Suburban exhaust

[Chromo Infesto]

Hi everyone. I've got a 1989 GMC Suburban SLX 2500 with the 350. I'm looking to modify the exhaust but, I'm not sure how to go about it. What to you guys think I should go with? Keep it single exhaust and just replace the stock muffler with a performance muffler, or go true dual? And what kind of mufflers do you guys like? Thanks!

 

[1987 GMC Jimmy]

Hi everyone. I've got a 1989 GMC Suburban SLX 2500 with the 350. I'm looking to modify the exhaust but, I'm not sure how to go about it. What to you guys think I should go with? Keep it single exhaust and just replace the stock muffler with a performance muffler, or go true dual? And what kind of mufflers do you guys like? Thanks!

Just curious, is it an R or a V Suburban? I'm glad you want to dig into the exhaust because that's a great place to correct some factory pitfalls. I'll say that the most important thing you could do is lose the manifolds and go to a long tube header setup with an upgrade to a heated O2 sensor. That motor has trouble exhaling the way it's set up originally. After that, if you can find a performance Y pipe to bridge it all together, and that'd keep it simple. If you can't, I'd see about getting one made. If you favor the look of duals, and you have the money to do it, that's perfectly okay. It'll project your sound in a more 180* rearward manner as opposed to the 180* sideward manner if that's of any consideration. I have catless true duals on my Jimmy, but I don't know if that would fly in NH. One or two pipes, I'd consider a universal high flow cat(s) and whatever muffler you want. I don't think it matters brand-wise. You can get a good sound for cheap or pricey, whatever good sound means to you. I like it in the moderate range favoring quieter. Maybe like 4-5/10 loudness. I do like to have a rumble in my tone so people notice me without being offended and know I'm an old truck and not Jane Q. Soccermom taking the kiddies to school. I like to think of my preference as comparable to Jesus in tuxedo t-shirt. It says, "I want to be formal, but I'm here to party, too." Some people like it quiet so they can minimize external noise and hear music and some people like it moderately or aggresively loud. Everyone's gonna suggest differently so I suggest listening to all the Borlas, Flowmasters, Magnaflows, and Cheapos you can find audio clips for and choose what complements your preferences. Performance isn't gonna come from the muffler, though. The biggest preference I have here is trying to keep a Y pipe that corresponds to the header exit diameter, even if you have to get it custom made, because that'll end up having fewer parts to keep track of and reduce the cost for what you'd have to spend in duplicates of what you already have.

 

[Chromo Infesto]

It's a V2500. In the end, it really does come down to money. I'm probably going to end up with just single exhaust. I just want a little more volume out of it. Thanks for the reply! I'll take all of it into consideration.

 

[1987 GMC Jimmy]

I gotcha. Yeah, if you're just looking to modify the sound, I'd just search a bunch of exhaust clips of Brand X, Y, or Z muffler behind a Small Block Chevy. If you have any dough to spare, definitely consider the headers, the O2 sensor, and the Y pipe.

 

[yevgenievich]

On stock TBI there is not much gain with headers unless you start modifying the rest of the motor. Heated O2 sensor will help as it is way down on the y pipe. There is also two versions of y pipes that I have seen. One is a chocking one that should be replaced and the one I have on my suburban appears to be a much better design similar to aftermarket y's

 

[skysurfer]

Keep in mind that you have a Suburban when you're getting recommendations on mufflers. That Magnagrowl Super Boomer muffler someone might suggest may sound great to the owner of a pickup, but the extra noise gets old quick when your passenger compartment is sitting right on top of it.

 

[yevgenievich]

+1 on the quieter muffler. I have a generic replacement muffler, but it still has more drone than I like. Been trying to figure out what biggest/quietest muffler to stuff and how to do it for a while. The much louder turbo muffler I had on my 85 short bed appeared to be less loud at highway speeds inside compared to what I have with the suburban

 

[glockholiday]

Here's my 88' TBI 350 with 3 different versions. All 3" single pipe.

#1 All straight piped, no CAT no muffer. Badass but obnoxiously and uncomfortably loud.
https://www.youtube.com/watch?v=aYUX_6RXZnk

$20 for a 4' piece of 3" piece of pipe from a local shop

#2 No CAT and Thrush welded muffler. Sounded good at idle but got quiet at higher rpm and had a moderate drone when cruising 55.
https://www.youtube.com/watch?v=HuThXpMprWI

I paid $30 for the Trush muffler https://www.amazon.com/gp/product/B001S8GWZA/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

#3 New CAT and 24" Glass Pack, perforated style not louvered. Don't get louvered style they restrict a lot of flow. I've been running this for months and think I'm going to stick with it.
https://www.youtube.com/watch?v=dIGYJXJmsLo

Paid $60 for the Glass Pack https://www.amazon.com/gp/product/B001S8GWZA/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
And $60 for the CAT at a local exhaust shop.

I'm a big fan of just swapping the muffler, if it's already 3" that's plenty of flow, just find the sound you like. I was in it under $200 and tried 3 different versions, you'll be in it a little more if you have a shop do the work but you don't have to buy the parts from them.

 

[glockholiday]

Or LMC truck has 2 full versions $200 for dual glasspacks or $240 for dual Turbo mufflers http://www.lmctruck.com/icatalog/csb/full.aspx?Page=161 If you need to pass emissions you'll have to add CATs.