To get a jump in power over std - may us CNC head / but may not if I can get a good jump with a cam and or high lift rockers and valves springs?

 

Is English your second language?

I will try to answer your question if you re-write that....

 

Makes sense to me, I was going to ask a similar question about these engines

 

suuuuuure...


Please tell me what this means:

 

Allow me. "May USE CNC heads, but might not if I can get a good increase with cam only"

I recon cam only should get you 60-70% heads the rest. Forget rockers, just get a proper cam straight off. UK emissions might mean you need to minimise overlap. Maybe a low 22x duration cam.

 

Lets see.....
Jellison is looking for a good cam to get a nice increase on power from his stock LS2 motor, he may look into having the Heads CNC ported if needed. High Lift rockers and springs he's unsure about.

Standard Cam for LS2 is the First gen LS6 cam (385hp)... I believe its something like a 206/212 or something like that... can't remember off the top of my head.
Standard Springs for the LS2 can handle up to around .550" lift, if you do a large cam upgrade then look at replacing those.
Stock heads are the GM 243 castings which are the same as the LS6 heads with Sold valves instead of hollow stem valves.
Standard Rockers Arms are 1.7 Rollers rockers (Non-Roller Tip).

You can upgrade the Rocker Amrs to Jessel, Harrop, Crane, Comp, etc 1.7, 1.75, 1.8 or 1.85 roller tips roller rockers (shaft mounted, pedestal mounted, etc all LS1 Rocker arms sets work for the LS2). Know that this will change the lift values of the cam.

I'll use the Lunati Voodoo 222/228 cam as an example (cause I have it installed and know about it):
The Voodoo Ls1 222/228 cam has a lift of .567" intake and .567" exhaust with a 1.7 rocker arm. Changing out to a 1.85 rocker arm the lift on this cam goes up to .617".
If you have the cam spec's you can simply do the following for a easy idea of how much lift you'll increase the cam with a set of longer rocker arms.
"Lift" divided by the "stock rocker arm length" then multiply by the "new rocker arm length". Mine was .567 inches / 1.7 x 1.85 = .617 inches of lift.
Note: some cam's have different lift spec's for the intak and exhaust valve.

Alot of the GTO folks are going with 224 to 232 intake lobe sizes and 224 to 238 exhaust lobe sizes and a closer lobe sepperation of 112 to 114 vs the stock LS2's 117.
Those cam's with the stock 243 heads can get you a decent gain from 30 rwhp to 75 rwhp increases, things very depending on intake and exhaust setups (ie Headers and a CAI or not).

Some have gone with the Hellion cam, a CAI, plus full exhaust and gotten great results.
I will not list the spec's out of respect for AZ Power & Sound.
I think they have hit just shy of 480 rwhp with that cam plus a Volant CAI and SW full exhaust (headers and cat back) on 05/06 gto's with LS2's (using stock heads with aftermarket springs as the only upgrade).

The main thing is going to be tuning the motor after you get your parts all installed, especially if you go with a very large cam shaft.
Theres Ls2Edit and HPTuner (I've got HPT) for full tuning.
As well as Vendors that you list your spec's to and send your CPU off to and they recalibrate it to your car's modifications.
Then theres local tuning shops that have LS2Edit, HPTuners, or other app's and train'd technicians to tune it (and install it).

Best bet is to contact one of the companies that specializes in LS1/LS2 tweaks to get a good setup for your vehicle and driving style. There are a couple of them listed on the right
It may cost you a little more up front, but it will be worth it in the long run if you don't know how to tune and don't have the software/hardware to do the modifications.

And as for emisions as long as you set the fuel injector pulse to start spraying after the exhaust valve is closed and to stop spraying before the intake valve closes you should be able to easily pass.... Tuning tuning Tuning.

 

Cheers Noise - that is Exactly what I was looking for. Sorry I was a bit crap on question - fingers faster than brain sometimes!

Exhaust and C) is easily gotten round (my system has very small cat sin the two very free flowing headers (tad down in size on std C5 Z06 but making same power as a std one now after ECU tuning).

Tuning is fine here - found a great tuner that does Holden stsufa ndhas started in on the new C6 (LS2 / 7) ecu's now (as well as the older 2/4/6 ecu's).

Hopefully mate will do this or I can do some of this for my car later on.

400bhp in 2450lbs will do for now!

Cheers
Jelly