The Official Downpipe/Test Pipe/Race Pipe Thread

[MS3-a(sore)ASS-rex]

**** UPDATED 2/2015! Thanks @Inquisitive;!

General:The downpipe on your Mazdaspeed vehicle (whether it's a gen1 MS3, gen 2 MS3 or MS6) is the first part of your exhaust coming off of the turbo. The stock or OEM downpipe on your vehicle contains one catalytic converter. Replacing your downpipe is a common upgrade that results in some very impressive power gains over your restrictive OEM unit, while giving your car a louder, more aggressive exhaust note.

Warning: It has been seen that after upgrading to a 3" downpipe that some vehicles will end up with smoking turbos. This is because of the reduced back-pressure on the turbo seals, which allows some oil to pass by. There are several easy fixes to resolve this issue, the first and simplest fix is to raise the idle on your vehicle through your tuning software. Another simple fix is to swap out the stock oil feed bolt with a smaller diameter feed hole, @bnoon makes and sells these bolts.

A Diagram of the OEM Exhaust:


NOTE: GEN 1 AND GEN 2 DOWNPIPES & TEST/RACE PIPES CAN BE USED ON BOTH GENERATIONS

Things you NEED to know: Downpipes for Mazdaspeed vehicles are manufactured in two different styles. The first style is generally referred to as just a "3inch downpipe", these units will replace your original downpipe and ONLY the original piece (these are generally coupled to a "race pipe" or "test pipe" *SEE DIAGRAM ABOVE*which removes your secondary catalytic converter). The other style is known as a "Long downpipe" or "Full downpipe", meaning the new part will replace BOTH your stock downpipe and also your stock "race/test pipe".

Downpipes are generally sold with two options. They are referred to as either being cat-less or as having a high flow cat (the term cat refers to a catalytic converter). A cat-less downpipe is exactly what it sounds like, it replaces your OEM piece with a new 3" downpipe possessing NO catalytic converters. One possessing a High Flow Cat, also, is exactly what it sounds like, it replaces your stock restrictive cat for a more efficient, higher flowing unit. Generally, cat-less downpipes provide a few more peak ponies and a more aggressive exhaust notes than pieces with a high flow cat, BUT at the risk of the car receiving a CEL (Check Engine Light). Note: If a downpipe contains a high flow cat it is generally a "Long/Full downpipe".

However, there are ways to help prevent this CEL by extending your rear/second o2 sensor away from the main flow of exhaust through the downpipe. Some manufacturers include these fixes with their products, while others do not.
Commonly spark plug de-foulers are used. The first is left alone and the second is drilled out to 1/2", seen here:

Companies also offer o2 extenders taking away the drilling work for you, seen here:


Here are some how-to guides for downpipe removal:
Gen 1 MS3 & Gen 2 MS3: http://www.mazdaspeedforum.org/forum/foru...-review-16310/ and Corksport also wrote a fantastic install guide here: http://support.corksport.com/instruc...-6-113-WEB.pdf REGARDLESS OF MANUFACTURE, ALL INSTALLS ARE RELATIVELY THE SAME BETWEEN 1ST & 2ND GEN MS3'S

You should take care of the HPFP limitations before considering the removal of a cat or going completely cat-less.

The DP is the most restrictive section of your exhaust system. The bell housing is so crimped; it is hard to imagine the waste-gate having enough room to open. It contains cat-1, which is heavy, but not as heavy as cat-2. If required for emissions control, if you do not have the software to cancel the CEL (in AP un-tick codes: P0038 and P0420 (if rear spark plug de-fouler does not work)) or if you are allowed to disable two codes only for emissions testing, you will need a fast cat with following oxygen sensor bung for the second sensor. A DP provides faster turbo response times and power gains across the rev range. The transition from decelerating to accelerating is much smoother. The engine just seems to breathe easier, probably due to the increased VE.

Divorce pipes reduce the turbulence caused by the opening and closing of the waste-gate. Also, the nature of bell housing designs creates turbulence as the chamber is expanded to cater for the turbo outlet and waste-gate. Having dedicated pipes respectively allows for same size pipes and thus, a smoother flow. By joining further down, they help to speed up the extraction resulting in faster opening of the waste-gate.

Descending Genpu purchased popularity order:

DownPipe (DP) and Full / Long DP

• UR DP
• Corksport DP
• CP-E DP & Long DP
• Cobb DP
• ATP Long DP
• eBay DP
• CNT Long DP
• M2 Long DP
• Gutted DP
• Kozmic DP
• Speed Daddy DP
• M2 DP
• TurboXS DP
• Full Race DP
• XForce DP
• AQ Motorsports Long DP
• QAS Long DP
• CES Racing Long DP
• Protuning Lab DP
• Best Mufflers DP

Test / Race / Track Pipe (cat-less) (TP / RP)

• Ultimate Racing (UR)
• CorkSport (CS)
• OBX
• CP-E
• TurboXS
• Street Unit (See Warning)
• Sure (See Warning)
• Cobb

2015 prices and availability:

First Section of Pipe Post Turbo

DownPipe (DP) and Full / Long DP
Test / Race / Track Pipe (cat-less) (TP / RP)

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DownPipe (DP) and Full / Long DP

3” Ultimate Racing (UR) DP

Available from: 3” Ultimate Racing (UR) DP
MS6 (Not found), MS3 Gen1 (Yes), MS3 Gen2 (Yes) cat-less Version 1 $295, cat-less Version 2 $345, Long DP Ceramic Cat $395, Long DP Metal Substrate Cat $445, extra wideband bung $25)

Corksport (CS) DP
MS6 DP

MS6 Long DP

MS3 DP

MS3 Long DP

Available from:
MS6
CS 6 DP
MS3
CS 3 DP
MS6 (Yes: cat-less $349.99, +$281 for cat (long DP)), MS3 Gen1 (Yes) $299.99 + $281 for cat (long DP) with 65mm or 80mm option, MS3 Gen2 (Yes) $299.99 + $281 for cat (long DP) with 65mm or 80mm option

CP-E Long DP
MS6

MS3

Available from:
MS6
http://cp-e.com/webstore/product/maz...kspl-downpipe/ / MS6 long catted
MS3
http://cp-e.com/webstore/product/maz...kspl-downpipe/ / MS3 long catted
MS6 (Yes, catted) $621.40, MS3 Gen1 (Yes, catted) $504.40, MS3 Gen2 (Yes, catted) $504.40

Cobb Long DP

Available from: Mazdaspeed3 SS 3" Downpipe with High Flow Cat / Long catted MS3 Gen 1&2
MS6 (Not found), MS3 Gen1 (Yes, catted) $695, MS3 Gen2 (Yes, catted) $695

ATP DP
MS6 Long DP

MS3 Long DP

MS3 DP

Available from:
MS6 Long DP MS6 ATP Long DP
MS3 Long DP MS3 ATP Long DP
Much less popular: ATP DP MS3 ATP DP
MS6 (Yes, V-band) $439 + Mazda 5-bolt to V-band $95, MS3 Gen1 (Yes), MS3 Gen2 (Yes) cat-less, no donut, 3”, Long DP $299, DP $259

CNT Long DP
MS3 cat-less

MS3 catted

Available from: CNT Long DP
MS6 (Not found), MS3 Gen1 (Yes), MS3 Gen2 (Yes) 76mm cat-less $259, catted $399

M2 Long DP
MS6

MS3

Available from:
MS6

MS6 long cat-less

MS6 long cat-less
MS6 long cat-less