What about TECH FAQ?

Q: What are some emmission guidelines and parts for exhaust?

A: 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)

Q: What are some Header basics?

A: Header Basics by Loren Barnes, President, S&S Headers, Inc.

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.

Q: What are stock Cam specs for an LS1 F-body?

A:
stock 98-00

[email protected] 198.86 intake 209.25 exhaust
lift .498 intake .497 exhaust
LSA 119.45

stock 01-02

[email protected] 196.37 intake 208.72 exhaust
lift .464 intake .479 exhaust
LSA 115.92

Q: What are some modding guidelines?

A: 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 [email protected] 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:

Q: What should I look for when upgrading my cam and what do those numbers mean?

A: What they are:
Higher Res cam pics:
http://gettinthere.ls2.com/cam1
http://gettinthere.ls2.com/cam2
http://gettinthere.ls2.com/cam3
http://gettinthere.ls2.com/cam4
http://gettinthere.ls2.com/cam5
http://gettinthere.ls2.com/cam6
http://gettinthere.ls2.com/cam7
http://gettinthere.ls2.com/cam8
http://gettinthere.ls2.com/cam9
http://gettinthere.ls2.com/cam10
http://gettinthere.ls2.com/cam11

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.

Q: What should I look for when upgrading my cam and what do those numbers mean? Part 2

A: Cam Overview:

-

- Your starting point:

Stock 98-00 trans am cam

[email protected] 198.86 intake 209.25 exhaust
Lift .498 intake .497 exhausts
LSA 119.45

Stock 01-02 trans am cam

[email protected] 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.

Q: What should I look for when upgrading my cam and what do those numbers mean? Part 3

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 )

- 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, g5x2 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 stuff can be found here and here and here

Q: What should I look for when upgrading my cam and what do those numbers mean? Part 4

A:

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

Q: What should I look for when upgrading my cam and what do those numbers mean? Part 5

A:
Lobe Separation Angle (LSA)



- 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.

Q: What should I look for when upgrading my cam and what do those numbers mean? Part 6

A:
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.

Q: Which cam is right for me?

A: - 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 lazy 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

Your application will have alot to do with which cam to get and also what LSA to have it on. As a general guideline a 112lsa will be well suited for an M6 car whereas a 114lsa will be well suited for an A4 car. That is by no means set in stone, but just what most people prefer. ANd yes there are A4 cars running 112's and even 110's. It's all up to how "driveable" you want the car. Cams on a 114lsa will also be a little better for N2O set-ups.

And please remember to do your homework on supporting mods. A cam needs to breathe. The more air you give it, the better it will perform. This will mean: Long Tube headers, a Y pipe, an LS6 intake or better, a ported TB, and a lid. Other mods to consider would be a ported or LS6 oil pump and new injectors. You also must get ungraded valvesprings, retainers, seats and pushrods. Most valvetrain parts you can get in a package from a sponsor. The factory equipment can barely handle stock power. For questions about the valvetrain go here. Other non engine mods to look at when installing a cam would be strengthening the trans, clutch and rear end. Also if you have an A4 get a compatable converter. i.e. a 233/236 cam would go well with a 4000+ stall. A 224/224 would work well with a 3400 stall and so on. Gears are another thing to look at. Usually the bigger the cam, the bigger the gear you need.

Q: What should I look for when upgrading my 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 : [email protected]"
Open Pressure : [email protected]"
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

jrp's 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



Pushrods


What they are:

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)

Q: What should I look for when upgrading my valvetrain? Part 2

A:
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.


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

Q: What do all the cam terms mean?

A: Cam Glossary

asymmetrical: one cam lobe with differing opening and closing ramp rates; it projects different images on either side of the lobe centerline; many modern cam grinds have asymmetrical lobe patterns, often with high opening rates using roller lifters, which allow their use

base circle (heel): lowest point of the cam lobe in relation to lift; the closed valve position occurs as this portion of the cam lobe turns against the lifter. All valve lash settings are made when each lobe has the base circle (or ?heel?) against the lifter (or lash pad on some OHC engines). When a camshaft is being ground, the base circle is the actual part of the lobe that is ground to form lift at the lobe

basic rpm: the rpm range in which the engine makes the best power

cam centerline: cam phasing in relation to the crankshaft; where the centerline of the intake or exhaust lobe is in relation to the No. 1 cylinder?s piston given in degrees of crank rotation after TDC. When degreeing a cam, you must know this figure to install it properly. When you do advance or retard the cam centerline (when degreeing a cam), you affect both intake and exhaust lobes; these are not individually adjustable

degreeing a cam: setting the camshaft?s phase (or position) in the engine in relation to crank position. Most cams today are ground with some advance to make up for timing chain stretch, around 4 degrees. If the installer places the cam ahead in relation to crank/piston timing, it has been advanced; if it?s moved back from straight up, it?s been retarded. Many people used to install a cam advanced, but since most are already ground slightly advanced, there?s usually no need. Always follow the manufacturer?s installation card or instructions carefully


duration: time (in degrees of crankshaft rotation) that the valve is open during its tappet lift; given in ?advertised duration? and at 0.050-inch tappet lift; when comparing cam specs, always compare duration figures at 0.050-inch lift because cam companies measure advertised duration differently

hydraulic cam: a cam using lifters that has a valve-controlled plunger inside its body, preloading the pushrod at the closed valve position through oil pressure lift: distance the valve is depressed from its seat when closed to the peak valve lift when open fully

lobe separation: actual spacing of cam lobe centerlines (in degrees) for a common cylinder; ground into camshaft?not changeable; largely responsible for the idle quality of an engine; narrow separation angles seal a cylinder for a longer period of time but also give a rough idle quality, while larger angles generally give a smoother idle in street engines

mechanical (solid) cam: a cam using lifters with only a radiused contact face in which the pushrod end sits without internal valves or other complexity; requires periodic lash setting

nose: full-lift portion of the cam lobe where the lifter is pushed open at maximum distance

ramps: portions of the cam lobes that lift or settle the lifter from the base circle of the cam; does not include the nose. They have different rates of lift in velocity and degrees of crank rotation. Symmetrical cams have individual lobes with the same opening and closing ramp rates, while asymmetrical cams have different opening and closing rates on the same lobe. Roller cams can use more radical ramp rates because of the nature of the roller lifter


roller cam: in either hydraulic or solid versions, these cams use lifters that employ wheels to contact the camshaft lobes, fixed in needle bearings; these cams often have higher valve opening rates than flat-faced cams and exhibit less friction; most roller cams require using a bronze distributor drive gear due to metallurgical differences in flat-faced and roller cam material, though some new ones do not. Rollers have been widely used in diesel and motorcycle engines previous to automotive gasoline engines

split duration (dual pattern): cams with intake and exhaust lobes of different specs

symmetrical: both sides of one cam lobe are mirror images of each other; they have the same ramp rates upon opening the valve and closing it; split evenly on either side of the individual cam lobe centerline


- CHP

The following questions ae made from a compilation Jaberwaki put together


Q: What's the deal with Nitrous?

A:
Nitrous Oxide (or N2O) is a chemical oxidizer; it is two parts nitrogen and one part oxygen. The oxygen is the part that makes power. Gasoline combines with oxygen in a combustible mixture. The more of both gasoline and oxygen you have, in the proper amounts, the more power you make. So why not inject pure oxygen? Simple: pure oxygen is much, much more intense of an oxidizer. Having about five times the intensity that N2O provides, pure oxygen would melt your motor.

Bang for buck, N2O is the fastest way to make power. That being said, N2O has a bad reputation for giving more BANG then people expected. Let me go on record as saying, this is not the N2O's fault. The fault is on the person trying to get away with spraying nitrous and only having $500 total to put into it. Nitrous is a SAFE power adder, if it is both set up correctly and used properly.



Setup Types

There are 3 major types of nitrous setups.
1. Dry
2. Wet
3. Direct port

As with most choices, there are pluses and minuses to all of them.

Dry:
A dry shot relies on the car's MAF, PCM, and fuel system to add the proper amount of fuel to balance the nitrous out. That is, the nitrous is sprayed in front of the MAF, which recognizes a sudden spike in O2 and signals the PCM, which decides the proper amount of fuel needed to balance the mixture. It is the cheapest of the setups to purchase. It also leaves no chance of fuel "puddling" in the intake. The weak point in this system is the car's fuel system. The dry shot is limited to the car's ability to increase fuel. Often a shot will find the weak spot in the fuel system, be it the injectors, the fuel pump, etc. Spraying N2O without the fuel to support it equals the kiss of death for your car.

Wet:
A wet shot does not rely on the car's MAF, PCM, or injectors to provide the proper amount of fuel to balance the mixture. It has a separate fuel line with its own jetting that is set up to spray the exact amount of fuel needed to go with the size nitrous shot you are using. In some cases, this may require you to step up your fuel pump, but you need not worry about your injectors. Some drawbacks are that with a separate fuel line and the fact that the spray is happening AFTER the MAF, any trouble with the system will go unnoticed by your PCM until it's too late. If your nitrous stops spraying but the fuel does not, then it will puddle and possibly introduce you to your hood-- the hard way... If the fuel side cuts out but the nitrous side does not, then you will go drastically lean and blow your motor. Threat of these things can be minimized. Buy GOOD parts, not the cheapest you can get away with.

Direct Port:
A direct port setup mixes the N2O and fuel, and directly injects the mixture into each individual cylinder. It is by far and away the safest and best way to use N2O. It does have one major drawback... PRICE. The direct port system by itself, can cost north of $1500. That does not include any of the supporting parts, that really are must-haves with ANY nitrous setup.


Accessories

Not just the base kit. If you plan on running N2O and would like your car to last more then just one or two runs down the 1/4, then you should compliment your base kit with the proper accessories. These include:

- RPM Window Switch: It will turn your nitrous kit off and on at preset RPMs, 1. so you don't spray under low RPMs, which can blow your motor; and 2. so you don't spray right into your rev limiter, same reason.

- Fuel Pressure Safety Switch: If your fuel pressure drops below a safe range while spraying nitrous, the safety switch will shut the nitrous off to keep from running the engine too lean.

- Bottle Pressure Gauge: It allows you to safely monitor your nitrous pressure from the passenger compartment.

- Throttle Position Sensor (TPS) Switch: Also called a WOT switch, it only allows your kit to turn on when you are at Wide Open Throttle.

- Automatic Bottle Heater: It will keep your bottle at the correct temperature and pressure to ensure that you are spraying the correct size shot. This is especially important in a wet shot setup, as the shot of fuel will not adjust to the lack of nitrous from a cold bottle.

- Purge Kit: This vents old nitrous left in the lines from the last time you sprayed, and keeps it out of your motor.


This is not everything there is to know about nitrous. It is only a quick, down and dirty introduction to entry-level knowledge that you should have before you go the N2O route.

(As a side note, it should be said that referring to nitrous as NAWS or NOS is a good way to get made fun of at the track, and could even get your ass kicked.)

Q: What is considered a "bolt-on"?

A: Bolt ons are any part that assists in the making of power, that does not touch oil. It is common knowledge that they are the starting point in modding your car, so the fact that you should complete your bolt-ons should go without saying. Let's look at some of them and what they do.

Lid:
A lid replaces your stock lid, which was designed with comfort, not power, in mind. Simply put, an aftermarket lid does not have the restrictive air silencing fins and baffle found on the stocker. It allows more air in, and is a "must do first or second" mod. A lid is a lid, don't ask which one is best.

Cold Air (Ram Air):
The factory placement of the lid is poor for two reasons: the amount of space that air has to get into the lid is minimal; and placing it right on top of the radiator all but insures that you will have hot air entering your motor. A cold air (or ram air) kit fixes both of these problems. Either drawing cool air from under the car, or sealing your factory ram air to the cool outside air. Both methods ensure that enough air is getting in, and that the air that gets in is not hot.

Headers:
Headers replace your stock exhaust manifolds. They assist in the evacuation of spent gasses from your heads. They do this two ways: 1. first, they are free-flowing, which is to say they do not restrict exhaust flow in the slightest. 2. being free-flowing is not enough - GOOD header designs take it one step further by creating something know as the "scavenging effect"; that is, the flow of one header primary as it travels to the collector, creates a void or vacuum in the other primaries, effectively sucking out the exhaust as it is released from the head. I have always preferred "stepped" headers, for this very reason. Steeped header primaries get larger as you move away from the head's exhaust port. This greatly increases the scavenging effect, and increases your power potential.

Underdrive Pulleys:
Most commonly the crank pulley; it is simply a smaller pulley. 1. The rotational mass of the pulley is less, and therefore lighter and easier for your motor to turn. 2. It effectively reduces the amount of power required to turn the rest of the accessories, much like shifting to a lower gear.

Electric Water Pump:
Following hand in hand with the underdrive pulley, the electric waterpump gives the motor one less accessory it has to turn, thereby freeing up a few more HP. Although there is debate as to how much, no-one (who isn't a moron) disputes that it does free up at least SOME amount of HP.

Manual Rack-And-Pinion Steering:
Along the same lines, the MRAPS gets rid of yet another accessory, thereby freeing up power. It also weighs considerably less then the stock power steering system.

Exhaust Systems:
While there is A LOT of bullshit that flies around the Internet about "this exhaust sounds better then that one", this post is not for posers who want to whine about rasp. The very best-flowing exhaust there is, is a true dual X-pipe or H-pipe setup, with or without bullet mufflers. The next best thing is a cutout in the I-pipe. No cat-back out-flows a cutout; no Y-pipe setup out-flows true duals. Period.

Intake and Throttle Body:
I put these together because much like heads and cam, they should be matched. Again all bullshit aside, the best is the LSX 90mm intake and a 90mm throttle body. They are very expensive. A cost-effective second place is the LS6 intake and a ported stock TB. Either of these two choices are worth it, and have been dyno-proven time and again.

Q: What are "short blocks"?

A: When you're ready to play with the big dogs, it is time to refer to older wisdom: "There's no replacement for displacement."

I will not speak to which vendor, or even which short block, is best. But there are a few staples that any good short block should have:
1. be completely balanced and blueprinted
2. forged internals
3. warranty on craftsmanship


1. it should be Completely Balanced and Blueprinted
This means that every part of the rotating assembly has been weighed and made to be in perfect balance with like parts; for example, all pistons weigh exactly the same within a tolerance of +/- 1 gram. This ensures that the motor is not vibrating itself to death. A perfectly balanced motor will always make more power, all else being the same. Blueprinting means that every clearance and tolerance has been checked, rechecked, and documented for you on a build sheet.

2. it should have Forged Internals
Getting a new short block is something you do not want to have to do twice. Forged internals will last longer, withstand more abuse, and support more power. Do it once, do it right.

3. it should have a Warranty on Craftsmanship
This should not be a hard one to understand. If a company will not stand behind its product, then why would you?Do not be fooled by a vendor who says no-one gives a warranty on short blocks. Yes they do, and if that vendor will not, then find one who will. It should be noted on the side, that this does not, nor should it, apply to power-adder cars (nitrous, forced induction). Too many things can go wronge in a power-adder setup, to ever hold the motor totally responsible.


Having a potent short block will most definitely make you the guy on your block to beat.

Ensure that you have the short block built for your specific application. Most builders do not have cookie-cutter short blocks. They build yours for your goals. Are you looking to be a naturally-aspirated (N/A) monster? Then a 427 mill with high compression may be your best bet. Or are you looking to be king of boost? In that case, perhaps a bulletproof low-compression iron 408 would suit you best. Tell your builder what you want to do with the short block, and they can help guide you to the one best suited for you.

Q: What are some basics of upgrading an M6?

A: First, let me congratulate you on buying the stronger of the two stock transmissions. With minimal changes, this tranny in near-stock form has been deep into the tens. And in built form, it has propelled an F-body to mid-9-second glory. Now for the bad news. You also possess the single most part-destuctive force known to civilized man. FACT. M6 cars break more stuff in the drivetrain then most A4 boys ever dream about. To avoid this (as best we can), we are going to talk about parts that are made ultra-tough, just to stand in defiance to this cruel tyrant called the M6 tranny.


1. Clutch

It's time to man up and start giving your left leg a serious workout. Your stock clutch (yes, even if it's a Z06 one) is weak. It is the skinny guy on the beach that all the other clutches walk by and kick sand in the face of. It will NOT hold much more than stock HP, and it won't even hold stock HP for long on sticky tires. If your plans are to run 11s or faster, then you can forget those oh-so-cheap Stage 1 and Stage 2 clutches. I hate the term "stage" because people get wrapped around the word and forget to think about what they are really buying. So you wanna be fast? Well, you have two choices of clutches:

Twin Disk
A Twin Disk clutch is very strong; it will most definitely get you where you want to be. It will also do so while retaining a very comfortable pedal feel, and streetablility. Sound good? It is. However, as always, with the good news comes the bad. It is well over $1200 for a respectable twin. If you want that comfort, you've gotta pay for it.

Sintered Iron Disk
Wow, just saying its name makes it sound manly, doesn't it? That's because it is. It's a MAN's clutch. Little pansy boys, who like to complain about too much rasp or the clanks and rattles that solid end links make, need not apply. If you do not love the feel of a race car, then DO NOT buy this clutch! But, if you want a clutch that will kick your car in the ass and say "giddy the fuk up pony!", then this is the clutch for you. Your reward for having balls? How does paying $400 less grab ya? Yeah, that's what I thought.


2. Driveshaft

First things first, you need to say to yourself over and over and over again: "ALUMINUM IS FOR BEER CANS, NOT DRIVESHAFTS!!!" When it comes to driveshafts, I will stand on this statement every day and twice on Sunday. If your plans include a lot of power and sticky tires, then you have three choices for driveshafts.

Steel
Steel is real. Steel is strong. Steel is easy to balance. Steel is afforable. Can anyone guess what kind of driveshaft I have? Thats right, steel. Steel, however, is not perfect; it does have two troubles. 1. It is heavy -- against its
lighter counterparts, it does produce slightly more parasitic loss. 2. In the rare occasion that they do break, they take a lot of stuff with them.

Chromoly
Chromoly... without going into a chemistry class, think of chromoly as having all the plusses of steel, and add to that it weights about 50% less. So why doesn't everyone have one? Price -- ah yes, the almighty dollar. These things are very pricey.

Carbon Fiber
All right! A real use for carbon fiber, other then making ricer hoods! Carbon fiber is light, very strong, and looks GREAT. One major asset that carbon fiber has that the other two do not, is that in the rare case that it does break, the fibers splinter and crack into what is best descibed as a broom. This means that as you are hitting the brakes and your broken driveshaft is still spinning, it is NOT hurting anything else. Hell, it might even clean off a thing or two.


3. Rear End

Let's face facts. When the General was building the F-body, he put no thought whatsoever into the choice of the 10-bolt rear. This rear is not even strong enough to hold the stock HP, and is one of the first things to break when a new F-body racer heads to the track. In the case of the M6 tranny, please do not make a $2500 mistake. If you have spent a week on LS1tech, then you have heard the words "12-bolt" and "9-inch" when it comes to rears. If you have an M6, then I want you to forget the first of those. You are about to spend $2500 on a rear; do you really want to break it? 12-bolts are for automatic cars. They last a long time in an auto. But you own the sledgehammer of parts, the T56, breaker of rears. For you, there should be only one choice -- the mighty mighty 9-inch.


Rear end parts... Now that you have chosen the correct rear, it's time to pick the parts you want in it. Most every place that sells these rears will give you these choices.

Posi-Traction: The best choice for a car that will not see much track time but still wants a super-strong rear.

Detroit Locker:The best choice for a car that will see a lot of both street and strip time. It is more noisy than the posi, but it is also stronger.

Full Spool: So you got a RACE car, huh? Well, this is what you want. Full spool is the least street-friendly of the choices, but it is hands-down the strongest.


Axles: The simplest way to approach axles is: the more splines, the better.

Gears: This is mainly a matter of personal preference. 4.11s are perfectly streetable while also performing well at the track. Numerically higher gears lean more to track use; lower leans more to street cars.