intake duration
Mar 15, 2005 | 04:02 PM
#21
TECH Junkie
Joined: Mar 2002
Posts: 3,019
Likes: 1
From: memphis tn
I'm not refering to a reverse split cam those are for special applications.A conventional pattern cam often has more exhaust duration than intake duration.You can only add as much intake charge naturally asperated as you can as you can remove without losing horsepower.
Mar 15, 2005 | 07:11 PM
#22
idk, i'd probably use a reverse split on my n-a motor right now 
an even larger one with some pacesetters & 3'' duals.
i was more trying to point out, how geoff compared same intake lobes w/ different exhaust lobes. the only difference being a later opening exhaust valve. it changed the power curve, but not the range...
an even larger one with some pacesetters & 3'' duals.i was more trying to point out, how geoff compared same intake lobes w/ different exhaust lobes. the only difference being a later opening exhaust valve. it changed the power curve, but not the range...
Mar 15, 2005 | 07:19 PM
#23
Originally Posted by SportSide 5.3
idk, i'd probably use a reverse split on my n-a motor right now an even larger one with some pacesetters & 3'' duals.
i was more trying to point out, how geoff compared same intake lobes w/ different exhaust lobes. the only difference being a later opening exhaust valve. it changed the power curve, but not the range...
an even larger one with some pacesetters & 3'' duals.i was more trying to point out, how geoff compared same intake lobes w/ different exhaust lobes. the only difference being a later opening exhaust valve. it changed the power curve, but not the range...
Mar 15, 2005 | 07:44 PM
#24
TECH Junkie
Joined: Mar 2002
Posts: 3,019
Likes: 1
From: memphis tn
Reverse splits are really nice on a track only f-body,but I wouldn't even consider one in daily driven truck.I suggest going with a more conservative cam with intake duration in the range of 208 to 216 and exhaust duration in the 212 to 220 range and a 112 to 115 lobe separation.
Mar 15, 2005 | 08:23 PM
#25
found this:
Duration is a major contributor to the torque curve and where it occurs in the engine's rpm band. Generally speaking, as you increase the amount of intake lobe duration, this makes for an earlier-opening and later-closing intake valve. This additional duration also extends the rpm point where peak torque occurs. This tends to increase peak hp (depending upon the other components used on the engine) while sacrificing low- and mid-range torque. Conversely, a very short duration camshaft opens the intake valve later and closes it sooner, reducing the potential for high-rpm horsepower but increasing torque at a lower engine speed.
Duration is a major contributor to the torque curve and where it occurs in the engine's rpm band. Generally speaking, as you increase the amount of intake lobe duration, this makes for an earlier-opening and later-closing intake valve. This additional duration also extends the rpm point where peak torque occurs. This tends to increase peak hp (depending upon the other components used on the engine) while sacrificing low- and mid-range torque. Conversely, a very short duration camshaft opens the intake valve later and closes it sooner, reducing the potential for high-rpm horsepower but increasing torque at a lower engine speed.
Mar 15, 2005 | 10:24 PM
#26
Originally Posted by moregrip
found this:
Duration is a major contributor to the torque curve and where it occurs in the engine's rpm band. Generally speaking, as you increase the amount of intake lobe duration, this makes for an earlier-opening and later-closing intake valve. This additional duration also extends the rpm point where peak torque occurs. This tends to increase peak hp (depending upon the other components used on the engine) while sacrificing low- and mid-range torque. Conversely, a very short duration camshaft opens the intake valve later and closes it sooner, reducing the potential for high-rpm horsepower but increasing torque at a lower engine speed.
Duration is a major contributor to the torque curve and where it occurs in the engine's rpm band. Generally speaking, as you increase the amount of intake lobe duration, this makes for an earlier-opening and later-closing intake valve. This additional duration also extends the rpm point where peak torque occurs. This tends to increase peak hp (depending upon the other components used on the engine) while sacrificing low- and mid-range torque. Conversely, a very short duration camshaft opens the intake valve later and closes it sooner, reducing the potential for high-rpm horsepower but increasing torque at a lower engine speed.
Mar 16, 2005 | 05:06 PM
#28
Originally Posted by marc_w
Yeah, that was my belief.
I was asking whitt about the exhaust lobe controlling powrband more in an LS series engine because that is its weak side as I understand it.
BigTex said he had some comments, has not responded yet.
seems the Cam world says intake is the determinate factor, but I'm not ruling out whitt's comment as every engine has its own characteristics.
I hope people aren't holding back for fear of being wrong
we are all here to learn, right? 
Mar 16, 2005 | 07:15 PM
#30
Originally Posted by SportSide 5.3
yeah, you have to be careful about that. no one wants their internet feelings hurt 