3" Quiet Exhaust

Discussion on fuel delivery & intake/exhaust tech & mods.
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bstoner
Posts: 21
Joined: Wed May 05, 2021 7:12 pm

3" Quiet Exhaust

Post by bstoner » Tue Jul 13, 2021 7:37 pm

I am in the process of developing/building a 3" performance exhaust that is quiet. Think factory quiet. I call this my Impala Taxi not a tricked out ZR1. It's a sleeper. I am going with 3" to support a LSA LS3 stroker build and will need the flow for big hp.

Probably go with 1 7/8" or 2" primaries long tube headers from Kooks or Stainless Works. Then high flow cats from either Kooks, SW, or Solo Performance. Now here is where I am stuck. I reached out to SW to build me a system and they were not interested at this time. I reached out to Solo Performance as well who strongly recommended their J pipes in place of rear mufflers to prevent drone. It makes sense. Get the length right to cancel the drone frequency but it would be too loud for me. I want, I need rear mufflers. I ran the Solo Performance Stealth series mufflers on my Grand Prix and they were fantastic. I also reached out to Borla but never heard back from them. I am close enough to them as well to drop off and build.

So what would be the quietest 3" performance exhaust I can make or piecemeal together? X or H pipe. Large resonator(s) 1 or more up front. Either dual or one large. Or even perhaps 2 in series. Large mufflers in the rear. Do you guys get drone (ignore DOD, I am removing it)? Am I going to need to install a J-pipe to cancel out drone? Run it along the midpipes perhaps?

I am not terribly familiar with the LS series. Coming from my old LT1 B-body then Grand Prix 3.8 supercharged.

Thanks,
Brett
2014 PPV Stock....for now

GammaFlat
Posts: 114
Joined: Mon Sep 21, 2020 2:26 pm
Location: NW Indiana

Re: 3" Quiet Exhaust

Post by GammaFlat » Wed Jul 14, 2021 5:37 pm

I am very interested in being quiet as well. I would not consider sacrificing the X-pipe for the sake of sound. I think it does good things for your performance (enough) so get your noise down with other components.

I am likely leaving my exhaust manifolds intact (and cats). I looked at HP differences between manifolds and headers and the cost of headers and new exhaust. 2-3K for exhaust for 10-25HP. Nope. I can spend a lot less on a stroke kit and get 50HP and loads of torque. I currently have axle backs and it is a little too much noise for me (and my neighbors at 4:00am). I may end up with a fully stock exhaust. I think the exhaust systems today are better than the "olden days".

Having said that, I'd be very interested in high flow mufflers (as much as possible) while keeping the noise down. I wonder how the factory mufflers are for flow. I'm betting it's near impossible to find a direct HP comparison of 2 things: 1) Fully stock yet tuned system and 2) Kook headers with Solo hi-flow cats and exhaust (tuned).

I spoke with Solo about a quieter solution than I currently have and they said that with headers, any other of their solutions would be louder than what I have (Solo Axle-Backs).
Current: 2013 9C3, deeper trans pan, 12VoltSolutions Remote, Class III hitch, Android Auto capable radio

Navy Lifer
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Location: Canton GA

Re: 3" Quiet Exhaust

Post by Navy Lifer » Wed Jul 14, 2021 5:57 pm

I don't think there's a "quiet" solution working with 3" all the way through the system.

Factory muffler options to consider are the G8 GXP, 2014 SS sedan, and not much else. The PPV mufflers are actually quietest, since they contain a built-in J-tube that is intended to mitigate the drone of 4-cylinder mode. If a muffler could be created that mimics the PPV's, but with larger pipe sizes, that might be an approach to consider. The Solo "no muffler" adjustable J-tube is too noisy on it's own, from what I've seen/heard.

Whether there are aftermarket options that can fit your parameters for flow vs sound is a tough thing to know--there's really not much in the "science" of mufflers that can trick an exhaust system to flow more than the most restrictive point in the system, but the sharing and filling of pipe volume & flow pulses of the firing order on each bank should favor the X-crossover as far as that aspect of any system design.

Muffler placement is restricted, but you might consult with Stainless Works about their ovaled mufflers - they can possibly be fitted under the car, and this would allow longer tailpipes and perhaps resonators where the mufflers currently reside. https://stainlessworks.net/smooth-oval- ... ess-steel/

The other approach might be something like this: https://stainlessworks.net/turbo-chambe ... ess-steel/

I'm not advocating for the SW brand, just thinking about what you're wanting and tossing out some ideas. I think some form of resonator or pre-muffler is going to be 100% essential to achieve your goal.

bstoner
Posts: 21
Joined: Wed May 05, 2021 7:12 pm

Re: 3" Quiet Exhaust

Post by bstoner » Thu Jul 15, 2021 2:02 pm

Thanks guys. I was thinking about the SW headers, cats, and catback. Now they don't make a kit for my 14 Caprice PPV but they have them for the G8 and SS. Which one would fit better? The SS headers for sure to clear the oil cooler. But I am not sure on the catback differences. I was thinking the G8 has the center crossover Magnaflow resonator. Weld in some Magnaflow or Vibrant bullet resonators, quiet mufflers in the rear.... May need to install a parallel j-pipe if there is drone. Come off after the crossover, run parallel, and tack it to the resonators. I need to do some measuring under there.

Anybody run a full SW G8 or SS kit on their Caprice?
2014 PPV Stock....for now

s/c'd cav
Posts: 1065
Joined: Mon May 30, 2016 8:12 am
Location: PHOENIX AZ

Re: 3" Quiet Exhaust

Post by s/c'd cav » Thu Jul 15, 2021 4:33 pm

not sure why you are hooked on shittyworks products

kooks offers a header/exhaust for the caprice , ive got 2" arh SS system for mine , as with anything SS or G8 based they need some length added to them since we are about 8" longer than they are

bumpc723
Posts: 4
Joined: Sun Apr 18, 2021 5:48 pm

Re: 3" Quiet Exhaust

Post by bumpc723 » Fri Jul 16, 2021 11:14 am

GammaFlat wrote:
Wed Jul 14, 2021 5:37 pm
I am very interested in being quiet as well. I would not consider sacrificing the X-pipe for the sake of sound. I think it does good things for your performance (enough) so get your noise down with other components.

I am likely leaving my exhaust manifolds intact (and cats). I looked at HP differences between manifolds and headers and the cost of headers and new exhaust. 2-3K for exhaust for 10-25HP. Nope. I can spend a lot less on a stroke kit and get 50HP and loads of torque. I currently have axle backs and it is a little too much noise for me (and my neighbors at 4:00am). I may end up with a fully stock exhaust. I think the exhaust systems today are better than the "olden days".

Having said that, I'd be very interested in high flow mufflers (as much as possible) while keeping the noise down. I wonder how the factory mufflers are for flow. I'm betting it's near impossible to find a direct HP comparison of 2 things: 1) Fully stock yet tuned system and 2) Kook headers with Solo hi-flow cats and exhaust (tuned).

I spoke with Solo about a quieter solution than I currently have and they said that with headers, any other of their solutions would be louder than what I have (Solo Axle-Backs).
Gamma,
I'm looking to buy the Solo Axle Back currently. If you're ready to part ways with yours, let me know!

Navy Lifer
Administration Staff
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Joined: Tue Mar 19, 2013 11:30 pm
Location: Canton GA

Re: 3" Quiet Exhaust

Post by Navy Lifer » Fri Jul 16, 2021 12:14 pm

s/c'd cav wrote:
Thu Jul 15, 2021 4:33 pm
not sure why you are hooked on shittyworks products
Easy, big fella....not sure where you're directing your comment. I'll own it, but I was only looking at what seemed to be readily available in 3". I honestly have no experience with their products, so I'm definitely not "hooked".

Quiet can be an elusive descriptor - stealth is the more realistic term, but what won't be achievable, at least in my mind, is an exhaust that doesn't have some roar instead of "whoosh" at full throttle that is going to flow adequately - it's just not the nature of an I.C.E. to be so tamped-down at high demand/output to be extremely quiet in the process.

I suppose it could be done, but the packaging limitations under the Zeta unit body & axle present little opportunity for a really high volume/flow setup with proper quiet mufflers. The PPV stock muffler, which is "ideal" as a design target, has internals that are too small for increasing flow, but if they could be duplicated at 2.5 or 3.0, with the J-tube, the result would be quieter than other options, but not stealth quiet.

bstoner
Posts: 21
Joined: Wed May 05, 2021 7:12 pm

Re: 3" Quiet Exhaust

Post by bstoner » Fri Jul 16, 2021 1:36 pm

I am curious why you don't like SW products? Headers fit poorly, poor grade steel that rusts, bad welds, bad customer service.... I have my headers and cat down pipes narrowed down to Kooks headers and Solo downpipes or Stainless Works setup. SW is cheaper. This is the first I have heard of people knocking SW. For catback I am leaning towards fabbing my own.

Here is my potential list:
Stainless Works headers and cat down pipes
Magnaflow 12469 dual in/out 3” crossover muffler
Dual resonators after the crossover (either Magnaflow or Vibrant)
3" stainless fab pipe to mufflers
Solo Performance Stealth Mufflers STL32
Exhaust Tips (whatever looks nice, need to measure to fit)

So far on both my previous builds (94 Caprice, 04 Grand Prix) I have made a quiet performance exhaust. I usually have to mix/match to get there. Big chambered mufflers and resonators. Maybe a J-pipe to handle resonance as needed. https://ls1tech.com/forums/generation-i ... ators.html

As for X vs H pipe.... My research indicates they are very similar for performance. X pipe gives a more raspy sound and a little better performance at high HP. H pipe gives a more deeper mellower sound and gives up a few HP at high RPM.

Also just to clarify on quiet..... Almost any aftermarket system will be louder then stock. But to me I try to attain as close to stock db without drone while having the flow I need. At idle it sounds like stock or just a little louder. At cruise it is pleasant, carry on a conversation in the car, and no drone. And at WOT not be pull me over obnoxious or hear me coming a block away. LOL
2014 PPV Stock....for now

s/c'd cav
Posts: 1065
Joined: Mon May 30, 2016 8:12 am
Location: PHOENIX AZ

Re: 3" Quiet Exhaust

Post by s/c'd cav » Fri Jul 16, 2021 4:20 pm

Navy Lifer wrote:
Fri Jul 16, 2021 12:14 pm
s/c'd cav wrote:
Thu Jul 15, 2021 4:33 pm
not sure why you are hooked on shittyworks products
Easy, big fella....not sure where you're directing your comment. I'll own it, but I was only looking at what seemed to be readily available in 3". I honestly have no experience with their products, so I'm definitely not "hooked".
nope wasnt directed at you bill , just the OP

bstoner wrote:
Fri Jul 16, 2021 1:36 pm
I am curious why you don't like SW products? Headers fit poorly, poor grade steel that rusts, bad welds, bad customer service.... I have my headers and cat down pipes narrowed down to Kooks headers and Solo downpipes or Stainless Works setup. SW is cheaper. This is the first I have heard of people knocking SW. For catback I am leaning towards fabbing my own.

Here is my potential list:
Stainless Works headers and cat down pipes
Magnaflow 12469 dual in/out 3” crossover muffler
Dual resonators after the crossover (either Magnaflow or Vibrant)
3" stainless fab pipe to mufflers
Solo Performance Stealth Mufflers STL32
Exhaust Tips (whatever looks nice, need to measure to fit)

So far on both my previous builds (94 Caprice, 04 Grand Prix) I have made a quiet performance exhaust. I usually have to mix/match to get there. Big chambered mufflers and resonators. Maybe a J-pipe to handle resonance as needed. https://ls1tech.com/forums/generation-i ... ators.html

As for X vs H pipe.... My research indicates they are very similar for performance. X pipe gives a more raspy sound and a little better performance at high HP. H pipe gives a more deeper mellower sound and gives up a few HP at high RPM.

Also just to clarify on quiet..... Almost any aftermarket system will be louder then stock. But to me I try to attain as close to stock db without drone while having the flow I need. At idle it sounds like stock or just a little louder. At cruise it is pleasant, carry on a conversation in the car, and no drone. And at WOT not be pull me over obnoxious or hear me coming a block away. LOL
their headers on my old 04 GTO fit worse than any cheap header on the market , they literally sat into the accordion boots on the steering rack , i had emailed them about that , and had some questions on their catback and switching from the 04 style mid pipe to the 05-06 midpipe and what the pipe spacing difference was , i get a email back , and the whole email reply was literally YELLING AT ME , HOW I CANT DO THIS OR DO THAT , AND HOW DIFFERENT THE 04 and 05-06 catbacks were from each other

this all besides the fact that 05-06 gto catback was shipped in a billion pieces to keep the size of the shipping box down to save cost , which meant the catback was hard to install and keep aligned , the mufflers had fallen off several times , unfortunately it wasnt driven alot being a race car and having to install things a bit different than a normal 05-06 gto , and being a 04 it had a custom muffler hanger on the pass side as they came with the dual exit on the driver side , and BMR had installed the battery shut off switch on the pass side where the muffler would normally sit , and i had parked the car shortly after , other wise i would have had the system welded up to keep it from moving around and falling apart

the headers were a basic install , and the headers were a very early run from them , and were on the car when i got it as was a custom catback used from their 3" 04 gto kit , and all the original work was done from BMR suspension , as the car was their test bed for gto products , and wrenching and modifying cars is something ive grown up doing

CrashTestDummy
Posts: 2180
Joined: Sat Feb 07, 2015 8:31 pm
Location: Pearland, Texas

Re: 3" Quiet Exhaust

Post by CrashTestDummy » Sat Jul 17, 2021 9:13 pm

We're running a modded G8 X-Force exhaust, and it's pretty quiet. As Bill said, 'quiet' is subjective, and while our system is louder than the factory exhaust, even when it had a split muffler, it's not 'H0ly Cr@p that thing is a beast!' loud. It really doesn't sound far from factory, and there's a controller I can use to open up the other side of the mufflers for a bit more sound, if I want it. So far, though, I've been fine with it closed up.

It is a 3" system from front cats to the muffler inlets, and all fits up under the car quite well. It seems to be a quality product, too, and the US-based X-Force people were quite supportive of my issues when I contacted them for parts on my modded-and-purchased-second-hand exhaust system.

The engine on our car is completely stock, though, except for SLP high-flow cats and a home-built intake resonator-delete, but it's been nice so far. Because of the added sound, know when it's in 4-cyl mode, but it's neither obtrusive, nor annoying.

Note that you will get some noise out of the headers, no matter how well-sealed up they are. The thin primary walls are always going to 'ting' some, so it won't ever be factory Caprice quiet.

Good luck on your project.
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2010 Tahoe PPV (her car)
1995 DGGM Impala SS
1996 BBB Impala SS (11-second DD)
1985 Firebird - 310 LS1 C Prepared autocross car.
And some others
Do YOU have my SPID?

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