Rear Trailing Arm Installation

Product:
Corvette Tri-Y Headers & Mid-Pipe
Part Numbers:
Complete Kits:
1150043 – Base/Z51 Complete Header Package with Cats
1150044 – Base/Z51 Complete Header Package without Cats
Applications:
Chevrolet Corvette, 2014 - Current
Description:
These Tri-Y Headers and Mid-Pipe are engineered to be a high
performance exhaust system for C7 Corvettes. Proper runner lengths,
merge angles, and tube diameters have been combined to provide
maximum scavenging and maximum power from LT engines.
Rev. 1/17/2013
What’s in the box:
Item
Left Header
Right Header
Mid-Pipe
O2 Sensor Bung Plug
V-Band Clamps
O-Band Clamps
Qty
1
1
1
1
2
2
Difficulty of Installation: Beginner |-----------------------------------x---------| Advanced
Reason: This product involves careful fitment and the use of a lift is recommended.
Expected Installation Time: 5 Hours
Recommended Tools:
 3/8” drive ratchet & extensions
 1/2” drive ratchet & extensions
 13mm wrench
 15mm wrench
 22mm wrench
 10mm socket
 13mm deep well socket
 15mm deep well socket
 18mm deep well socket
 19mm deep well socket
 21 mm deep well socket
 5/8” Spark plug socket
 Various ratchet extensions and swivels
 Torque wrench
 Anti-Seize compound
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Prepare Vehicle for Service
This installation should be performed by a professional installer. If you do not have
proper tools, safety equipment, and training you run the risk of injuring yourself of
damaging your car. The use of a lift is strongly recommended to perform this
installation. It is highly recommended to spray various nuts and bolts in the factory
exhaust with a penetrant such as PB Blaster or WD40 and allow it to soak for a few hours
to avoid damage to seized bolts.
Step 1: Raise Vehicle
Securely support the vehicle on a lift or 4 jack stands with at least 24 inches of clearance
from the frame rail to the ground. Remove the front wheels at this time (19mm socket).
Step 2: Disconnect Battery
Remove the negative battery cable to battery nut and separate the cable from the battery.
Step 3: Remove Dipstick Tube
Cars not equipped with the “Dry-Sump Package” require the dipstick tube to be removed
to get the manifold out and the headers in. Remove the bolt securing the tube to the head
and pull upward on the tube to unseat the bottom end from the oil pan (15mm socket).
Step 4: Remove Fuse Block and Tray
Remove the plastic cover on top of the fuse panel in the engine compartment. (Photo 1)
Free the fuse block by first releasing the four clips around the panel retaining the handles.
Lift/Rotate the handles ~170 degree to the center of the fuse panel (Photo 2), and then
back out to ~90 up from the panel (Photo 3). Gently pull straight up will free the fuse
block from the tray.
To the remove of the fuse panel, two battery connections can be found to the rear of the
fuse block (Photo 3). Remove the nut retaining these to the fuse panel (13mm Socket)
and slide the terminals up over the post and free of the panel.
NOTE: Lift the fuse block carefully as to not damage the pins on the underside of the
fuse block. Failure to do so will result in electronics damage to the car.
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Battery connections here
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Remove the five colored plugs from the bottom of the fuse block. Each of the five plugs
has a curved retaining clip on the outer edge of the tray. By squeezing this clip slightly
the plugs can be slid outward ~1 inch and then lifted up and out of the tray.
Remove the three nuts (10mm socket) that retain the fuse block tray to the engine
compartment and lift the tray free from the car and the plugs.
Step 5: Remove Spark Plugs
Remove the spark plug wires and spark plugs to avoid damaging them during installation
(5/8” spark plug socket).
Step 6: Remove the Tunnel Brace
To gain access to the tunnel and to the Mid-pipe, remove the 34 small fasteners (13mm
socket) and two larger fasteners (18mm socket) from the tunnel holing the brace in place.
NOTE: Two of the small fasteners are in slotted grooves and can be left loosely in place
to keep the tunnel brace from falling while you remove the other fasteners.
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Step 7: Disconnect O2 Sensors from Engine Wiring Harness
Disconnect the primary and secondary O2 sensors from the engine wiring harness. The
connectors can be found near the rear of the engine block and beginning of the tunnel.
Primary O2 sensor connectors are black, secondary O2 sensor connectors are gray.
Step 8: Disconnect Dry Sump Lines (if equipped)
If your Corvette is equipped with a dry sump oiling system, remove the two dry sump
lines from the passenger side of the pan (13mm socket). Approximately 9 quarts of oil
will drain from the sump system, so be sure your drain pan has sufficient capacity to
catch the used oil. Also be sure that you have at least 10 quarts of fresh oil on hand to
refill the sump after the header install.
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Step 9: Lower the Subframe
With the engine mounts unbolted from the subframe (13mm socket, four nuts) and the
engine supported, remove the eight upper control arm bolts (13mm socket). Be sure to
make note of how many washers are behind each bolt for reinstallation.
(Front Upper Control Arm Bolts)
Remove the four bolts holding the front shocks to the lower control arm (10 mm deep
well socket and wrench).
(Lower shock mounts)
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With the suspension unbolted and secured, remove the two front subframe bolts (21mm
deep well socket) completely and loosen the four rear bolts (21mm deep well socket)
holding up the subframe. Take care to keep a few threads engaged before you completely
support the subframe and remove the driver or passenger bolts completely as needed to
put the headers in place.
(RH Lower Subframe Bolts)
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NOTE: Be sure all the preparation steps are completed prior to attempting OEM
manifold removal or new Pfadt Tri-Y Header installation. IT JUST WON’T
WORK!
OEM Exhaust Removal
Step 1: Remove Factory Mid-Pipe
Remove the two nuts securing the mid-pipe hanger springs to the mid-pipe (13mm deep
well socket). Remove the nuts and bolts attaching the mid-pipe to the cat-pipe (15mm
deep well socket). Loosen the O-band clamps connecting the mid-pipe to the overaxle
(15mm deep well socket).
Carefully remove the mid-pipe from the vehicle.
Step 2: Remove Exhaust Manifolds
Remove the nuts securing the primary cat-pipe to the exhaust manifold and remove the
cat-pipe. It may be necessary to raise the engine slightly from the subframe in order for
the flange on the cat-pipe to clear the studs on the manifold.
It may be helpful to raise the engine with a screw jack or floor jack, being careful to
distribute the load across the bottom of the oil pan with a wood block or other method to
avoid damaging the cast aluminum pan.
Remove the five bolts securing each exhaust manifold to the head (13mm socket and
short extension). Remove the manifolds and gaskets from the vehicle. Inspect the head
surface and carefully clean it with a gasket scraper if needed. Take care not to gouge or
scratch the sealing surface of the aluminum head.
It may be helpful to leave the header hanging by 2 bolts while the lower sections of the
stock exhaust are removed and the various line and wires are moved aside.
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Step 3: Remove O2 Sensors from Factory Exhaust
Remove the primary and secondary O2 sensors from the factory exhaust (22mm wrench).
Retain the O2 sensors for use in your Pfadt Power Products exhaust.
(OEM O2 bungs)
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NOTE: Be sure all the preparation steps are completed prior to attempting OEM
manifold removal or new Pfadt Tri-Y Header installation. IT JUST WON’T
WORK!
Pfadt Tri-Y Header Installation Procedure
Step 1: Install O2 Sensor Extensions
If provided, connect the O2 sensor extensions to the engine wiring harness. The primary
O2 sensors do not need extensions. The secondary O2 sensor connectors can be found at
the rear of the block on all Corvettes. Extension kits are available through Pfadt Race
Engineering.
Do not connect the actual O2 sensors at this time, but it is recommended that you test fit
your O2 sensors in the weld bungs on the headers and mid-pipe (for catted systems).
Some wideband O2 sensors are too large to fit through the pre-drilled hole. If that is the
case with your particular wideband sensor, carefully enlarge the hole as necessary with a
hand file or carbide burr on a die grinder. Take care not to damage the threads in the
bung!
If rear extensions are not provided, it may be necessary to extend the rear O2 sensor
wires (Catted Mid-pipes only). We recommend having a confident and capable technician
do this if you are not.
Cut and splice in ~ 10inches of wire on the sensor side of the connection. Be sure not to
splice wire before the connection! O2 sensors are much easier to replace than engine
wiring harnesses!
Step 2: Install Driver Side Header
Install the driver side header from the bottom of the vehicle. It may be necessary to raise
the engine slightly to allow enough clearance to fit the header between the subframe and
the side of the block. Take care not to damage the clutch or brake lines running along the
firewall with the header flange during installation.
NOTE: Do not install the header bolts at this time; just leave the header sitting in place.
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Step 3: Install Passenger Side Header
Install the passenger side header from the bottom of the vehicle. It may be necessary to
raise the engine slightly to allow enough clearance to fit the header between the subframe
and the side of the block. Take care not to damage the wiring harness heat sleeve running
along the firewall with the header flange during installation.
NOTE: Do not install the header bolts at this time; just leave the header sitting in place.
Step 4: Install Header Gaskets
Re-install the header gaskets and header bolts. DO NOT use any sort of gasket sealer on
the header gasket. O2 sensor and catalytic converter failure may result.
NOTE: Orientation of the gaskets is critical for fitment and good sealing. Pay attention
to the gasket labels and be sure the “Manifold Side” lettering is facing the header and not
the engine.
Leave the header bolts loose (only engage a few threads) to allow easier alignment of the
V-band flanges with the mid-pipe.
Step 5: Install O2 Sensors
Apply a thin coat of anti-seize to the threads on all O2 sensors. Install one primary O2
sensor (black connectors) in each header (22mm wrench). It does not matter whether
you install the factory O2 sensor in the forward or rear bung in the passenger side header.
If a wide-band O2 sensor will be used, install it in the extra bung in the passenger side
header. If no wide-band sensor will be used, apply anti-seize to the threads of the
provided bung plug and install it in the extra bung (10mm hex bit socket).
NOTE: To ensure the front O2 sensors will reach, be sure to remove the connectors
from the retaining clips on the heat shield. This will give the wires enough length to be
properly installed.
Connect the primary O2 sensors to the connections and tuck the wires out of the way of
the headers. It is convenient to zip-tie the O2 wires to the various fluid lines running
along the firewall to keep them away from the headers.
If the Pfadt Tri-Y exhaust system has catalytic converters, install the secondary O2
sensors (gray connectors) in the bungs in the mid-pipe (22mm wrench). If the exhaust
system does not have catalytic converters you will no longer need the secondary O2
sensors.
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Step 6: Install Mid-Pipe
Slide the provided O-band clamps onto the rear ends of the mid-pipe and slip the midpipe onto the overaxle. Leave the clamps loose.
Install the mid-pipe hanger posts through the holes in the stock hanger bracket and (if
removed) install the stock hanger bracket in the stock mounting location (13mm socket).
Align the V-band flanges on the headers with the flanges on the mid-pipe and install the
V-band clamps. Tighten the nuts far enough to ensure the flanges won’t slip out of the
clamps, but leave them fairly loose for now (13mm deep well socket).
Step 7: Raise Subframe, Reinstall Suspension and Torque Fasteners
Raise the subframe back into position and start the four front subframe bolts (21mm
socket).
With all six bolts started, slowly raise the subframe into place. Take care to ensure the
engine mount bolts are aligned with the subframe and inserted correctly. When all 6
fasteners are aligned, raise the subframe completely into place and torque the fasteners.
With the subframe in place, reinstall the four lower shock mount bolts into the lower
control arms (10mm socket and wrench). Carefully lift the upright and upper control arm
into place and replace the eights fasteners (four each side, 13mm socket). This is easily
done near the ground with a jack under the lower ball joint.
NOTE: Be sure to put the correct number of washers in the correct location as noted
during disassembly!
Step 8: Connect Secondary O2 Sensors (only for mid-pipes with cats)
Connect the secondary O2 sensors to the extensions installed previously (or extended
wires if extensions are not available. It is OK for the sensors to cross and connect to the
wiring harness on the opposite side of the car. The included heat resistant sleeve can be
slipped over the connectors to protect them from the heat of the cats.
Route the O2 sensor wires to the corners of the transmission tunnel and secure them in
place with zip-ties if needed.
Step 9: Torque Header Bolts
Install and torque the header bolts at first pass to 11 ft-lbs (15 N-m). Begin with the
center two bolts and alternate from side to side, working toward the outside bolts.
Torque them at final pass to 18 ft-lbs (25 N-m), again starting with the center bolts and
alternating from side to side as you work outward toward the ends of the flange (13mm
socket, various extensions).
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Step 10: Torque Fasteners
Torque the O-band clamps at the rear of the mid-pipe to 32 ft-lbs (44 N-m) (15mm deep
well socket).
Torque the V-band clamps to 12 ft-lbs (16 N-m) (13 mm deep well socket).
NOTE: To prevent thread galling, do not use a high-speed driver such as an
impact gun on the V-band clamp nuts. Only tighten by hand and torque to spec.
Step 11: Reinstall Dry Sump Lines (if equipped)
If dry sump lines were disconnected earlier in the installation, reinstall them now and add
oil. Torque the bolts securing the fittings to the pan to 16 ft-lbs (22 N-m) (13mm socket).
Add oil to the sump tank per the owner’s manual to replace the oil lost when the lines
were disconnected. This is typically approximately 9 quarts, but may vary from one
installation to another.
Step 12: Reinstall Dipstick Tube
If the dipstick tube was removed earlier in the installation, reinstall it now (15mm
socket).
Step 13: Reinstall Spark Plugs
Reinstall the spark plugs and plug wires. If you have difficulty getting any spark plugs
started in the holes, refer to the gasket installation step to ensure the header gaskets are
not partially covering any of the plug holes.
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Step 14: Reinstall the Tunnel Brace
Reinstall the tunnel brace on the two slotted bolt holes. Start all the small fasteners
(13mm socket) and two larger fasteners (18mm socket) in the tunnel before torqueing any
of the fasteners.
Torque the tunnel plate bolts to 18 ft-lbs (25 N-m).
Step 15: Check for Leaks
Double check that all fasteners have been tightened, wiring is not dangling on headers,
spilled oil is wiped off headers, and that there is adequate clearance between the headers
and any other components. Start the car and check for exhaust leaks, oil leaks, or coolant
leaks.
If the car is equipped with a dry sump system check the oil level per the owner’s manual
and adjust oil level accordingly.
Congratulations, you have successfully installed your new Pfadt Power
Products headers and mid-pipe and are now ready to reap the rewards of a
carefully engineered exhaust system!
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Fastener Torque Specifications
Application
Engine Mount Nuts
Mid-Pipe Hanger Bolts
Header Bolts (First Pass)
Header Bolts (Final Pass)
V-Band Clamps
Tunnel Plate Bolts
O-Band Clamps
Subframe Bolts
Lower Shock Mounts
Upper Control Arm Mounts
Dipstick Mount Bolt
Metric
65 N-m
25 N-m
15 N-m
25 N-m
16 N-m
25 N-m
44 N-m
65 N-m
25 N-m
32 N-m
25 N-m
Torque Spec
English
48 ft-lbs
18 ft-lbs
11 ft-lbs
18 ft-lbs
12 ft-lbs
18 ft-lbs
32 ft-lbs
48 ft-lbs
18 ft-lbs
24 ft-lbs
18 ft-lbs
Please contact Pfadt Customer Support with any questions!
Warranty and Use Restrictions
Our warranty covers the workmanship and materials of the headers and mid-pipe for the
original purchaser on the original vehicle of installation for five years. Headers and midpipes that are sold to another person or removed and installed on another car are
excluded. Catalytic converters are covered for one year. Pfadt is not responsible for
premature failure of a catalytic converter due to tuning/tuning related issues or other
negligence on the part of the installer or end user. If you have a catalytic converter
failure outside the limits of the warranty, we will ONLY charge you for the replacement
of the cats and provide you with a free mid-pipe for up to 5 years from original date of
purchase. Pfadt reserves the right to replace individual components.
All Pfadt headers are for off-road use only. These exhaust systems are intended for use
on “racing vehicles” (i.e. a competition vehicle used exclusively for competition on
closed-course circuits) and do not require an exemption or Executive Order from CARB
to be sold in California for such purpose. However, such parts are prohibited from use on
many state’s public roads, including California, even if occasionally used “off-road.”
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1055 S 700 West
Salt Lake City, UT 84104
888-972-2464
www.PfadtRacing.com
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