GT Griller

iTrader: (8)

I wouldn't go any lower than the 220/220 just so that u know ur making enough power and i would suggest headers first just so that u can reach the fool potential of any kind of cam.

AN1313

Here is some info for you.


The following link shows the results of a test Comp Cam performed on an LS1. (I wish they did a similar test with LS6 heads.)

http://www.compcams.com/Community/Ar...ID=-1044516358

You can see what cams they recommend. However, they are using longtube headers which are illegal in CA.


In terms of emissions, I have heard that -3 degrees of overlap or less (more negative the better) is needed to definitely pass a sniffer test.

Degrees of Overlap = (intake duration + exhaust duration)/2 - 2*LSA


In terms of spring life, I have read that the cam lobe ramp rate, maximum lift, and maximum rpm are all major factors. So getting a low lift aftermarket cam may not necessarily eliminate the need to check the springs.

I would like to see a durability comparison between Comp 918's and GM LS6 springs. The 02+ Z06 has a .551 lift, a 6600 redline, and can go 100K+ miles. Would the 918's be able to do this?

jz06man

Use this formula for overlap= it a bit easier but the same.

-Degrees of Overlap = (intake duration + exhaust duration)/4 - LSA * 2

Examples:
The 224/224 LSA 114 cam = -2 overlap will not pass California use 921/Patriot or VHP Springs

Z06 Cam 204/210 LSA 117.5= -28 does pass use Z06 springs or 918

Comp Cams Xtreme 216/220 .114 LSA= -10 pass. Can use 918 but these are better 921/ Patriot or VHP Springs

LS1 GT2 205/212 .116.5 LSA= -24.5 This cam is about the same as an Z06 cam-power use Zo6 or 918 springs

LS1 GT2-3 207/220 .571/.578 118.5 LSA= -11.75 pass- 921/Patriot or VHP Springs

GM Hot Cam 218/227 .525/.525 112 LSA = -1.5 will not pass use 918 but these are better 921/Patriot or VHP Springs

220/220 553/533 112+4= -4 might not pass, but with the 4 degrees of advancement, might help emissions. use 918 but these are better 921/Patriot or VHP Springs

Check out the VHP Cam's 047 or 062- http://www.vincihighperformance.com/CAMSHAFT%20SPEC%20LIST%20PAGE%20LS1%202.htm

These cam will pass california and have lots of bottom end torque & HP up top.

047-DUR @ .050" 210*/218* .531 / .531 LSA 112 overlap= -10 pass

062-DUR @ .050" 210*/218*.551 / .551 LSA 112- overlap= -10 pass
I would only use 921/Patriot or VHP Springs.

On any cam with more lift than .551 and or with higher ratio than stock rockers- I would only use 921/ Patriot or VHP Springs.

These springs should last quite a while, but i have not seen any tests that show how long. I hope some of the magazines and/or sponsor, do some testing in the future.

Use should check springs anytime you change to a more aggressive cam every 10K-15K miles- The may last 25K or more.

I personnally would rather change the spring every 15K and be safe than lose a valve or much more and cause damage($$$ and down time).
Spring kit and labor to change, if you don't do them yourself should be from:
Springs $329 VHP- 921 kit $560 Speed Inc.
Labor $2-3 hr at $75 per- 150-225. Total to sleep better at night $480-$785....every 15K to who knows 25K or 40K??.


Here is what you were asking for : "I wanted to go with the TR224 cam, but its got the spring life issues. I dont want to have to worry about the springs at all._ I guess this mean you don't want a 224/224 cam?

Here are some cams i picked out. My car is an M6, i need the cam to work well with 85 - 100 dry shot of n20. The car needs to pass smog here in california. Someone let me know which one would be best for my application. Also, which springs should i use? Comp 918s or LS6 Springs?" Any of the cam's you choose or someone recommendated will work with N2O.
I believe these 918 or LS6 will work ok, but you take a chance with the higher lift. Now that your adding a nitrous shot this changes. As you know the nitrous will stress everything in you motor. The typical parts on our LS1/LS6's, that are the weakess for adding more power is.
The Piston's(Hyperjunk and does not like Boost/N2O), the wrist pin's, rod's and springs & pushrod's....
I know you did not ask about the pushrods, but I think that we all assume, anyone would change these when changing to a higher or more agressive cam.


So their you have it. Pick your cam(By the way everyone on here will have a
different opinion on cam's).- That's how things are: Everyone I'm sure is right basised on their experience's and needs.

So pick a cam, upgrade to quality springs kit (retainers, seats seals) and pushrods.


Hope this helps-have fun in the process and enjoy driving your car.

AN1313

I caught a couple errors in your long post and made a few comments. I just wanted to keep things as accurate as possible.

I think you meant:
Degrees of Overlap = (intake duration + exhaust duration)/2 - LSA * 2


I think you meant:
224/224 LSA 114 cam = -4 pass


I think you meant:
Z06 Cam 204/218 LSA 117.5= -24 pass


I think you meant:
GT2-3 207/220 .571/.578 117.5 LSA = -21.5 pass


On the edge, may pass. Anyone actually tried?


This should pass. Anyone actually tried?

AN1313

Also, did you mean Comp 918 springs when you wrote 916? I never heard of a 916.

jz06man

I did have a few error's thanks for fixing. This happens, when your interruppted a few times. But the calculation for overlap is correct.

224+224=448/4=112 then - LSA 114=-2X2= -4

I caught a couple errors in your long post and made a few comments. I just wanted to keep things as accurate as possible.

Quote:
Originally Posted by jz06man
-Degrees of Overlap = (intake duration + exhaust duration)/4 - LSA * 2 This is Correct !




I think you meant:
Degrees of Overlap = (intake duration + exhaust duration)/2 - LSA * 2

In this example 224+224=448/2=224-LSA 114=110x2=220 Not Correct
Quote:
Originally Posted by jz06man
Examples:
The 224/224 LSA 114 cam = -2 overlap will not pass California use 921/Patriot or VHP Springs




I think you meant:
224/224 LSA 114 cam = -4 pass Yes this is now correct.


Quote:
Originally Posted by jz06man
Z06 Cam 204/210 LSA 117.5= -28 does pass use Z06 springs or 916




I think you meant:
Z06 Cam 204/218 LSA 117.5= -24 pass It's correct now. Z06 is 204/218 not 210.



Quote:
Originally Posted by jz06man
LS1 GT2-3 207/220 .571/.578 118.5 LSA= -11.75 pass- 921/Patriot or VHP Springs


He posted this -LS1 GT2-3 207/220 .571/.578 118.5 LSA=-23.5 it's correct now.


I think you meant:
GT2-3 207/220 .571/.578 117.5 LSA = -21.5 pass


Quote:
Originally Posted by jz06man
GM Hot Cam 218/227 .525/.525 112 LSA = -1.5 will not pass use 916 but these are better 921/Patriot or VHP Springs


This actually-218+227=445/4=111.25-112=-.75x2= -1.5.. Will not pass or very close.

On the edge, may pass. Anyone actually tried?


Quote:
Originally Posted by jz06man
220/220 553/533 112+4= -4 might not pass, but with the 4 degrees of advancement, might help emissions. use 916 but these are better 921/Patriot or VHP Springs




This should pass. Anyone actually tried?

Ok, I think we're straight now.
Thanks
__________________

AN1313

Due to order of operations (math dork here), I always did it this way:

(224+224)/2=224,
then 114*2=228,
then 224-228=-4

To do it your way, the eq should look like this:

[(Int Dur+Ex Dur)/4-LSA]*2

Since we are getting the same answer, who cares. That 4 just caught my eye for some reason.

I checked the GT2-3 LSA on the 21st Century Muscle Cars website. I'm pretty sure it is 117.5.

Sorry to nitpic your post. You should share your results in this thread. If I remember correctly they are pretty impressive and CA legal (other than the headers).

jz06man

The way you know wrote the formula is correct....Same anwser different way of doing it or expressing it..He and other should get it.
If that's what the cam site said, great, I just when with what he posted.

My results with the enclosed signature with the VHP 062 (light cam by everyone's standard) & VHP rockers-1.79. 420HP & 405Torque....