LS swap exhaust too loud.... Options - The 1947 - Present Chevrolet & GMC Truck Message Board Network

04ls1gto · 10-22-2018, 08:35 PM

Just got my 71 suburban out for the maiden voyage after swapping a ly6 6.0 and 6l90. Exhaust setup is speed engineering 1 7/8 long tubes, magnaflow mufflers to true dual 2 1/2" SS out the back. It is way to loud, do I swap mufflers? Add h pipe? Add resonators or maybe a combination off all three. Let me know what your setup is and how you like it

**mongocanfly** · 10-22-2018, 08:41 PM

Hard to imagine it's to loud in a burb...resonators may help...diff mufflers would also make a diff....I have a set of walker super quite for mine...I have a set of magflow...not magnaflow..on my other truck dumping in front of the axle and it's not to loud...

Overdriven · 10-22-2018, 09:20 PM

Magnaflow mufflers are available in different lengths and styles (traditional oval shape, round), what do you have? H pipe doesn’t have much effect on sound level. Swapping mufflers is probably your best bet, chambered mufflers are usually quieter.

04ls1gto · 10-22-2018, 09:32 PM

Here's what I have

https://www.summitracing.com/parts/mpe-11256

SBTork · 10-23-2018, 09:43 AM

Quote:

Originally Posted by 04ls1gto

Here's what I have

https://www.summitracing.com/parts/mpe-11256

I have a similar setup on my '85 Suburban. Mine has TBSS manifolds, 2 1/2 pipes, 2 magnaflow mufflers (exactly the same as yours) and I have it dumping just above the rear bumper. Mine is pretty loud, excessively loud at about 2,100-2,400 rpm lol. But it's suuuper quiet at idle and under light throttle around town. I've been thinking and I might switch to the larger case magnaflow mufflers in the future. I have 1 single larger case magnaflow muffler on my '83 K5 and it's a lot quieter but still has a good tone. I'd recommend you switching to some larger case magnaflow mufflers and I bet you'd be happy with that.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

davepl · 10-23-2018, 10:04 AM

Mine's near silent with manifolds and cats. It's the headers, for a start, I think. I have Dynomax and they're fairly quiet until opened up.

04ls1gto · 10-23-2018, 11:15 AM

I ordered a set of resonators to install. well see if that helps. There is no room for a bigger muffler the way its setup unfortunately

Willie Makeit · 10-23-2018, 11:54 AM

6.0 liter LS engines are very very hard to make quiet without the use of cats and/or resonators.

SBTork · 10-23-2018, 12:32 PM

Quote:

Originally Posted by 04ls1gto

I ordered a set of resonators to install. well see if that helps. There is no room for a bigger muffler the way its setup unfortunately

That makes sense, good idea. Let us know how the resonators help!

72MARIO · 10-23-2018, 09:29 PM

Both my swaps are very quiet. Both have camaro manifolds and catalytic converters. The suburban has super 40 flowmasters I can hardly hear it now before with the 327 it was abnoxous.

The 1967 truck has magnaflows and its wisper quiet catnt hear it at all with the wondows up

Rich84 · 10-24-2018, 08:05 AM

My 6.0 has 2.5 dual exhaust out behind the rear tires and was way too loud with 40 flowmasters. The droan was hideous. Much better with the added resonators.

04ls1gto · 10-24-2018, 12:25 PM

Quote:

Originally Posted by Rich84

My 6.0 has 2.5 dual exhaust out behind the rear tires and was way too loud with 40 flowmasters. The droan was hideous. Much better with the added resonators.

Headers of manifolds? Resonators should be here today and plan is to install this weekend. Hopefully my brake issue is something simple

Rich84 · 10-24-2018, 01:58 PM

Trailblazer SS manifolds.

crazy longhorn · 10-26-2018, 08:21 PM

My thoughts.....add the resonators, but do add the h pipe! The H will tame the sound a tad, give more mid power, & also "sweeten" the sound

Longhorn

04ls1gto · 10-27-2018, 06:12 PM

Resonators are in, weather did not allow for a test drive as there's no wipers on the truck right now. Much quieter so hopefully thats it. Gonna drive it tommorow

cornerstone · 10-27-2018, 09:42 PM

I'm hoping the volume is to your liking, and looking forward to your thoughts after you get the chance to drive it. I will be in the same boat soon and really don't want a loud truck. Curious to see how and where you placed the resonators so any pictures would be great if possible.

04ls1gto · 10-28-2018, 08:28 AM

Quote:

Originally Posted by cornerstone

I'm hoping the volume is to your liking, and looking forward to your thoughts after you get the chance to drive it. I will be in the same boat soon and really don't want a loud truck. Curious to see how and where you placed the resonators so any pictures would be great if possible.

I'll get picks of exhaust for you. It was a ***** to build with getting around trailing arms

jjzepplin · 10-28-2018, 08:41 AM

I had an h pipe on my 67 Firebird and it was very quiet with glasspacks dumped before the rear axle. It still set off car alarms with a very low tone. Tamed those glasspacks though. At high rpms, they did not rap like normal packs. I never liked them but at the time they were free. Subbed for info.

04ls1gto · 10-28-2018, 02:42 PM

Went for a test ride and exhaust is much better. Rasp is gone and sounds really good. Still a little loud but there is no sound deadoning in the truck. Seams like with every success comes a issue. Went for a 20 min ride, got back to shop and was checking a few things and the truck overheated. Electric fans stopped working and she was hot. Gonna dig into that issue this week, bad temp sensor maybe? Bad fan controller? Wiring issue?

10-22-2018, 08:35 PM	#1
04ls1gto Registered User Join Date: Aug 2014 Location: Portsmouth ri Posts: 363	LS swap exhaust too loud.... Options Just got my 71 suburban out for the maiden voyage after swapping a ly6 6.0 and 6l90. Exhaust setup is speed engineering 1 7/8 long tubes, magnaflow mufflers to true dual 2 1/2" SS out the back. It is way to loud, do I swap mufflers? Add h pipe? Add resonators or maybe a combination off all three. Let me know what your setup is and how you like it

10-22-2018, 08:41 PM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,579	Re: LS swap exhaust too loud.... Options Hard to imagine it's to loud in a burb...resonators may help...diff mufflers would also make a diff....I have a set of walker super quite for mine...I have a set of magflow...not magnaflow..on my other truck dumping in front of the axle and it's not to loud... __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

10-22-2018, 09:20 PM	#3
Overdriven Registered User Join Date: Mar 2016 Location: Long Island NY Posts: 598	Re: LS swap exhaust too loud.... Options Magnaflow mufflers are available in different lengths and styles (traditional oval shape, round), what do you have? H pipe doesn’t have much effect on sound level. Swapping mufflers is probably your best bet, chambered mufflers are usually quieter.

10-22-2018, 09:32 PM	#4
04ls1gto Registered User Join Date: Aug 2014 Location: Portsmouth ri Posts: 363	Re: LS swap exhaust too loud.... Options Here's what I have https://www.summitracing.com/parts/mpe-11256

10-23-2018, 10:04 AM	#6
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: LS swap exhaust too loud.... Options Mine's near silent with manifolds and cats. It's the headers, for a start, I think. I have Dynomax and they're fairly quiet until opened up. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

10-23-2018, 11:15 AM	#7
04ls1gto Registered User Join Date: Aug 2014 Location: Portsmouth ri Posts: 363	Re: LS swap exhaust too loud.... Options I ordered a set of resonators to install. well see if that helps. There is no room for a bigger muffler the way its setup unfortunately

10-23-2018, 11:54 AM	#8
Willie Makeit Registered User Join Date: Oct 2013 Location: Alabama Posts: 1,206	Re: LS swap exhaust too loud.... Options 6.0 liter LS engines are very very hard to make quiet without the use of cats and/or resonators.

10-23-2018, 09:29 PM	#10
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,052	Re: LS swap exhaust too loud.... Options Both my swaps are very quiet. Both have camaro manifolds and catalytic converters. The suburban has super 40 flowmasters I can hardly hear it now before with the 327 it was abnoxous. The 1967 truck has magnaflows and its wisper quiet catnt hear it at all with the wondows up __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

10-24-2018, 08:05 AM	#11
Rich84 Registered User Join Date: Mar 2012 Location: Woodbury, Ct. Posts: 1,663	Re: LS swap exhaust too loud.... Options My 6.0 has 2.5 dual exhaust out behind the rear tires and was way too loud with 40 flowmasters. The droan was hideous. Much better with the added resonators.

10-24-2018, 01:58 PM	#13
Rich84 Registered User Join Date: Mar 2012 Location: Woodbury, Ct. Posts: 1,663	Re: LS swap exhaust too loud.... Options Trailblazer SS manifolds.

10-26-2018, 08:21 PM	#14
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: LS swap exhaust too loud.... Options My thoughts.....add the resonators, but do add the h pipe! The H will tame the sound a tad, give more mid power, & also "sweeten" the sound Longhorn __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

10-27-2018, 06:12 PM	#15
04ls1gto Registered User Join Date: Aug 2014 Location: Portsmouth ri Posts: 363	Re: LS swap exhaust too loud.... Options Resonators are in, weather did not allow for a test drive as there's no wipers on the truck right now. Much quieter so hopefully thats it. Gonna drive it tommorow

10-27-2018, 09:42 PM	#16
cornerstone Registered User Join Date: Apr 2014 Location: Azle,Texas Posts: 2,249	Re: LS swap exhaust too loud.... Options I'm hoping the volume is to your liking, and looking forward to your thoughts after you get the chance to drive it. I will be in the same boat soon and really don't want a loud truck. Curious to see how and where you placed the resonators so any pictures would be great if possible.

10-28-2018, 08:41 AM	#18
jjzepplin Registered User Join Date: Feb 2012 Location: Ruskin Florida Posts: 4,544	Re: LS swap exhaust too loud.... Options I had an h pipe on my 67 Firebird and it was very quiet with glasspacks dumped before the rear axle. It still set off car alarms with a very low tone. Tamed those glasspacks though. At high rpms, they did not rap like normal packs. I never liked them but at the time they were free. Subbed for info. __________________ 70 swb 4x4 406sbc 700r4 203/205 d60/14blt locker yadda yadda http://67-72chevytrucks.com/vboard/s...88#post6935688 Yeller 72 Blazer 2wd conversion project "No Daggum Money" http://67-72chevytrucks.com/vboard/s...d.php?t=550804 LS1-T56 3.73 LSD super budget build Blanco-2014 Sierra SWB https://67-72chevytrucks.com/vboard/...d.php?t=810350

10-28-2018, 02:42 PM	#19
04ls1gto Registered User Join Date: Aug 2014 Location: Portsmouth ri Posts: 363	Re: LS swap exhaust too loud.... Options Went for a test ride and exhaust is much better. Rasp is gone and sounds really good. Still a little loud but there is no sound deadoning in the truck. Seams like with every success comes a issue. Went for a 20 min ride, got back to shop and was checking a few things and the truck overheated. Electric fans stopped working and she was hot. Gonna dig into that issue this week, bad temp sensor maybe? Bad fan controller? Wiring issue?



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