Interpret/compare these Valve Events...
Interpret/compare these Valve Events... Please compare these three sets of camshaft valve-events, based upon the "baseline" information provided:
Baseline Cam (actual dyno data):
HP Peak: 5700rpm
Tq Peak: 4500rpm
(LSA 111.5+2, XE Lobes, .559" int, .564" exh)
--------.006----.050----.200
Int Dur...267.......214......133
Exh Dur..273.......220......138
IVO........24.......-2.5
IVC........63.......36.5
EVO.......70.......43.5
EVC.......23.......-3.5
Overlap...47........-6
Compare these two (below) to the Baseline specs above.... I realize the differences are subtle (Option-A is basically identical at .050"), but how would the HP and Tq peaks change, and by how much (as a guesstimate)? Would the torque/power "hold on" longer or shorter after their peaks for Options (A) and (B) when compared to the Baseline? What else do you "see"?
Option (A):
(LSA: 112+2, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........22........-3
IVC........62........37
EVO.......69........43
EVC.......21........-5
Overlap...43.......-8
Option (B):
(LSA: 112+1, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........21........-4
IVC........63.........38
EVO.......68.........42
EVC.......22.........-4
Overlap...43........-8
Thanks so much!!
Baseline Cam (actual dyno data):
HP Peak: 5700rpm
Tq Peak: 4500rpm
(LSA 111.5+2, XE Lobes, .559" int, .564" exh)
--------.006----.050----.200
Int Dur...267.......214......133
Exh Dur..273.......220......138
IVO........24.......-2.5
IVC........63.......36.5
EVO.......70.......43.5
EVC.......23.......-3.5
Overlap...47........-6
Compare these two (below) to the Baseline specs above.... I realize the differences are subtle (Option-A is basically identical at .050"), but how would the HP and Tq peaks change, and by how much (as a guesstimate)? Would the torque/power "hold on" longer or shorter after their peaks for Options (A) and (B) when compared to the Baseline? What else do you "see"?
Option (A):
(LSA: 112+2, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........22........-3
IVC........62........37
EVO.......69........43
EVC.......21........-5
Overlap...43.......-8
Option (B):
(LSA: 112+1, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........21........-4
IVC........63.........38
EVO.......68.........42
EVC.......22.........-4
Overlap...43........-8
Thanks so much!!
Last edited by 02RedHawk; Sep 18, 2006 at 08:07 PM.
Just looking at the overlap, it seems that the profile on top would make power at a higher RPM than the two profiles on the bottom. Not to mention the extra duration it has. The two profiles on the bottom probably won't make as much top end power, but should make more bottom end torque.
Of course, this is all speculation and would really depend on the rest of your combination.
Of course, this is all speculation and would really depend on the rest of your combination.
For comparison purposes, assume everything else being the same (ported heads, headers), only cams would be different.
Edited my original posting to include the durations as well. Should've had that in there the first time.
Also, Option (C): (LSA 113+2, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........21........-4
IVC........63.........38
EVO.......70.........44
EVC.......20.........-6
Overlap...41........-10
I'm looking for something that would mimic the Baseline cam as much as possible (ie, peaks at same spot or *slightly* earlier, but with gobs of low-end torque) but also hopefully holds the torque a bit longer before falling off - when using a slightly smaller duration cam (214/220 baseline to my 214/218 "Options") & also more aggressive lobes (XE Baseline to my XFI-spec'ed "Options").
Edited my original posting to include the durations as well. Should've had that in there the first time.
Also, Option (C): (LSA 113+2, XFI lobes, .600" int, .590" exh)
--------.006----.050----.200
Int Dur...264.......214......139
Exh Dur..270.......218......141
IVO........21........-4
IVC........63.........38
EVO.......70.........44
EVC.......20.........-6
Overlap...41........-10
I'm looking for something that would mimic the Baseline cam as much as possible (ie, peaks at same spot or *slightly* earlier, but with gobs of low-end torque) but also hopefully holds the torque a bit longer before falling off - when using a slightly smaller duration cam (214/220 baseline to my 214/218 "Options") & also more aggressive lobes (XE Baseline to my XFI-spec'ed "Options").
Last edited by 02RedHawk; Sep 18, 2006 at 08:07 PM.
Originally Posted by 1989GTA
What are the lobe lifts? Also do you know the duration at .200 lift?
Intake Lift: .559"
Exhaust Lift: .564"
Duration at .200": 133 int, 138 exh
The "Options" XFI:
Intake: .600"
Exhaust: .590"
Duration at .200": 139 int, 141 exh
BTW, yep the heads flow well up to .600" lift.
Last edited by 02RedHawk; Sep 19, 2006 at 04:16 PM.
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Rule of thumb is 100 rpm per degree of IVC - so 100 to 200 higher peak HP for option B cam and better hi rpm carry because the overlap is split even where as the other 2 cams have exh overlap bias. The DCR appears to be the same with baseline and option B.
Last edited by voda1; Sep 21, 2006 at 10:11 AM.
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Verdad Gallardo Would you think the two cams (Option B) and the Baseline should peak about the same then, since the Baseline has a slightly bigger duration at .006 and .050?
Last edited by 02RedHawk; Sep 24, 2006 at 01:30 PM.