Headers on a 6.2L with Stock Muffler/Cat-Back?

[91RS]

Another thing about the power gain, this is one of the other few videos on YouTube of headers with a stock exhaust but you really can’t hear the exhaust but the picture of the dyno graph at the end shows the power increase all the way up the powerband and also an increase of over 50 tq.

 

[randeez]

I think a 6.2, especially 2wd, should put down more than 300hp stock. I've seen that vid before tho, most of them do 330-340hp on 3rd gear pull.

Mine was on 2 different awd dynos when cammed, over 400hp on 3rd gear pulls, 4th gear is sketchy af strapped down at 120mph. but was never happy with tunes. I've dropped 1/4mile times another .5 second with nothing more than tuning.

 

[91RS]

That’s great! I wasn’t even really thinking that number was a little low or not, I was mainly looking at the before and after and how the increase was across the whole powerband, which ultimately is what matters since (before and after in the same dyno that is). The cam in your video seems to make dang good power, that 0-100+ was pretty fast for a giant SUV! Who specced that cam? Didn’t sound like the idle was that lopey either, unless that was just the cold start. I like you retained the VVT as well, I think that makes such a huge difference in the way these trucks drive compared to the older 6.0L trucks.

I pulled the trigger on 1 3/4” headers yesterday. Should be here in a few weeks since ARH are built to order. I’ll also need to knock out my leaking rear main seal at the same time since long tubes usually make getting the transmission out a bit difficult. Good thing mine is 2WD.

 

[Agent WD-40]

That’s great! I wasn’t even really thinking that number was a little low or not, I was mainly looking at the before and after and how the increase was across the whole powerband, which ultimately is what matters since (before and after in the same dyno that is). The cam in your video seems to make dang good power, that 0-100+ was pretty fast for a giant SUV! Who specced that cam? Didn’t sound like the idle was that lopey either, unless that was just the cold start. I like you retained the VVT as well, I think that makes such a huge difference in the way these trucks drive compared to the older 6.0L trucks.

I pulled the trigger on 1 3/4” headers yesterday. Should be here in a few weeks since ARH are built to order. I’ll also need to knock out my leaking rear main seal at the same time since long tubes usually make getting the transmission out a bit difficult. Good thing mine is 2WD.

What year is your Yukon? GM changed the stock exhaust when they added AFM (believe 2010+) and it got a lot quieter. The 2007-09? 6.2 SUV had a fairly deep, throaty stock exhaust (still fairly mild, but not silent). The later ones had exhaust that was near silet (likely to combat the annoying sound with AFM and loud exhaust).

Your experience with headers will be depend on what factory exhaust you have. The video you posted originally sounded a lot like the 07-09 exhaust sound, just a bit louder. In my experience, adding headers to stock exhaust, just makes it louder but keeps the tone.

I helped a friend put headers on a 2010 Camaro L99 (6.2L w/ AFM). Stock exhaust was extremely quiet - not at all appropriate for a sports car. Headers made it louder but not annoyingly so. I would liken it to a mild catback system. No drone, same tone, just louder.

I had a 2012 Denali and it was near silent stock - nothing like the 2007 Escalade my friend had. I put Corsa Sport on my 2012 and was happy with it (great tone, no drone). The sound (and slight vibration) with AFM engaged annoyed me so I had that tuned out. I didn't want to mess with headers on my family vehicle (wanted to keep it closer to stock).

I'm guessing I could have achieved a similar tone with just headers and stock exhaust but that wasn't my priority.

Good luck and let us know how this turns out.

 

[91RS]

It is an 08. You're right about the exhaust getting quieter on the later ones, I completely forgot about that. That would explain why the one in LMR's video on the dyno didn't sound much different. I don't have a problem with the way it sounds now so I'm hoping the tone doesn't change and just gets louder and I'll be happy with that. That video I originally posted made me nervous about how it was going to sound. I was originally going to get a Corsa Sport but I switched from the cat-back to headers once I found out I could get a pretty nice power gain from headers and a tune. It's highly possible this truck would need a Corsa Touring with the headers also. I'll keep an eye out for a used one and buy whichever pops up if the money is available. I will post some videos hopefully that turn out better than the current ones available to help the two people in the future who might be interested in doing headers with the stock cat-back.

 

[Agent WD-40]

If don't like the sound of the stock exhaust after headers you can always try to add a resonator to tone it down. Cheaper than a whole new system.

My brother purchased a CTS-V with cam, headers (no cats), and Corsa Sport. Needless to say it was loud and a times a touch raspy. He added MBRP cylindrical packed muffler/ resonator. That took the edge off and gave it a bit of a deeper, smoother tone so should work here as well.

 

[992dr]

Any updates?

 

[91RS]

Not yet. Still waiting for the headers to come in, they usually take 10-14 days to make plus a few more in shipping so I’d guess I’ll have them sometime next week. I’ve got my new rear main seal housing that needs doing at the same time since every other vehicle I’ve ever put headers on made the transmission difficult to get out. Once they headers come in, I’ll have to find the time to do it all.

 

[langsbr]

Did you get longtubes with a catted or catless y pipe? I am about to do longtubes on the wife's 08 Escalade, but I really don't want the smell from catless. I'm also too cheap to drop the money on Kooks, especially for a 10 year old vehicle. I'm gonna do the speed engineering 1 7/8 setup and probably add my own cats. I think a pair of the Kooks 3" bullet cats are only $150, which is a small price to pay to prevent the unburned fuel smell. If I knew I could get away with a single 3.5" cat, I might consider going that route instead, but it will really be up to what fits better. It will all have to be fabbed regardless since Speed Engineering only offers a catless y pipe.

 

[91RS]

I went with American Racing 1 3/4” catted y-pipe. ARH is all I will spend money on. I’m a big proponent of you get what you pay for. I’m not going to spend $1000 for something with cheapo metal that doesn’t fit right. ARH headers always fit perfect and I also like that they take the time to design them where the stock plug wires fit so I don’t have to waste money on some stupid socks or “racing” wires that don’t do squat. I’ve had fitment issues with Kooks so I won’t buy them and I’ve heard a lot of opinions that Kooks aren’t what they used to be.

 

[iamdub]

For the rest of the exhaust, is it Corsa cat-back or nothing? Since you decided to spend your allocated funds on headers and tune, which I would've done, you could have the whole package for just a couple hundred more (less if you weld it in yourself) if you went with a more affordable muffler. Unless the Corsa cat-back is a different size of pipe or if you want that brand for bragging rights, I don't see any benefit in replacing the stock piping and there are plenty of cheaper muffler options that give a quiet but noticeable sound with no drone. You could get one of the Magnaflows that are always mentioned here and whatever dual exit tip you want and have it welded to the stock piping. The Magnaflow 12589 is the most comparable to the stock sound. There are copies made by AP Exhaust that are virtually identical but without the Magnaflow logo stamped in the case for about half the cost. I got AP's copy of the Magnaflow 12259, which is one step more aggressive than the Magnaflow 12589 (18"L by 8"W body versus 22"L by 11"W body) on sale on Amazon for $31. No drone when cruising and has a deep but mellow tone when accelerating. Next to a retaining wall or under an overpass with the passenger side windows down, it sounds pretty wild at WOT. I think it's the best of both worlds and at a bargain price. I understand that there are good and not-so-good qualities of exhaust system materials and builds. But, it's just hot gasses- it doesn't care what name is stamped on the pipe it's going through. The stock exhaust is perfectly adequate in size and quality for you at this level and a packed fiberglass muffler is pretty hard to screw up, popular brand name or not.

 

[91RS]

It would pretty much be Corsa or nothing but it certainly isn’t for bragging rights. I don’t do anything to impress other people. I like the sound of Corsa, no drone, and I love the angled twin side exit tip. I’ve never liked the sound of Magnaflow on any LS engine (I did like it on the I6 Trailblazer I had). I like Borla’s sound but they’re usually a bit droney. I’ve also like Billy Boat on Corvettes but the drone was pretty terrible on those. That being said, I’m hoping the stock catback sounds fine and I can just leave it.

 

[992dr]

Not yet. Still waiting for the headers to come in, they usually take 10-14 days to make plus a few more in shipping so I’d guess I’ll have them sometime next week. I’ve got my new rear main seal housing that needs doing at the same time since every other vehicle I’ve ever put headers on made the transmission difficult to get out. Once they headers come in, I’ll have to find the time to do it all.

Sounds good. I'm looking forward to seeing the ARH LTs. I was leaning in the Speed Engineering direction for a long time but after some thought and quite a few reviews, I'm looking elsewhere.
Are you doing the work yourself?

Did you get longtubes with a catted or catless y pipe? I am about to do longtubes on the wife's 08 Escalade, but I really don't want the smell from catless. I'm also too cheap to drop the money on Kooks, especially for a 10 year old vehicle. I'm gonna do the speed engineering 1 7/8 setup and probably add my own cats. I think a pair of the Kooks 3" bullet cats are only $150, which is a small price to pay to prevent the unburned fuel smell. If I knew I could get away with a single 3.5" cat, I might consider going that route instead, but it will really be up to what fits better. It will all have to be fabbed regardless since Speed Engineering only offers a catless y pipe.

Another small cat option is Magnaflow spun metallic cats. You can cut them down and modify them to your liking. I bought a 59956 2.5" in/out cat and turned it down to be a 3" in/out. Made it super short to fit in tight spaces. Just a thought.

I went with American Racing 1 3/4” catted y-pipe. ARH is all I will spend money on. I’m a big proponent of you get what you pay for. I’m not going to spend $1000 for something with cheapo metal that doesn’t fit right. ARH headers always fit perfect and I also like that they take the time to design them where the stock plug wires fit so I don’t have to waste money on some stupid socks or “racing” wires that don’t do squat. I’ve had fitment issues with Kooks so I won’t buy them and I’ve heard a lot of opinions that Kooks aren’t what they used to be.

I've heard the same about Kooks.
What model LTs did you get from ARH?

 

[91RS]

I'm using the GM62-07134300LSWC.

 

[97audia4]

Stock muffler and resonator with speed engineering headers, catless y pipe and a tune.

No drone inside at all, for 950 for the headers and install and tune I couldnt pass it up, and they didnt need to be modified at all.

Also Summit ceramic plug wires, didnt want to worry about the heat.

 

[91RS]

What year is your truck?

My headers still haven't made it so maybe this week.

 

[the_tool_man]

I'm not trying to rain on your parade. Just curious, more than anything. Won't long tubes hurt low end torque? I get that a 45hp increase at WOT, high rpm will be fun. But how much time will you spend driving it that way?

Again, just trying to learn, as my Denali has started breaking manifold bolts. So if LT headers don't kill torque, this is a good time for me to switch.

 

[91RS]

1 3/4" primaries help keep the low end torque. 1 7/8" will hurt low end torque unless you have big power/cubes. The VVT also helps a lot with low end torque on these. If you look at the dyno graph in LMR's video I posted on the previous page, it shows before and after and the power and torque gain is pretty well consistent across the entire powerband.

 

[97audia4]

What year is your truck?

My headers still haven't made it so maybe this week.

2009 6.2 Yukon Denali.

Headers with a tune, has low end enough and top end has picked up big time.

 

[91RS]

I got my rear main housing replaced and headers installed yesterday. It went fairly smoothly, only had one broken manifold bolt to fish out and one of the studs on the stock cat-back snapped right off so I popped that out and used a bolt and nut. Of course, once I got the headers in I realized they actually aren’t at all in the way of getting the starter or transmission out, which is a first for all the vehicles I’ve installed headers on but it’s done and I have no more leaks to worry about.

I’m very pleased with the headers and stock cat-back. That first video I posted really had me worried and I’m happy to say it does no justice for how it really sounds. At idle and at cruising its almost not even noticeable compared to stock and under harder acceleration it is definitely louder but far from deafening. I actually would have still been happy if it were a bit louder. It does have the bit of raspiness to it that long tunes add so it kinda adds a Corsa-ish tone to it. It sounds great though and I’m very happy. It doesn’t sound out-of-place being on an Escalade either which was also something I was a little nervous about. Even with the catted y-pipe the P0420 and P0430 set before I even got home! It was late by the time I was done so I only took this one video of acceleration from inside the truck, all windows up.