Cobb Tuning Mazdaspeed 3 Catback Exhaust
 

Introduction:

Cobb has been very quiet since the release of their FMIC in the beginning of the summer. For fall, Cobb has released their Catback Exhaust. Suggested at a retail price of $725, how could Cobb compete in an already saturated catback market? It's quite simple actually, their catback system is the quietest system out there, without compromising horsepower and that in itself, makes this a contender.

The cat back is made from 3 inch mandrel bent T304 stainless steel with a custom resonator and high-flow muffler, weighing in at 35 pounds. The system uses a custom made muffler and resonator to achieve a performance sound, but remain within 11 dB below the SAE J1169 sound limit. Even with a aftermarket downpipe, the system still remains below the SAE limitation. For those of you running a racepipe or racepipe with a downpipe, know how loud the markets catback's are. I know prior to installing this system on my car which consisted of a racepipe and GHL catback, the car was loud, obnoxious and lost its cool factor. Ive been complaining for over a year about the noise of this car. GHL made claims about how their system is drone free, which is a false statement all in its own. If anything, i felt like the typical ricer out there, making all kinds of noise and drawing unwanted attention to the eyes local law enforcement. Not very cool in my book and could get you a nice fine for violating smog laws, among other things. Please review this link and this link about the seriousness of SAE J1169 and its 95 decibel limitations which could render the majority of catbacks, illegal if continued lobbying goes through. California and various other states now have legislation that makes exceeding this limit an offense, resulting in a "fix it" ticket and required testing certification. Ask your local Evo and STi owners about it...

One of the most unique factors about the Mazdaspeed 3 is its sleeper status, which is lost with any catback out there, especially with the addition of a race pipe or racepipe/downpipe combo. Sure, you could keep your stock 2.5 catback system, choked up with smaller diameter pipe, 3 resonators and a restrictive muffler. On top of that, people have sealing problems with most racepipes/downpipes of 3 inch diameter due to the 2.5 pipe transition. This catback is the answer for people who want a civil car again, without lacking performance. For those of you who like your noise and aren't concerned about it, this CBE system is not for you.

Another thing unique to the Cobb CBE, unlike all of the other systems out there is the fact it doesn't use slip joint connections. The Cobb CBE comes in a rather large box consisting of 2 pieces with a simple flange holding the entire setup together. The flange is then tightened using the supplied 2 bolts/nuts and a custom flange gasket. Although stainless steel has great sealing abilities when used with quality wide exhaust straps for slip joint systems, it can be an absolute pain when uninstalling, or you end up with the dreaded black carbon drip at the seams which is quite messy and ugly in appearance. The Cobb CBE is beautifully tig welded and highly polished.

Next, we begin the basic installation of the Cobb CBE with an addition of a new racepipe...

[multipage=Cobb Catback Exhaust Installation]

Cobb Catback Exhaust Installation:

Since we already had an aftermarket exhaust system on the car, our uninstall of the system was much easier, than that, of someone uninstalling the stock system. A LARGE rubber mallet was used to pursue our 14 month old catback system to break apart at the slip joints. Like i said earlier, stainless steel is impressive at sealing itself when used in a slip joint configuration and definitely needs some muscle to break it loose.

For those of you who have the stock 2.5 CBE system, you have 2 choices. You can go the difficult route and drop the rear suspension to uninstall in one piece, or choose the more logical approach and cut in in several sections. Below we begin with the removal of the stock midpipe...

[multipage=Installation Continued]

Installation Continued:


[multipage=Conclusion]

Conclusion:

I have helped several local Mazdaspeed guys install various exhaust systems on their cars for the last 18 months. Each one of them had quirks, such as poor fitment, to almost perfect alignment fitting. The GHL i had on my car had roughly an extra $120 added into it, to fix its problems, such as the 2.5 inside diameter tip, with a 4 inch outside section, mated to a 3 inch system? I had to get a new tip which was 3" inside diameter and 4" outer diameter, which costs me $49 with shipping. That made absolutely no sense on GHL's part and the exhaust system was poorly jigged, causing fitament issues, banging, etc. I invested unnecessary money and resources into it, just to get it to fit and look right. Than i was greeted with obnoxious noise and to much drone.

I had no complaints on how the Cobb CBE system installs on this car. Fitment is excellent, as well as craftsmanship with its beautiful tig welds. As noted, the resonator on the Cobb CBE is larger in diameter than the entire muffler on my GHL catback. Their proprietary in house design of the muffler makes for a very nice, low volume performance sound, keeping tolerances within the SAE J1169, which will keep yourself from going to some kind of California Smog Ref Station, where EVO/STi owners are getting hammered on a daily basis if you live in Socal. I do have one complaint and it should be addressed. Considering how much the catback costs, it really does need to come with a new OEM donut exhaust gasket. This is very important for sealing properties. Also, for those that who have asked, this exhaust system sealed right up to the aftermarket corksport racepipe with no sealing or leaking issues. Again, i want to reinforce, to use a new gasket, which can be purchased from one of our vendors, StreetUnit.com for $45, which will save you roughly $12-18 dollars from buying it at your local Mazda dealership, who probably wont have it in stock anyhow.

For the first time since I've owned this car, i can hear the turbo whistle, its really that quiet. I really love it, FINALLY, the car is quiet!!! My hat's off to Cobb for listening to those of us who are tired of the obnoxious exhaust note, while trying to uncork the restriction of the stock system. I was really surprised by the large deduction of interior noise as well.

** Update **

Below you will find some comparisons with other systems out there. The DB or SPL meter was 20 inches away from the exhaust tip in these readings:

• Stock CBE and Stock Midpipe: 91 Db Idle / 117 Db WOT
• Greddy CBE and Stock Midpipe: 94 Db Idle / 117 Db WOT
• Catless DP, Catted Midpipe, Stock CBE: 100 Db Idle / 115 Db WOT
• Cobb CBE, Catless Midpipe: 94 Db Idle / 110 Db WOT
• GHL CBE, Catless Midipe: 102 Db Idle / 121 Db WOT

Audio Clips:


Cobb 10 Feet Away:
http://www.mazdaspeedforum.org/forum/reviews/cobb_cbe/cobb10feet003_NEW.mp3
Stock 10 Feet Away:
http://www.mazdaspeedforum.org/forum/reviews/cobb_cbe/stock10feet003_NEW.mp3
Cobb Close:
http://www.mazdaspeedforum.org/forum/reviews/cobb_cbe/cobbclose003_NEW.mp3
Stock Close:
http://www.mazdaspeedforum.org/forum/reviews/cobb_cbe/Stockclose003_NEW.mp3
Cobb Interior:
http://www.mazdaspeedforum.org/forum/reviews/cobb_cbe/cobbcabin003_NEW.mp3
Audio Files Zipped:

http://www.mazdaspeedforum.org/forum/revi...bb_cbe_wav.zip

The Cobb CBE fits absolutely perfect on this car, just like a glove. Sure, Cobb had a few quality issues with their STS and SRI, which caused Cobb some delays and upset customers. They have since reinforced and stepped up their QC program to a incredible level to stop serious issues like those, from happening again. This has caused some product delays and setbacks until they were sure they got a handle on things. All is good and Cobb is back on track and has their catback available now as well as the downpipe & Cobb SRI, ready for sale by the time to read this. If you would like to discuss this review, please see this thread. Below you will find more information on the Cobb downpipe:


COBB 3” Downpipe for MazdaSpeed3
Intelligent engineering, exceptional craftsmanship and premium materials go into this extraordinary piece
Salt Lake City, Utah
November 13, 2008
COBB Tuning announces the immediate availability of the COBB 3” Downpipe for the 2007-2008 MazdaSpeed 3,
which is a study in engineering design and artistic execution. The COBB 3” Downpipe replaces a very restrictive
element in the Mazdaspeed3 exhaust system. Considerable effort was spent designing a flow path with the fewest
number of direction changes and minimal degrees of bend in order to eliminate restrictions. This beautifully fabricated
downpipe delivers significantly improved exhaust flow, resulting in faster turbo response time and power gains across
the entire rev range, while still protecting the environment with its highly efficient custom catalytic converter.
The engineering that went into the COBB 3” Downpipe started with the CAD designed investment-cast turbine outlet,
made of 304 stainless steel for enduring corrosion resistance and reduced heat transfer to the engine bay. The shape
of the outlet flange makes optimal use of the tight confines of the MS3's engine bay, smoothly blending turbine outlet
and wastegate gases. The outlet flange is configured with two O2 sensor bungs; one to accommodate the stock O2
sensor and another with a pre-installed plug that can be removed to allow an aftermarket wideband O2 sensor or
datalogging device with easy engine bay access.
A custom spun metal substrate high flow catalytic converter comes next. This one piece 400 grade stainless steel
cat has a much higher flow rate and longer lifespan compared to ceramic or “brick” style cats. It also reaches
operating temperature faster than other style cats for cleaner cold-start emissions. A third O2 sensor bung is
located immediately after the cat to be used by the second OEM O2 sensor.
The stainless steel flex section used in the COBB 3“ Downpipe is internally lined (unlike most flex sections) and provides
smoother exhaust flow and much longer lifespan for the steel braiding. The placement of this flex section in the
factory location (before the first exhaust hangers) is critical in absorbing engine movement and eliminating damaging
stresses that would otherwise be applied to the flange, cat, exhaust hangers and chassis. This increases the longevity
of the downpipe as well as downstream exhaust components.
All tubing used in the fabrication of this downpipe is polished 304 stainless steel for increased corrosion resistance
and a mirror-like finish. The 304 stainless steel hangers are cross-welded and well braced to eliminate a point of
fatigue that is evident in other aftermarket downpipe designs.
The end flange uses the stock donut gasket and factory spring bolts to aid in flex, longevity and proper fitment. This
provides an improved seal compared to other methods, as well as reduced noise. An additional benefit is that it makes
the COBB 3” Downpipe compatible with any cat-back exhaust that mates to the factory cat section.
When researching downpipes for your MazdaSpeed3, consider COBB's intensive engineering, quality of materials,
impeccable fabrication and all around versatility. The COBB 3” Downpipe is unmatched in the marketplace!
COBB 3” Downpipe for MazdaSpeed3 Features:
• Increased horsepower and torque
• CAD designed cast turbo outlet for maximum flow
• Minimal bends for less restriction
• 304 stainless steel throughout for corrosion resistance
• Custom spun metal substrate high flow cat
• Internally lined stainless steel flex section
• Three O2 bungs for factory sensors plus aftermarket
• Cross-welded and braced hanger section for added strength
• Polished tubing and cat for attractive finish
• Factory location of flex section eliminates stresses
• Stock donut gasket for optimal sealing and long life
• Compatible with all cat back exhaust that mate to factory downpipe
[/quote]
http://www.mazdaspeedforum.org/forum/pics...S3downpipe.jpg
http://www.mazdaspeedforum.org/forum/pics...3downpipe2.jpg
http://www.mazdaspeedforum.org/forum/pics...b_cbe/Flex.jpg

I would like to say thanks to Christian & Josh over at Cobb for sending us this piece in for review.




Sources:

Cobb Tuning:
Salt Lake City, Utah
CobbTuning.com - Home Page

** Updated **

Audio Clips Now Added