Jump to content

Performance Upgrade Package

brothernov
 Share

Recommended Posts

brothernov Enthusiast

brothernov

Posted
Posted

I recently purchased an AT4 withe the 6.2L.  I love most everything about it, but I'm considering adding the GM produced/installed cold air intake and cat-back exhaust.  All I'm looking for is a little more rumble, not trying to announce to the world I'm driving by or wake the neighbors when ever I pull in.  There's very little in terms of reviews or vids out there to give me some insight.  What do you guys think, Is the dealer's performance upgrade offering on the "tame" end of intake/exhaust mod offerings?  Will it be an annoyance inside the cabin while driving down the highway?  I know these are pretty subjective questions, and thank you in advance for any insight you can offer.  

  • Replies 132
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

OnTheReel
OnTheReel

The exhaust isn’t obnoxious at all but certainly a noticeable difference over the stock exhaust which is basically silent at all engine speeds.   If I’m honest, it was a little louder than I

SierraAT4
SierraAT4

This video convinced me to buy one:   

Chips
Chips

Curious On this . These “Catback” exhaust systems are just that, from the cat back replaced. why pay all that money to replace GMs OEM piping which is already stainless!   The only

Posted Images

OnTheReel Senior Enthusiast

OnTheReel

Posted
Posted

The exhaust isn’t obnoxious at all but certainly a noticeable difference over the stock exhaust which is basically silent at all engine speeds.

 

If I’m honest, it was a little louder than I expected for a “factory” part and it took a little getting used to. Overall, I have no complaints there because it calms down VERY nicely at cruising speeds. There is no drone at all and sounds pretty much the same as it did before on the highway. Stop and go, in-town type driving you do hear some more rumble in the cab, but it’s not to the point of having to speak up or anything.

 

Cold starts are on the loud side until the idle drops but that’s the only time I hear it from in my house. 

 

I think it’s a very nicely designed kit and I’m very happy with it. The performance boost is a great plus, as it’s good for 13hp on the 6.2.

 

Videos are very tough to judge how it sounds. I am going to make more shortly but for now I just have the two vids below. Obviously a Chevy, but the same exhaust part # and engine you have.

 

 

 

  • Like 2
  • Thanks 1
Jon D Enthusiast

Jon D

Posted
Posted

I did both and am happy with the outcome. Much better sound and the truck just feels a bit more lively. 

  • Like 1
Rduatctt Enthusiast

Rduatctt

Posted
Posted

I installed both on my Denali with the 6.2. It was a little loud for me so I added resonators just prior to the tips and that toned it down a bit. I wanted to know it was a 6.2 but did not want it too be obnoxious 

brothernov Enthusiast

brothernov

Posted
  • Author
Posted

Would it make any sense to only add the cold air intake, or only the exhaust?  As I type it it feels like a dumb question, if I increase the air in I'll probably need to increase the trucks ability to expel it, but I know practically nothing about exhaust systems.

Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted
19 minutes ago, brothernov said:

Would it make any sense to only add the cold air intake, or only the exhaust?  As I type it it feels like a dumb question, if I increase the air in I'll probably need to increase the trucks ability to expel it, but I know practically nothing about exhaust systems.

You can att the CAI by it's self but to get the most benefit the exhaust is also needed. 

Schmoe Enthusiast

Schmoe

Posted
Posted

I just had the performance exhaust placed on my 6.2 AT4 yesterday. Love it. Did not do CAI. I just couldn’t find anything that definitively said it was worth the money. I’m not opposed to doing it (or maybe one of the other aftermarkets) in the future if it will improve performance/ mpg’s. The exhaust itself did everything I wanted it to for the sound. 

  • Thanks 1
OnTheReel Senior Enthusiast

OnTheReel

Posted
Posted
2 hours ago, Schmoe said:

I just had the performance exhaust placed on my 6.2 AT4 yesterday. Love it. Did not do CAI. I just couldn’t find anything that definitively said it was worth the money. I’m not opposed to doing it (or maybe one of the other aftermarkets) in the future if it will improve performance/ mpg’s. The exhaust itself did everything I wanted it to for the sound. 

Same here. The exhaust is good for 13hp according to GM. No numbers for the CAI alone, but GMC reports that the CAI AND exhaust add 15hp in the AT4 performance package. That would leave 2hp to be attributed to the intake.

  • Like 1
Schmoe Enthusiast

Schmoe

Posted
Posted
21 minutes ago, OnTheReel said:

Same here. The exhaust is good for 13hp according to GM. No numbers for the CAI alone, but GMC reports that the CAI AND exhaust add 15hp in the AT4 performance package. That would leave 2hp to be attributed to the intake.

Yeah, a lot of my decision was based on your posts, lol. So, if anyone else is curious, I have found OnTheReal’s info to be quite accurate and reliable. ??

  • Thanks 1
OnTheReel Senior Enthusiast

OnTheReel

Posted
Posted

Thanks! I don’t mean to repeat myself about it, but the same questions keep popping up about their CAI. GM could squash it by posting the numbers themselves, but I suspect they don’t for a reason...:rolleyes:

Trwtow Enthusiast

Trwtow

Posted
Posted

anyone got the part number handy I have a 6.2 hicountry gonna try just the exhaust thanks

BLACK AT4 Enthusiast

BLACK AT4

Posted
Posted

Save yourself the money on the GM Cat Back System. The restriction is the flapper valves. Each one has a 1.25" restriction when wide open. I have posted the picture of the flapper valve many times on this site. I will post one more time. I cut both off and installed a Magnaflow 12909 and left the resonators because they do not restrict the flow. The entire cost was less than $200 including the labor at the exhaust shop.  here is the muffler on  Amazon  https://www.amazon.com/gp/product/B000XQM1LC/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

The Magnaflow is a straight through muffler, You can hear it on the freeway but after about 400 miles it quiets down. 

 

20190321_144638.jpg

  • Thanks 1
Jmonty Enthusiast

Jmonty

Posted
Posted
22 hours ago, BLACK AT4 said:

Save yourself the money on the GM Cat Back System. The restriction is the flapper valves. Each one has a 1.25" restriction when wide open. I have posted the picture of the flapper valve many times on this site. I will post one more time. I cut both off and installed a Magnaflow 12909 and left the resonators because they do not restrict the flow. The entire cost was less than $200 including the labor at the exhaust shop.  here is the muffler on  Amazon  https://www.amazon.com/gp/product/B000XQM1LC/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

The Magnaflow is a straight through muffler, You can hear it on the freeway but after about 400 miles it quiets down. 

 

20190321_144638.jpg

Any drone? How much louder did it get?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,903
    Total Members
    8,960
    Most Online
    RyGuy43
    Newest Member
    RyGuy43
    Joined

  • Who's Online   1 Member, 0 Anonymous, 509 Guests (See full list)

  • Latest Articles

  • Posts

    • davester
      2015 Silverado 3500 right rear turn indicator failure

      By davester · Posted

      consider doing electrical testing?  I would guess some power or ground wire/connection has a problem.   alldata.com has wiring diagrams, connector pinouts and diagnostic procedures you can use to find where the problem is.
    • davester
      My First Project and GMC has me stumped

      By davester · Posted

      can you tell if the reader is actually trying to get codes, and the pcm is reporting none, or is your reader just silently failing because it's not communicating with the pcm?
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Any joy with this truck seems to be short-lived.   The CEL for P0172 ("bank 1" too rich) is now "intermittent".   I'm not sure where to check, or re-check, and my energy to keep chasing problems with junk is wearing thin. The P0172 seems to set as I'm coming to a stop, completely off the throttle, when fully warm. At least, that's what it's done the 3? times it's set.   Everything appears normal on the scanner EXCEPT long term fuel trim. There's only one bank on this vehicle because it's an OBD 1.5 with only one upstream O2 sensor. At idle, it's around -16.4% and will dip to -18% occasionally at idle or off-throttle. LTFT approaches 0 when throttle is held at 2500rpm. Short term appears normal, much closer to zero all the time. The LTFT tells me the engine is running rich at idle but compensating at higher load. But, why?   The EVAP purge valve doesn't appear to be leaking/sucking fuel vapor continuously. Is it sticking just as I come to a stop and the engine is choking on fuel vapor and sets the P0172? But that doesn't explain the persistently negative LTFT. Disconnecting the purge valve doesn't seem to make any difference.   I suppose that leaves another dang issue with the fuel injector. A leaking fuel pressure regulator, a new leak in the spider, or a leaking fuel injector/poppet valve I didn't see, or a small crack in one of the spider legs.   The vacuum line leading to the fuel pressure regulator doesn't have raw fuel in it. It doesn't even smell like fuel when it's pulled off, not until you suck air through it, then you can tell it leads to a fuel component. I'd consider that normal? Nothing is signaling this is a FPR issue from the outside, at least.   The oil smells like fuel but it's not building volume. I've noticed most oil in most engines smells like fuel to some degree so it's hard to say if the smell is an issue or not. Or if the engine just still smells like fuel because the crankcase was full of it a few hundred miles ago. But it's been changed twice since that original issue of the leaking fuel line dumping fuel into the intake.   Patience is running very thin. Every win seems to be accompanied by two steps backwards, or another issue that leads to removing at least the top half of the intake manifold. Enough! LOL
    • Chuck FB
      Tire pressure for 37s

      By Chuck FB · Posted

      First off you mentioned "Toyo Says" and then gave the pressures 45/50, was this some person at the tire shop that pulled those numbers out of his head ?   Now of course I can't know your exact axle weights front and rear, however I have much the same pickup as yourself other than not knowing your starting weight as per the pounds the truck rolled out of the factory at due to the options yours did or didn't come with or what you have added beyond the extra tire weight. The correct way to know 100% where a person is at is by weighing each axle with the typical weight the vehicle is driven with and that means taking into account passengers and making sure you figure in a full tank of fuel and a little grace for whatever you may put in the bed "groceries" !    I am looking at and not that it really matters as all the tire companies use the same charts anyway, but I am looking at the comprehensive Toyo tire chart in the section that your tire falls under and I know it sounds confusing but your tire is not an LT metric tire like your factory tire but instead because its a standard inch measured tire its under a different category called an LT floatation series tire. That makes a difference as LT metric tires they don't want to see run below 35 psi at highway speed where as with the LT floatation series it can be run down to 25 psi on the highway as long as the weight on the said size of tire is agreeable with or less than that minimum 25 psi. It blows many people away that how is this physically possible, an empty truck for one thing and larger tires with the same size wheel diameter have a lot more air volume so they can carry the same weight as the smaller tire with less air pressure.    So my truck, I have the stock 275/65R20 wheels and tires and I have a bit of weight in the box with a bak flip cover and a rubber bed mat and some tools and spare gas. The front of my gas truck weighs a bit more than some trucks of the similar spec due to double batteries and alternators. However with full fuel and just me in the truck I am weighted such that I can run 40 front and 35 rear and so that is what I have done since day one.    If I base your truck at or slightly below the weight of my truck, in theory with your tires going by the tire chart you might be right around a minimum of 30 pounds front and 25 pounds rear. Of course that would hit pretty much minimum cold inflation pressure one could run with that tire size and a near empty truck. If you have access to an accurate weigh scale to do individual front and rear axle weights I would suggest you do that and make sure your topped up with fuel and whatever else in the truck before you weigh it and then you will have a great starting point to work off of and figure out what your bare minimum pressures are you can safely run. If you do much in the way of hot weather high speed driving, bumping up a bit for a safety margin is never a bad idea but just depends on what type of driving you do. I will include the Toyo chart and the floatation series sizes start on page 31. Without a doubt at these pressures I am speculating at minimum wise for your truck, it would most certainly ride very different then it did when you were using 55 lb front and rear.     https://www.toyotires.com/media/pxcjubjs/application_of_load_inflation_tables_20200723.pdf
    • Snowcamo
      Possible lifter tick after DOD delete

      By Snowcamo · Posted

      Take an automotive stethoscope to the vacuum pump. Iirc those tick as well. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...