Vibrant Downpipe-back Exhaust
Pros:
Vibrant has been making exhausts for a long time, and their products continue to grow in popularity. It's safe to say they know what they're doing. Our TPV exhaust bolted right up where it should, sounded great, and made power and torque across the board-as much as 11 whp in the midrange. Full stainless construction ensures a lifetime of use without fail.
Cons:
The Mazdaspeed3's factory exhaust is a really well-engineered piece, so it's tough to improve upon. This is the first Vibrant exhaust we've tested that used coupling clamps to join some of its sections, and we were a little hesitant of the design at first-we feel more comfortable with typical nut-and-bolt flanges-but the Vibrant piece fit together for a leak-free seal. Given the advantages it brought over the stocker, this is a minor detail.
Parts:
Three sections, two clamps, re-used hardware, gasket, and hangers
Tools:
14mm, 17mm sockets and wrenches, extension, WD-40, Sawzall or angle grinder
Installation Time:
20 minutes
Notes
By this point in testing, we really began to realize how much the '3 hates heat. The hotter it became on the dyno, the more power it lost...as much as 20 whp during one pass! Keeping our temperatures consistent, however, the benefits of modification became apparent...as did the value of running the car within its ideal temperature range.
CorkSport Downpipe
Pros:
We didn't expect large gains from the CorkSport downpipe once we eyed it up for the first time-there's just not much to it. Sure, its full stainless construction, TIG-welded mandrel-bent tubing screams quality and durability, but it's a physically small piece and doesn't replace much. Upon removing the OE downpipe and comparing the two, the benefits of the CorkSports piece were obvious-FAR less restrictive than stock, for increased flow and power across the board-nearly 30 lb-ft of midrange torque!
Cons:
None. Some may argue that it could've been constructed to eliminate the cats, but not us-this is a street car, and keeping it able to pass a visual inspection and sniffer are a priority.
Parts:
Downpipe and re-used gaskets
Tools:
12mm, 14mm sockets and wrenches, extensions, 22mm O2 sensor socket or wrench, impact gun or breaker bar
Installation Time:60 minutes
Notes:For those of you reading who may want to remove your cats for even more power (...only on race day, mind you) CorkSports manufactures a bolt-in test-pipe-a test we'll be saving for another day.
 Dyno 3: Vibrant Performance...  Dyno 3: Vibrant Performance TPV Exhaust
Peak HP: 267.1 / Peak TQ: 303.6
Peak Gains Over Fujita Intake: +12.1HP And +18.8TQ
Horsepower Gain
* 2,500 to 3,500 HP range: 0.0 to 13.6
* 3,500 to 5,500 HP range: 0.8 to 15.3
* 5,500 to redline HP range: 0.0 to 15.3
Torque Gain
* 4,000 to 5,500 HP range: -1.8 to 22.9
* 4,000 to 5,500 TQ range: 1.1 to 16.1
* 5,500 to redline TQ range: 0.0 to 13.6
Temp 88.7
Temperature difference from previous run: +4.7 degrees Fahrenheit |  Dyno 4: Corksport Power Series...  Dyno 4: Corksport Power Series Downpipe
Peak HP: 272.9 / Peak TQ: 310.9
Peak Gains Over Vibrant Exhaust: +5.8HP And +7.3TQ
Horsepower Gain
* 2,500 to 3,500 HP range: 0.0 to 13.6
* 3,500 to 5,500 HP range: 0.8 to 15.3
* 5,500 to redline HP range: 0.0 to 15.3
Torque Gain
* 4,000 to 5,500 HP range: -1.8 to 22.9
* 4,000 to 5,500 TQ range: 1.1 to 16.1
* 5,500 to redline TQ range: 0.0 to 13.6
Temp 80.7
Temperature difference from previous run: -8.0 degrees Fahrenheit | |