This page last updated on March 21, 1997
What will you find here...
This page contains all the sound related information you could hope for! I will put here actual recordings of my exhaust before and after the installation. Also, thanks to the WAIL guys we now have a way to compare the noise level against other systems people have installed.
dB Readings - TRIFLO readings now included!!!
Fellow NAISSO member, Chris Bauer, was knid enough to send a dB meter out to me so I could record the sound level of the exhaust system before and after the installation. I was trying to figure out exactly how to set this up when the WAIL guys post results they obtained from similar testing. I decided to try and duplicate their tests so we could compare the TRIFLO's with other systems. The test as they setup, is to stand directly behind the car, approxiamately 10 feet from the bumper, holding the dB meter at chest level. Readings were made at idle, 4000 RPM and 5000-5500 RPM (WOT burst). I did the same test here and came up with similar results so I think the comparison will be valid. I will test again with the new exhaust. I will also run a separate test with the dB meter inside the car on the back seat, I will then do a WOT acceleration test, and then separate tests with the car at different RPM/Speeds. All of these tests are being recorded on tape and I will try to get those recordings up as soon as I figure out how I want to do it! Here are the dB results from the WAIL group, with mine included.
10' Back, Standing Still, dB Testing
|System||Owner||Idle||4000 RPM||5000-5500 RPM|
|Stock||J Shukla||58 dB||80 dB||?? dB|
|Stock||Ken Pauley||60.5 dB||78 dB||86.9 dB|
|Flowmaster Cat-Back||Karl Ellwein||66 dB||85 dB||93 dB|
|SLP Cat-Back||Ray Lopez||67 dB||84 dB||95 dB|
on '89 Firebird Formula
|B&B TRIFLO||Ken Pauley||65 dB (+4.5)||82 dB (+5)||92.7 dB (+5.8)|
Moving, dB Testing
Note: The only tests I did myself are the ones on my car. The rest were handled in a totally different state, using a different dB meter. Therefore, you cannot make a direct comparison, but it is good enough for an educated guess!
During the dB testing of my car above, I had a tape recorder with an external microphone attached. I then transfered these recordings to 22kHz, 8-bit mono WAV files. These are not of the quality you will hear from the WAIL group, but then again I don't have a DAT!. These aren't as accurate as the dB tests because it all depends on your speakers on your computer. However, playing all of the sounds from the same computer can at least give you an idea about the before and after sounds. There are two recordings, before.wav and after.wav, you can access them below.
- 324 Kb
after.wav - 1,129 Kb
I did another recording, per someones request, to show a series of rapid throttle blips. I don't think I got exactly what he wanted, but at least it sounds good!
- 1,222 Kb
Comments - Opinions
I received a note from Randy Stone with his impressions of different systems from the above tests......
LOUD. Sound is uncontrolled at idle, but has a classic muscle car
sound at speed. When you imagine the sound of a 60's hotrod,
you're probably imagining the sound of this muffler. Also, 99 dB
is a LOT louder than 93, like nearly twice as loud, subjectively.
2-chamber Flowmasters with resonators: The resonators greatly help with idle sound quality. Makes the exhaust much more rumbly. Sounds exactly like the 2-chambers at WOT, only not so loud.
Flowmaster cat-back: This system sounds almost exactly like the 2-chambers with resonators, except it is actually louder from inside the car, although not by much. This may have something to do with the different tailpipes.
SLP cat-back: Although we only got a reading of 95 dB for this setup, it actually seemed as loud as the 2-chamber Flowmasters. This may have something to do with the lower sound of the SLP not registering as well on the meter. However, the main feature of this setup is not the volume, but the TONE. It is a LOT lower than the flowmasters, like maybe an octave. I think this might have something to do with the bigger diameter pipes, although that's only a WAG (Wild Ass Guess). Another feature of this system I like is that it quiets the popping that is so annoying on the flowmasters.