TTS headers

B&B
Bassani
Borla
Borlamouth
Camshafts
Corsa
Custom
Dynomax
Dynomouth
Edelbrock
Flowmaster
GHL Motorsports
GMMG
Headers/Cutout
Hooker
MAC
Magnaflow
Mufflex
Random Tech
SLP 2otl
SLP Dual-Dual
SLP Loudmouth
Spintech
Stock
True Duals
TSP Rumbler
Unknown

Submit details or your clip!

Having problems sending a large file? Click here!

TTS headers, cats, Y pipe and Corsa cat back

Listen to the sound clip!

Introduction: After one year of quiet driving with my 98 convertible Trans Am I felt the need of some additional HP. I didn’t want to open the engine, which reduced the modifications to basically intake and exhaust.; As I decided to replace my complete stock exhaust I made some researches on the web to understand the differences between the systems present on the market and to know what products were available for my car.; I decided to buy TTS headers, cats and Y-pipe followed by a Corsa cat back. At the same time I replaced the stock spark plugs with some NGKs.; After a successful installation I decided to write this report to help other people to prepare and install this exhaust system.; Please forgive my bad English: my mother language is Italian and I work in a German speaking state. I love English but I don't have too many occasions to use it, so please allow me some mistakes.

Car: 1998 Pontiac Trans Am Convertible LS1 Engine Automatic transmission
Headers: TTS headers with oval cats and Y-pipe; Price: $1,250
Catback: Corsa with Pro-Series 3.5" Tips; Price: $680

Installation results: Power gain: good SOTP at all (especially middle) rpm.; No dyno values.
Noise: I can't judge the headers alone because I installed the cat back at the same time. As declared by Corsa the idle is "a little" louder than stock, at WOT expect a something like a plane taking off! The exhaust is louder if cold, a warm up takes 10 to 15 minutes depending of the air temperature.
Vibrations: Some plastic parts vibrate at low rpm, especially when the engine is cold.
Floor clearance: Reduced but enough (lowest bolt at about 4" cm from floor). The car isn't lowered.
Pan clearance: No problems at all. The system fits the car floor like a glove.
Error codes: None.
PCM tuning: None.

Pictures of the installed headers.

Time spent: Web research: some nights…; Preparation of the parts: about 10 hours; Installation of headers, cat, Y pipe, Corsa cat back and new spark plugs: about 20 hours (alone, with a car lift).

Thanks to those people who helped me to realize this project

Michael F.
Dennis G.
Fred F.
Doug

To find out more about headers see my posts on those forums (look for username tici):
www.automotiveforums.com
www.fbodycentral.com
www.carandtruckforums.com
www.kyfbodies.org
www.ls1forums.com
www.fastls1.com
www.ws6zxr.com
www.ls1tech.com
www.ls1.com

Here some good headers installation descriptions and general information:
www.go-fast.org/z28/headers.html
modernmusclecars.net/articles/mac.html
riptide63.homestead.com/restrictor.html
www.headersbyed.com
www.carcraft.com/techarticles/868/index.html
www.chevyhiperformance.com/techarticles/4533/index7.html
www.chevyhiperformance.com/techarticles/49178/index.html
www.mustang50magazine.com/techarticles/29618/index.html

Disassembling the stock exhaust
General prepare: The night before disassembling spray all the exhaust bolts with WD-40. (Don’t spray the lubricant where the wires enter the O2 sensor! They generate a voltage by comparing the exhaust oxygen content with the amount of this gas in the air. An oil coat will generate incorrect values).; Leave the car cool down during the night.; Disconnect the negative pole of the battery.; Unplug the MAF and the air temperature sensor and remove the complete air filter.

Muffler: I didn’t wanted to take the rear axle apart as described by GM, so I decided to cut the Intermediate pipe. Best cutting place: after the 1st elbow of the intermediate pipe, between elbow and a small restriction. The muffler can be removed easily, the rest of the intermediate pipe too (see the Corsa catback installation manual).

O2 sensors: Easy to unbolt, no particular problems

Y-pipe and catalysts: Loosen all the bolts. Some of them will break, depending on how rusted are they.

Driver side manifold: Disconnect the AIR hose and unbolt the connection to the exhaust manifold.; Disconnect the engine temperature sensor.; Remove spark plugs and ignition wires.; Unbolt the manifold.

Passenger side manifold: Disconnect the AIR hose and unbolt the connection to the exhaust manifold.; Disconnect the EGR cable, unbolt the flange to the exhaust manifold and the connection to the intake manifold. Remove the complete EGR system without disconnecting the valve from the pipes.; Remove spark plugs, ignition wires and ignition coils.; Remove the oil dipstick.; Unbolt the manifold.; There is a plastic hanger for a coolant hose right on the way to the last header bolt… mine has been cut away after I badly scratched my hands on it.

Preparation of headers, cats and Y-pipe
Headers: AIR pipes enter the exhaust pipes of about 3/4", apparently for a better mixing of the injected air (I called TTS for an explanation). No other manufacturer do it, why? The Stock manifolds have those pipes flush to the exhaust pipe wall so I decided to cut the excessive pipes of the TTS headers (A Dremel will help to do a nice job).; Ceramic coat is very delicate (easy to scratch).; Rests of sand blast are present in some spots (have been ceramic-coated too).

Catalytic converters: The original converters have been cut (in- and outlet) and new connections have been welded on them by TTS. New cats have to be ordered by TTS or custom made locally.; One outlet didn’t fit the Y-Pipe (was slightly flat) and had to be adjusted.; The heat shields were slightly flat and had to be bent back (a shipping issue?); The Manufacturer is not specified, the previous model was a bullet style, with apparently low flow (see Install University); Case material: aluminized steel; Flanges aren't coated, just raw steel.

Y-Pipe: Material: aluminized steel.; The welds aren't coated.; The flange to the hanger isn't coated.; The holes for the O2-Sensors had a lot of burrs in the inner side of the pipe. A grinding job was absolutely necessary.; There were rests of bending lubricant in the pipes (a lot! It can be washed with hot water and a brush).

Gaskets: The kit doesn't include gaskets.; The local GM shop only had gaskets for the heads-headers connection, so I decided to manufacture the missing gaskets by myself (AIR; EGR and connection headers-cats).; All gaskets were cut from a 1/16" thick "Freznelit nova press 200" (high temperature gasket paper for exhaust manifolds).; Between headers and cats it's supposed to use an high temp. silicone, this is included in the kit.; Exhaust manifold gasket: P/N = 12558573; EGR gasket: P/N = 12553047; AIR tube gasket: P/N = 12553617

Clamps: No coating, not stainless steel.

Flanges heads – headers: 1/2” thick steel plates, plasma or flame cut (not laser).; The flanges weren't flat and had to be machined. Cause: heat warp during welding. The coating is partially responsible for the uneven surface too.

Flanges headers - cats: 1/2” thick steel plates. The flanges are cut by the headers manufacturer using plasma or flame (not laser).; The connection headers-cats is a triangular flange (standard exhaust flange).; The holes are not on a perfect triangle, so don’t buy a standard gasket because it won’t fit. Cats and headers fit together (the holes are “wrong” by the same way).; Both cat-flanges weren't flat and had to be machined. The welding heat warped them and about 1/16” of steel had to be grinded out to get them flat. The headers weren't that bad, but had to be machined too.; As I called TTS to know how to seal this connection they told me that the parts are flat machined, and a thin layer of silicon will be enough… a joke?

AIR restrictions: Not sure if they were necessary, I decided to install them at the same time as the headers (thanks to Doug).

Protection: I sprayed a high temperature paint on cats and Y-pipe.

Spark plugs: By most of the stock spark plugs the platinum disc weren’t there anymore, this at 36'000 Mi. New spark plugs: NGK TR55 Gap = 1.524 mm (0.06 in) A couple of pages about spark plugs replacement:; C5 Forum
Install University

Installation of the TTS headers
Note: I didn’t wanted to remove or lift the engine nor the transmission, I just wanted to be able to install and remove the headers in an easy way: some grinding an bending were necessary.

Driver side header: A square piece of the engine block (1” by 1”) had to be removed completely, a Dremel did the job in about 15 min.; The part of the body close to the gas pedal had to be bent back of about 3/4”.; Remove the heat shield, it will be reinstalled later.; Install the header from the bottom.; Install the gaskets and the bolts from the top.; It isn’t necessary to install new gaskets but I did it to stay on the safe side.; According to GM the bolts have to be secured with a compound similar to Loctite 270 (start from the 4th thread and not from the top of the bolt).; The original bolts can be reused.; Tightening order: 5-3-1-2-4-6; Tighten the bolts a first pass to 15 Nm (11 lb ft), tighten the bolts a second pass to 25 Nm (18 lb ft).; Install the spark plugs, tighten them to 20 Nm (15 lb ft).; Install the ignition wires using a silicon lubricant.

Passenger side header: A square piece of the engine block (1” by 1”) had to be removed completely, a Dremel did the job in about 15 min.; Remove the heat shield, it will be reinstalled later.; Install the last spark plug from the bottom.; Install the header from the bottom.; It isn’t necessary to install new gaskets but I did it to stay on the safe side.; According to GM the bolts have to be secured with a compound similar to Loctite 270 (start from the 4th thread and not from the top of the bolt).; Tightening order: 5-2-1-2-5-6; Torque: there isn’t enough place to fit a torque wrench on this side, so I did it by feeling.

Catalysts and Y-pipe: If both catalysts are on place it will be impossible to install the Y-pipe after them. Here a procedure to make the job easier:; Install first the driver side catalyst.; Connect the two pieces of the Y-pipe and the passenger side catalyst without tightening the clamps.; Slide the Y-pipe & catalyst in the driver side catalyst and rotate the assembly until it's horizontal, then bolt it to the hanger.; Bolt the passenger side catalyst to the header.; Note: the angle of the Y-pipe wasn’t correct and I had to take the two ends of the “Y” apart of about one inch (I used a car jack).; The outlet of the “Y” was too long and I had to cut out about 1” of the intermediate pipe of the cat back.

Bolts in general: I lubricated all the bolts with an high temperature (1100°C) copper based, lead free anti seize compound. Spark plugs included.

Pipes connections in general: I lubricated all the pipes connections with the same compound as for the bolts. I just toke care to don’t let the compound reach the catalysts or the O2 sensors.

O2 Sensors: I used a small amount of the copper anti seize compound as for the bolts and I installed the sensors with a new copper ring to insure tightness.; Extensions are necessary for both front sensors (12” or longer).

Heat shields: The heat shield that have been removed to install the headers should be reinstalled before the cats.; To protect cables and body from the heat I installed additional heat shields between headers and all the parts that were closer than 1" (I used an industrial heat shield: 1 mm aluminum plate wit a 5 mm fiberglass layer). Consider to install the additional shields before the headers (after it will be more difficult).

Cross brace: The 4th generation convertibles have an X brace that just allows the installation of the stock (flat) Y-pipe.; The X-Brace has to be modified or custom made from new.; I don't know, if the SLP part #30055 fits the TTS, but I assume that it does.; It's not a problem to drive around for a while without it. To be sure I'll make made a new one using a 3/16" steel plate.; More information about headers and convertibles at LS1.com.

Installation of the Corsa catback
Preparation: Some connections were oval and had to be adjusted to fit the next piece of pipe.; The connection to the Y-pipe is too wide and a rolled 1 mm metal sheet had to be inserted between clamp and Y-pipe (stock and TTS are the same).

Install: Follow the instructions, they are fine.; At the beginning it looks like all the pipes are bended in a wrong way… put everything together, pull and push and shake… and suddenly it fits! No clearance issues, no problems at all.

Comment: This report may look like a negative comment about the TTS kit: this was not my goal! I believe that all other headers on the market aren't much better and everyone that approaches this installation will have to do some extra job to have a nice result. Just bolt the parts together isn't enough!

Next steps: The clamps of the new Y-pipe are reducing the floor clearance of about 1 1/2" and I "filed" them already a couple of times on the floor. I'll remove the clamps and weld the two pieces of the Y-pipe and the catalysts together.; Custom made X-brace; The complete exhaust is extremely noisy, in and outside the car. I'll wrap the Corsa muffler with an insulating material (1/2" fiberglass). The external protection will be an aluminum or a stainless steel sheet. This should take care of the internal noise and vibrations, for the external noise I'm planning a glass-pack between Y-pipe and muffler.; I have no idea if this modification combined to a pre-installed FIPK II has changed my A/F ratio. There is contradictory information about it on the web, so I decided to find it out by myself. Planned scan tool: Autotap for Palm (enhanced parameters), planned "programmer": MAFT.; One year ago I made the mistake to buy an Hypertech Power Programmer: I'll see if this device combined with the MAFT will give me some more power. The Power Program alone never developed the promised 20 HP. I'll maybe adjust the shift points and the shift firmness too.

by Stefano Tenzi (tici) - 19. Jan. 2004