I just got my custom catback installed, seems a little loud, looking for feedback/ideas, here's the setup.

91 Integra LS, 155k
Installed: AEM FPR, BLOX IM, MSD Wires/Cap/External Coil, JG Bored 62mm TB, CAI, AEM alt. pulley (+ full suspension).
Sitting in garage awaiting install: Crower 404's cams, AEM cam gears, Apexi VAFC, AEM pwr. str. pulley, unorthodox crank pulley.

Exhaust: DC Sports 4-2-1 header, magnaflow 2.25" cat, 2.25" piping, 22" resonator, magnaflow street (14 X 5 X 8 oval).

FYI - Many of the mods listed are to fully take advantage of the future cam install.

The exhaust setup was based on significant research and feedback on my NA build. The goals: (1) of course increased flow, (2) especially staying as quiet as possible. My research led me to believe that keeping in the cat, adding a 22" resonator (replaced shorter stock one), and using a magnaflow street would meet the flow needs of my build while staying quiet.

I didn't really meet goal # 2. Options include adding another resonator or putting in a 30" resonator to replace the 22". Ideas on why its loud? Feedback? Ideas for quieting? Thanks in advance.

 

I had the exact same problem after I cobbled together an exhaust like yours.

Part of the boomy resonance you're getting is due the diameter of the pipe.. but the volume of noise is due (mostly) to insufficient sound absorption.

I wound up scaling my plans back dramatically, which included selling my DIY exhaust for the Apex'i WS2.

In your case, I'd try to emulate the formula Greddy uses for their GR2 exhaust.... and that means a large volume, single-pass muffler at the end of the exhaust.

If Walker still sells their Quiet-Flow brand of reflection-absorption mufflers, I would start by replacing your rear muffler with one of theirs.

By increasing the overall capacity of the rear muffler, you're going to see a greater reduction in overall volume than by just adding another 8 inches of perf-core resonator.

 

I looked into Walkers quiet flow, they have three versions. All purport to be quiet, but what about increased flow over stock?

 

The muffler line was originally designed for street rods and customs.

Since those rides are generally powered by at least a 5+ liter V8, I'm quite sure that a built 1.8 liter I4 won't be choked down. :run:

 

you could try a flowmaster huspower....its a resonator plus has insulation/sound deadening material

 

Thanks all. My wife noticed it but hasn't freaked, that's the ultimate test. Of course, I never went WOT with her in the car I also painted it black today, a little less noticable. As a wise man once said to me: "Nothing says "citation please officer" like a 4" chrome tip". Plus I like to think I'm building a sleeper

 

I would think that with 2.25" piping, a 22" resonator, and relatively meaty muffler, it would be relatively quiet.

I'll bet most of the noise comes from the muffler. If it were a chambered or twin loop muffler, it would quiet things down a bit. I would swap out the muffler for a twin loop so you can still retain flow but quiet things down if the noise bothers you.

 

thanks, I may look into that or just some larger muffler if I don't like it, its not a big deal, just louder than I thought. Might I add, that your Strichmu has very large breasts.