Tech Info - Installing a Catback Exhaust

Special thanks to Corsa Performance for allowing use of some of their graphics and text.

Easily the most common complaint of Viper ownership is living with the sound of the exhaust system.  In its stock form, it tends to be too quiet and has an exhaust note that is not in keeping with the otherwise aggressive nature of the Viper.  This upgrade is all about how to change that.  There are a number of cat-back exhaust systems on the market, which vary in sound quality and volume, quality of construction and ease of installation.  This Corsa 3” cat-back exhaust is generally considered to give the most mellow exhaust note of the options available, is made of long lasting stainless steel, and has excellent workmanship evident in its construction.   Installation is relatively easy with 100% bolt-on construction and the exhaust tips are some of the best looking available.  Installation for other systems would follow the same basic path, although the details may vary.

The graphic below (courtesy of Corsa Performance) shows the basic layout of their exhaust system.  It replaces the stock side resonators with new mufflers and replaces the single rear muffler with dual mufflers.  There is a crossover pipe just before the rear mufflers.

Corsa Exhaust Layout

Below is a link the Corsa website.  They have sound files on the website which give a good representation of the sound quality of their system. 

  http://www.corsaperf.com/viper.htm

In general, the idle sound is noticeably louder with a deeper rumble to it.  When first started, the Corsa exhaust has a different sound that it does when warmed up.  When cold, the sound at idle is a little louder and has a little more of a BLAT sound to it than it does once it is warmed up.  When cruising, the drone of the stock exhaust system is pretty much completely gone.  Under acceleration, the sound is a little louder and more aggressive sounding than stock.   Due to its unique uneven firing V10 design, no exhaust system will make a Viper sound like a V-8 with a good exhaust.  Whether that is good or bad is up to the ear of the beholder, but the unique sound of the Viper is hard to beat.  High flow cats will further  increase the sound volume and raspyness of the exhaust tone.

When you get your new exhaust, it is always a good idea to completely unpack it and ensure all parts are present and that there is no damage BEFORE removing your old exhaust, just in case.   Also test fit the slip joints together in case the ends have become a little deformed.  If they have, they can easily be straightened using an adjustable wrench or pliers. The kit consists of the following contents:

BOX 1

• Rear Muffler Assembly

•  Rear Muffler Lateral Adjustment Bar

BOX 2

• Drivers Side Under Axle Pipe (has a label marking it)

• Passenger Side Under Axle Pipe

• Driver Side, Side Muffler

• Passenger Side, Side Muffler

• (4) 3-inch TORCA Clamps

•  (2) 2 ½-inch TORCA Clamps

• Anti-Seize Compound.  Note:  The anti-seize compound should be put on the threads of all clamps before installing them.  It can stain the stainless steel and care should be used to not get it on appearance surfaces

Corsa Provided Exhaust Components

1.  Get the Viper into the air safely

For this installation, you are going to want to get the rear of the Viper at least about 10” off the ground.  This is easily accomplished with a suitable floor jack and jack stands.  In my case, I also ran the front up onto some Rhino ramps, which gave about 7” of clearance on the front as well.  Alternatively, jack stands could have been used on all four corners.  Of course, if a lift is available that is even better.

Rhino ramps are a common, inexpensive ramp that is just wide enough to fit the front tires on the Viper.  Unfortunately, even though they are low profile, they still do not clear the Viper low angle of attack.  A simple modification that can be made to them to make them work with the Viper is shown below.  Two 2x12’s or 2x10’s are cut with angled ends and staggered about 18” apart to act as a ‘pre-ramp’ for the Rhino ramp.  These are screwed together and the end of the wood that contacts the ramp is cut to the same angle as the ramp so that the wood won’t tend to kick up as the Viper climbs the ramp.  I also drilled a hole through the end of the wood and into the ramp.  Into this oversized hole, I drop a long screw, which serves as a pin to keep the wood and ramp from separating while the Viper is climbing the ramp.  Once the Viper is safely up on top, the pin can be removed and the wood portion of the ramp moved for easier side access.

Rhino ramps

Next you need to get the rear of the Viper up on jack stands.  There are a number of ways to do this.  In my case, I have an inexpensive 3 ½ ton floor jack which has a low profile (4”), but not much of a reach to it.  Because the jack gets higher towards the rear of it, it will not fit far enough under the Viper to reach the frame rails.  To work around this, I found it easiest to just jack the side of the Viper up using the rear jack points at the end of the door sill just enough to place a piece of 2x12 under the rear wheels on one side.  That then gave me enough clearance to get my jack under the frame rails of the Viper.  Alternatively, it could have been driven up on pieces of wood, but I did not want to attempt this since I was running the front up onto ramps and though I might be pushing my luck running up all 4 tires up on wood at the same time.  Placing the jack under the frame rails just behind where they curve out allows the entire rear to be lifted at the same time.  I used some old carpeting between the jack and frame to prevent damage to the frame rails.  Once the Viper has been jacked up to the desire height, place the jack stands under the frame rails.  Ensure the jack stands are set to the same height and are not tilted in any way.  I also used old carpeting on the jack stands to protect the frame rails.  When lowering the jack, do so slowly and make sure the Viper settles onto jack stands properly and the jack stands do not cock or tilt.

Jacking up the Viper

This shows where I located the jack stand on the frame.

2.  Remove the Rocker Panel Covers

Removal of the rocker panel covers is pretty straightforward.  They can be removed before or after the Viper is raised in the air.  I removed mine before so I did not have to worry about damaging them while using the jack.  There are a total of 10 sheetmetal screws holding each cover in place. There are 4 screws under the bottom of the cover located in small indents which should be removed.  Then there are 6 on top of the door sill to be removed.  Two of these are clearly visible and accessible when the hood is opened.  The remaining 4 are hidden under plastic covers visible on the door sill when the door is opened.

Shows basic location of 10 screws

To remove the plugs on the door sill without damaging anything, use a tappet feeler gauge or similar thin tool to slip under the edge of the plugs.  There are two detents on either side of the plug.  When the feeler gauge is pushed into the detent, it releases the latch and the plug can be lifted up on that side.  Repeat for the other side and remove the plug.

Using a feeler gauge to remove hole plugs

This Pic of the Plug shows the latches that you want to depress for removal

Once the plugs are removed, the 4 sheetmetal screws under them can be taken out.  In my case, several of the sheetmetal screws were stripped and would not come out.  Finally, I hit on the idea of grinding down a small flat bladed screwdriver to a fine point.  I placed a rag on the top of the rocker panel cover to protect it and slid the screwdriver between it and the doorsill.  The sharp point could be slide under the head of the screw, which could then be unscrewed as pressure was applied with the screwdriver.

Once the screws are all removed, the rocker panel cover can be simply slid straight off.   Once removed, place them in a safe location to prevent chance of damage.  While they are off, this is also a good time to clean them up.

3.       Disconnect the O2 Sensors

The O2 sensors are screwed into the top of the exhaust pipe just as it curves from the side sills to around the rear tires.  It has a small bundle of wires which connects to it.  I found an open-ended 22mm wrench to be the easiest tool to get mine off as the 02 sensor socket I had would not fit due to relatively little clearance room.  A short profile O2 socket probably would have worked OK.  There is a sensor for each side of the exhaust and they should both be unscrewed and tucked up out of the way to prevent damage to the sensor or wires during the rest of this process.

O2 Sensor Located On Top Of Exhaust Pipe In Front Of Rear Wheel Well

4.       Remove the Stock Exhaust

Now is probably a good time to take a break, but before you do, hit the main exhaust clamping screws and slip joints with some Liquid Wrench or similar rust busting spray and let it set for a few minutes.  Removal of the stock exhaust is primarily an exercise in separating rusted components and you might as well make it as easy on yourself as possible.

Loosen all of the clamps on the old exhaust.  There is a clamp between the catalytic converter and the side resonator on each side as well as a pair of clamps near the rear muffler.

Loosen Clamp to Remove Resonator from Catalytic Converter

Remove the two bolts from the rubber insulator mount/hanger on each side muffler.  These are located near the wheel well of the Viper.  Keep the hardware for later reuse.

Side Insulator Mount/Hanger

Using the hammer, tap the intermediate exhaust pipe away from the inlet of the rear muffler until the pipes separate.  Twisting the exhaust pipe while tapping will also help with this operation.  Then move to the side of the Viper and tap the resonator towards the rear of the vehicle in order to separate it from the catalytic converter.  The entire side resonator/intermediate pipe assembly can then be removed from the car.

Remove the rubber insulators from each side resonator hanger.  There may be a better technique to get these off, but I used a small screwdriver to pry the rubber over the swaged end of the hanger.  Some lubricant may help in this operation.  Keep these for later reuse.

The Old Resonator Has Been Removed And The Catalytic Converter Is Left Hanging In Place

Next, remove the two fasteners from the rear muffler center-mounting bracket.  Keep these for later reuse.  I had removed the rubber mount, but it may be easier to just remove the hanger bracket as shown below 

Rear Muffler Fasteners

The front of the rear muffler can now be lowered and the entire assembly slid toward the front of the car and removed. 

The old rear muffler is shown next to the new one below.  Notice the difference in the size of the stock 2 ¼” exhaust pipes compared to the new 3” ones.  The stock exhaust tips are about 3” across; the Corsa tips are 4”.

Comparison of tips, rear muffler

This shows the difference between the stock exhaust piping and the new 3” stainless steal

5.       Install the New Exhaust

Attach the LATERAL ADJUSTMENT BAR to the REAR MUFFLER ASSEMBLY loosely using the nuts provided.  Keep the assembly loose enough that it can slide easily in the slots.  This will allow the ends of the exhaust tips to be aligned horizontally in the rear fascia opening later in the process.

Shows how the Lateral Adjustment Bar Mounts to Rear Muffler

First step will be to install the REAR MUFFLER ASSEMBLY.  With the LATERAL ADJUSTMENT BAR facing up, position the REAR MUFFLER ASSEMBLY with the tips extending through the rear fascia opening and the ends of the LATERAL ADJUSTMENT BAR slid into the factor rubber hangers.  Just let the REAR MUFFLER ASSEMBLY hang loose for now and do not attempt to secure the rear muffler center mounting bracket to the frame hanger yet.

Now move to the drivers side and slide one of the 2 ½” TORCA clamps over the inlet side of the DRIVERS SIDE, SIDE MUFFLER.  Also slip one of the rubber insulator mounts/hangers removed from the old exhaust over the wire hanger bracket.  Position the side muffler into place in the door sill and slide the inlet of the side muffler assembly over the outlet of the catalytic converter.  Move the to rear of the side muffler assembly and start the mounting bolts of the rubber insulator/hanger to hold it in place, but do not tighten any bolts yet.  The TORCA clamp at the catalytic converter can now be snugged down to keep it in position, but not fully tightened yet.  You will want all joints to be able to move freely until the entire exhaust system is in place.  On all of the TORCA clamps, ensure that the clamp is positioned so that the edge of the clamp is aligned with the edge of the pipe being clamped and that the tightening nut on the clamp is oriented 90° from the slits in the pipe to minimize the chance of exhaust leaks.

Next locate the DRIVER SIDE UNDER-AXEL PIPE (which is labeled) and slide it through the frame with the expanded end toward the outlet of the side muffler.  When oriented correctly, the O2 sensor threaded opening should be pointed up.  Slide a 3” TORCA clamp over the outlet of the SIDE MUFFLER and fully insert the UNDER-AXEL PIPE into the SIDE MUFFLER.  Again position and snug the clamp in place, but do not tighten yet.

Repeat this process to install the PASSENGER SIDE MUFFLER and UNDER-AXEL PIPE the same way.

Next slide a 3” TORCA clamp over each of the REAR MUFFLER inlet pipes.  Insert the UNDER-AXEL PIPES into their respective REAR MUFFLER inlet.  Work each pipe into position by alternately pulling the REAR MUFFLER toward the front of the vehicle and sliding the UNDER-AXEL PIPES into the REAR MUFFLER.  Position and snug down the clamps, but do not tighten yet.

Now that the basic system is located, the center mounting bracket which was removed from the old exhaust system should line up with the REAR MUFFLER ASSEMBLY mounting holes.  Install the two fasteners for the center mounting bracket and tighten securely.

Recheck all slip fit connections and ensure they are fully seated.  Also ensure that the exhaust clears all points on the Viper by at least ¼” to prevent rattles.

Check the rear exhaust tips to verify that they are centered horizontally in the opening of the fascia.  If it is not, tap the assembly into position and then tighten the LATERAL ADJUSTMENT BAR nuts using a 13mm wrench.  There is no vertical adjustment and it is common for the rear exhaust tips to press down slightly on the bottom of the fascia bowing it slightly.  A piece of rubber could be used to isolate the two if desired.

Now it is finally time to go back and securely tighten all clamps and hanger brackets

6.       Reconnect the O2 Sensors  

The O2 sensors are simply screwed back into the mounting points in the new exhaust.  Twist the sensor counter-clockwise several times before threading into the pipe so that the wires are not twisted too tightly once reinstalled.

7.       Check for Exhaust Leaks

Before reinstalling the side sills, the Viper should be started and a check for exhaust leaks should be made around the new slip joint connections that were made.  Use care as the catalytic converter gets hot very quickly when the Viper is running.

8.       Reinstall the Rocker Panel Covers

Installation of the rocker panel covers is just the reverse of the removal procedure.  Use care to prevent damage to the covers while reinstalling them.

9.  Lower the Viper and Enjoy

To lower the Viper, reverse whatever procedure you used to get it in the air. 

Here it is all ready to RUMBLE

Back        Home