nickmckinney

Just to throw a monkey wrench in the system, Bullet/MHS has all new cam specs coming. There are now 5 NPI specific NA cams, 6 specific 4.6 PI NA cams, and 5 specific 5.4 PI NA cams (and 5 specific TFS NA cams). All PI cams now have smaller lobes on the exhaust and all NPI cams are so aggressive they will only work in NPI heads and will bend the valves in a stock 4.6 PI motor, even the smallest Stage 1 NPI spec.

Rather than try to make specs fit all motors each spec is now optimized for its application. The NPI and the 5.4 really should use different specs than the 4.6 PI and now its done (other than updating the specs online)

massred98gt

i didn't see that you already dynoed ur car. so like what the other guy said 280-310! these were the first bullet cams he's tuned. he said he rarely gets a cammed 99-04 stang over 300 no matter what the cams are. so i'm not far off. so you should be right aroud there. the car runs so much smoother than it did before. the tune didn't really change the numbers much from the junk tune, but it def made the drivability 10 times better

massred98gt

damn nick two months after i bought these lollol. thanks for the heads up. how do the stage 2's i have now stack up to the new profiles?

mrtstang

Cool! If any of them don't require a spring change or notched pistons, then i'm very interested. We talked a while back, and you may have mentioned something about these...i'm not sure.

I'm just looking to get 290-300 hp and have a decently choppy idle as cheap as possible. If i need some extra power i'll just flip the switch!

mrtstang

So now that the car is tuned correctly, can you honestly say these cams made a worthwhile difference? Does it pull hard on the high end without much loss down low?

I heard your vid clips, and they do sound pretty good for such small grinds. If i hit 290 hp i'll be totally satisfied.

Mustang_NTriangle

nice numbers so it looks like you gained 20 rwhp with these cams. In looking at your graph these cams start to fall off around 5700 rpms - they appear to be mild cams how do they sound?

nickmckinney

Right in the middle of the Stage 1 and Stage 2 profiles.

The new NPI profiles are advanced to 106 intake centerlines with a smaller LSA of 109. They would give about the same peak HP in comparison to yours but the midrange torque curve would be "fatter"

I learned a lot with the NPI heads recently and came to the conclusion that if I used all of the extra piston to valve clearance they give over a PI head it would probably make a nice option instead of a PI head swap. It makes a cam spec you cannot use in a PI head unless you notch the pistons. I called Bullet and they liked the idea enough to make the new lobes needed.

BTW - IMHO and don't take this the wrong way - the porting you have described is not helping you any with those heads. NPI heads are a biach to port, its about double the time for me over PI heads. They need a LOT of metal removal before you see any significant gains, and none of it is near the gasket edges.

nickmckinney

Then his dyno is like the local ones here. A NA 300RWHP 2V on the local dynos is running high 11's at the track and making 325+ on some of the other dynos in other locations. A stock cam 2V PI is making 250RWHP with full bolt ons and long tubes and a stock NPI is barely breaking 200RWHP around here.

nickmckinney

Biggest difference the exhaust lobes are smaller for all PI head cams as that is what seems to work the best with the plastic intake/PI head combo since the exhaust port is so "happy". I am going to test fit a 225/223 110/110 110LSA cam and see what the clearance is but its probably going to be the max effort for a stock PI head 4.6 as I am expecting around 0.030" clearance give or take. The Stage 1 is a 220/218 110/110 110LSA cam. I tested a 220/218 108/108 108LSA cam and found 255RWHP on a stock PI motor with our local "low output" dynos so that tells me the smaller cams are still making good power. This cam only had 0.015" of piston to valve clearance so the specs had to be changed to the 110/110.

The stock PI cam has only 200 degrees of duration but its still making peak power at 5000 or so. This shows how much the intake manifold is dictating the power curve. Most of the fastest NA 2V cars that are still on the stock shortblock had 224-225 intake lobes at 108-110 intake centerlines and none dynoed over 280RWHP that I can remember but nobody has beaten their mid to high 11 times yet. Basically it took a "history lesson" to learn what might be a better cam spec.

mrtstang

So, will any of these perform better than the stage 2's without changing springs or notching the pistons?