2018 Tahoe premier flowmaster 40 exhaust

[Ghost10]

Good morning, first off I hope I am placing this in the right area. I purchased a 2018 Tahoe premier last year finally got around to at least dropping the stock muffler and welding on a flowmaster 40 series with flapper removed and stock resonator still inline it sounds good BUT a lot of low end bass from the exhaust inside the cabin which I am starting to not like.

 

[Ghost10]

Pretty much unless I'm on the gas it makes a deep low rumble inside the cabin. I'm thinking I need to remove the resonator (big can on the back) and add 3" pipe with a nice 4" tip to help this

 

[avalonandl]

You need to put the resonator/flapper back on to get rid of the drone from the cylnder change. Alternatively you can try the Range device which keeps it in V8 mode. But you lose mpg....

 

[iamdub]

Pretty much unless I'm on the gas it makes a deep low rumble inside the cabin. I'm thinking I need to remove the resonator (big can on the back) and add 3" pipe with a nice 4" tip to help this

That "deep low rumble inside the cabin" is drone. It's common with louder aftermarket mufflers and especially chambered styles and ESPECIALLY Flowmaster 40s. Changing pipes, adding tips, etc. won't do anything to help. A larger rear pipe could actually make it worse as well as reduce low-end power. You can (A) change the muffler or (B) attack the drone specifically if you like the sound of the muffler but just want to eliminate the drone. The second option is cheap and relatively easy, but requires math... How big a nerd are ya?

 

[Ghost10]

That "deep low rumble inside the cabin" is drone. It's common with louder aftermarket mufflers and especially chambered styles and ESPECIALLY Flowmaster 40s. Changing pipes, adding tips, etc. won't do anything to help. A larger rear pipe could actually make it worse as well as reduce low-end power. You can (A) change the muffler or (B) attack the drone specifically if you like the sound of the muffler but just want to eliminate the drone. The second option is cheap and relatively easy, but requires math... How big a nerd are ya?

Well that kind of sucks so I spent 260 bucks to add on a Flowmaster 40 for some obnoxious low rumble and crappy hum while cruising

 

[Ghost10]

You need to put the resonator/flapper back on to get rid of the drone from the cylnder change. Alternatively you can try the Range device which keeps it in V8 mode. But you lose mpg....

as far as the range device goes I can just stick it manual shifting but it’s still a constant hum
No matter if I’m on the freeway or cruising through the city it’s it’s a hum I was thinking if I was to remove the resonator that would help with back pressure on that super 40 that’s causing the ham

But it sounds like I just wasted money even though I did a lot of research a lot of reading watched a lot of videos

 

[iamdub]

Well that kind of sucks so I spent 260 bucks to add on a Flowmaster 40 for some obnoxious low rumble and crappy hum while cruising

C'mon, man! You've been a member here since 2017- you should already know to ask the TYF fam before performing any mods!

All is not lost. Known good mufflers are ~$60 and, if you can change your own oil, you can install it yourself with a hack saw and clamps. Maybe an adapter or two. Or, if you're committed to the Flowmaster 40, you can add a Helmholtz chamber to the exhaust to kill the drone. It's just an extra exhaust pipe that comes off the existing pipe, turns 90°, and runs parallel to the existing pipe with the end capped off. It just has to be a specific length. A couple of members here have done it with great success. This would require the pipe and welding, so it's not a driveway job for most.

 

[iamdub]

as far as the range device goes I can just stick it manual shifting but it’s still a constant hum
No matter if I’m on the freeway or cruising through the city it’s it’s a hum I was thinking if I was to remove the resonator that would help with back pressure on that super 40 that’s causing the ham

But it sounds like I just wasted money even though I did a lot of research a lot of reading watched a lot of videos

So the drone isn't specific to 4- or 8-cylinder mode. The resonator is a Helmholtz chamber designed to attack the frequencies created when in 4-cylinder mode. But, it is designed for "clean up" after the muffler, which has been changed, so it is much less effective. Removing it would make it 100% ineffective. It's not a factor of too little or too much back pressure. It's a factor of reduced muffling and the resulting increase in sound volume and its resonance.

 

[Ghost10]

C'mon, man! You've been a member here since 2017- you should already know to ask the TYF fam before performing any mods!

All is not lost. Known good mufflers are ~$60 and, if you can change your own oil, you can install it yourself with a hack saw and clamps. Maybe an adapter or two. Or, if you're committed to the Flowmaster 40, you can add a Helmholtz chamber to the exhaust to kill the drone. It's just an extra exhaust pipe that comes off the existing pipe, turns 90°, and runs parallel to the existing pipe with the end capped off. It just has to be a specific length. A couple of members here have done it with great success. This would require the pipe and welding, so it's not a driveway job for most.

So what am I looking to spend to get this sounding good.

Here's my take so far.
The drone sucks, I can't hear the exhaust when past 3k rpm as in no mids or highs.

I want to hear my v8 but not sound like a dragster as it is the family wagon on weekends and days off it is a daily driver and I do want to hear my v8. If I had the cash a corsa exhaust would be perfect but I don't have that kind of money so if I can do this on a budget that would be awesome

 

[iamdub]

So what am I looking to spend to get this sounding good.

Here's my take so far.
The drone sucks, I can't hear the exhaust when past 3k rpm as in no mids or highs.

I want to hear my v8 but not sound like a dragster as it is the family wagon on weekends and days off it is a daily driver and I do want to hear my v8. If I had the cash a corsa exhaust would be perfect but I don't have that kind of money so if I can do this on a budget that would be awesome

There are a handful of favorites that produce a great sound and no drone. I can only speak for what I have experience with. Also, I tend to be cheap since the name embossed into the muffler case or how much money was spent on it doesn't mean shít to the engine farts blowing through it. The tried-and-true crowd favorites are the Magnaflow #12589 (22") or the "one notch higher" #12259 (18"). Magnaflows are nice, but pricey, so I opted for the clone made by AP Exhaust, from their Xlerator line. When my exhaust was otherwise stock (manifolds, cats, etc.), I had the AP XS1259, AP's clone of the Magnaflow #12259. IMO, it was absolutely perfect. It only came alive when on the throttle, and I'd lower the right rear window when next to a wall just to hear it. When cruising, you'd hear a distant V8 hum if you were listening for it. NO drone at all. It was about $33 on Amazon back when I bought it, and is currently $62. Their clone of the Magnaflow #12589, which is the same muffler just with a 4" longer body, is $63 on Amazon (XS2589). You could call this a "stock+" muffler since it's almost as quiet as stock, just with a hair more attitude at idle and when cruising, but would have a decent bark with hard throttle. There are similar ones, if not the exact same muffler in a different box, branded as Jones MAX Flow. Their part numbers are basically the same as AP's, such as the 22" Jones MF2589 ($84 at Summit) and the 18" MF1259 ($51 at Summit). Having a Flowmaster 40, I think you'd prefer the one-step-louder 18". The Jones MF1259 is the cheapest of the bunch, but look at shipping, etc. and compare to Amazon.

 

[Ghost10]

There are a handful of favorites that produce a great sound and no drone. I can only speak for what I have experience with. Also, I tend to be cheap since the name branded onto the muffler or how much money was spent on it doesn't mean shít to the engine farts blowing through it. The tried-and-true crowd favorites are the Magnaflow #12589 (22") or the "one notch higher" #12259 (18"). Magnaflows are nice, but pricey, so I opted for the clone made by AP Exhaust, from their Xlerator line. When my exhaust was otherwise stock (manifolds, cats, etc.), I had the AP XS1259, AP's clone of the Magnaflow #12259. IMO, it was absolutely perfect. It only came alive when on the throttle, and I'd lower the right rear window when next to a wall just to hear it. When cruising, you'd hear a distant V8 hum if you were listening for it. NO drone at all. It was about $33 on Amazon back when I bought it, and is currently $62. Their clone of the Magnaflow #12589, which is the same muffler just with a 4" longer body, is $63 on Amazon (XS2589). You could call this a "stock+" muffler since it's almost as quiet as stock, just with a hair more attitude at idle and when cruising, but would have a decent bark with hard throttle. There are similar ones, if not the exact same muffler in a different box, branded as Jones MAX Flow. Their part numbers are basically the same as AP's, such as the 22" Jones MF2589 ($84 at Summit) and the 18" MF1259 ($51 at Summit). Having a Flowmaster 40, I think you'd prefer the one-step-louder 18". The Jones MF1259 is the cheapest of the bunch, but look at shipping, etc. and compare to Amazon.

This is very over whelming for me lol!
So pretty much the series 40 is not good for my truck and the only way to get that v8 Chevy sound I want is to swap it out? Curious if I run it for 30 days the sound might mellow out some or do I need to just realised that the series 40 was a bad idea and I ******* my self ?

 

[iamdub]

This is very over whelming for me lol!
So pretty much the series 40 is not good for my truck and the only way to get that v8 Chevy sound I want is to swap it out? Curious if I run it for 30 days the sound might mellow out some or do I need to just realised that the series 40 was a bad idea and I ******* my self ?

Don't overcomplicate it!

The 40 series is just a loud style of muffler- on your Tahoe, on a '93 Silverado... anything with a small or large engine. It's a chambered/baffled muffler so it just bounces sound waves around rather than muffling them. The sound waves bouncing around do collide with others, so there's some small amount of muffling from the cancellation. But it's just cancelling whatever frequency of waves that are colliding. Which, obviously, are not the low frequency notes that carry longer distances and resonate throughout the cabin. There's nothing inside to "break in", so the sound won't change over time unless a baffle actually breaks (failed weld). Then, it'd likely be a little louder and with a rattle.

All you gotta do is cut out the Flowmaster and replace it with another muffler that will do what you want. It's not rocket surgery. Did you weld in the Flowmaster or had a shop do it? You said you spent $260, so I hope that was on parts and labor and not just on the muffler! Regardless, I'm sure the Flowmaster has 3" inlet and outlets. It's also shorter than the stock muffler, so there would be a length of pipe welded in to make up the difference. Cut out the Flowmaster and however much of the make-up pipe necessary to splice in the new muffler, then connect it with the necessary couplers and cinch it down with clamps. It'd take probably an hour, tops, with a good hack saw blade and a ratchet to tighten the clamps. You could sell the Flowmaster to recoup the cost or most of the cost of the new muffler.

 

[Ghost10]

Don't overcomplicate it!

The 40 series is just a loud style of muffler- on your Tahoe, on a '93 Silverado... anything with a small or large engine. It's a chambered/baffled muffler so it just bounces sound waves around rather than muffling them. The sound waves bouncing around do collide with others, so there's some small amount of muffling from the cancellation. But it's just cancelling whatever frequency of waves that are colliding. Which, obviously, are not the low frequency notes that carry longer distances and resonate throughout the cabin. There's nothing inside to "break in", so the sound won't change over time unless a baffle actually breaks (failed weld). Then, it'd likely be a little louder and with a rattle.

All you gotta do is cut out the Flowmaster and replace it with another muffler that will do what you want. It's not rocket surgery. Did you weld in the Flowmaster or had a shop do it? You said you spent $260, so I hope that was on parts and labor and not just on the muffler! Regardless, I'm sure the Flowmaster has 3" inlet and outlets. It's also shorter than the stock muffler, so there would be a length of pipe welded in to make up the difference. Cut out the Flowmaster and however much of the make-up pipe necessary to splice in the new muffler, then connect it with the necessary couplers and cinch it down with clamps. It'd take probably an hour, tops, with a good hack saw blade and a ratchet to tighten the clamps. You could sell the Flowmaster to recoup the cost or most of the cost of the new muffler.

I had a shop do it thebdudde is a old guy he refused to straight pipe it like I originally wanted lol glad I didn't though because I'm in Cali and I'm sure it's illegal and would just be super loud. I'll just go back to the guy next week and hopefully he's cool with helping me figure it out without dropping another couple hundred

 

[iamdub]

I had a shop do it thebdudde is a old guy he refused to straight pipe it like I originally wanted lol glad I didn't though because I'm in Cali and I'm sure it's illegal and would just be super loud. I'll just go back to the guy next week and hopefully he's cool with helping me figure it out without dropping another couple hundred

Just get this: https://www.summitracing.com/parts/jex-mf1259 or this: https://www.amazon.com/AP-Exhaust-Products-XS1259-Muffler/dp/B004A5QJN8 ($7 cheaper and might arrive sooner). Bring it to him and just say "please help me" in your best pathetic voice.

 

[Ghost10]

Just get this: https://www.summitracing.com/parts/jex-mf1259 or this: https://www.amazon.com/AP-Exhaust-Products-XS1259-Muffler/dp/B004A5QJN8 ($7 cheaper and might arrive sooner). Bring it to him and just say "please help me" in your best pathetic voice.

Sound clips?
Do you recommend I remove the resonator ?

 

[iamdub]

Sound clips?
Do you recommend I remove the resonator ?

I have some of when it was stock with no resonator, when I first installed the XS1259 (same as Jones MF1259), then exactly a year later (plus about 23 minutes ). Lemme find some links...

Stock, no resonator:

With AP XS1259:

AP XS1259 after "broken in":

It has to be the way the camera picked up the sound, but the "stock" video sounds louder. This is not the case.


As for losing the resonator, I couldn't tell any difference when driving. I MIGHT have heard a slightly healthier grumble when idling if I really listened for it, but that could've just been in my head. Besides, it's for killing an exhaust note when in V-4 mode, and it only idles in V-8 mode. Really, I removed the resonator for aesthetics. It's very visible from behind and I wanted a cleaner-looking, snazzier tip. That little project is outlined in the first page of my build thread: https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/post-1115977

Yes, mine's a GMT900, but the engine size, firing order, etc. is the same and the exhaust stuff is all similar enough to be comparable to your generation.

 

[Ghost10]

I have some of when it was stock with no resonator, when I first installed the XS1259 (same as Jones MF1259), then exactly a year later (plus about 23 minutes ). Lemme find some links...

Stock, no resonator:

With AP XS1259:

AP XS1259 after "broken in":

It has to be the way the camera picked up the sound, but the "stock" video sounds louder. This is not the case.


As for losing the resonator, I couldn't tell any difference when driving. I MIGHT have heard a slightly healthier grumble when idling if I really listened for it, but that could've just been in my head. Besides, it's for killing an exhaust note when in V-4 mode, and it only idles in V-8 mode. Really, I removed the resonator for aesthetics. It's very visible from behind and I wanted a cleaner-looking, snazzier tip. That little project is outlined in the first page of my build thread: https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/post-1115977

Yes, mine's a GMT900, but the engine size, firing order, etc. is the same and the exhaust stuff is all similar enough to be comparable to your generation.

Thanks for posting those videos.
Found the XS1259 For $58

Just curious why are most of you guys never recommending flowmaster, is it just over priced branding ?

 

[STORMIN08]

You need to put the resonator/flapper back on to get rid of the drone from the cylnder change. Alternatively you can try the Range device which keeps it in V8 mode. But you lose mpg....

the lose of MPG is a completely false statement...mine lost no MPG, and since going with a tuner...even lifted with larger tires, it is maintaining the same mileage


the type of muffler, Flowmaster particularly has a noticeable drone on most SUV's...even our older 99 with a 7.4, drones. that truck has been the test bed for several exhaust cat backs...i have not changed on exhaust on an SUV since. my 2011 tahoe received the SLP resonator delete, and that was the best sounding one to date.

 

[Ghost10]

BTW I just learned yesterday that tow haul mode is amazing when not towing anything.

 

[Ghost10]

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