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heads and cam package

20K views 54 replies 16 participants last post by  2007ThunderV 
#1 ·
iam considering my options on a heads, cam set up.
have a few questions before i dig to deep into this.
1. can i do a head/cam swap without pullin the motor?
2. what other supporting mods do i need(ie injectorts, fuel pump, ect) or is the stock set ok.
iam lookin for something to net me maby 440-460 whp nothing to crazy.
3. iam looking to buy everything from one vendor if possible, dont want to buy one part here, one part there ect...
my current mods on my car are, corsa cat back, magnaflow high flow cats, pinsoft shifter, got some dss 1000hp axles on the way. will be getting some kooks long tubes to install at the same time as heads,cam
my car is a 2007.
i was lookin at texas speeds heads and was going to add a cam to match the heads?
http://www.texas-speed.com/p-1386-prc-60l-stage-25-cnc-ported-heads.aspx
http://www.texas-speed.com/p-1158-texas-speed-camshaft-package-w-dual-valve-spring-kit.aspx
guy with heads/cam upgrade steer me in the right direction, not lookin to go crazy, but want to make some more power out of the ls2
thanks in advance
 
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#2 ·
1. You do not need to pull the motor to swap the heads and cam.
2. Depending on the cam, you may need bigger injectors. I ran a head and cam setup for about a year with the stock injectors, they were at the top end of the duty cycle. You will have to get something crazy to end up at 460 rwHp.
3. Texas speed has good setups as they are one of the foremost aftermarket LS companies. If you purchase those heads, you will not need the complete cam kit. Your best bet is to call them and ask their opinion, they really do know their stuff. I would recommend that you go big with the cam, I don't think I've EVER heard anyone say "My cam is too big.", or "I wish I would have gone with a smaller cam." Any good tuner can get you good driveability in the low rpms with a stock bottom end and a cam that isn't just retardedly overlapped or has a super low LSA.
 
#3 · (Edited)
Call Ron at Vengeance Racing out of Georgia. They have very complete kits with Trickflow heads and all of the supporting gaskets, pump recomendations and if you need injectors. You can even ad a FAST intake if you would like. I would recommend a VRX5 cam to go with your wishes. It's a little big, but when you get the urge to go to a 402 this cam will work for that also!
In case your wondering I am a customer of theirs and there kit was very complete! They were also helpful with tech support and realistic numbers.
Good Luck,
 
#6 ·
You cant go wrong with Texas Speed.
 
#8 ·
crankedupforit had his head/cam package done by Katech.
Very happy with his build and can give you some pointers.
Some pictures and a write up are listed up in the new perfomance section of the forums as well...
 
#12 ·
Texas Speed is a good oufit (as is Katech, Vengenance Racing, Thunder Racing, Advanced Induction, Total Engine Airflow, and some others) and they will give you good advice. The trick to getting the best advice from any of these folks is to be completely honest with them and yourself about what you want. For example, if you are going to use the car as a daily driver but not in heavy trafffic you can get away with a pretty big cam. On the other hand, if you spend 40 minutes every week day morning and another 40 minutes every week day afternoon sitting in stop and an go traffic you will grow to hate a big cam.
 
#13 ·
I'm in the process of putting together a new LS6 to replace the one I blew up at VIR a couple months ago. I have an unported FAST 90/92 intake, had the old heads from the dead engine ported by TEA (not too crazy, just a "stage 1.5" job), and plan to go with a not-too-crazy cam, too. I already have Kooks 1.75" headers w/cats.

Based on what I've read in various threads, it seems like the stock injectors should be up to the task, but I just wanted to get confirmation. If the stock injectors would be pushing it, then I'll go ahead and upgrade now while it's easy to do so.
 
#14 ·
I am still running stock injectors on 407rwhp/393rwtq setup and my tuner said I did not need larger injectors. I did not get a duty cycle percentage so I do not know how much headroom I have left. With the right cam and your headers you may make more power than my setup.
 
#15 ·
My duty cycle was at the upper limit with the 90mm TB I first had. I went to 42lb Bosch Green tops. My tuner tells me that at the the duty mine were pulling my injectors were acting more like a switch than a valve.
 
#16 ·
One must be sure to discuss injector duty cycle with a tuner and the intended purpose of the car. I've experienced tuners who were not averse to running over 95% duty cycle on injectors, telling it "it's okay". It's not okay, unless the car is strictly street or perhaps an autocross once in a while. Open tracking a car where the injectors are pushing high duty cycles is a mess waiting to happen. I think the stock LS2 injectors maintain a decent duty cycle up to 430-ish rwhp on a dynojet. Dunno the size of the LS6 injectors. I think an LS6 with ported heads, a FAST intake, headers, and a mild cam will push the 430rwhp limit.
 
#17 ·
The stock LS6 injector is rated at 300 cc per minute, which equates to 28.6 pounds/hour (based on 43.5 psi fuel pressure). According to one duty cycle calculator (http://www.witchhunter.com/injectorcalc1.php4) that translates into a 87.5% duty cycle on a stone stock LS6. I am a little skepical about that calculation though. If it is correct, my set up would be at a 105% duty cycle. If that were correct, I would think I would be throwing lean codes every time I pegged 7k rpm, and I am not.
 
#20 ·
I was searching around for info the other night, and something doesn't make sense with the injector sizing. Most of the online calculators assume 43# fuel pressure, or somewhere thereabouts, but the LS6 runs quite a bit higher than that. If you assume they're rated 28.5#/hr at the "standard" 43#, then the calculations almost work out, but only for stock levels of power. And I know that plenty of people are running quite a bit more than stock power levels without issues. :confused:
 
#22 ·
You basically have two options wih two different prices...

1. DIY
Benefits, cheaper on labor, the job will be done at your pace so you just have to answer to yourself. Lastly you feel a sense of accomplishment for its your sweat, tears and blood on and in the car...
Downside, You need to buy the tools to pull the crankpulley, torque the parts back on, and a few others as well. Removin the parts is a bit of a squeeze, the front bumper has to come off, the rad and condensor removed as well. And lastly you need to retune the car so you need to install a wb and have either of the following on hand, diablo tuner, efilive or hptuner...All about the same price, but the diablo is more sensitive than a pregnant woman...


2. Taking it to a proper performance shop,
benefits, its done properly and to the best standards. They can make you a deal on parts and labor. they can tune on a dyno for a turnkey situation. You have an excuse to sit on the porch and drink...
downside more costly than DIY, the shop may delay on your job for a more important customer.

I stuck to one shop and they designed, built and dynoed my engines for me. Presently i have a mean tahoe wih a 6.0ltr engine, and a 415ci caddy that has a bad habit of smoking the tires
 
#26 ·
Our PCM doesn't record Injector duty cycle specifically. PID.6200 and PID.6201 are the average pulsewidths for bank 1 and bank 2. You can use those, mapped against RPM to determine IDC.
 
#27 ·
I have the ScanTool OBD Link SX. The free software that came with it is OBDwiz. It will record fuel flow rate. I presume if the fuel flow rate reaches the rated flow ability of the installed injectors, you should upgrade. If either of you want to use it, I'll loan you the cable and software.
 
#29 ·
Probably doesn't want you to spend the money on injectors, and possibly not need them. He probably wants to dyno the new set up first, then go from there. Personally, I think you're going to need larger injectors to stay below 85% dc while on track. Is he aware that you intend to regularly OT the car?

Based on what I've read on the HP Tuners forums, it seems the PCM may boost the fuel pressure when it detects it needs more fuel. Probably to a point, though. I saw a couple OEM maps for LS6 injectors, and the flow rating ramped up from the OEM spec to something in the 30s, that's why I think the PCM does do some kind of compensation. That may be why some tuners say they have no problem pushing the injectors 105% (no Red October references needed :p). That would still reduce the longevity of the injector. How much, I don't know, but pushing something that's supposed to be precise that hard can't be good in your case.
 
#30 · (Edited)
They may work at 105% but are they actually metering fuel or running wide open? Tuners worry about smoothing AFR tables. On the street where people WOT for a few seconds you may get away with it. On the track wringing the motor out lap after lap ????
 
#31 ·
so much info to read thorugh...
as for installation, i will be tackling it my self, i feel real confinident i can do it. there arent many reputitable performance shops around me.
if i was in the states where there are a shit ton of shops around i would drop it off and pick it up done, but thats not the case here.
anyways, my mind is pretty much set on texas speed, i will take the plug and order the parts up once my harley truck sells.
 
#32 ·
ok been researching... my mind hurts.
should i be going with ported ls2 heads with cam to match or
l92 heads with cam, and by the looks of it i will need intake a tb as well?
can guysthat have done a head/cam swap, post up there head choice and rwhp totals after install?
also if i go the l92 head route will a fast intake fit clearance wise? how are they for tuning, my buddy and i will be using efi live,
 
#33 ·
You can make good power with your existing LS2 heads by having them CNC'd by either Total Engine Airflow (talk to Mike Schmidt or Brian Tooley) or Advanced Induction. You can also make good power with L92 heads, if and only if, you get the right cam. If you do the L92s, I would have the cam specified by a cam expert (like PatrickG) or an engine builder that has done L92/LS2 set ups. Your 90mm throttle body should be adequate on another intake.
 
#39 ·
http://www.texas-speed.com/p-1170-precision-race-components-ported-ls3l92-heads-cam-package.aspx
this was the route i was thiniing about, along with fast intake, i was also going to use my factory tb, will this work well? and get me to 450 ish rwhp
i will be runnin by then some kooks 1 7/8 long tubes with corsa catted connections
I would talk to Texas Speed and others (mentioned elsewhere in this thread), but I think on 6.0L I would use stock L92s rather than ported ones on a street motor. That may depend, of course, on the design of the port work.
 
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