View Full Version : Exhaust Write-Up

03-03-2009, 05:14 PM

There are 3 main different types of headers: shorty, mid-length, and long tube. Each have their advantages and disadvantages.

GOOD- Price, Size, Ease of fitment
BAD- flows less, Compact design can cause plug wire clearance problems

GOOD- Flow slightly better then shortys, Fitment easier then long tubes
BAD- Less flow then long tubes, bit more expensive

Long tubes
GOOD- Extremely high flow
BAD- Expensive, tougher to install

Headers should be an important part of anyone’s MOD plans. Stock manifolds on the 3.4's and the early 3.8's are very restrictive. In 2000 tubular manifolds were added. While they are an improvement, there is still much to be gained with headers. No matter what mods you have to help increase the air flow into your engine, if you can't get that air out it will do you no good. Headers are the first and most important way of doing this.

Your headers flow is determined by 3 main things: primary size, primary length, and collector size. The rule of thumb here is bigger is better, but that’s only to a certain extent. Having larger primaries and collectors decreases backpressure. By doing this it increases horsepower, but moves your torque higher in the rpm range. This is good to a certain point. If you get to large you will have a serious loss of torque due to low backpressure. All the headers made for the f-bodes have large enough primaries to help with power, without giving up torque on the low end.

Another important part of headers is the material they are made of, as well as any coating that is applied to them. Their are many different metals that headers are constructed out of, including mild steel and 304 stainless. While mild steel helps to make a more cost effective header, stainless is the best for quality and durability. Once your material is chosen, the next step is to determine if you want a coating on them. Some opt just to paint them with a high temp paint (which will bake off fairly quickly). While this is again the most cost effective, this does little to protect the metal. If your headers are made of mild steel and merely painted, they are more apt to rust though. The next option is to wrap the header in exhaust wrap. This has been around forever and is effective in keeping the heat in the header, and out of the engine bay. The only problem with wrap is that it can hold moisture against the header, and cause some rusting problems. The last, and best option is to have the headers ceramic coated. Their are different temperature coats that can be applied. The good thing about ceramic is that it holds heat inside the header, and provides protection for the metal.

Basically your choice should come down to what your goals are. If you just want a bolt on car that’s fun to daily drive and might see a little track time, then shorty or mids are your answer (pacesetter, Clear Image, RK Sports). If your going all out with it and want max power (using FI of some sort, stroker, or other big N/A build) the long tubes are for you.

Catalytic Converter (cat)

A catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust into harmless compounds.

The three harmful compounds are:
· Hydrocarbons (in the form of unburned gasoline)
· Carbon monoxide (formed by the combustion of gasoline)
· Nitrogen oxides (created when the heat in the engine forces nitrogen in the air to combine with oxygen)

Carbon monoxide is a poison for any air-breathing animal. Nitrogen oxides lead to smog and acid rain, and hydrocarbons produce smog.
In a catalytic converter, the catalyst (in the form of platinum and palladium) is coated onto a ceramic honeycomb or ceramic beads that are housed in a muffler-like package attached to the exhaust pipe. The catalyst helps to convert carbon monoxide into carbon dioxide. It converts the hydrocarbons into carbon dioxide and water. It also converts the nitrogen oxides back into nitrogen and oxygen.
Once headers are done, the cat is the next most restrictive part of the exhaust. It’s very common for our cats to become clogged, causing a loss of power as well as mpg’s. Even if they are not clogged, however, they are a bottleneck for the exhaust. If the blockage does occur, it can simply be replaced with any universal cat that has in and out diameters that match your current exhaust size.
For the performance aspect, there are many high flow options available. The trade off with a high flow cat is that it allows more of the harmful compounds into the air. This can cause you to throw ODB2 codes, and even fail emissions test that your state may have. These codes can be corrected with an O2 simulator, or by having the codes deleted via HP Tuners. This will allow certain people that only have and ODB2 emissions test to pass; however if you have to do a sniffer test you can still fail. Another option is to completely remove the cat, and replace it with a piece of pipe. **Warning: its illegal in any state to modify the emissions part of vehicle. So do this at you own risk. V6f-body.com does not condone doing this. While this will provide the best flow there are two downsides. This allows all the harmful compounds the engine produces to be released into the air, it causes even more rasp in the exhaust, and can have a horrible smell as well.

Cat-back Systems

They are what the name implies…a full exhaust system from the catalytic converter(s) back. Since it is unlawful to remove cats before 50,000 miles (or unless they’re damaged…in most states…check local laws), most exhaust companies offer such systems.

There are many advantages to choosing this route. For one thing, the tubing diameter of most aftermarket exhaust systems is usually larger and this configuration, usually offers more horsepower. Of course, not all manufacturers test and build their systems the same way.

Material used is a big part of selecting your exhaust. The cheaper cat backs will use aluminized metal. While this is cheaper, it is more apt to rust out after a couple years of use. The more expensive exhaust will use stainless steel. This is a much more durable metal, that will hold tough for many years to come.

With today’s engines and exhaust tracts being offered as highly efficient right from the factory, extensive testing is required to actually gain horsepower. There are many companies that simply offer a bigger pipe and a muffler that is freer flowing and while the vehicle is louder, they can not quantify any horsepower gain.

**It is recommended to have any cat back system completely welded instead of clamped together. This helps to prevent leaks, and keep the performance gains where they should be.

Shop-Built Systems

Another option for a cat back is to have a local shop custom build for your application. Most shops now have a mandrel bender that can accomplish the same smooth bends you will get from a pre bent system. You will usually pay a bit more since this is a one-off build that is labor intensive. A small downside here is loosing all the research the big exhaust companies have in dyno testing their systems.

Universal Mufflers

If you are just looking for that rumble and do not care about the performance aspect, simply adding a muffler is probably for you. Nearly all major suppliers that offer cat backs will have the mufflers available for individual sale. You can even usually find these mufflers with the in and out diameters matching your stock, so they are a simple clamp on application. Just like with cat backs however, it is suggested to have it fully welded to prevent leaks.

Which should you buy?

It depends upon your budget and goals for the vehicle. If you want it done right, a properly engineered, dyno tested cat back system is the best choice, hands down. In situations where lack of availability of such a system or associated costs are prohibitive, consider some of the alternatives we’ve presented here.

03-03-2009, 05:18 PM
Headers available (Prices vary greatly depending on brand. **All websites listed are just an example of where they can be purchased. Other sites offer these as well.)

1.Pacesetter (best bang for the buck)
3.8 painted headers w/ y-pipe
Price- $250 new.

3.8 Ceramic Coated w/ y-pipe
Price- $400

Info-Mid-length, primaries 1 1/2in, 3-bolt flange, 16 gauge mild steel, 3.8 in. flange, 2.5in collectors

2.CIA (clear image headers)-(Believed to be the best quality)
Price-$295 for mild steel headers, add $165 for Ceramic coating, add $150 for y-pipe

Info-The header is made of 14 gauge mild steel. The flanges are laser-cut and 3/8" thick. The primaries are 1 1/2" into 2 1/2" collectors. They are satin ceramic coated inside and out. The custom Y-pipe is dual 2 1/2" pipes into a single 3" pipe. It is aluminized 14-gauge tubing and available for both the manual and automatic transmissions. Our headers have a superior fit and do not leak. We are known for our quality, performance and excellent customer service.

Price- around $500 (ceramic coated)

Info-The RKSport V6 header system offers individual tubes that are 1 3/4 in. in diameter with 3/8 in. flanges. Each system includes flanges at the end of the main header section, and the "down" pipe for the connection between the header pipe and the catalytic converter. All header systems come with ceramic coating and are manufactured from extremely strong 14-gauge steel. (1993-1995 3.4L V6; 1995-1998 3.8L V6)

4.FFF long tubes (only long tube offered)
Price-$750 for headers, add 100 bucks for the y-pipe

Info- -304 SS 16 gauge construction
-1.5" primaries
-2.5" collectors
-TIG Welded

The 3.4 f-bodies have the option of the Pacesetters or the RKsports headers. They can be found on the same sites listed for the 3.8's.

Catalytic Converters (high-flow) There are endless high flow cats that can be used for our application. It basically comes down to the old saying
"You get what you pay for". Listed below is a widely known, and used high flow cats.

Magnaflow Catsound Cat
Price- $80

Info- these can be had in an array of different Lengths and diameters. These can cause exhaust codes to be thrown. To fix this, either an O2 sim must be added, or the code must be removed from your computer.

Cat-back Systems Listed below are most cat back systems available for our cars. Some require the addition of a SLP adapter kit to work (or a little custom work by our exhaust shop). If this is so, it will be noted at the bottom. To answer the question before it comes up, no exhaust is going to give you the true V8 sound. You may get close at idle, but all v6’s will have rasp in the higher rpms.

Price $450

Price $405

Price $335

Price $390
*Will require SLP adapter Kit

SLP Loudmouth I/II
Price $430
*Will require SLP adapter kit.

http://www.gripmotorsports.com/pi~pn~Borla+Cat+Back+Exhaust+System+Split+Rear+Exi t+Chevrolet+Camaro-5666.html
Price $830

Price around $1000
*Will require SLP adapter kit

TSP Rumbler
Price $250 with no tips
*Will require SLP adapter kit.

05-13-2013, 05:10 AM
credit to grayman99 :link to info


Thanks to all the helpful (and patient) forum members (ellik/blldog to name just a few) who helped with my initial understanding of our stock exhaust systems and some of the basic differences in the various aftermarket cat back kits and their respective ‘model years’ that are available for the L36 Camaro/Firebird. If any of the following information is incorrect it is not their fault, but rather this authors. This page is intended as a basic overview for those of you who are just getting started in modding the exhaust system of your car. Please follow up with your own research regarding your particular year vehicle, engine type, intended aftermarket system, etc., as well as any emissions requirements your particular state may have.


The stock exhaust system for the 3.8L F-Body is 2.25” ID
The stock Y pipe terminates (welded at factory) at the catalytic converter and is 3” ID.
The stock CAT is 3” ID in and 2.25” ID out.
The stock S pipe has an O2 sensor boss for the rear O2 emissions sensor.
The stock S pipe is 2.25” ID as is the rest of the exhaust piping from that point on up to the muffler ‘IN’ port.
The stock tail pipes…if you have stock dual tips are 2.0” ID at the muffler ‘OUT’ ports.
Mandrel Bent: Mandrel bending allows the piping to retain its full diameter through bends. This is much preferred over non mandrel bent pipes. Non mandrel bends severely crimp and pinch the pipe through bends and this greatly reduces the ID of the pipe. Most muffler shops DO NOT have a mandrel bender. Name brand aftermarket catback systems feature mandrel bend pipes.

Dedicated (designed specifically for) V6 cat back systems are 2.5” and typically start AFTER the S pipe. They are made for your specific year of vehicle so they require no further modifications. They are the easiest to install and should come with everything you need.
3” cat back systems are originally designed for the V8 F-Body but can be easily adapted for use on the V6 F-Body car.
Not all 3” (v8) cat back systems come with an S pipe. (model year dependant)
V8 tail pipe hangers are different than v6 tail pipe hangers.
Not all cat back systems come with transverse ‘under gas tank’ oval muffler. Some (such as the SLP LM) come with a bullet style ‘resonator’ that usually mounts inline in the mid pipe.
Not all cat back systems feature dual tip exhaust.

Aftermarket CATs have collars that slip OVER the appropriately sized exhaust pipe. Example…The stock Y pipe is 3” ID. A 3” in CAT will slip over the Y pipe…to be clamped or welded. If you have a 3” ID S pipe…a 3” out CAT will slip OVER the 3” S pipe to be clamped or welded. Get it? In other words…muffler and cat diameters are sized with ends that will read 3” or 2.25” etc., but the ends have collars that are slightly bigger than that diameter as they are intended to slip over the respective 3” or 2.25” main exhaust piping.

We use 12” oval cats on the 4th gen F body. Some manual transmission cars require an Air Tube…auto trans cars do not. Our rear ‘O2’ sensor boss is in the factory S pipe. Depending on whether or not you plan of doing a full 3” conversion or if you are adding a ‘built for your year v6’ cat back you may need to add an O2 sensor boss to your list of parts. The sensor boss can be welded in to the S pipe by pretty much any muffler shop. Another option when doing a full 3-inch conversion is to order a universal 3x3 cat with rear O2 sensor boss. I used a magnaflow/carsound universal 12” oval 3”x3” no air tube #94039…not for California…about $75. Whether or not you plan to SIM your O2 sensors…you still need to look official, right?

Heavy Duty U-bolt clamps: Just as titled these babies are heavy-duty clamps. I got mine from NAPA for $4. They have a retainer welded on the pressed metal clamp portion to inhibit spreading. (see fig. 1)

Hangers: Specific systems for your specific year vehicle should (in most cases) also come with the appropriate style tail pipe hanger mounts for that particular year. If you plan on converting different year/engine type (v8 to v6 for example) cat backs to your v6 you will most likely need appropriate ‘stock’ chassis hanger mounts for that year/engine type or you can use universal hangers or possibly adapt/convert what you already have. This is nothing that you can’t work out with a little effort and a trip to your local parts store. You can even rig something up that is safe but temporary and then use your old hanger mounts and have a muffler shop weld those on appropriately for your new system if you are doing the main work yourself and don’t have welding equipment. (see fig. 2)

Bullet Muffler (or resonator): If you are using a standard F-body exhaust system that features a transversely mounted oval muffler mounted under the gas tank then you may also be interested in adding a ‘race ready’ high flow bullet muffler in the mid pipe section of the exhaust system. (see fig. 3) I have had great results with a Dynomax 18” bullet. They also come in 12” length. My current system is 3” so I ordered a 3” bullet. The end collars just slip over 3” exhaust piping and are then welded or clamped. This thing is just a hollow ‘perf tube’ that does not inhibit performance to any noticeable degree if at all but it does deepen the overall tone of the system as well as reduce high-end raspiness to a substantial degree. They are rather affordable (about 30 bucks or so) and can easily be found at summitracing.


Let’s start off with some basic ‘reviews’ and general opinions that you might find if doing an in depth search on aftermarket exhaust systems for our cars:

Bigger is louder. The fatter the ID of the main exhaust piping the louder your car will be. When you also consider that you are putting on aftermarket…hi-flow / hi performance exhaust systems then figure for even louder than loud.

If for some reason you remove the catalytic converter…. figure on more loudness and a much harsher overall tone.

Going for a cut out? Then you don’t need my help.

Upgrading to headers? Yes, better breathing = louder but generally improved performance sound as well. What performance enthusiast doesn’t appreciate headers? No direct support for headers here, though, but perhaps some of the following basic cat back info will be of help. Well, one thing I will say is that if you have a 2000+ model year car then you have tubular manifolds from the factory. These babies are very nice. If you have em…you can move headers much further down your list of mods as they already flow very well. They can handle a lot of major upgrades such as valvetrain/cam, P&P heads and Superchargers.

What do different mufflers/systems sound like? Well, you are sorta on your own for sound bites and stuff. If you have found my Project Unleashed website then you already know how to find some specific camaro/firebird v6 exhaust sound clips. The only VERY specific info that will be given on this site concerns the installation of a 3” Magnaflow V8 LT1 cat back system on a 2001 v6 Firebird.


With an emissions related SES code popping up you will not pass OBD2 emissions tests in your state. Some states even visually inspect during the emissions test….under car…looking to see that all sensors are where they should be, etc. It would be best to know beforehand what is involved in passing and the testing procedures in your state before making serious modifications to your exhaust system.

You will often times set off a SES code when you change from a 2.25” out cat to a 3” out cat. I do not know for sure about going to a 2.5” out cat.

Headers = SES code. In other words…don’t be surprised.

If you are going from a stock 2.25” system to a 2.5” cat back system sold for your year vehicle...(not including headers) you should be ok. It seems that most of the emissions (OBD2) problems come from the more extreme 3” full systems.

The above info is either my personal experience or what seems to be a general consensus regarding these issues.

This website will not get involved in the “is 3in. exhaust better than 2.5in.” exhaust debate. It will be assumed that you already know what you want out of your car and what kind of modifications you plan for your over all project and performance goal. The more fuel and air you put into the engine the more exhaust gases that need to be expelled from engine.

Catback Systems – What fits what?

I cannot possibly cover every combination of 4th gen v6 F-Body and all the different cat back systems. There are some basics, however, that should help nail down what you get with basic cat back systems for given year vehicles….for both ‘designed for’ the v6 and ‘designed for’ the v8 aftermarket systems. The V8 option is very important here as they represent a wide range of 3” system kits that may or may not include everything you need for a complete conversion to a full 3” system.

Once again…I do not have experience with EVERY brand/year/v6-v8 cat back. You should also visually inspect your exhaust system. It may have already been modified, etc.

Conversion vs. Replacement: Most all v6 cat back systems (2.5”) sold for your particular year vehicle will come with everything you need to complete the project. (see fig. 4) The tail pipe hangers will be correct and the actual exhaust piping will bolt right up to what is already on the car. You will still have your stock 3”x2.25” cat and probably the stock 2.25” S pipe as well…with the new system starting post S pipe. You should not have a problem with emissions and there should be some performance gains.
If you plan on going with a full 3” system then consider it as a conversion. There is no full 3” system built for the v6 F-Body…. but some kits will get much closer than others in providing everything you need and you can also purchase a 3” conversion kit to adapt some systems to your car. This is where it becomes handy to know what year cat backs… v8/v6 come with what components, etc.

1994-97 v6 and v8 F body. These cars came from the factory with a FLANGED CAT. Whether or not the CAT is welded to the Y pipe is no big deal…BUT on these year cars the S pipe is connected to the CAT with a 2-bolt flange. In other words…the cat is not welded to the S pipe but rather bolted. The S pipe is then band clamped to the mid pipe. (or intermediate pipe) Therefore these model year systems will often times come with an aftermarket S pipe. (see fig. 5)

1998-2002 v6 and v8 F Body. These cars come with the CAT welded to the Y pipe and also welded to the S pipe. The S pipe is then band clamped to the mid pipe. Since these years of cars use a welded S pipe these year cat back systems will often times not come with an aftermarket S pipe. This is where something like the SLP 3” conversion kit is handy. (see fig. 6)

3” Conversion Basics

Converting to a 3” exhaust system is the most involved option as far as additional modifications and additional parts that will be required. A conversion such as this is, however, quite easy to perform. The least involved method as far as extra parts is concerned are many of the LT1 V8 cat backs for 1994-97 V8 F-Bodies. On those year cars the CAT is attached to the S pipe with a 2-bolt flange so those systems often come with a 3” S pipe. The S pipe will not have a 02-sensor bung but as mentioned earlier you can weld one in or get a cat that already has a rear O2 boss. You will also need a 3x3 cat to mate up correctly. Just cut the flange off of the new S pipe and the 3” out cat will slip right over. The tail pipe hangers will not match your stock hanger mounts…this is where universal hangers come in. Just use the chassis bolts/holes from your old stock mounts to attach the universal hangers to the chassis or find some v8 chassis mounts or save your original hangers for integrating in the new system.

Find out all that you get as far as components from any giving cat back system. Some will require a 3” conversion kit such as the one sold by SLP.

Horizontal S pipe hanger: If you change to a 3” S pipe the stock tranny/exhaust horizontal hanger will have to be removed. There is ‘shock absorbing’ main mount that can still be used, however. To see an example of a custom replacement see figure 7.

Check out my page detailing the removal of stock exhaust system and installation of the Magnaflow #15620 1994-97 LT1 V8 cat back system complete with 3x3 cat and a rasp inhibiting 18” Dynomax bullet muffler in the mid pipe HERE.

What Comes With What?

Magnaflow 15620 LT1 V8 (1994-1997) Comes with 3” S pipe but will need tail pipe hanger modification as well as custom S pipe horizontal hanger. VERY EASY.

Hooker LT1 V8 (1994-1997) cat back comes with an S pipe. As with other V8 systems the tail pipe hangers do not match the V6 system. Check out the Hooker LT1 install and review by ‘black98V6’ HERE

Magnaflow (and most all other???) LS1 1998+ cat backs do not come with a S pipe.

It is unknown what other LT1 (94-97) cat back brands come with a S pipe. 3” catback systems that don’t come with a S pipe will need to have one made or purchased.

SLP Installation Kit: This is mainly a stainless steel 3” S pipe. It is needed when you do not get a 3” S pipe with your particular Cat Back system yet you want to use a 3x3 cat and convert the exhaust to a full 3” system. Unfortunately for some it does not come with an O2 sensor bung welded in it. You will have to have that done separately if you do not get a CAT that has a rear O2 bung already in it. In the picture below you can see how one end is flanged. You can cut the flange off and a 3” CAT will slip right over it. The other end is ‘crimped’ to a smaller diameter so that it will fit into a 3” mid pipe. Part Number is: SLP-30045 - Installation Kit, 1993-02 V6 F-Car $72.95 http://www.ftpp.net/V6Main.htm

Tbyrne also has the SLP installation kit… http://www.tbyrne.com/v6catalog.html

As well as LMPerformance: http://www.lmperformance.com/1576/2.html


NOTE: There is a cheaper (about 30 bucks) SLP install kit. That kit is just hangers and does not include an S pipe.

Jegs has a more affordable option for an S pipe. They have a 3” mandrel bent U Pipe for about $30 I believe. The U pipe can be cut and welded into an S shape quite easily. The end that mates with a 3” mid pipe may need to be crimped down in diameter…or a slip over collar may have to be welded over the connection, for example. I never used this ‘u pipe’ solution and have never seen it. This might be it…please double check before you purchase…
642-10719 Magnaflow Exhaust J BEND 180 DEGREE 3'' $25.99 http://www.jegs.com

Example of an O2 Sensor bung: $10 at http://www.lmperformance.com/1783/2.html
Most muffler shops should already have this item.


Magnaflow / Carsound universal 12” oval 3”x3” no air tube w/ rear O2 sensor boss #94039…not for California… $75 bucks. http://www.bestautopartsonline.com/94000CONVERTERS.html

O2 Sim: Caspers rear O2 simulator: $45 182-104035 GM 1997-02 w/One Sensor $44.99

Summit racing also has the casper sim as well as zzperformance and many other shops.


(note the different part numbers. Welded CAT year cars will not come with a replacement S pipe)


(notice how this model year kit comes complete with a replacement S pipe)




05-13-2013, 10:07 AM
No info about duals?

05-13-2013, 04:00 PM
Anyone know a part number of the u shaped pipe or an equivalent one pictured here? Thanks

05-13-2013, 07:42 PM

05-13-2013, 08:49 PM
Can't believe that little u bend is 65 fucking dollars. there goes my idea

05-13-2013, 09:53 PM
No info about duals?

There custom, so the options are limitless. The main point of the write up is stock style exhaust .

05-14-2013, 12:47 AM
Hmm I know I have pacesetters, hi flow cat, and a catback but do i have upgraded s pipe?

05-14-2013, 09:02 AM
Obx catback isn't listed :0