Importdestroyer

iTrader: (1)

I posted over at LS1.com, Id figure Id ask here too.

Im running a 220/224 580/580 114 cam in which final lift #'s are attained using crane's 1.89 variable ratio rocker arms. With Patriot stg 2 heads, SVO 30 lb injectors, and LG LT's with cats my LS6 couldnt throw down more than 404 rwhp, 395 rwtq on an eddy current dyno with 91 octane.

I want more power, I was looking at monster cams and the G5x3 caught my eye, but from a few local shops around my area they advised against it. One said with that much duration it will make great #'s on paper but wont have much midrange power, the other shop said it wouldnt be a good cam for a DD and that 112 would surge a lot.

I had a 112 lsa cam in my blown TA of late, and it did surge but it didnt bother me. I am concerned with making power and useable power at that. One of the shops recommended to stay within 22# duration for good midrange power. The other had a valid point that 112 would NEVER pass the sniffer, at this point I could care less about smog, MORE POWER!!

The other shop also mentioned that the G5x3 wont work with Patriot heads, I spoke with patriot and the deck height is identical to LS6 heads, the combustion chambers are smaller and that is how the 10.7 compression is made. Valve diameter shouldnt matter right?

I plan on ditching the crane rocker arms for stock ones, and stock length pushrods to work with a bigger cam.

Any suggestions?

SSilverSSurfer

iTrader: (8)

nothings ever too big!!! whered you get the specs from? ive never seen them

Importdestroyer

iTrader: (1)

what specs? The ony aformentioned specs are of my current cam set up, LG doesnt list the duration of the G5x3.

I did some research today and Im not sure but the G5x3 might have to much lift on the exhaust side to use with PP heads without flycutting the pistons.

30th t/a

iTrader: (51)

i had the g5x3 112. i had to flycut the pistons .080 on the intake side. my heads were milled. not sure how much though. the heads were 5.3 style and i know after they were milled the CC was 60.4. i really liked the cam but i would not want to drive it in stop-n-go traffic everyday, maybe 1-2 times a week wouldnt be bad. my car is also a 6 speed so that makes it even suck more in stop-n-go traffic.

Importdestroyer

iTrader: (1)

Ok cool, thanks for taking the time to let me know that, the PP heads are LQ9 castings that have had their chambers welded up and re-machined, Im assuming the deck height is the same as that of an LS1-LS6 but I dont feel like taking a chance with over .600 on the exhaust side. I think Ill just save up for my 402 LS2 and let it be.

PREDATOR-Z

First of all, lifts have little to do with PTV clearance.
Durations, valve events and valve size is what you have to watch for.
.080 int/ .100 exht is safe for street, especially on M6. Tighter is playing with fire.
From what I could gather around here, the G5X3 is 234/242, .600/.610 112/114 lsa (could be 236/242, .600/.610 112/114 looking at lobe charts)
Putting a cam that big, you'll loose low end response, no if/but about it, tighter gears are in order to soften that effect. (4.10/4.33) but you'll loose top end speed.

IMO, get a nice set of heads like AFRs and pick up a good 30+ rwhp without affecting your bottom end and emmissions.

Importdestroyer

iTrader: (1)

I hear AFR's arent putting out much more power than ported LS1 style heads for the $, and I cant afford them right now anyways. 4.10's would be rediculous in a C5 Z, right now the M12 is geared about as aggressively as a f body with 4.10's. I ran a friends camaro a few days ago, he has 4.10's and we were shifting at almost the same speed ( into 2nd at 45, 3rd at 70, 4th at 100mph).

I would loose too much top end, the stock gearing in a Z is just right, if I ever throw down more than 500 rwhp and I have that kind of $$ Im getting a built rockland standard gear M12 with C6 ZO6 gearing.

PREDATOR-Z

I didn't pay attention to the ZO6. I was thinking F-Bod.
But was your friend shifting at the same rpm than you?
I know of ZO6's with 3.73s...big cams.
As far as the AFR go, you heard wrong. Check a post by LG on their G5X3/AFR combo with flycut. Show me a cheaper LSx head doing the same with 205 intake runners.

mike c.

iTrader: (1)

i run the g5x3 cam 112lob w/AFR 205 heads and i have no bucking,surging problems and i don't have a big lo-end power loss.i do have 4.11's w/a m6. this is an awsome cam and it's not too big.if you think it is the x2 cam is just as nice(i had it too) and only about 8hp less.
IUMPORTDESTROIER-you heard WRONG. i hade a set of ported ls1 heads from a sponcer and my AFR heads gained me another 47.6hp over the other ls1 heads. i also went from the x2 to the x3 cam so the heads alone got me 38 to 40hp.

SouthFL.02.SS

The AFR's will generally outperform up top, but most importantly, provide kick *** mid numbers to retain usable power when compared to ported GM castings.

Even better, ET Performanece 215's will provide velocity, more PTV clearance, and similar numbers to AFR 205's with about .100 extra clearance on a 62cc chamber.

Tuning plays a major role in driveability.

And finally, what the hell are you doing over at LS1.com for tech advice? hahaha.

Importdestroyer

iTrader: (1)

Those ETP's heads sound awesome. Well I called Patriot, the piston to valve clearance issue here is with the valve diameter in these heads (2.02/1.57).

Patriot mentioned that a few customers are using Futral's F13 112 without issues (230/232 .585.580 112) and that might be as big as I wanna go without putting clay on the pistons.

JRracing

iTrader: (35)

I have a X2 and TEA 5.3's I'm about to get installed and I think they flow like 295/225 @.600 with 59cc chainbers.

I'm a little worried about flycutting these. WILL THIS EFFECT THE INEGRITY OF THE PISTONS??

Importdestroyer

iTrader: (1)

I dont know personally, but Im sure someone here does. I just dont want to flycut as it sounds expensive. Do the pistons have to come out or can they be cut in the block? If I had to flycut my pistons, Id also change the crank and pistons themselves at the same time.

FUN LS1

Yeah, I was going to say, just swap gears and it won't be too big. After installing 4.10's, I don't even think about "low-end torque" problems anymore

orangeapeel

iTrader: (18)

Get some aftermarket pistons with valve reliefs. run any cam you want.

Ksett

Those heads are holding you back big time. From all the posts I've seen on the final numbers on setups with these heads, they seem to be making about 10 hp more than stock LS6 heads. There a complete waste of money when upgrading from an LS6 head. I would ditch these and go with a 59 cc 205 AFR or ETP 215's milled to 59cc. This will make a nice setup with your current mods and you should see at least 30 rwhp more. Do it right if you can afford it and get those cheap heads off your poor Z06.

J&J Speed Shop

iTrader: (8)

Agreed 100%, I have seen lots of ported head cars at my shop and around the local race tracks. None of them seem to run like an AFR headed car with a milder camshaft

Importdestroyer

iTrader: (1)

Youre right, when I purchased the heads I did a ton of research. And a certain article in GM high tech performance led me to believe they could make good power. I dont know whether to attribute my low #'s to the heads or the crane 1.89 rocker arms, or both.

I cant post my graph here as I dont have it, but at 6k the power takes a dive and then recovers at like 6300 rpm, only thing we could attribute the drop off to is the rocker arms.

I wish I had the $ to make things right now, but I dont. Im hoping ditching the rocker arms for stock ones and running more duration and less lsa will cure the drop off and make more power. I dont plan on ditching these heads just yet, people are making ok power #'s with them, but youre right, not much more over stock LS6 heads.

Right now Im looking at $1200 in parts and labor for a cam swap, to maybe a futral f13 112. Im praying that puts me around 430 rwhp, Im pretty optimistic as I know a few stock headed LS1 owners with longtubes and cams in the 230's putting down 420-430 rwhp.

00Vette

iTrader: (4)

Are you talking about RWHP? I currently have LS1 heads that have been milled for 11.8:1 SCR and have also been port and polished with a valve job (2.02 intake, 1.575 exhause).

Do you think I'd also gain as much as you did with a swap of my cylinder heads?

30th t/a

iTrader: (51)

I also had 4:10s with my g5x3 112 and i loved them. id get the 4:10s because you still got 2 overdrive gears. i could cruise at 80mph and be at 2200rpm. you say you would loose to much top end. if you want to get max performance in the 1/4, definately get the 4:10s. if you plan on doing 180mph alot of the time, keep the 3:42s.