G5x3 cam too big?
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?
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.
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.
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.
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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.
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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.
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.
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.
I'm a little worried about flycutting these. WILL THIS EFFECT THE INEGRITY OF THE PISTONS??
I'm a little worried about flycutting these. WILL THIS EFFECT THE INEGRITY OF THE PISTONS??
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.
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.
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?





