someone had to ask it, so I'll ask it...LOBES??
05-23-2007, 02:32 PM
#1
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someone had to ask it, so I'll ask it...LOBES?? Can someone PLEASE lay the whole Lobe thing down...XER, LSK, etcetcetc
WHY, WHAT, and HOW do these differ, and make power?? When were they developed, what do the acronyms mean....maybe someone could create a STICKY mu ha ha hahah!
THANKS
E
WHY, WHAT, and HOW do these differ, and make power?? When were they developed, what do the acronyms mean....maybe someone could create a STICKY mu ha ha hahah!
THANKS
E
05-23-2007, 02:48 PM
#3
I think XE stands for extreme energy. The R might be for roller or retro-fit. Not sure on either.
The more aggresive the lobe's "ramp rate" the faster "****" happens. So, it's harder on the valvetrain, but makes more power. That's how I think of it, but I'm not even close to in the know. Just throwing that out there until people with real knowledge come around.
The more aggresive the lobe's "ramp rate" the faster "****" happens. So, it's harder on the valvetrain, but makes more power. That's how I think of it, but I'm not even close to in the know. Just throwing that out there until people with real knowledge come around.
05-23-2007, 02:50 PM
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Hmmm, I'm not exactly sure but the cam faq says:
"Lift:
- Lift is defined as the difference in height between the radius of the circle and the height of the eccentric. This is called lobe lift."
Therefore, I would say that means that bigger lobes equate to higher lifts. I could easily see how larger lobes would create more aggressive valve events, and the greater force created by this cam spinning would result in a bit more torque compared to a cam with a lower lift. I think LSK lobes are very aggressive and XE-R are one of the more aggressive ones.
"Lift:
- Lift is defined as the difference in height between the radius of the circle and the height of the eccentric. This is called lobe lift."
Therefore, I would say that means that bigger lobes equate to higher lifts. I could easily see how larger lobes would create more aggressive valve events, and the greater force created by this cam spinning would result in a bit more torque compared to a cam with a lower lift. I think LSK lobes are very aggressive and XE-R are one of the more aggressive ones.
05-23-2007, 02:56 PM
#5
I'm just a newb, but I think we're talking about ramp rates/lobe profile rather than duration/lift.
From http://www.ls1howto.com/index.php?article=23
Of course, I'm probably wrong.
From http://www.ls1howto.com/index.php?article=23
Lobe Profile
The Lobe profile of a cam basically is the curve at which a valve is opened and closed. Some lobes are very EXTREME and will snap a valve open very quickly and then slam it shut, while others are "softer" and slowly open and close valves. The more extreme the lobe, the noisier your valvetrain will be and the harder it is on your valve springs...however, a more extreme lobe will generally idle better than a less extreme lobe with the same duration at 50 thousandths. If your cam has very aggressive lobes and your cam lift is up there, I'd suggest you try to lighten your valvetrain by getting titanium retainers if possible.
The Lobe profile of a cam basically is the curve at which a valve is opened and closed. Some lobes are very EXTREME and will snap a valve open very quickly and then slam it shut, while others are "softer" and slowly open and close valves. The more extreme the lobe, the noisier your valvetrain will be and the harder it is on your valve springs...however, a more extreme lobe will generally idle better than a less extreme lobe with the same duration at 50 thousandths. If your cam has very aggressive lobes and your cam lift is up there, I'd suggest you try to lighten your valvetrain by getting titanium retainers if possible.
05-23-2007, 03:17 PM
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Historically, cam lobes have been symmetrical (opening and closing ramps were a mirror image of each other) and the rate of opening and closing and opening was pretty sedate. As times have progressed and performance cam design has been studied a lot more in terms of physics, cam manufacturers have developed more aggressive (even radical) lobe designs. Some of the earlier, more aggressive designs by Competition (Comp) Cams were designated XE for "Xtreme" Energy. XER and LSK are also Comp Lobe Designs that are more aggressive than XE. Comp has some good information on this sort of thing as do the other manufacturers. Many of the LSx series cams sold by a lot of the suppliers/sponsors on LS1Tech.com use Comp cams and lobes even for their own custom cams and that's why you see XER lobes quoted on a lot of websites. For more information, look here http://compcams.com/Technical/Catalo...obeCatalog.pdf. Some of the more aggressive lobes are asymmetrical (not mirror images) and all open very quickly off the base circle. So the lifter, pushrod, rocker arm and valve open very quickly in the first portion of the opening cycle and then the rate of opening decelerates progressively.
Hope that this helps. This explanation only scratches the surface.
Steve
Hope that this helps. This explanation only scratches the surface.
Steve
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05-23-2007, 09:20 PM
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ok, well, how does one determine lift then?
Basically what I am getting at is , regardless of the type of lobe, be-it XER, LSk, or XE, lift can be anything you spec it out to?
What lobes come with the MS3?
Erik
Basically what I am getting at is , regardless of the type of lobe, be-it XER, LSk, or XE, lift can be anything you spec it out to?
What lobes come with the MS3?
Erik
05-24-2007, 07:52 PM
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Explain your question a little more.
1. Do you want to know how to determine the kind of valve lift that best suits your needs or application? or
2. How you determine the valve lift for a given lobe lift? or
3. Both 1 and 2. or
4. Something completely different.
Steve
1. Do you want to know how to determine the kind of valve lift that best suits your needs or application? or
2. How you determine the valve lift for a given lobe lift? or
3. Both 1 and 2. or
4. Something completely different.
Steve
05-24-2007, 10:59 PM
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If you're asking what I think then yes, there is a set lift for a set duration.
For example:
XE: 224 duration has .563 lift
XE-R: 224 duration has .581 lift
For example:
XE: 224 duration has .563 lift
XE-R: 224 duration has .581 lift
05-25-2007, 05:53 AM
#14
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Read JRP cam sticky atop this forum. It is all in there.
https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html
https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html
05-25-2007, 09:29 AM
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Originally Posted by Steve Bryant
Explain your question a little more.
1. Do you want to know how to determine the kind of valve lift that best suits your needs or application? or
2. How you determine the valve lift for a given lobe lift? or
3. Both 1 and 2. or
4. Something completely different.
Steve
1. Do you want to know how to determine the kind of valve lift that best suits your needs or application? or
2. How you determine the valve lift for a given lobe lift? or
3. Both 1 and 2. or
4. Something completely different.
Steve
Question 1....I know WHAT lift is when looking at cam specs, DUH..
What I am asking is how does one go about determining the lift for THEIR set up....like If I have a sheet metal intake and good heads do I get a cam with A LOT OF LIFT, etcetc
THANKS