just flashed it to stock knowing that it was going to pass no problem.
 

RooTBeeRthe1st

Full Access Member
Joined
Jul 11, 2018
Posts
1,087
Reaction score
2,470
Only the past two years. Had O2s and other things turned off in '17, so I've passed four emissions inspections with it, the final one in '21 with it cammed/modded with no cats. No visual inspections here although that's easy enough to pass. I don't believe they've changed anything in the testing.
You passed well cammed and catless?
Yeah, visual is also what can get you. Because even though the computer says everything's happy, they could see you did something that's not supposed to be there and being a hole about it and fail you.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
26,209
Reaction score
39,279
Location
Stockton, Ca.
Supposedly a year or two ago, they started checking that you have a stock tune or at least one that was made smog legal like the one I have from Whipple.

When I had to get smog last year, I was just going to leave my HP tune on it just to see, but I actually ran out of time and so I just flashed it to stock knowing that it was going to pass no problem.
ya, I just gave the smog guy the hypertech box with the carb number on it, I don't know if they would have detected it otherwise or not
 

iamdub

Full Access Member
Joined
Apr 23, 2016
Posts
20,821
Reaction score
44,943
Location
Li'l Weezyana
Supposedly a year or two ago, they started checking that you have a stock tune or at least one that was made smog legal like the one I have from Whipple.

When I had to get smog last year, I was just going to leave my HP tune on it just to see, but I actually ran out of time and so I just flashed it to stock knowing that it was going to pass no problem.

I recall that being discussed. Didn't know it was put into action. Damn.
 

iamdub

Full Access Member
Joined
Apr 23, 2016
Posts
20,821
Reaction score
44,943
Location
Li'l Weezyana
You passed well cammed and catless?

Cammed, catless and tuned to exaggerate the idle lope rather than smooth/hide it lol. No visual or butt sniffs here. They test the gas cap seal and plug in to the ALDL to check readiness monitors.


Yeah, visual is also what can get you. Because even though the computer says everything's happy, they could see you did something that's not supposed to be there and being a hole about it and fail you.

For visual cat test, I'd just run exhaust tubing through the stock cat shell. It'll have the proper numbers on it and will just look like an OEM replacement cat was installed. Maybe go a step further and drill holes in the tubing and pack the shells with steel wool so they'd at least have some active function as small mufflers. Still, you can't beat the butt sniffer.


I'll just have to enjoy my freedoms while I still have 'em.
 

Just Fishing

Can't fix stupid
Joined
Aug 30, 2020
Posts
3,926
Reaction score
8,503
Location
Utah
Changed the low beams with Sylvania xtra vision bulbs.

Not too difficult of a job once you know about the side bolt in the wheel well.
 
Joined
Apr 11, 2018
Posts
7,124
Reaction score
14,364
Location
St. Louis
Cammed, catless and tuned to exaggerate the idle lope rather than smooth/hide it lol. No visual or butt sniffs here. They test the gas cap seal and plug in to the ALDL to check readiness monitors.




For visual cat test, I'd just run exhaust tubing through the stock cat shell. It'll have the proper numbers on it and will just look like an OEM replacement cat was installed. Maybe go a step further and drill holes in the tubing and pack the shells with steel wool so they'd at least have some active function as small mufflers. Still, you can't beat the butt sniffer.


I'll just have to enjoy my freedoms while I still have 'em.
Years ago to pass a visual we used to hollow out the cats by taking them off and ramming a piece of rebar or pipe into it to break up the honeycomb inside and shake the broken up pieces out.

My '33 and '95 don't have cats. They're both old enough to be exempt from emissions, even though the engine in the 33 is a GM 350 crate motor from 2010
 

iamdub

Full Access Member
Joined
Apr 23, 2016
Posts
20,821
Reaction score
44,943
Location
Li'l Weezyana
Years ago to pass a visual we used to hollow out the cats by taking them off and ramming a piece of rebar or pipe into it to break up the honeycomb inside and shake the broken up pieces out.

My '33 and '95 don't have cats. They're both old enough to be exempt from emissions, even though the engine in the 33 is a GM 350 crate motor from 2010

All the ones I've done, they stayed on the vehicle. Just unbolted the cat-back pipe and wired it to the side and took a hammer, pry bar, large screwdriver and whatever else would fit in the hole to the ceramic. Periodically start the car and rev it to blow out the dust and chunks. Repeat as necessary.

You ever think about all the cats you've hollowed out over the years and how much money you threw away and/or what chemicals and elements you exposed yourself to? :D
 

Forum statistics

Threads
132,318
Posts
1,865,875
Members
96,910
Latest member
mckaywolf
Top