Question about Lobe Center Angle
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Melting Slicks
Joined: Jun 2002
Posts: 2,844
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From: Orrtanna Pa.
Question about Lobe Center Angle
I found a Motown 415 article and when I saw the torque curve it had I was impressed.Has anyone run 106 degrees LC on the street and regretted it?
From the looks of this dyno pull,I can"t see a problem,but then I couldn't tell if the idle cracks the windshield or not.
http://www.hotrod.com/techarticles/89518/index1.html
[Modified by The Money Pit, 1:20 PM 12/13/2003]
From the looks of this dyno pull,I can"t see a problem,but then I couldn't tell if the idle cracks the windshield or not.
http://www.hotrod.com/techarticles/89518/index1.html
[Modified by The Money Pit, 1:20 PM 12/13/2003]
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Question about Lobe Center Angle (The Money Pit)
Tends to have poor idle vacuum but pulls great in the mid and upper range. I ran either 106 or 108 and loved the cam. Best cam I ever owned. I am presently running 112 for better idle vacuum.
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
Re: Question about Lobe Center Angle (norvalwilhelm)
Norval,
I'd love to cut a hole in my hood and stick a 6-71 on,but with 4 kids and a single income family I'm stuck with minor tweaking for now. If you look at cam listings there's not many listed with 106 LC's except for circle track cars,which ironically a Vette is perfect for.Roller cams are out of my peanut butter and jelly budget too,so I thaught next round I'd try a solid or a hydraulic 106 LC cam to try to maximize the punch without spending a small fortune on a blower.I figure I'm around the 500hp level now and still drive on the street passing police cars with no incidence.(Kinda neat.)
Anyway the LC of a cam from what I've read and seen in dyno tests seems to be somewhat of an overlooked tweak that I'd like to try.Just wondering what ill effects I need to expect.In other words how nasty is the idle and very low speed driving.From what I can tell from the Motown 415 dyno sheet,once moving this thing is unstoppable with over 480 lbs of torque from 2500-5000 rpms.
I'd love to cut a hole in my hood and stick a 6-71 on,but with 4 kids and a single income family I'm stuck with minor tweaking for now. If you look at cam listings there's not many listed with 106 LC's except for circle track cars,which ironically a Vette is perfect for.Roller cams are out of my peanut butter and jelly budget too,so I thaught next round I'd try a solid or a hydraulic 106 LC cam to try to maximize the punch without spending a small fortune on a blower.I figure I'm around the 500hp level now and still drive on the street passing police cars with no incidence.(Kinda neat.)
Anyway the LC of a cam from what I've read and seen in dyno tests seems to be somewhat of an overlooked tweak that I'd like to try.Just wondering what ill effects I need to expect.In other words how nasty is the idle and very low speed driving.From what I can tell from the Motown 415 dyno sheet,once moving this thing is unstoppable with over 480 lbs of torque from 2500-5000 rpms.
Safety Car
Joined: Feb 1999
Posts: 3,631
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From: Fountain Hills AZ
Re: Question about Lobe Center Angle (The Money Pit)
The effect of LSA is also dependent on the cam's duration. The rougher idle comes from the increase in overlap that results when duration is increased, LSA is reduced, or a combination of both. The benefit of a narrower LSA is that, with everything else being equal, it allows for more time with both valves closed and therefore more torque and hp once intake velocity is high enough to overcome the movement of exhaust back into the cylinder. Up until that point though, performance isn't so hot. A tighter LSA (with everthing else being equal) is likely to increase cylinder pressure so if you're already borderline on pre-ignition due to high dynamic compression, it may not be a good idea.
