TexasSteve

Took the GTA for a spin today & I can't stand the stock silent exhaust on my truck anymore! Gonna go look into putting on True Duals, no single in/dual out muffler for me.

Cats will be staying & headers are not happening right now. I'm thinking 2.5" pipe & mufflers would be more than adequate for the 4.8 since I won't be supercharging, swapping to a 6.0 or doing big internals for quite awhile now. X-pipe may or may not happen at first.

Please no suggestions of removing the cats or adding headers now. Cats are staying since I wanna drive it, not pay double the Inspection cost to a crooked Inspector & I don't wanna get my truck impounded off the roadside. And unless you wanna buy me headers? I can't afford headers right now. Gotta talk to the shop about me supplying the x-pipe or if he'd rather build it himself.

So.....2.5" for true duals sound right or go on up to 3"?

usmc3521

iTrader: (2)

2.5in or 3in un-balanced or balanced will just about destroy your low-end without mods, high stall TC, to the trans. I run true 2.5in duals on mine, however, I'm also running tri-y's as a balancing tool along with a 3k stall. If you just want more noise, I would suggest just doing a muffler. Probably not what you want to hear, but if you're planning on doing mods in the future, a muffler swap may end up saving you money in the long run.

TexasSteve

Thanks for the info. I don't wanna lose what low end I have, 4.8s aren't the strongest on the bottom end but I don't have any real need to tow. But I do love the bottom end grunt of vehicles moving NOW & not later so don't wanna lose any bottom end. My GTA really spoiled me on loving bottom end torque! LOL

But I also love the sound of true duals vs just the split outlets from 1 muffler.

This is why my mods happen slowly.....My indecision & not wanting to spend the money to do things twice because I wasn't happy with the first choice.

usmc3521

iTrader: (2)

I understand man. Trust me, it took me a year to decide which headers I wanted. In my opinion, these are the mods that should be done to make a 4.8 competitive in no particular order.

1). Custom tune
2). Gears
3). Exhaust
4). Beef up the trans + High stall converter
5). Cam/internals
6). Supercharger/N20

Or you can bypass headers, gears, N2O and supercharging, save up, and throw a Turbocharger on there. There's 1001 ways to mods these trucks and no two are the same. Just take your time and do your homework.

Scrapin'4.8

iTrader: (3)

I suggest a dual in/dual out magnaflow with the built in x pipe. I've ran several vehicles with this muffler. Save a lot of weight and money from only having to buy 1 muffler and not buy an x pipe. I actually put on a jones max flow muffler MF2268, which is the same thing as a magnaflow (magnaflow PN is 12268) and it's half the cost.

TexasSteve

I won't be going as far as cam.trans build etc. Maybe just for the posi rear (thinking Lock Right instead of True Trac if i can't find a posi rear or keep my stocker) and the bigger brakes of a later model. The GTA takes care of my speed fix. The Sierra will stay as my reliable "easy" daily driver.


I looked through lots of youtube videos for various muffler sounds.....Borla/Magnaflow/Flowmaster (i love the Super 44!)... & after looking at various dyno run results in a magazine report I decided that while the Borla XS did make the best hp/torque, I preferred the sound of the Flowmaster Super 44, like my old Camaro, & the 6-8 hp/3-4 lb fts loss was worth it by going with Flowmaster/Magnaflow vs the double cost Borla XS mufflers.

After looking through the videos, that actually had decent sound in them, I came to the conclusion that 90% of the people didn't know how to make good videos despite the whole point of them uploading them was to show off their sounds. I'm not building an all out performance vehicle striving for that last .5 hp, so the better sounding muffler wins.

Never heard of Jones Max but am looking through the 'net & videos, not much with NBS though. How does yours sound? Got a good video of the sound?

TexasSteve

A question about our cats though......

Is there 2 pre-cats & 1 cat? That would explain why all the kits I see for sale are all single in/dual out mufflers. Or is it 2 just small cats, then the muffler? Unfortunately I am not physically able to get under my truck & look or I could see for myself, so I'm turning to you guys to hopefully know what is on my truck. Bone stock afaik.

03BlackSSS

The dual in/out mufflers are great, especially magnaflow's with the built in x-pipe, although the x-pipe in the muffler is too far back in the system to gain any scavenging. It's more for a smoother more balanced sound.

Just swapping out the muffler in his case would be the direction I would go, save up for later when you do other mods and can support a larger exhaust system.

nonnieselman

iTrader: (10)

There are two small cats.. one on each bank of the Y pipe.. then it goes to 1 pipe at the Coupling for the cat back. Then the muffler.

TexasSteve

Yeah,....But I meant is there a 3rd cat after the Y? Or just the 2 small cats? I think the LS1 F-bodies had 2 pre-cats & then a single cat.

Meaning....Would it be illegal to build a True Dual like was build back in the 60s? If it is legal, then why are none of the manufacturers building dual pipe duals? Why are they are dual tailpipe singles? Sure, 2 pipes weigh more than 1 so "less weight is better" but.....