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OK I finally got the cash saved to buy the new exhaust system for my 5.7, 1999 Suburban. What I ordered:

Thorley tri-Y long tube headers. They come with a new Y pipe as well. I paid the extra to have them ceramic coated to keep the engine compartment heat down, and they will just plain last longer. This particular brand seems to be well known for making good low end torque, and Lord knows I could use more of that


Magnaflow Cat-Back exhaust. Another nice system that is all stainless steel and comes with a nice 4" polished stainless tip. Their tech people assured me I will be pleased with the sound as their muffler is insulated and double walled to reduce/eliminate that dreaded "droning" sound.

K&N air filter. Hey, gotta have it.


I'll post back here with my performance observations after it's all installed and I get a chance to pull the Outback again. Hopefully I can get the system in before we leave for Yosemite in two weeks
 

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Jim,

Congrats on saving some money and then spending it quickly....


Is your system going to have one pipe exit or two?

I have been considering something similar, but I want to keep the exhaust noise down, I don't like the noisy pipes. I have heard some systems sound like running a straight pipe, I don't want that.

K&N is also on the list.

Good luck with the install.

Kevin
 

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Yeah that cash just seems to fall out of my wallet sometimes
I'll soon be done with the Burb so the bleeding is coming to and end!

I went with the single swept side exhaust as this is a good combination of improved flow and backpressure. I think the dual exhaust conversion is too much flow and will hurt low end performance.

I too was very concerned about the truck being too loud. I really don't care about sounding like a hot-rod, I just want performance. Although, a little "throaty" sound wouldn't bother me
Magnaflow assured me their system is not disturbing, and the way they make their mufflers sounds like they have given this alot of thought. Only time will tell I guess.
 

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California Jim said:
Thorley tri-Y long tube headers. They come with a new Y pipe as well. I paid the extra to have them ceramic coated to keep the engine compartment heat down, and they will just plain last longer. This particular brand seems to be well known for making good low end torque, and Lord knows I could use more of that
Long tube headers will indeed give you more torque. And Thorley makes some highly regarded stuff.

California Jim said:
Magnaflow Cat-Back exhaust. Another nice system that is all stainless steel and comes with a nice 4" polished stainless tip. Their tech people assured me I will be pleased with the sound as their muffler is insulated and double walled to reduce/eliminate that dreaded "droning" sound.
Time will tell about the in-cab resonance. Seems like most of the LS1-based GM motors suffer from that problem. I know there are a LOT of problems with the 6.0 and aftermarket exhaust systems. That's the biggest reason I haven't done it yet; I don't want any droning.

Make sure you get a side exit too. If you have that dumping straight out the back you'll HATE the towing experience because the exhaust sound will bounce off the trailer and right back at you. That can be maddening.

California Jim said:
K&N air filter. Hey, gotta have it.
While I'm no fan of K&N it is a good idea to make some type of intake mod. After all, if your motor can't inhale any better then it surely won't be taking full advantage of all those fancy new exhaust mods.
 

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Thanks Jim:

Yea, the noise level of the muffler is my biggest concern and only taking the plunge will tell if it's acceptable or not. I'll soon know as the cat-back will arrive any day now and I'll probably install it before the headers which are on backorder for ceramic plating. I did by a swept side exhaust which exits the vehicle in the stock location.

The tech guy at Thorley told me something interesting. When I asked him about the noise level of the headers he said essentially ZERO
He told me that the headers will produce no more noise level than the stock cast iron manifolds that are in there now. And the muffler is basically the only regulator/producer of exhaust sound. Interesting.

I'll get a chance to hear the difference as the two components will be installed at different times.

As it stands right now the headers probably won't be here in time for my Yosemite trip. So I will be using the Magnaflow cat-back and K&N on this trip. I'll report back here with my findings.
 

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California Jim said:
The tech guy at Thorley told me something interesting. When I asked him about the noise level of the headers he said essentially ZERO
He told me that the headers will produce no more noise level than the stock cast iron manifolds that are in there now. And the muffler is basically the only regulator/producer of exhaust sound. Interesting.
He's mostly correct. Headers can indeed affect the sound -- making the exhaust note louder or softer -- but the muffler is, by far, the biggest contributor towards the noise level. And new headers will often times make the exhaust note change, because of the different air dynamics they cause.

Did you tell the people you ordered the muffler from that you were installing long tube headers? That might make a difference in the muffler you need, seeing as how they will produce more back pressure then shorties (or the stock headers) will.
 
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