||This is what the
"Y"-Pipe looks like for the 1999 CA/NLEV Maxima.
The official name for this part is "Front Exhaust Tube
Assembly". Note it is a two-piece design which includes the
forward pre-cat as a separate assembly. Both the
Stillen and Cattman replacement pipes for CA/NLEV vehicles do not eliminate the forward
pre-cat, as they do on Federal Spec cars. It stays in place exactly
as-is and is necessary to maintain the car's OBD II compliance. The rear-pre-cat,
however, is removed completely from the aftermarket design. The car will
still pass emissions with flying colors, and will be a lot more
powerful. The mighty VQ30DE engine is dying to be unleashed, and
will be once the stock pipe is replaced.
||If the above illustration from
the 1999 Shop Manual doesn't give you a feel for how the 1999/2000 CA/NLEV
exhaust looks, this photo was taken standing directly in front of the
car looking straight down at the forward exhaust manifold. The
blue wire leads to an oxygen sensor which is installed in the manifold. The Federal Spec 4th-gen Maximas have the O2 sensor but
it is not as visible as the CA models. Also, the pre-cat is
surrounded by a heat shield so you can't actually see it. The
Federal Spec vehicles do not have the heat shield, since the pre-cat is
not attached directly to the exhaust manifold as it is in the '99/2K
||Here are the Nissan OEM
gaskets necessary to
install the Y-Pipe. The large, flat gasket goes between the Y-Pipe and
the catalytic converter. The smaller crush ring gaskets are for
the Y-Pipe connections to the rear exhaust manifold & forward
pre-cat . Note the crush
rings are different for the CA-spec vehicle. The smaller
crush ring (top) is for the forward pipe section. Nissan
part numbers are visible on the bags. Prices from Nissan
were as follows: Small crush ring - $2.76, Large crush ring -
$5.16, Cat gasket - $3.43. Cattman normally supplies crush
rings with their production pipes. They do not supply a
new cat gasket, which should probably be obtained from a dealer
||The first prototype Cattman Stainless Steel pipe
design utilized a three-piece system which was held together by a
series of slip joints. The joints are extremely precise
and require no welding or clamping to hold them in place. Unlike
the Stillen pipe and the stock Nissan unit, Cattman's original design
eliminated the flex pipe in the aft section. It was
discovered later that this design, although ideal for a
race-prepped Maxima, was not ideal for a street-driven
car. Once could argue that the Y-Pipe should not even be
placed on a street car, and in fact it comes with such warnings,
but the truth is that most people who have this mod are power
enthusiasts who do not race. The use of a flex pipe
helps to isolate engine vibrations and prevent them from traveling
down the entire length of the exhaust during hard acceleration.
I chose to go the extra
step and have Cattman polish the pipe using a two-step process
which results in a show-like finish.
pictures show each of the three pieces up close, and finally all
three pieces assembled together as they will go on the
car. The slip joints are very precise and will be
"gas-tight" without any welding, crimping, or
Below is a series of shots showing the stock
Y-Pipe exhaust system before installation of the Cattman pipe.
|Before taking off the
stock Y-Pipe, both the main 3-way catalytic converter heat shield and
forward pre-cat heat shield must be removed.
nuts must be removed from the rear exhaust manifold. A
universal joint is necessary to get at one of the harder to
reach nuts, but it comes off no problem.
CA-spec 1999 and 2000 Maximas like mine, the forward pre-cat has
to stay put or the Engine Control Unit ( ECU) will be very unhappy.
The front pre-cat needs to be loosened slightly at the forward
exhaust manifold in order to get the stock Y-Pipe out. It
is a little tricky. Note the forward O2 sensor
embedded in the pre-cat. This stays put as-is.
The stock Nissan Y-Pipe has the nuts built into it,
so when you put the Cattman pipe on you have to screw on 3 of
your own nuts to match the stock bolts. The nuts required
are 1.25 pitch, and can be purchased at any hardware
store. This picture shows
the bolts already removed. The three bolts go in from the
opposite side of the picture.
the two pipes side by side. The clean, smooth design of
the Cattman exhaust flow compared to stock is easily apparent in
pipe was the first Cattman pipe ever built for a CA-spec '99/2K
vehicle, part of what we were doing was checking the fitment of
the piece to ensure quality in the production versions. As
you can see, the part of the Cattman pipe sticking out beyond
the flange was a little bit too much, so we had to shorten
it a bit. No problem, since my shop had the tools
necessary to do this. Production versions of the pipe will
obviously have the correction. The second picture shows
the forward part of the pipe after it was cut down such that
only a very small portion stuck out beyond the flange - just
enough to provide a spot for the crush ring gasket to seat
itself. Don't worry - you won't have to do this on your
||This is not the best
picture, but it shows the Cattman pipe connected to the forward
pre-cat after the slight length adjustment was made.
||The Cattman pipe fit
perfectly to the stock catalytic converter. The stock
hanger is re-used, and supports the pipe at the converter.
This is where Cattman's use of slip joints really comes in
handy. If the alignment is a little off, all you have to
do is rotate the rear pipe within its sleeve to correct. A
perfect fit results every time.
||Here is the completed
pipe, looking very happy in its new home. There is a
definite and noticeable power gain with this pipe, without much,
if any, gain in noise output. I have a Stillen muffler,
which tends to drone a little bit in the 2200-2400 RPM range,
but the addition of this pipe only changed the tone, and not the
volume of the exhaust note. I have a feeling that the
addition of this pipe to a totally stock Maxima exhaust would
result in virtually no noise gain at all, but this is just a
amazed at the quality and fitment of this pipe, especially
considering it was a prototype. I would like to thank Master Mechanic Joe, at Unorthodox
Racing for being the true genius behind this install.
He made it look easy, although this job is not something I would
recommend for an average do-it-yourselfer. Thanks also to
Brian Catts of Cattman
Performance, for finally getting so sick of me bugging him
for a stainless steel version of his Y-Pipe for my car, he had
to go out and make one.