3800 muffler options (Page 1/2)
cam-a-lot AUG 30, 09:16 PM
Hello

I realize this is an old topic, covered many times

Curious about what currently available muffler is being commonly used for 3800 swaps. I have WCF headers running the stock Fiero route. Would like a 3" inlet, dual 2.5" outlet, preferrably somethingt that helps with the annoying drone sound

Any tips/video/audio of your exhaust would be appreciated
cam-a-lot AUG 31, 06:21 AM
I would like to add- my question relates specifically to CURRENTLY available muffler choices- as many of the old threads seem to reference mufflers that do not seem to be available

thanks again
shemdogg AUG 31, 09:38 AM
Transverse muffler is the keyword to search, for a camaro firebird. I got one off ebay 3"in dual 2.5" out

shem
fierosound AUG 31, 12:16 PM
Transverse/crossflow mufflers with 13-inch body are hard to come by (most are 18" long)

Dennis installed one that's still available.
https://www.fiero.nl/forum/...HTML/131937.html#p24

Flowmaster 40/44 series are 13" body mufflers but "aggressive sound".
https://www.holley.com/prod..._chambered_mufflers/

On my Indy I have a Jones Full Boar with 2.5" inlet pipe
Quieter than an Afterburner with 3" inlet that I had before.
https://www.ebay.com/itm/304797263974

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Spoon SEP 01, 08:32 PM

quote
Originally posted by cam-a-lot: I have WCF headers running the stock Fiero route.



I also have WCF headers running the stock route with new Cat and original muffler. Sounds more tame than the GTP it came out of. I have a Flowmaster 40 on the shelf but I heard too much about the droning. Let me know what you end up with and how it sounds.

Spoon

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jelly2m8 SEP 02, 12:14 AM

I had to build a Fiero Style Muffler to get rid of any droning, basically I gutted a stock muffler and redid it with 3" in, 2.5" out, internally the peforation holes ( for lack of a better term) I made like 3 times bigger then what's found in a stocker. I basically took a factory muffler and made the internals bigger. I do run a catalytic convertor also that I built.

This one isn't mine but a customers done similarly

[This message has been edited by jelly2m8 (edited 09-02-2023).]

cam-a-lot SEP 02, 08:03 AM
Very cool idea on the muffler. Would you be interested in making more? I have a customer in Halifax that can plasma cut the plate for you

[This message has been edited by cam-a-lot (edited 09-02-2023).]

Dennis LaGrua SEP 02, 10:10 AM
I've tried installing quite a few mufflers for the 3800SC swaps that we used to do. The Flowmaster has a good sound but is too big to have a full sized trunk and/or enough road clearance. The Flotech Afterburner fits fine but after using one on my install it proved far too noisy on the trip to Carlisle. I scrapped it and went to Spintech that uses a unique non-restrictive spin sound trap. While not completely quiet it had the lowest exhaust sound of any tested. Further sound reduction was achieved by exhaust wrapping the tail pipes. If you call SpinTech they will build exactly what you need in a 13" L case. Jelly2m8's seems like the best engineered but presents a lot of work for the novice. We have a large Hobart welder here w some metal working equipment but still prefer to just buy something ready made.
IMO, running with a CAT will additionally help to achieve a low exhaust sound but in an engine swap configuration with an untouched trunk its a very tight fit

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[This message has been edited by Dennis LaGrua (edited 09-02-2023).]

fierosound SEP 02, 03:01 PM

quote
Originally posted by jelly2m8:



I basically took a factory muffler and made the internals bigger.




I like this. Probably the best answer so far.

There are muffler components available for DIY-ers.
https://www.coneeng.com/mufflers.html
https://martelius.com/en/un...itse-rst-vaimentimet

[This message has been edited by fierosound (edited 09-02-2023).]

jelly2m8 SEP 02, 03:21 PM

quote
Originally posted by cam-a-lot:

Very cool idea on the muffler. Would you be interested in making more? I have a customer in Halifax that can plasma cut the plate for you





Sorry the amount of work and material would probably make it quite an expensive muffler and I'm going to be honest, my end plates and dividers and shell is made from Mild steel and I have already had to patch the outer shell from rust through.

If I were to do this again I would have it done in stainless steel, and that is not going to be cheap.