Hi guys, first time Tahoe and chevy owner here and first time using a forum. So please bare with me.
Welcome and +1 for pics!
Not gonna "bare" with you- I just don't swing that way.
I would like to do upgrades that benefit its durability first while increasing performance....Also I live in California so some enhancements are off the table.
So the first burning question is, AFM? Should I buy a tuner like (Range)? Or is there better options or is AFM not really as bad as it sounds?
You're starting off on the right foot aiming for durability first. As previously mentioned, get everything up to par, particularly the soft stuff. The metals should be primo, but bushings, hoses, belts, etc. degrade with age. Hoses are the biggest kicker cuz they always seem to appear fine, but when you're caught in a traffic jam on the 405 in the dead of summer, that's when one splits and pukes the coolant. Replace ALL of the fluids from front to back as they age as well and can even become acidic and corrode bearing materials. I'd switch all oils to full synthetic. Any chance you can find out the maintenance/service history from the PO?
I'd be surprised if it's had any of the AFM updates performed (updated VLOM and lifters). Regardless, I'd just disable it. At 15K miles, the feeble AFM components have virtually no wear and no sludge or varnish should be in the system so it should be in perfect condition. To best way to keep those components in this condition for as long as possible is to not use them. Disable the system so the AFM lifters don't cycle and, theoretically, they should be almost as reliable as the non-AFM lifters. I'd get a custom tune, such as from Black Bear, since you can have the sloppy transmission shifting and other factory shortcomings cleaned up in addition to disabling the AFM. The tuning improvements will not only put more power to the wheels (safely), but will extend the life of the transmission's internals before they've even worn yet (lucky you!) and greatly improve the overall driving feel with better responsiveness and more sharply-appointed shifts.
The other option is to keep AFM alive, but maintain it scrupulously by keeping the oil clean. Run top quality full synthetic oil and filters and replace it when it gets to be about a mahogany color, which should be around 3-5K miles. DO NOT GO BY THE OIL LIFE MONITOR (OLM) ON THE DRIVER INFORMATION CENTER (DIC). It should be pretty solid for a good while, but the time bomb will still be ticking, figuratively, and eventually, literally. You could have the updated AFM lifters and VLOM installed and continue your meticulous maintenance and you may never have a problem for 300K miles. But, if you're gonna go that far into the engine to increase it's reliability, you may as well delete the AFM and be done with it forever.
This is where your want to perform "upgrades that benefit its durability first while increasing performance" comes to fruition. To delete AFM, you have to replace the cam. This is your opportunity to drop in a nice "truck" cam for more power across the board with no sacrifices made anywhere else. As a little bonus for you due to your low-mileage mill, you'll just have to buy 8 non-AFM lifters and can continue to run the original 8 of the non-AFM cylinders.
What are good options for cat back systems and cold air intakes? Engine upgrades?
Looking for any must do, unavoidable upgrades
I've never seen the point of a cat-back system other than where the factory system needs to be replaced (damaged or rusted) or upgraded in size and the owner just wants to do it themselves as they are mostly a DIY, bolt-on design. Or maybe where the owner wants to have pretty pipes that they paid a premium for cuz it makes 'em feel good. IMO, swap the OEM muffler for one of your choice and you'd have the same for hundreds of dollars less. Hell, I even went a step further and got the knock-off of one of the famed Magnaflow mufflers for $31. The only difference I could tell in mine versus the MF is that mine doesn't have the MF logo embossed in it and the height and width dimensions are slightly different but the length is the same. I'm sure this was to avoid copyright infringements.
Cold air intake? Lucky you- yours came from the factory with one! They all did! The factory air intake ducts air from outside the engine bay and into a filter box that is very well sealed. Yeah, it's not the prettiest thing with that accordion coupler and those Helmholtz chambers. Fortunately, Airaid makes a sweet and simple bolt-on fix with their MIT. I'd also make sure the foam seal between the filter box and fender is in good shape. They tend to lose their adhesion with age and fall in. If needed, replace it with a new factory one or (better yet, IMO) get some foam rubber weather seal from the hardware store and make your own, heavy-duty seal.
There really aren't any significant engine upgrades to be had with your implied goals. We've already addressed the few factory faults...
...Well, since you said "unavoidable"... I'd classify a catch can and the updated driver's side valve cover here. LS engines tend to pass a lot of oil mist through the PCV system and it ends up puddling up in the back of the intake manifold and most of it ends up in the back two cylinders. Most of it burns off, but, over time, carbon can build up in those cylinders and the piston rings can get stuck, leading to a whole world of hurt. Your engine, being so new, can be sheltered from ever having to know anything of this. The AFM system operating is a huge contributor to this since it sprays a plume of atomized oil into the crankcase when the lifters collapse. GM designed a shield for this that's only $8, but, you have to remove the oil pan to install it. You can buy a plug-in AFM disabler or tuner for less than the cost of time and labor to install the shield. The other contributor to the oily PCV is the hole in the baffle of the driver's side valve cover. It was originally located right over one of the rocker arms and the oil stream squirting up from the push rod side of it would make a bullseye right into the hole, filling the baffle with oil that would get sucked up by the PCV flow. The revised cover relocates the hole. You probably haven't driven yours enough yet to note any oil consumption. But, between AFM operating and (likely) having the original valve cover, you'll see a loss of oil. It may be something small such as a quart over 3-5K miles but it can be much worse.
Finding out your Tahoe's service history would be really convenient in this case cuz you can't tell by looking at the outside of the valve cover which revision it is. After disabling or deleting AFM and getting the updated cover, there will still be some oil passed through the PCV system- It's just "an LS thing". For this, anyone in the know about LS engines will recommend installing a catch can. There's tons of info on the interwebz about this. What has worked great for me is one I got from catchcans.com years ago. I added a stainless steel scouring pad (like a "Chore Boy" pad, but not copper) to mine and it increased the amount of oil the can traps.
All of these are details we can all discuss once you start a build thread to introduce (and name?) your rig and document the changes.
I'm not interested in lifting it (maybe, unless convinced otherwise), but definitely am going to change the wheels and get some all terrains.
IMO, I think the 4WDs look better more level. They're certainly a little more capable with a little lift. I understand not needing or wanting a lift. But, if it's a cheap and harmless mod to give it better look that would complement some nice all-terrains, I'd do it. You can bolt on a tiny front lift in about an hour at a total cost of about $30. I'm not one to lift a 2WD and my ultimate goal was to lower it, but I lifted mine 2" in the front and 1" in the rear just cuz I ended up with a deal on some slightly aggressive looking all-terrains. I also installed some 1.5" spacers to give it a little wider stance. The mild lift/more level stance fit the look of the tires and I liked the overall appearance for the year that I ran it like this. I already had the 1" coil spacers and the 2" front lift was about $25 on Amazon. I spent an extra $5 on grade 8 hardware for peace of mind. It's a cheap and easy bolt-on mod that would actually be functional on a 4WD and it wouldn't harm anything or require changing a bunch of other things down the line. If you make any suspension changes, an alignment is recommended. It's good practice anyway if you get new tires and some places require it to honor a tire warranty.
Here's hoping you guys can help guide me in the right direction and keep me from spinning out of control. I'm open to any ideas and any questions, thanks
We're great at spending everyone else's money! You're at a good place, though. We won't lead you astray. We do have a few idiots here, but they're harmless and seem to roll with their earned punches just fine. A general rule is that you can easily identify and weed them out by their terrible misuse or total lack of punctuation or coherence in their rambling posts. Even then, these idiots aren't always incorrect with their input.
