Exhaust help
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2nd gear
Joined: Jan 2026
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Exhaust help
I got the cats removed on my ls400 so now it’s stock headers, then no cats, then an x pipe, and a resonator on each side. It was tame but still loud when i needed it with cats and resonators but now it’s rediculous. It even makes a flabby sound in lower rpm. Any recommendations on what to do? keep resonators and add mufflers? or remove resonators in favor for mufflers? I don’t know anything about the resonators welding and fab is something i don’t know so they are whatever the shop keeps in stock.
i would say to add the cats back, but likely this is the most expensive option to "tame" the sound.
next would be to keep the resonators and add rear-most mufflers (which is how the stock exhaust is)! the more chambers you have the quieter it will be, generally.
if you want to retain some sound, you can delete the resonator in favor of a muffler as you last suggested.
any muffler shop should have what you will need. just explain to them what you're after and they should be able to set you up!
next would be to keep the resonators and add rear-most mufflers (which is how the stock exhaust is)! the more chambers you have the quieter it will be, generally.
if you want to retain some sound, you can delete the resonator in favor of a muffler as you last suggested.
any muffler shop should have what you will need. just explain to them what you're after and they should be able to set you up!
Driver
Joined: Jan 2021
Posts: 84
Likes: 24
From: California
I'd personally have kept the cats. Not sure if you have to smog where you're at, but the cats and resonator on these cars aren't too restrictive in stock form. Resonators change tone and volume as they clog with more carbon from the car running - carbon that was ideally being managed in the cats before they were deleted. If you like the tone you have now, running cats will most likely keep your tone similar and bring the volume down. Cinsidering the cost of cats, you could also apply a set of mufflers after your resonators to just deal with volume - the muffler chambering you choose will have an impact on how much quieter your end result is.
Thread Starter
2nd gear
Joined: Jan 2026
Posts: 2
Likes: 0
I'd personally have kept the cats. Not sure if you have to smog where you're at, but the cats and resonator on these cars aren't too restrictive in stock form. Resonators change tone and volume as they clog with more carbon from the car running - carbon that was ideally being managed in the cats before they were deleted. If you like the tone you have now, running cats will most likely keep your tone similar and bring the volume down. Cinsidering the cost of cats, you could also apply a set of mufflers after your resonators to just deal with volume - the muffler chambering you choose will have an impact on how much quieter your end result is.
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mtimmons4
LS - 1st and 2nd Gen (1990-2000)
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Jul 23, 2009 06:11 AM
