"Torque out of my ears"... questions??
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"Torque coming out of my EARS"... questions?? Ok, Patrick G's thread "Torque coming out of my EARS! (cam change)" has gotten me and everyone else thinking. I'd like for some of you camheads (is that even a word?) to tell me if I'm on the right track. All of the following numbers came out of Comp Cams catalog. Let's say you have a cam ground with the Xtreme XER lobes and it specs out at 228, 232 @.050 and the durations @.200 are 149, 153 with a 110 LSA. (Which according to Comps catalog should have a RPM Operating Range of 2200-7100 RPM's) Now we take the same durations @.200 149, 152 and grind them on a XFI lobe. Now the durations @.050 are 224, 230 on a 110. So we're dropping duration @.050 but keeping about the same @.200. The third cam is ground using LSK lobes and again, the duration @.200 is 149, 153, but the @050 numbers drop even more to 223, 227 on a 110. So all of these cams have the same basic durations @.200, but the durations @.050 have dropped because of the different lobes used. Will all of these cams behave the same?? Obviously, they will idle differently (right??) but will they all have the same powerband because of the similar .200 duration number???
Last edited by Gearhead1; Apr 25, 2006 at 03:58 PM.
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Originally Posted by cantdrv65
The more agressive the lobe the more the overall amount of valve opening to work with. Thus you get more air in and out of the engine. Make sense?
So does that mean wwnts2go100 is wrong when talking about lsk ramp rates giving it more power? or again am I sniffing my own exhaust fumes again and getting ramp rates n lobes all gafooey? 
)
I swear it seems like once a week I have to go back and read that damn cam guide
)I swear it seems like once a week I have to go back and read that damn cam guide
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guys how is the lsk less aggressive if it has les duration at .050 and more at .200 than a xer. that means its got a faster ramp rate. it goes like this least agressive to most aggressive xe,xer,xfi,lsk
Originally Posted by UltraZLS1
the LSK lobe is less aggressive than the XE-R from .006" lift to .050", it is more aggressive than the the XE-R at .200
The reading I've been doing seems to point to the actual valve events (IVO,IVC,EVO,EVC) in terms of crank degrees having the most effect on torque production and powerband. The lay man finds it easier to sum these up with duration and LSA numbers, but the guru picks the cam using these points and desired lobe type, then lets the chips fall where they may.
with that said, the cams mentioned all have slightly different valve events between .006 and .05 lift. I guess the question is: at what lift is a valve open enough to have an effect on reversion/scavenging.
if I've added nothing to this thread, consider it typing practice.
Nick
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Originally Posted by slt200mph
Waiting on the cam gurus to check in..where are Patrick and Jrod when you need them... 
- IVO and EVC equal distance from TDC, more bias towards the exhaust if street use is paramount.
- IVC at 42-44 (@.050), once again for good TQ on the red-light to red-light seen..
- Get you DCR up over 8.5 (I am not going to comment on how high) through milling, gasket thickness and valve events.
When Pat and I were debating my latest cam I made it clear to him that I wanted to get more TQ down-low and if I lost anything up-high I would get it back with a FAST 90/90, going in next week... I hit my 450 goal with my previous cam (no FAST) but I wanted more pull down-low. So hopefully the FAST setup and my current cam will get me both…
Last edited by SideStep; Apr 26, 2006 at 10:19 AM.
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I need to get a copy of Microsoft office so I can view the cams spreadsheets and compare them side by side. I also need to get the DCR calculator to work on my computer. That alone would help answer most of my questions. 
