i have a 2004 phamtom 11 with straight limbs with "a" cams 27.5 draw lenght and set at 45 draw wieght with only 215 fps what can i do to speed this bow up ???? what if i put 14"magnum limbs on this bow with "a" cams will this speed this bow up ??? i would like to speed this up to at least 250 fps or an i only dreaming ???? any help will be appreciated thank you
Nitrous won't work on a Phantom II with mag limbs, only straight and elite.
Don't know what weight arrows you are shooting but I think you're dreaming. I just converted one of my Phantom IIs over to Straight Nitrous from Mag Fuzion and I only expect to gain 5fps if anything.
With my heavy 500gr-ish arrows that might end up 245fps but more likely 240fps, that's at 29" and 65lbs.
I don't have my notebook with me but I think it's something like 10fps per inch. 1-2fps per 5 grains of arrow weight. 2-3fps per pound of draw weight.
I guess the bow to be 310-315IBO. That would put you at around 222fps with 225gr arrows.
2004 phamtom 11
If you don't mind can you tell what lb limbs are on this bow ? Thanks
The Doctor is in.....
I need more info and maybe we can get you there. What is the intended purpose of the bow? hunting, target shooting, be specific. What release are you shooting, who's strings are on the bow, what arrrows, what rest, what vanes on the arrows, how long have you been shooting, how much do you practice? All of this matters !!!!
Now that I've had time to get mine tune and chrono'ed I can say what I'm getting.
28 1/2" draw, shoot through, B cams, 475gr arrows, about 66lbs draw.
20 strand 452x string, 14 strand cables, minimal serving, string leeches, Surz-a-peep, string loop.
That is a pretty heavy arrow for 66lbs. The bow might actually feel better with a lighter arrow. What limbs are you using ? Who built your strings?
Those are my light overdraw arrows
Originally Posted by PLASTIC PAUL
I'm planning on removing the overdraw and going with 520gr arrows eventually.
Wouldn't lighter arrows allow more noise and more shock?
Besides that, I'm all about hunting. I care more about momentum than I do about speed. I'm getting much better with shooting the X system. If I can get where I can shorten the stabilizer before hunting season it will go hunting with me.
I built the strings (and the bow for that matter).
When you get a chance play around with the KE program Easton has on thier web page you will be surprised at what you find. As for noise, that is true if you get below about 4.5 grains per lb. Those of us with draw lengths would be better off if we used the AMO chart for arrow weight as opposed the 5 gpi. The Phantoms can shoot a lighter arrow and still not create a great deal of noise. The X system is also quiter because there is no cable guard for stuff to rub on. How many strands did you put in your cables? At 66lbs i would be shooting about a 300 grain arrow and my bow would still be whisper quiet. Oh, My draw is 27".
No I won't. I've already done that and you get the most energy bang for your buck shooting arrows around 500gr before the increases in KE start dropping off, at least on bows that IBO in the 300-315 range.
Originally Posted by PLASTIC PAUL
Lighter arrows net you less KE over most of the scale, not more.
But KE is not momentum, I want momentum so I can shoot large diameter mechanicals. You can have a 22 caliber bullet carrying a lot of KE but it doesn't have the momentum to make you want it to be your dangerous game rifle does it?
If you'd shoot 300gr@66lbs (4.5gpp) you would be voiding your warranty.
You may get away with it at a shorter draw length but it still voids your warranty. I can't believe a staff shooter is recommending to shoot under 5gpp. Some competitions won't even let you shoot that light because they don't want that danger on the line.
I don't know what AMO chart you're reading but the one I see has recommends over 5.5gpp for 29" even if I call it an energy cam instead of speed cam (and TAP rates my bow's speed closer to where the AMO chart rates a speed cam), AMO is based on 6gpp@30".
I've already messed up and shot one of my Phantom IIs without a point on the arrow once which put me about 5.5 grains per pound and I know it was a lot louder and had a lot of hand shock, but it was fast.
I figure I could get around 280 shooting 5gpp, but I know it would be loud, been there, done that. I also don't want to risk my limbs, warranty or not.
At 27" what kind of speeds to you get out of your P3 @45lbs?
The X-system is quieter than what? My Nitrous-X Phantom II Straight is certainly not quieter than my Dyna Phantom II Magnum or than what my Fuzion Phantom II Magnum was. Draws smoother, shoots faster, is more accurate but it's certainly not quieter.
It only makes sense since the Nitrous is sending more energy out, enough to increase the speed over 10fps.
Further reference for shadowcat55.
I moved my draw length back to 29", an increase of 1/2". I got about about 5fps for the 1/2" to 254fps. I dropped 2lbs of weight and was at 250fps, I lost about 2fps per lb.
I'm 29" on a 29.5" cam, you're 27.5" on a 27.5" cam with the same bow so our cam efficiency numbers should be similar.
Where you're losing it is your draw length and your draw weight.
Between those two you're losing about 75fps from IBO speeds. Add in junk on your string and extra arrow weight and you're right where you should be. Short of stretching your arms and drawing more weight there's not much you can gain in speed on that bow. The only other limb choice with the Phantom II Nitrous is Elite and I think they're slower than Straight.
I figure you're at around 300gr arrows so there's really not much speed you can pick up there either. DO NOT shoot under 5 grains per pound, if you value your limbs you will stay up around 5.5-6gpp, but at least if you stay at or around 5gpp you will be protected by Martin's warranty.