From the first moment I got my Spyder, the first recommendation from
everyone was "gut your cats!" But hey, that manifold is like right next
to the motor! That’s mechanical
stuff! How am I supposed to deal with that? Well it turns out, that
with the proper tools and a lot of time on your hands, its not that
difficult.
Tools and consumables:
From my little
precat removal experience, I’ve found out that the following is
essential to an stress-free experience. I strongly suggest not starting
this little project without:
1) deep and regular hex sockets (esp 12mm and 14mm)
2) breaker bar
3) PB Blaster
4) socket extension
5) lots of daylight
The essential tools that are required are:
1) ramps
2) 14mm, 12mm and 10mm sockets and ratchet
3) 2 gaskets from MrT (see diagram below)
Optional but nice to have are:
1) new studs
2) new bolts
Procedure:
Here’s a diagram of the entire disassembly process. Please refer to this often:
For more diagrams, check here.
The
first step is to put your car on ramps. Remember to have someone always
spot you when using ramps. Also, keep your handbrake engaged for more
control:
Access
to the nuts that need to be removed from underneath the car is hindered
by the rear diaper. You will have to remove this with a socket wrench.
The screws are easily removed:
You can see the spots where screws need to be removed here:
It is also eases access if you remove the mid-diaper. The screws and poppets that need to be removed are highlighted:
From
underneath the car, take a gander at the "3 Amigos", they will be your
biggest challenge in this project. Refer back to the diagram to see
where this is in. It’s in Area 4 in the lower left hand side of the top
diagram, near the 2 gaskets:
Use
PB Blaster or similar product and drench the 3 Amigos. PB Blaster is
cheap, frustration is expensive. Let sit for a couple of minutes (or
hours, or days). Using a breaker bar, 12mm DEEP HEX SOCKET, and socket
extension, pry the nuts loose by rotating counter clockwise.
It
is essential that your socket is HEX shaped, as any other shape will
easily make the nut lose it’s thread due to the amount of force being
applied.
You will need a DEEP SOCKET, as the studs extend past
the end of the nut, making it difficult for your socket to have
sufficient grip.
You will need a socket extension, as the
location of the nut is very difficult to get at (maybe even impossible)
without a socket extension.
After
removing the 3 Amigos, you will need to remove 2 bolts that brace the
manifold to the frame. They are directly to the top of the 3 bolts you
just removed. Use PB Blaster to loosen. The left bolt is 14mm, the
right is 12mm. There may not be room to use the breaker bar.
You’re
done with removing the nuts and bolts from underneath the car! Yay! Now
to deal with the bolts on top. Pop the lid off the engine bay, and
remove the rear strut bars. Instructions for this can be found here:
http://spyderchat.com/forums/index.php?sho…c=44014&hl=
Now
to remove the top heat shield, which is held down by 4 bolts. Refer to
the 1st diagram, this will be Area 2, top left hand side. You will see
2 bolts. Use PB Blaster to loosen the bolts, and use a 12mm socket and
the breaker bar to remove the bolt by rotating counter clockwise:
Refer
to Area 6 on the diagram. This is where the last 2 bolts that hold down
the heat shield are. Use PB Blaster to loosen the bolts, then remove
with a 12 mm socket and ratchet. There will not be enough room for a
breaker bar, but the bolts will hopefully give before the bolts lose
thread or snap 
The
heat shield is now loose, but the 02 sensors need to be remove first.
Refer back to the diagram. This will be in Area 1. Left side:
Right side:
The 02 sensor harnesses can be disconnected easy, by pressing on the tab to unlock, then pull apart:
Now
to remove the 02 sensors. You will need an 02 sensor socket. This is
looks like an ordinary socket, with a slit on the side for the sensor
wire to pass through:
Soak
the 02 sensor in PB Blaster. Wait a couple of minutes. Place the 02
socket on the 02 sensor, passing the wire through the slit, like so:
You can now remove the 02 sensor using a ratchet, or a breaker bar if space allows:
Here’s what it looks like removed:
After taking off the other 02 sensor, you’re now free to take off the top heat shield:
You’ve
now exposed the manifold! See Area 3 in the diagram on top for
reference. There are 5 12mm bolts that connect the manifold to the
engine. Use PB Blaster to loosen the bolts. Use 12mm DEEP SOCKETS and
the breaker bar to remove the 5 bolts.
Pull out the manifold, and remove the heat shields from it. You’re halfway there! Now to re-assemble everything!
So here’s your engine bay. Lots of space without the manifold:
Install the gasket that mounts to the engine. Refer to Area 3 in the diagram. Easy:
Install
the 2 smaller gaskets that mount near the 3 amigos. Refer to Area 4 in
the diagram. You may have to shape the gaskets so that the fit around
the 2 openings snugly:
Mount the gutted manifold / header on the 5 studs:
Prep all areas that will be bolted down by spraying with WD40 or similar product, then install the nuts and tighten by hand:
Underneath the car, line up the bottom of the manifold/header, and put on the 3 amigos and tighten by hand:
Install the bolts that brace the manifold against the frame. Remember, 14mm on the left, 12mm on the right. Tighten by hand:
At this point the manifold should be aligned properly, with all nuts and bolts tightened by hand.
Use
the ratchet, socket extender and 12mm deep sockets to tighten the 3
nuts at the bottom of the manifold. Refer to Area 4 in the diagram:
Use
the ratchet and 12mm and 14mm sockets to tighten the bolts that hold
the manifold to the frame, directly above the nuts you just tightened:
Bottom part is done for now!
Back on top, tighten the 5 nuts at the top of the manifold by using the ratchet and 12mm sockets. See area 3 in the diagram:
Mount the top heat shield:
Install and tighten the top 2 bolts using a ratchet and 12mm sockets:
Install and tighten the 2 lower bolts using a ratchet and 12mm sockets:
Install and hand-tighten the 02 sensors:
Tighten the 02 sensors using the 02 sensor socket and the ratchet:
Reconnect the 02 sensor harnesses:
Finally,
reinstall the rear diapers, reinstall the rear strut braces, take the
car off the ramps, go for a drive, and sleep at peace for ever after
not worrying about pre cats anymore! 
Driving impressions
Well,
I never expected any benefit from decatting, but there actually was!
The engine seems to breathe more freely, and there is a slight increase
in bass from the exhaust. Not a bad thing at all!
