how to - mazdaspeed3 downpipe

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phillyb™
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how to - mazdaspeed3 downpipe

postby phillyb™ » 10/15/13 @ 00:49

downpipe has 5 nuts that bolt it to the turbo. getting access to them requires you to remove 2-3 pieces of heat shielding. you will also have to take the primary o2 sensor off in order to access the nuts.
removal of the o2 requires an o2 sensor socket. use 22mm or 7/8.
when the car is hot, removal of everything is easier.
spray o2 with pb blaster.
get under the car and unclip the o2 sensor clips. you will be able to phollow the wires to where they are. they are a bitch. this is one of my least favorite things about this install.
once unclipped, grab a 1/2 inch ratchet, attach o2 socket, HOLD THE HEAD OF THE RATCHET, and loosen it slowly.

here is a pic that shows the o2 removed and the heat shielding. this picture is kevin's...

image

heat shield on the manifold are 8mm.
heat shielding on the dp are 10mm, iirc.
take off the top and bottom heat shield for the manifold.
take off the heat shield on the dp.
you meow have access to the 5 nuts on the dp to turbo connection.

image

nuts are 14mm. spray them with pb blaster. hopefully the car is still a bit hot. if you see smoke and it smells nasty, then the pb blaster's working. lol.
wait a couple of minutes, and loosen very slowly the nuts. you will access all from the top of the car. yes, even the one on the bottom that's closest to the engine. you will need various extensions, and various sockets. have fun. they all come out. don't break the studs. a ratcheting wrench will also come in hand.
once those are loose, get under the car, and loosen the dp to mid pipe.
i normally leave the 2nd o2 sensor on the dp while taking it out. once loosened from mid pipe, you will be removing a bracket that is still holding the dp in place.
4 total bolts. all 14 mm. get a breaker bar, angle it in a weird way and unbolt all 4. this part also kind of sucks...the bracket to dp is easy. the bracket to the block sucks.

image

with the bracket out of the way, the dp should be loose.
unbolt mid pipe to cbe. take mid pipe off of any hangers. remove mid pipe.
remove down pipe, be careful with the o2 sensor. be careful with the insulation.
with the downpipe out, remove the 2nd o2 sensor. honestly, an impact works really well. don't take my word for it though. ask lenny's o2 sensors. ask cornerfreak's o2 sensors. ask s.ilejay's o2 sensors. works like a fucking charm.

installation of new dp should be pretty straightforward at this point. slide the shit in. the shorty's are much easier. the cobble, cp-e, exhaust depot are somewhat of a pain to twist, turn and slide in. oh well. deal with it and get it in there.
bolt it up to the turbo loosely, put antiseize on the nuts, get all 5 nuts on there loosely.
depending on what you have, bolt up the new mid/race/test pipe to the downpipe. use all necessary gaskets. bolt it up loosely. bolt up mid pipe to the cat back. use hangers if necessary. use all gaskets. some mid/race/test pipes will require you to remove the donut gasket off of the oem midpipe and install on mid pipe -> cbe.
put antiseize on the o2 sensor threads and reinstall those, carefully.
tighten everything.
it's up to you whether or not you want to put the heat shielding back on the manifold. i think most people put the top one back on.
with the car still lifted, start it, put your hand next to the dp -> turbo, and feel for air. that will be a leak if you feel it. if you do, kill it, and tighten nuts.
start car, double check.
get under car and feel for air from the other places it can leak. dp -> mp and mp -> cbe. tighten if necessary.

faq and tips
yes, you can reuse the dp gasket.
the downpipe goes out from the bottom. do not try and bring it through the top of the car.
all nuts are accessible from the top.
wear gloves.
deep 14mm sockets and 14mm ratcheting wrenches will be your friend.
use pb blaster when taking shit off.
use anti seize when putting shit back on.
don't get caught

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