Cat-back exhaust options - looking for quiet options

T

TheRealDefman

Member
:
2008 MS3
I'm just looking for improved airflow and not tone, I'd like it to as close to stock volume as possible. I know those kind of contradict either other but I really don't want a car that sounds like a bumble bee in a beer can. I'm 42, fat, and white so my chances of any coolness are loooong gone! :)


I saw copperkid's post on the Racing Beat setup (http://www.mazdas247.com/forum/showthread.php?t=123725398) and it looks like a mostly nice kit, although the welds appear to have been done by Cro-Magnon Man, and he says it pretty close to stock sounding.

What other options do I have that fit that bill?
 
Go with Cobb's new cat-back. Sounds pretty much stock but deeper. Runs $725 with great performance gains. The quality is second to none as well.

There is a full review of the exhuast on mazdaspee d forums dot org.

cheers.
 
If quiet is what your after then don't get an aftermarket catback. The catback exhaust is pretty much a purely sound mod. The exhaust will give you barely . . if any hp. The exhaust restriction is in the front half of the exhaust (downpipe / test pipe).

All aftermarket exhausts will be louder than stock. You could reduce this a little buy purchasing cats and / or resonators but thats a significant investment for 1 or 2 hp.

I dont know what mods you have but my advice would be a test pipe. Its cheap, very easy to install, will free up much more airflow than the much more expensive catback. Don't quote me on this but I think the dyno'd hp for the test pipe was 10 whp over stock. Very nice for an easy / cheap bolt on. It also doesn't really affect the loudness of the exhaust. Took me just over 30 min to install.
 
coyfish said:
If quiet is what your after then don't get an aftermarket catback. The catback exhaust is pretty much a purely sound mod. The exhaust will give you barely . . if any hp. The exhaust restriction is in the front half of the exhaust (downpipe / test pipe).
Click to expand...

Absolutely correct. The stock cat-back has a higher flow rate than the engine is capable of producing in stock form. In fact, I've gone to a 3 inch DP/RP and see no need to change the cat-back even though there is a slight neck-down where the RP joins the cat-back.

The gains come from ditching the highly restricitive stock DP/RP combo. There's really no need to change the catback unless you want more noise or unless you are going to replace the turbo with a bigger one and get a custom tune.

Shorter answer: see the quote above - he's right.
 
MSMS3 said:
Absolutely correct. The stock cat-back has a higher flow rate than the engine is capable of producing in stock form..
Click to expand...

Engine or turbo. With a full set of bolt on's and a tuned edu, would the turbo push more air than the fatback can handle?
 
The Racing Beat and Cobb CBE are the quietest options. I have a Racing Beat CBE on my MS3 and it's very quiet.

The Corksport CBE is not quiet at all. My friend has one and its loud.
 
copperkid said:
The Racing Beat and Cobb CBE are the quietest options. I have a Racing Beat CBE on my MS3 and it's very quiet.

The Corksport CBE is not quiet at all. My friend has one and its loud.
Click to expand...

corksport is loud?? maybe at wot when its a fll tbse setup did you hear hks....ts loud...and with dp is ******* loud
 
whats the loudest? turbo xs? i heard c-pes without the resonator or muffler is the loudest option, not to thread jack or anyhting.. but im just wondering
 
every exhaust is louder with a downpipe. That video has a DP and a mid pipe. Why does it matter anyways, he's not looking for a TBE, just a CBE. All I'm saying is the damn HKS is only loud at WOT.
 
Last edited:
My CorkSport CBE isn't loud at WOT, it's actually "quiet", the loud part is there only when your in stop and go traffic at 2500-3k, it's got this high tone that gets a bit annoying with the windows down, windows up not bad at all. If the car is crusing it's very nice and quiet with barely any noise with the windows up or down really.
 
itrhybrid said:
Engine or turbo. With a full set of bolt on's and a tuned edu, would the turbo push more air than the fatback can handle?
Click to expand...

I assume you meant cat-back and ECU. My typing is bad too. Stock turbo - no. The ultimate limitation on the intake side is the size of the turbo itself. Higher flow intake alone will produce gains -- there are plenty of dyno pulls posted here that prove that. DP/RP + higher flowing intake does = even more power. A different cat-back is not going to help in the HP department, IMHO.

The turbo runs out of steam at 5500 rpm, as we all know. This is because the turbo thermal efficiency is shot after 5500. The turbine and the housing are sized for quick spool-up with minimal turbo lag. When asked to push an ever greater volume of air through that small housing, the compressed air eventually gets too hot, even too hot for the intercooler to tame, so power falls off quickly. Hot air has fewer oxygen molecules for the same volume than cold air. Thus, lower power.

Going to a bigger turbo will solve the problem. The trade off is that a bigger turbo housing and turbine will push a greater volume of air at the same turbine speed and same boost pressure, but will have more lag on the low end. This affects day-to-day drivability for many people. The bigger turbo, however, would produce enough extra air flow and exhaust to justify the need for high flow 3 inch pipes both on the intake side and from the turbo outlet all the way back. I'm not ready for that now, and like having some boost available down at 2500 rpm.
 
When sound clips of Cobb's CBE come out everyone will wish they had waited. Or the marketplace will fill with exhausts.
 
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