C6Performance Journal

install will vary from car to car and from the type of header you choose, some are easier to install then others.

– Great Pacesetter install guide done by foff667
– SLP guide (done by bomax if i recall)

A few install tips:

– Patience; if after working for several hours without any apparent results take a break. Things often have a way of working out coming back from a fresh start.

– A breaker bar is your friend.

– All LT’s go in from the bottom.

– The stock cat bolts will often break, especially on the older 98-99 cars, don’t worry about it.

– Use plenty of penetrating oil on all the cat to manifold bolts.

– Have a buddy/wife/gf help you out when need be.

– Remove the oil diverter for a bit more room on the drivers side install.

– May or may not have to knotch the K-member and floor board clearance (CamaroCain).

– Steering shaft removal may or may not be required. (For my install I couldn’t get the damn thing to budge, so I used a die grinder to grind down the block tab to get the drivers side header to slide up). Heed the warning on the steering shaft before removal.

– Have all the proper tools before the outset of installation; jack/jack stands and/or ramps, basic hand tools (3/8, 1/2 drive ratchet, 10mm, 12mm, 15mm, ect sockets), hammer. Optional but very handy tools that may or may not be needed; sawz-all, die grinder, 2×4 4×4 pieces of wood and/or some bricks.

– Get the car as high as safely possible. It’s alot higher then you think. (During my own install I had the rear on ramps and the front was propped up with my jack on a 4×4 piece of wood to get the extra clearance need.)

– Don’t think it has to be mentioned but I’ll say it anyway; use safety goggles where applicable and make sure your car is secured on the ramp/jack stands before getting under the car and working on it. Basically don’t do any stupid shit

– Give yourself plenty of time to get the install done; first time around factor in 5-12hrs. Don’t worry if it takes you longer, just concentrate on getting it done right and gaining the experience

– Typical prices a shop will charge for an install are 300-500 dollars depending on location. If you have the time, you owe it to yourself to give the install a shot yourself. It’s not that hard and doesn’t require alot of technical knowledge or experience. If you run into trouble during the install come to the boards in a calm and collected manner and you’ll get your answer in no time.

– Will you need tuning after headers: Every car varies, you wont know until the headers are installed and you’ve put some miles on the car. Headers usually cause the car to run a bit rich but its nothing stock tune cant handle. If you want full advantage of the new headers then you’ll want a tune. Just plan accordingly; if you know your not going to install big mods (h/c) sometime in the near future then I’d go ahead and get a tune. If you plan for a new cam and/or heads then hold off on tuning for the headers and get a tune once the h/c is installed, it’ll save you the time and money of having to tune twice. If you don’t want to pay for a full tune you can always pick up a used MAFT (mass air fuel translator) and dial in your A/F ratio a bit.

– Where to buy:

1) Pacesetters: TSP (http://www.texas-speed.com) has the best deals on pacesetters. And they are the only place to get the TSP Rumbler catback and dual setup

2) Kooks: Contact Matt from TTP (http://www.ttperformance.net/) you’ll usually get the best deal from him.

3) Jet hot/hookers: Go to the sponsor forums, every so often there is a GP (group purchase) on jet hots and you can get a great price.

4) QTP: Contact Barry from QTP (http://www.quicktimeperformance.com/) and see what kind of price he can get you.

5) FLP: Cruise the sponsor forum and look for anyone offering online discounts; you can usually get 10-15% off the price.

C. Y-Pipes

What they are: Jet hot catted/ory SLP stock replacement Y Mufflex Random Tech stock replacement catted Y Pacesetter ORY

– Catted Y denotes a Y with cats; ORY denotes a Y with no cats

What they do: Connect the headers to the catback and aid in exhaust flow provided it matches the rest of your system. Meaning keep the diameter relatively consistent, 3″ is the most popular, a 2.5″ is fine as well and will give you a bit more clearance if your lowered.

What to look for: Y pipes come in all different shapes and diameters, if you can, get the Y made by the same company that you got your headers from. Meaning if you get the Hooker LT’s then get the hooker Y, ect. All Y pipes are not directly swappable. If you wish to use another manufactures Y for your setup you are most likely going to have to modify it to fit.

-Those looking to get Pacesetters; there Y is a toss up, some people’s are “acceptable”, others are straight shit. Pace didn’t put to much time or development into making a quality Y and it shows in the collector. Your best bet is to go with a custom Y or modify your Pace ORY like Larry did.

Those with Hooker/Jethot/Pacesetters can now rejoice, TSP has just come out with a 3” Catted Y pipe to fit your headers. They use high flow carsound cats. At 350 a pop you can rest assure that this is the Y-pipe you want to get. They also offer an ORY as well.

– A custom Y is great since its taylored to your exact setup and will allow you to get the best fitment and clearance. Just pick up a Flowmaster merge collector and cats if you need and have a shop fab up the rest; depending on shop it should run you 100-200 bucks not including parts (i.e. merge collector)

– Do Not invest in a new Y pipe unless you plan to stick with shorties/stock manifolds, and even at that it’s barely worth it since you’ll gain practically nothing by a new Y on stock manifolds. If you buy a new Y for stock manifolds/shorties you’ll need to replace the Y you just bought if you add LT’s or mids in the future.

– If you need cats for emissions purposes then do not purchase an ORY and then try and weld cats in them, just spring for the catted Y or purchase some cats, flowmaster merge collector and have a shop fab the rest. Alot of ORY’s don’t have enough room to accommodate cats. If you still want to try it then get the smallest cats you can; slp’s or random tech.

– The ‘98-’99 Y-pipe won’t work on a 2000-2002 because it doesn’t have a flange on the passenger side pipe. It has to be welded in place. It took them till the 2000 model year to figure out it might be better to have both sides flanged and secured with bolts. (xtrooper)

D. Duals

What they are:

1) X-pipe setups 1 (South FL) 2 3 (DVST8OR) 4 (Y2KSS).
2) H-Pipe setup: 1 (Lanes)

What they do: See Y pipe

What to look for: Your only actual viable option is an X pipe or H pipe. Which is better will always be debated. Most people go with an X pipe, in a nutshell an X-pipe will net you more power and torque and an H-pipe will have a slightly better sound. Both are great, so choose what you like, either is better then a traditional Y setup. Where duals shine is power under the curve.

– When it comes to duals you have 2 options; dumped before the axel or going all the way out the back. The former is a more popular option because of cost. A complete dual setup dumped should run you 500 bucks or less. If you desire to go out the back it’ll cost you, you’ll need some custom over the axel work or you can go a cheaper route and go under the axel. Both have there advantages; dumped are very cost effective and have a great hp/$ ratio. However since the exhaust is now exiting under the car; cab noise is more prevalent, you’ll notice rattles you never knew you had, and you’ll feel the resonance. Duals out the back are more expensive but you’ll get the hp and sound of the duals without the little annoyances of the dumped setup. (My advice would be to go with dumps first and see how you like it and whats acceptable to you, if you find the annoyances unbearable you can always complete the duals out the back, just pick up where the dumps left off and go over the axel or under.

– TSP has pretty much hit a home run with its new exhaust line, in addition to the Rumbler catback, Catted and ORY, they have introduced a direct fit bolt on True Duals. The system is a direct bolt on to the Hooker/Jethot/Pacesetter LT’s, others will work but you will need adjusting and fitting. The mufflers used are 18” Dynomax Bullets which offer a slightly more subdued sound over a 12” bullet. The setup runs around ~$430.

More pics of the TSP Duals:
– 1
– 2
– 3
– 4
– 5

– If you plan for dumps you can go 3″ piping all through out. If you are lowered or plan to lower or want duals all the way back go with 2.5″, you’ll have more ground clearance and more room to allow for going over the axel depending on how you set it up. You can also go 3″ up to the X pipe and then reduce to 2.5″.

– Both 2.5″ and 3″ will support plenty of power, most likely more then you’ll ever produce. Choose your piping based on fitment and clearance, not power.

– When you run duals you’ll want an X/H pipe for the scavaging and equalizing effect, you wont get that from straight pipes off of the collector.

– True Duals w/ Side Pipes 1 2

How to install: You have a few options:

– Have a shop fab up the whole setup for you
– Buy just an X/H pipe from jegs or summit and mufflers and have a shop fab the rest
– Buy a Dr. Gas kit and have a shop fab the rest

E. Cut-outs

What they are: Flowtech QTP electric cutout
What they do: http://ourworld.cs.com/jrpws6/mod+guide/QTECDiagram.gif

What to look for: An electric cutout is the best bet, you can be loud when you need/want it to be and quite when you need/want it to be all at the flip of a switch. A standard cut you you’ll need to get under the car to cap or uncap it. A cutout is a great mod for cheap horsepower and sound.

How/Where to install: For an electric cutout follow the wiring guide instructions. For both type of cutouts you’ll need to have them welded in. You have a few options of placement. The easiest is the I-pipe as there is plenty of room. You can also run dual cutouts in place of where the cats would be (on a LT’ setup). Dual cats and cutouts can be done but the fitment will be very close and you’ll need to run some small cats.

E. Misc/Emissions

http://ourworld.cs.com/jrpws6/mod+guide/exhaustaccessoriesa.jpg

– Gaskets: Stick with the metal gaskets, either new or re-used. Don’t bother with the paper gaskets that often come with your headers, you’ll just increase the chance of leaks.

-Header Bolts: Oem bolts are fine, again new or re-used. If you want to spend the money you can get some stage 8 locking bolts, they are not necessary though. Header bolts are only required to be torqued down to 18ft-lb’s, which is not alot. Do Not over torque the bolts as you run the risk of stripping the threads on the heads. They are aluminum after all. Torque the bolts from the center out.

– Clamps: Invest in some good band clamps; they can be had from a variety of sponsors or found at your local parts store. U-bolt clamps are pieces of shit. Another option you have is to flange your system.

-If you’re using clamps and are still having exhaust leaks try buying some aluminum tape that can be found at Lowes or home depot. Wrap the tape around the collector; whether header or Y pipe, for thicker area for the clamp to seal up too.

– Cats: Magnaflow/Carsound cats are the best overall option; they flow great and can be had for a great price, especially on ebay.

1) You’ll want pt# 94106 for a 2.5″ inlet/outlet and 94109 for a 3″ inlet/out.

– o2 Extension and Sims: When buying Long tubes you’ll need to get 2 o2 extensions to connect the front o2 sensors as the o2 bungs have now been moved so far down the sensor wont reach the connection. Most Y/X/H pipes do not have rear o2 provisions so you’ll need to run 2 o2 Sims to prevent an SES light. You can also turn off the codes with edit/hp tuner/predator and bypass the need for the Sims.

A. Emission

1) When buying headers you have the option to buy them with or without emissions provisions. Find out your states/counties emissions standards before buying.

2) If you know your emissions requirements you can buy whichever setup meets your needs.

3) If your state only has OBDII testing you may remove your Air and/or EGR setup (only 98-00 cars have EGR). You can purchase the racing headers and get rid of the above systems. As long as you arent throwing any codes you will pass the OBDII test.

4) If your car has a sniffer/visual test you’ll need to decide how you want to play it; either comply with the rules and keep your Air/Egr and purchase the headers with the emissions provisions or try and find a shop that will over look those missing systems.

5) 9 times out of 10 you will not pass the sniffer test without cats.

6) Go here (bomax) to remove your Air/Egr.

7) If you want to swap 98-99 and 00-02 headers around you’ll need to remove your Air system or purchases the Air tubes from the year the headers were made for since the 98-99 and 00-02 have different Air tube setup.

8) It should go without saying but if you want to swap 01-02 headers on your 98-00 you’ll need to remove you EGR system.

9) 00 are an oddball year as the EGR and Air setups are different then the 98-99.

10) When removing the Air system on the 00+ cars you’ll be left with a vacuum hose that you’ll need to plug up.

11) Removing your Air/EGR/rear o2’s will set off an SES light but will not effect performance at all.

12) If you plan to keep your Air system with your LT’s you’ll want to run Air Restrictor plates (bomax)

You have probably heard words like: back pressure, scavenging, tuned length, merged collector, rotational firing order, compatible combination and many others that meant something, but how they relate to a header may be a little vague. This article should give you a basic understanding of how a header works, what the terminology means, and how it plays a part in the header’s performance gains.

The first misconception that needs to be cleared up is that a header relieves backpressure, but a certain amount of backpressure is needed for optimum performance. Just the opposite is true. A good header not only relieves the backpressure, but goes one step further and creates a vacuum in the system. When the next cylinder’s exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term “Scavenging” means.

The first consideration is the proper tube diameter. Many people think “Bigger is Better”, but this is not the case. The smallest diameter that will flow enough air to handle the engine’s c.c. at your desired Red Line R.P.M. should be used. This small diameter will generate the velocity (air speed) needed to “Scavenge” at low R.P.M.s. If too small a diameter is used the engine will pull hard at low R.P.M.s but at some point in the higher R.P.M.s the tube will not be able to flow as much air as the engine is pumping out, and the engine will “sign off” early, not reaching its potential peak R.P.M. This situation would require going one size larger in tube diameter.

The second consideration is the proper tube length. The length directly controls the power band in the R.P.M. range. Longer tube lengths pull the torque down to a lower R.P.M. range. Shorter tubes move the power band up into a higher R.P.M. range. Engines that Red Line at 10,000 R.P.M. would need short tube lengths about 26″ long. Engines that are torquers and Red Line at 5,500 R.P.M.s would need a tube length of 36″. This is what is meant by the term “Tuned Length”. The tube length is tuned to make the engine operate at a desired R.P.M. range.

The third consideration is the collector outlet diameter and extension length. This is where major differences occur between four cylinder engines and V-8 engines. The optimum situation is the four cylinder because of it’s firing cycle. Every 180 degree of crankshaft rotation there is one exhaust pulse entering the collector. This is ideal timing because, as one pulse exits the collector, the next exhaust valve is opening and the vacuum created in the system pulls the exhaust from the cylinder. In this ideal 180 degree cycling the collector outlet diameter only needs to be 20% larger than the primary tube diameter. (Example: 1 3/4″ primary tubes need a 2″ collector outlet diameter.) The rule of thumb here is two tube sizes. This keeps the velocity fast to increase scavenging, especially at lower R.P.M.s. Going to a larger outlet diameter will hurt the midrange and low R.P.M. torque.

The amount of straight in the collector extension can move the engines torque up or down in the R.P.M. range. Longer extension length will pull the torque down into the midrange.

Engines that “Red Line” at 10,000 R.P.M. would only need 2″ of straight between the collector and the megaphone. This is just enough length to straighten out the air flow before it enters the megaphone. This creates an orifice action that enhances exhaust velocity.

In the case of V-8 firing order, the five pulses fire alternately back and forth from left to right collector, giving the ideal 180 degree firing cycle. Then it fires two in succession into the left collector, then two in succession into the right collector. If the proper collector outlet diameter is being used (two sizes larger than primaries) the two pulses in succession load up the collector with more air than it can flow. This results in a very strong midrange torque, but causes the engine to “sign off” early, not reaching its potential peek R.P.M. The improper firing order on a V-8 engine results in the need to use large diameter collectors so the engine will perform well at high R.P.M.s. Unfortunately the large diameter collectors cause a tremendous drop in air velocity, resulting in less scavenging through the entire R.P.M. range.

Often cams are used with extended valve timing to help the exhaust cycling. This results in valve timing overlap (Intake and Exhaust valves both open at T.D.C.) which causes a “Reversion”cycle in the exhaust. When this happens, exhaust actually backs up into the cylinder causing intake air to be pushed back out the intake. This reversion causes “Standoff” (fuel blowing out of the Intake) at low R.P.M.s. This whole improper cycling has resulted in a number of “Cure Alls” to help stop this reversion and standoff.

The plentum intake was created to stop the fuel “Standoff”. Then came “Anti Reversionary” Cones in the exhaust tubes, and stepped tube diameter in the header, extended collector lengths and even plentums in the exhaust tubes.

In this chain of events beginning with improper firing order, a series of cures has developed, each one causing a new problem.

The optimum cure to this whole problem is to correct the exhaust firing cycle. The two cylinders that fire in succession into each collector have to be separated. This can be done partially by a “Tri-Y” header, where the four primary tubes from each bank merge into two secondary tubes (separating the two pulses firing in succession) and finally collect into a single collector. This type of header helps, but the two pulses are still coming back together at the collector.

The second optimum cure is to cross the two center tubes from each bank, across the engine running them into the collector on the opposite side. This makes the firing cycle in each collector 180 degrees apart, the same as a four cylinder engine. Once this firing order is achieved, the small collector outlet diameter can be used and the “High Velocity Scavenging” at low R.P.M.s cures the reversion problems and eliminates the need for extreme cam duration.

This sounds so easy, you are probably asking why wasn’t this done from the start?

If you have ever seen a set of 180 degree headers you would understand.

On today’s cars, with space virtually nonexistent, crossing four tubes either under the oil pan or around the front or rear of the engine presents major problems. On racing applications where it is possible, there is still the problem of keeping the tube length down to a reasonable 32″ long. If that’s not enough challenge, then try to arrange the tubes into each collector so they fire in a “Rotational Firing” pattern. Then you have, what has been called “A Bundle of Snakes”.

Arranging the tubes to fire rotationally adds to the scavenging capabilities. The exhaust gas exiting one tube, passing across the opening of the tube directly beside it, creates more suction on that tube than it would on a tube on the opposite side of the collector.

The next problem is “Turbulence” in the collector. When four round tubes are grouped together in a square pattern, so a collector can be attached, you notice a gapping hole in the center of the four tubes. The standard method in manufacturing headers is to cap this hole off with a square plate. This plate in the center of the four tubes creates dead air space, or turbulence, disrupting the high velocity in the collector. This problem is solved by using a “Merge Collector”. This collector is formed from four tubes, cut at approximately an 8 degree angle on two sides. When the tubes are all fitted together they form a collector with a “Pyramid” in the center. This has eliminated the need for the square plate and has taken up some of the volume inside the collector, speeding up the air velocity.

Other methods of curing this problem are: fabricating a pyramid out of sheet metal and welding it over the hole between the tubes, or squaring the tubes on two sides so they fit together forming a “+” weld in the center eliminating the hole all together.

You can see that there are a great many factors that go into making a good header. When the header, intake system, and cam timing are all designed to operate to their maximum in the same R.P.M. range, then you have a “Compatible Combination”. This combination can be tuned to deliver maximum power at any desired R.P.M. range.

These are some of the “Basics” you need to know about building a good high performance header. There are many other adjustments that can be made to fine tune a header, but this should give you a basic understanding of how all the components work together.

III. Internals

Preface:

The LS1 like any other engine works as a system, treat is as one, you want to get as much air in and out as you can. The plethora of mods out there will allow you to do that. Things to consider before you start on your modding process:

1) There is no “best” part when it comes to mods.
2) When you want to start modding your car come up with a tangible plan.
3) Do not go into modding blindly; you will end up wasting money, time, and effort.
4) Do your research before you buy mods.
5) Find out your states/counties emissions requirements before choosing mods
6) Be realistic on what your going to do with your car
7) Usable power under the curve is what you want to shoot for, do not just look at peak gains
8) Work within your budget
9) If your are still under warranty Contact your own dealership and discuss your warranty and modding issues.
10) Work on matching your parts well, meaning:

– do not buy 2500+ stage 3 heads that flow 330cfm@.600 if you have a stock cam or very low duration/lift cam (i.e tr220)
– LSX intake and 90mm TB for a basic bolt on car
– dont run 230+ cams on stock manifolds or shorties
– dont run a big cam and a small stall (i.e tsp231 and a vig 2200)
– dont over/under gear your car (i.e tr230, a4, 2.73’s)

(Credit given where applicable. Info/pics taken from personal experience, around the Internet, and ls1tech/ls2.com.) Special thanks to the guys on ls1tech (J-Rod, JMX, ect) [:worship:]

A. Cams

What they are: http://www.ls2.com/boggs/cam/cranecam.jpg

What they do: Cams are the “brain” of your engine and dictate how your engine will perform; power, idle quality, valve events, ect.

What to look for:

– Get a basic understanding of cams before purchasing. It’ll also help you understand the info/advice that is given on the boards.

– ALL gains are relative to your own setup

1) For example if you installed S2 heads and a tsp231 cam and only put down 390rwhp tuned don’t fret if you started with a base of 290rwhp.

– When researching cams look at the average gains. Don’t look at the highest gains you see (395rwhp with say and ls6 cam) and expect to get the same results when the average is 360-380rwhp depending on setup

– Can a cam be your first mod; yes. Should a cam be your first mod; no.

1) Cams need to breath, that means a complete intake and exhaust setup. The bigger the cam the more prevalent those mods become.
2) A4 guys; match your stall and cam appropriately

– Don’t be afraid of older or smaller cams (T1/B1, tr220, comps 218, ect). They might not use the latest and greatest lobe technology or break speed records but they are proven cams and are great for the guys looking for 400 > * rwhp cam only.

– Take Internet reviews of cams with a grain of salt and use them as reference only. Contact your local fbody club or ask around your local regional forum and find as many guys who have cams as you can. Hear and drive/ride along with as many different cam setups as you can. The reason for this is everyone has there own idea of what streetable is since that is a RELATIVE term. Decide on your own what streetable is to you

– Don’t let someone talk you into a cam if it doesn’t meet your requirements and fit your specific applications and goals.

– Keep in mind there is more then one way to make the same amount of power

– If you have the sniffer for emissions either go with the cam of your choice and pray you find a good enough tuner and have luck on your side or keep the duration 226 and under on a 114 and a decent tune and you should be fine.

– When buying a used cam ask for the cam card and/or serial numbers. Take that serial number and email or PM the company or board representative with that serial number. They will be able to tell you if in fact it is one of there grinds and if it’s the one you had planned on purchasing. That is the only way short of having the cam spec’d on a cam doctor to know exactly what cam you are buying. Here’s the serial number from my old TR230.

– Don’t get caught up in peak HP. These are ls1 boards not Honda boards [;)] . Under the curve power is where it’s at.

– To make things easier most sponsors offer cams as a package deal that includes all that you’ll need for an installation. Here was my old cam kit.

I. Cam Overview:

– http://www.ls2.com/boggs/cam/camanatamy.jpg

– Your starting point:

Stock 98-00 trans am cam

Duration@.050 198.86 intake 209.25 exhaust
Lift .498 intake .497 exhausts
LSA 119.45

Stock 01-02 trans am cam

Duration@.050 196.37 intake 208.72 exhaust
Lift .464 intake .479 exhausts
LSA 115.92

When buying a cam it comes with a cam card. This card gives you the exact specs of the cam. Here is an MTI/Lunati B1 cam card and a LGM G5X2 cam card.

A. Duration:

– The amount of time (in degrees) that lift is generated is called the duration of the lobe. Camshafts operate at half engine speed. This is easy to see because the gear that turns the camshaft is twice the diameter of the crank gear that drives it. That means that the cam spins at half engine speed. Because of this, camshaft duration is always expressed in crankshaft degrees. This makes it easy when it comes time to degree the cam to ensure it is positioned accurately in the engine.

– As you can see in the 2 cam cards there is duration @ .050 and duration @ .006. Duration @.050 is pretty much industry standard and that’s what you’ll see when looking at cam specs from the various sponsors and what most people are talking about when discussing duration

– Duration @.050 and Duration @.006 is a way you can determine the difference between two or more cams with the same given duration at .050. For example a TR224, TSP 224, and Comps 224. The lower the duration @.006 the more aggressive the ramp rate. The more aggressive the ramp rate the more overall and under the curve power.

– If you know the advertised duration (.006) of a cam you can calculate the ramp rate. To do this you take the duration @.006 and subtract it from the duration @ .050. A number of 53 or higher denotes an XE lobe or other mild lobe and a number of 49 or lower denotes an XE-R lobe or other aggressive lobe (Beast and 99 Black Bird T/A [:cool:] )

– Using the B1 and G5X2 as examples is as follows:

B1: 281 (.006) – 221 (.050) = 59

G5X2: Intake 281 (.006) – 232 (.050) = 49
Exhaust 289 (.006) – 240 (0.50) = 49

– Most cam companies use Comp lobes; either an XE or XE-R, the later being the more aggressive of the two. TR uses its own proprietary lobe and FMS uses Cam Motion lobes.

– Intake opening (IO) usually occurs before top dead center (BTDC), while intake closing (IC) happens after bottom dead center (ABDC). For the exhaust side, exhaust opening (EO) occurs before bottom dead center (BBDC) and exhaust closing (EC) after top dead center (ATDC). These data points are listed on the cam card that comes with each new cam.

– Traditional Splits refers to more exhaust duration and lift then intake (tsp231/237, g5×2 232/450, ect). Reverse split refers to more intake duration and lift then exhaust (TR 230/224, X1 230/227). Single patterns are defined as having both the same intake, exhaust duration, and lift. (TR224, TR220, FM4 226/226). Which cam is better depends on your application.

– GREAT technical discussion on cams started by J-Rod from ls1tech: here

– Valve Events (VE) calculator can be found here

– Other good technical shit can be found here and here and here

B. Lift:

– Lift is defined as the difference in height between the radius of the circle and the height of the eccentric. This is called lobe lift.

– When viewing cam specs the lift portion is the gross lift, meaning its calculated with the 1.7 stock rockers.

– To get the lobe lift you take the advertised (gross) lift and divide it by 1.7. If you follow the B1/X2 cam card you’ll see that they list both lobe lift and gross lift.

– If you want to add higher ratio rockers and want to know your new lift you do the following using the B1 as an example:

.559 / 1.7 = ~.329, you then take that lobe lift and multiply it by whatever rocker ratio you want. With SLP 1.85 rockers your new lift specs become .329 X 1.85 = ~ .609

– LSA is defined as spread in camshaft degrees between the intake centerline and the exhaust centerline.

– Overlap is the number of crankshaft degrees that both the intake and exhaust valves are open as the cylinder transitions through the end of the exhaust stroke and into the intake stroke

– LSA is ground into the cam and cannot be changed without grinding a new cam

– Bigger duration cams will have more overlap then a smaller duration cam even if both are on the same LSA.

– The key to making overlap work is maximizing the power in the rpm band where you want it.

– Long overlap periods work best for high-rpm power. For the street, a long overlap period combined with long-duration profiles combine to kill low-speed torque

– Reducing overlap on a long-duration cam will often increase midrange torque at the expense of peak power, but if the average torque improves, that’s probably a change worth making.

– Many enthusiasts purchase a camshaft strictly on the basis of how it sounds. A cam with generous overlap creates that distinctive choppy idle that just sounds cool.

– You’ll find that a 112 or 114 LSA with a 108 and 110 ICL respectively is the best all around street setup.

– While doing my research on the T1 I cam across this dyno in which if I recall Tony (Nineball) stated that the blue graph was a T1 (112 lsa) and the other 2 where a B1 (114) lsa. 112 vs. 114

– What really affects where the cam makes the most power is the intake timing events. What affects drivability most is the exhaust-closing event.

D. Advance and Retard:

– When you see cams specs like 224/224 .563/.563 112+4; the +4 denotes that the cam has 4 degrees of advance ground in.

– Most off the shelf cams have 2 or 4 degrees of advance ground in. This lowers the power band slightly and offers more low end and midrange at the sacrifice of a bit more top end power

– For cams used primarily on the street the advance is best appreciated. For a strip or racing setup 2 or 0 degrees advance will net you more peak power in the upper ranges of the power band

– To find out if you cam has advance ground in you can check on the cam card. Besides the +2, +4, you can determine the number by looking at the intake center line (ICL). Referring back to the B1 cam card you’ll see that it states that those are the specs when installed on a 108 ICL.

– Subtracting the ICL from the LSA will give you the advance: 112 – 108 = 4 using the B1. Or 113 – 109 = 4 using the G5X2.

– Retarding the cam does the opposite of advancing it, it pushes the power band up slightly and gives more top end power.

– With an adjustable timing chain or degreeing the cam you can install the cam at different ICL’s.

– Keep in mind as stated; most cams already have advance ground into them so if you buy an adjustable timing chain and advance 2 degrees you’ll increase the overall advance to 6 degree’s if the cam has 4 degree’s ground in.

– Also with big cams and/or milled heads piston to valve clearances starts becoming an issue. If in doubt always clay the heads and find out your PtV clearance before installing/advancing especially if your cam has a big intake duration as advancing starts the intake valve events sooner.

– Installing dot to dot or degreeing at the said ICL is the best bet.

II. Which cam is right for you

– The key to cam selection is to be brutally truthful when it comes to how you intend to use the engine in question.

– Don’t succumb to the temptation to put the biggest cam you can find into your daily driver.

– If you want to be a lazy fuck and not do your own research to find the cam that best suits your application you can just pick up a tr224 114 cam which is the quintessential all around great daily driver cam.

– Pretty much any 220 to 230 duration, .550 to .590, 112 or 114 cam is considered relatively small and great for a daily driver application with the right tune.

– A few of the more popular and latest and greatest cams in no particular order:

TR224 .563/.563 112 +4
TR 224 .561/.561 114+4
Comps 224 .581/.581 112
TSP 231/237 .598/.595 112 (unsure of advance)
G5X2 232/240 .595/.609 112 or 114+4
G5X3: specs unreleased but bigger then the X2
TR Trex 242/248 .608/.612 110+2
FMS FM4 226/226 .575/.575 112 or 114
FMS FM 10 228/228 .581/.581 112 or 114
FMS FM 13 230/232 .591/.585 112 or 114
02+ LS6 cam 204/218 .551/.547 117.5
LPE GT2-3 207/220 .578/.581 118.5
GM HotCam 219/228 .525/.525 112
TSP 225/225 .589/.589 112
TSP 233/ 233 .595/.595 112

II. Valvetrain

A. Springs

– For any cam swap you MUST change out valve springs. The stock springs are only good enough for the stock cam and barely at that.

– As far as springs go you have a few but not limited to the following choices:

1. Comp 918’s: A few years back they had some problems with non-blue stripe springs breaking but they have seemed to rectified the problem. The beehive design is also a superior setup. Your stock steel retainers can be reused with the 918’s but titanium retainers are recommended for lightening up the valvetrain and for strength.

Outside Diameter (O.D.): 1.290″/1.060″
Inside Diameter (I.D.): .885″/.656″
Installed Pressure: 130 lbs @ 1.800″
Open Pressure: 318 lbs @ 1.200′’
Coil Bind: 1.085″
Maximum Lift: 0.625″
Rate (lbs/in): 313 lbs/in

2. Manley Nextek: Also a single spring like the 918’s but not of the beehive variety. They are a good spring and come in a package deal from SDPC for 178 and that includes titanium retainers. The springs are rated for up to .600 lift.

Max Valve Lift : .600″
O.D. : 1.255″
I.D. : .830
Installed Pressure : 115@1.750″
Open Pressure : 350@1.175″
Coil Bind : 1.100″

3. Crane Duals: A dual spring setup rated for up to .650 lift. When buying duals you’ll need the dual springs (obviously), titanium retainers, new dual spring seats, and new valve stem seals.

The installed seat pressure is 112 lbs @ 1.800′’ with a maximum recommended lift of .650′’ at the valve with an accompanying open pressure of 352 lbs. The 1.275′’ O.D.

112lbs @ 1.800
352lbs @ 1.150
will handle .650 lift with .045 coil clearance

*INFO REGARDING CRANE SPRING REVISION*

4. Comp 921’s: Also a dual spring like the Cranes above and come as a kit with everything you need for installation, rated for up to .650 lift

O.D: 1.300
I.D: .870 (outer spring)
I.D: .655 (inner spring)
135 LBS @ 1.770
400 LBS @ 1.220
COIL BIND @ 1.040
MAX LIFT .650

5. Patriot Gold Duals: See Crane and 921’s. The PP Golds are currently the best direct drop in spring, they are the stand set for the new AFR heads and come on all PP heads. PP are the only genIII spring setup to use the super 7 locks.

O.D 1.29
135lbs @ 1.800
385lbs open
coil bind @ 1.08
.650 lift

My Personal Indepedently tested PP golds:

seat: 143 lbs @ 1.800
open: 363 @ 1.200
coil bind: 1.060
Clearance: .140
spring rate: 367

6. PRC Dual Spring Kit: Kit comes with Dual springs, tit. retainers (using stock locks), seats, valve stem seals. good for up to .660 lift

seat : 140lbs
open: 390lbs
install : 1.800
coil bind: 1.07
1.290 O.D.
max lift : .660
matl : super pure chrome silicone

Comp 977’s: dual spring (requires machining of spring pockets)

O.D: 1.46
I.D: .700
seat pressure: 155 @ 1.850
open presure: 419 @ 1.250
coil bind: 1.195
spring rate: 441

Comp 978’s: Dual springs (requires machining of spring pockets)

O.D: 1.46
I.D: .697
seat pressure: 126 @ 1.850
open presure: 368 @ 1.250
coil bind: 1.195
spring rate: 403

Comp 987’s: Dual Springs (require maching of spring pockets)

O.D: 1.430
I.D: .697
seat pressure: 121 @ 1.800
open presure: 388 @ 1.200
coil bind: 1.150
spring rate: 344

B. Pushrods

What they are: http://www.ls2.com/boggs/cam/cranepr.gif

What they do: transfer the motion of the cam to the rockers

What to look for:

– New pushrods aren’t absolutely necessary but they are highly recommended.

– The pushrod was never designed to be a fusible link in the valvetrain. Several years ago we even had a member (might have been in the old LS1.com days) that was an engineer from Jesel (don’t recall his ID) and he was adamantly opposed to the notion that the LS1 pushrods were designed to break in the event of a mechanical over-rev. The job of the pushrod is to accurately transmit the motion of the cam lobe (via the rocker arm) to the valve. If it’s flexing under load, then its simply not doing its job.

Look at it this way; you CAN mechanically over-rev any engine – pushrod, OHC, rotary, or otherwise – and cause damage. There is nothing unique or special about the LS1 pushrods making them fusible.

This is like saying that you broke your ring gear on a missed shift so therefore everybody should continue using the weak 10-bolt rear ends. Just a silly, backwards argument IMO – especially when you’re considered an aggressive cam with heavier valve springs (Fulton 1)

C. Rockers

What they are: HS 1 HS 2 Comp Magnums Comps Crane SLP 1.85

What they do: transfer the cam motion along from the pushrods and accentuate the valves to open

What to look for:

– New rockers are also an optional choice during a cam install.

– The stock roller tip rockers have been known to loose there bearings but it’s not an overly common occurrence.

– With companies like Harland Sharp coming out with affordable high quality roller rockers it makes the choice to upgrade that much easier

– Yellow Terra’s (YT) are also a relatively economical choice for roller rockers

– Adjustable rockers allow you to adjust lifter pre-load

– Higher ratio rockers can be used to increase lift (see cam lift for more info). Along with increasing the valve lift adding higher ratio rockers also nets you an extra degree or two of duration and increased overlap.

D. Others

– It’s a good idea to install a new timing chain as well. The stock ones are notorious for having a lot of slack in them
– You can either get a single or double
– The double chains come with the needed spacers to clear the oil pump
– 98-00 cars should also factor in a new oil pump
– A new chain and oil pump should run you about 200 dollars