Car Chemistry Inserts

I have always thought it was a bit on the loud side.  Even though my neighbors have never shown up with pitchforks and court orders, it still bothered me.  I started with the specified short pipe with one Speedway auger each side, which was deafeningly loud while driving it.  I then lengthened the pipes and added another auger.  This was in the right direction but still too loud.  While trolling through car magazines I noticed an ad for Car Chemistry exhaust inserts claiming to allow an “open header look with muffler noise levels”.  Intrigued, I started searching for information.  There was quite a bit of good feedback in various hot rod forums, so I took the plunge.

Car Chemistry 3 Disk Insert


The exhaust insert is formed from a perforated center tube with three perforated disks that match the ID of the exhaust collector.  There are two end caps provided with each insert.  The advice on the website conflicts with the instructions provide with the product regarding the use of the solid end cap.  I welded the cap with the hole on the upstream end of the insert (the end with the longer tube extension) for the first tests.  I ended up welding both end caps on and leaving the solid cap completely closed.  I only used spot welds, so it would not be hard to remove for experimentation.

Yesterday I installed them.  I gathered some data to see how much, if any, difference there really was.  I didn’t have a helper so I elected just to do some quick SPL measurements for trends.  With the car in the garage with completely open pipes at idle I walked my dB meter back to where I measured less than 100dB and marked that spot.  I then tried different configurations of exhaust and measured at the same spot.  I would prefer to have someone else take measurements while I drive by at different speeds, but I don’t have any friends nearby that loyal!  Not too mention driving by with open headers probably would bring out the pitchforks and court orders…

Here are the measurements:

Open Headers: 97dB

CC Inserts with upstream plug (0.87″ diameter): 87dB

CC Inserts with upstream and downstream plug (closed):  83 dB

Complete long pipes with CC inserts and speedway augers: 73dB

24dB decrease is HUGE. It is quiet enough that I don’t think I will suffer irreparable hearing damage if I drive to the gas station without ear plugs and the tone is much nicer.  The previous exhaust sounded flatulent.  The CC Inserts have cut down the high frequency and made it more of a roar than a howl.  My butt dyno thinks the engine is running stronger, but that could be placebo…overall I am very happy with them.


3 Responses to Car Chemistry Inserts

  1. Brian Fox says:

    Great article, thanks for sharing. I just installed Car Chemistry 3″ 3 disc header mufflers with turndowns on my Duster. The noise was obnoxious to say the least. I’m putting the full restrictor plugs on tomorrow and will see how much it quietens down if any. I do however appreciate the compact size, light weight construction and quick installation of these mufflers though.

  2. Brian Fox says:

    Following up from my previous comment on Car Chemistry header mufflers, I installed the full restrictor plugs and it quietened down some, not near as obnoxious and I may leave them permanently installed now. I drilled two holes in the perimeter and used sheet metal screws to fasten plugs in place.

    • Joe Biden says:

      I found this blog post when researching the conflicting information about the solid plugs between the website and the hard copy. For my application (Ducati M944 twin cylinder motorcycle) I ordered a pair of the 2 disc inserts. Strictly for noise reduction, my exhaust is meant to be run fully open for max power but my neighbors would despise me. Review: AWESOME, throaty sound (like a roaring lion) when run without end caps or packing…but still too loud 😦 added strips of the steel wool packing to each insert and safety wired them into place. A *little* less loud but not by much and the sound became more tinny/high pitched/not good. Finally added the caps, solid and drilled. Volume is now reasonable but I’m not a fan of the sound. Raspy imo.

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