2004 6.0 NV4500 Tahoe

[Dantheman1540]

I can't answer about the chambered discrepancy. Unless there's an area in it that doesn't have packing behind the perforated core to let sound bounce around in there?

I've never given the packing of the AP a thought. I just did a little digging and found a review on Summit where a buyer said it was fiberglass. I did a one-year comparison video for the 18" and couldn't tell a difference. But, that's with the chilly ~500-degree exhaust from an NA 5.3.

Fiberglass isn't bad Magnaflow and Vibrant both use it but they layer stainless steel mesh first to take the majority of the heat while also absorbing some sound. The AP would probably survive just fine unless it was very close to the downpipe on a turbo or the collectors on a blown setup.

I am on hold with Magnafuxk now.

 

[Dantheman1540]

Wow the customer service guy told me the giant 7x7x30 will be louder than my current muffler. He said it is not straight through there is no packing whatsoever its just 3 chambers and will be raspy and pop like crazy. I kinda don't believe him, that picture is directly from a verified purchaser and it is very obviously straight through. However, some other reviews I've found are very conflicting on sound level and many people say its ridiculously loud.

He said the quietest straight through muffler is 12589 which is the same thing I have now but single I/O with double the packing.

About to call flopro.

 

[Dantheman1540]

Well before I could dial the Flopro number they responded to the email I sent Saturday. I asked about the difference between the three 9x12x24 models they have.
Their response:
"Howdy, the real only difference the chamber size inside and the size of the pass through holes in the chambers. The 2506 and 2505 will flow slightly more than the 2500. The 2506 outlets are the same as the 2500 which flow slightly more on one bank than the other. The 2505 does not have the offset orientation of the outlets and will flow the same for both side."

I think I'm leaning towards their 2505 now as the 2500 was almost perfect it was just lacking a hint of sound and I didn't like how it necked down. Plus I think I can fit the ultra quiets in if need be.

 

[Dantheman1540]

Yes I know I'm talking to myself at this point.


I called Flopro and the same guy that emailed me picked up the phone (He sounds like a Canadian, but I won't hold it against him). He was so much more knowledgable and friendly than the Magnaflow guy I talked to him for about 10 minutes. The 2505 not only stays true to 3" all the way through, but it also has larger perforations in the baffle tubes. Another major difference contrary to the website which he told me is wrong the inlet and outlet are both in the same spot front to back. The other models 2500/2506 have one of the outlets offset which forces the majority of the exhaust out a single outlet until the restriction becomes too much and then forces it out both sides. The 2505 does not have that restriction. He said they sell a ton of the big oval mufflers for guys that get sick of trying to find another brand that doesn't kill them once they do headers and delete cats.

I just ordered a 2505 and it should be here Friday just in time to use my neighbors lift and try to get this thing installed myself.

 

[iamdub]

He said the quietest straight through muffler is 12589 which is the same thing I have now but single I/O with double the packing.

The 12589 is what is widely known as the "stock but slightly meatier tone" replacement for our rigs. It matches the factory center in/offset out configuration. The XS2579 I have is the clone of the MF 12579. Same muffler, but with a center in/center out configuration. I'd have to agree with the MF rep. I'd say my Tahoe, with cats in place, would sound almost 100% stock with the 12589 or 12579 (or the AP clones).

I kinda get what you're saying with "I was guessing that since I have twice the area for the sound and air to escape from that I would need either the same amount of mufflers as someone with a single exhaust or possibly more because it would be like running a 4cylinder on a single 3" which usually shrieks". But, most 4-cylinders would be 1.x - 2.5ish liters. Looking at yours like two 4-cylinders, they'd each be 3 liters, which is about what many small V-6s are. Although oversized unless it's boosted, the V-6 seems to do a little better than the 4-cylinder with the 3" exhaust. Yours, having an extra cylinder in that 3 liters of displacement, would produce a lower-pitched note which is easier to muffle. Also, you should have an H-pipe ahead of the mufflers. This would balance the sound and the connecting pipe, being perpendicular to the flow, would act a little as a muffler itself with some minor wave manipulation. An X-pipe would balance sound as well, but it's geared more towards and wouldn't manipulate the wave any. Well, aside from any that may collide in the X.

 

[iamdub]

Yes I know I'm talking to myself at this point.


I called Flopro and the same guy that emailed me picked up the phone (He sounds like a Canadian, but I won't hold it against him). He was so much more knowledgable and friendly than the Magnaflow guy I talked to him for about 10 minutes. The 2505 not only stays true to 3" all the way through, but it also has larger perforations in the baffle tubes. Another major difference contrary to the website which he told me is wrong the inlet and outlet are both in the same spot front to back. The other models 2500/2506 have one of the outlets offset which forces the majority of the exhaust out a single outlet until the restriction becomes too much and then forces it out both sides. The 2505 does not have that restriction. He said they sell a ton of the big oval mufflers for guys that get sick of trying to find another brand that doesn't kill them once they do headers and delete cats.

I just ordered a 2505 and it should be here Friday just in time to use my neighbors lift and try to get this thing installed myself.

I though you wanted a straight-through style muffler? Aren't these "turbo" style? That would explain the need for the larger perforations.

 

[Dantheman1540]

The 12589 is what is widely known as the "stock but slightly meatier tone" replacement for our rigs. It matches the factory center in/offset out configuration. The XS2579 I have is the clone of the MF 12579. Same muffler, but with a center in/center out configuration. I'd have to agree with the MF rep. I'd say my Tahoe, with cats in place, would sound almost 100% stock with the 12589 or 12579 (or the AP clones).

I kinda get what you're saying with "I was guessing that since I have twice the area for the sound and air to escape from that I would need either the same amount of mufflers as someone with a single exhaust or possibly more because it would be like running a 4cylinder on a single 3" which usually shrieks". But, most 4-cylinders would be 1.x - 2.5ish liters. Looking at yours like two 4-cylinders, they'd each be 3 liters, which is about what many small V-6s are. Although oversized unless it's boosted, the V-6 seems to do a little better than the 4-cylinder with the 3" exhaust. Yours, having an extra cylinder in that 3 liters of displacement, would produce a lower-pitched note which is easier to muffle. Also, you should have an H-pipe ahead of the mufflers. This would balance the sound and the connecting pipe, being perpendicular to the flow, would act a little as a muffler itself with some minor wave manipulation. An X-pipe would balance sound as well, but it's geared more towards and wouldn't manipulate the wave any. Well, aside from any that may collide in the X.

That's exactly what I was getting at with the 4cylinder talk. Thats a good point that its a deeper tone that should be easier to muffler.

I also agree a 12589 with everything else stock would likely sound close to stock but as soon as other restrictions are removed its far to loud for me at least.

I do not and really don't have a way to do an H pipe myself but It has been a thought after watching the 6 different "Engine Masters" episodes on muffler differences and seeing that an H/X pipe makes a significant difference at lower RPM.

Also yes I did/do want straight through but it is somewhat unobtainable with the low sound level I'm after. At least with the space provided and the amount of money I'm willing to throw at it. Also like we agreed earlier dual 3" is way more than this motor can fill and cause a restriction with. For the future when it may see boost engine masters showed that the boost did not care about the muffler and still made amazing power.

Lastly speaking to the flopro rep made me really want to get another 2505 and cut it open. He said they are significantly more free flowing compared to the 2500 and 2506.

 

[iamdub]

...For the future when it may see boost engine masters showed that the boost did not care about the muffler and still made amazing power.

Love me some Engine Masters.

Any thoughts on how you would you boost it? Turbo? That alone would make for a great muffler so it'd be extra quiet if you can manage to get it where you want it now, NA.

 

[Dantheman1540]

Love me some Engine Masters.

Any thoughts on how you would you boost it? Turbo? That alone would make for a great muffler so it'd be extra quiet if you can manage to get it where you want it now, NA.

It's really a toss up and I have 3 ideas.

1: Basic T6 Trick turbo kit nothing crazy let him spec a turbo that would work well for towing and leave it on low boost because this motor has unknown miles and gen 3 rods.

2: Put turbo on my Silverado and put the wonderful torque monster TVS1900 on the Tahoe but keep it running 6 rid belt drive and around 8-10psi. Not max effort like it is now.

3: Torqstorm really looks great makes plenty of power for me has amazing customer service and is cheap!!!!!!



But I think a turbo is what I lean towards now because quiet, efficient and makes cool noises.

 

[iamdub]

My thoughts:

You already have a blower, so switch it up and go turbo.

The Silverado is a 4x4 so the instant torque from the blower makes sense here. And it's already installed.

The turbo on the Tahoe makes more sense because it's your daily so you can hear them cool noises err'day and the slight bit of lag might help not blow the tires off so easily since it only has two wheels pushing it.


...Never heard of Torqstorm. Googling...