Which(size & brand) cams are you running with your ported head?
Apr 12, 2007, 11:53 AM
#46
Yes, I suppose it's more of an old school term. Descriptors like "stage 6 with supersized valves" are more commonly used as an excuse to relieve consumers of (even) more of their cash these days.
I'm larger than a GT35R now, but the engine behaves as if the turbo were smaller. Hmmmm . . . .
I'm larger than a GT35R now, but the engine behaves as if the turbo were smaller. Hmmmm . . . .
Apr 13, 2007, 07:42 AM
#53
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I have AMS' ported race head with GSC 272 cams. I felt a noticeable increase on the top end with the butt dyno after install. I can see the bump around 5500 rpm with the mustang dyno so I know I gained some significant oomph in the higher rpms. I didn't have a dyno run prior to the head install so I don't have hard numbers to give you. My current hp/tq numbers are in the sig..all on 93 octane and 22 psi. This dyno reads low, even for a mustang so take that for what it's worth.
Apr 13, 2007, 10:10 AM
#54
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Thanks for your post, Cirrusly Evolvd 
I have AMS' ported race head with GSC 272 cams. I felt a noticeable increase on the top end with the butt dyno after install. I can see the bump around 5500 rpm with the mustang dyno so I know I gained some significant oomph in the higher rpms. I didn't have a dyno run prior to the head install so I don't have hard numbers to give you. My current hp/tq numbers are in the sig..all on 93 octane and 22 psi. This dyno reads low, even for a mustang so take that for what it's worth.
Apr 16, 2007, 12:03 PM
#57
the problem is that in the end a larger port is going to produce more top end power via delaying the peak mass flow point. there is no such thing as variable port geometry technology, well there could be but that's going to be terrible to apply.
the closest you get is variable valve timing. a good question is how much peak flow is affected by having a comparatively large port but restricting the valve valve lift at the lown end? and then how to apply this to keep the bottom end response there. but my guess is that whatever you do... larger port means larger delay.
larger intake manifold also usually means the same. this is also why i'm not sure how to interpret ludikraut's experience of swapping the ams intake mani and seeing NO spool change... i don't know if this is a fluke or a what because even if we look at ams's own tests on a 9 (mivec) the intake mani made things spool up slower!
Apr 18, 2007, 10:07 PM
#60
but one has to admit that head design and cam application has a lot to do with both power and low end response.
the problem is that in the end a larger port is going to produce more top end power via delaying the peak mass flow point. there is no such thing as variable port geometry technology, well there could be but that's going to be terrible to apply.
the closest you get is variable valve timing. a good question is how much peak flow is affected by having a comparatively large port but restricting the valve valve lift at the lown end? and then how to apply this to keep the bottom end response there. but my guess is that whatever you do... larger port means larger delay.
larger intake manifold also usually means the same. this is also why i'm not sure how to interpret ludikraut's experience of swapping the ams intake mani and seeing NO spool change... i don't know if this is a fluke or a what because even if we look at ams's own tests on a 9 (mivec) the intake mani made things spool up slower!
the problem is that in the end a larger port is going to produce more top end power via delaying the peak mass flow point. there is no such thing as variable port geometry technology, well there could be but that's going to be terrible to apply.
the closest you get is variable valve timing. a good question is how much peak flow is affected by having a comparatively large port but restricting the valve valve lift at the lown end? and then how to apply this to keep the bottom end response there. but my guess is that whatever you do... larger port means larger delay.
larger intake manifold also usually means the same. this is also why i'm not sure how to interpret ludikraut's experience of swapping the ams intake mani and seeing NO spool change... i don't know if this is a fluke or a what because even if we look at ams's own tests on a 9 (mivec) the intake mani made things spool up slower!
http://www.mne.psu.edu/me415/fall05/SAE/intake.html
Yes your 3000000% correct, head and cam combos change this however I would like to think that internal specifications and turbo choices play a more major role. that it will be ridiculously expensive, difficult, and complex but god damn it would be sweet paired with some variable geometry turbos and variable valve timing, I can dream......
Scorke