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Old 08-11-2005, 02:20 PM
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Hey Brian feel free to add your facts on these new cams.
Give us the + and - vs the XER lopes.
Many feel the car will idel better with a faster ramp rate. Also it would make since for those wanting not to glycut the pistons but get as much as possible out of a head and cam swap.
Shed some light.
Old 08-12-2005, 12:55 AM
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Originally Posted by Brian@CompCams
lol....I would agree with you but, that is not what you said.


I may just have to sit on the sideline on some of this discussion.
I tried to keep it simple for it's own sake, but yes, I was wrong.
Old 08-14-2005, 05:59 PM
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Originally Posted by Patrick G
That statement is absolutely FALSE. The LSK lobes were designed by Comp to have more high rpm stability than XE or XE-R lobes.

XE-R lobes are 49 degrees from .006" to .050". That's fast.
LSK lobes are 50 degrees from .006" to .050. Not quite as fast.

Where the LSK lobes shine is the arc they form from .050" to peak lift. According to Comp, the LSK lobes better follow the natural arc of the cam. See, fast ramps and low lift (like an XE-R lobe) make the lifter want to "loft" off of the cam lobe. By adding more lift into the lobe design, Comp feels they can get more stable rpm ability.

My new Thunder Racing TRak Cam uses the 231 LSK lobe on the intake and it revs to the freakin' moon. I need to raise my rev limiter ASAP because the 6800 rpm redline feels like 6000. It would go 7500 no problem. For rev assurance, I'm running Comp 921 springs, but I could have shimmed my duals that came with my AFR 205s and been fine.
We used some of the very large LSK lobes and also had some major valve float issues and we had good stuff and Morel lifters. Put the regular lobes back in and the power and rpm came back. I'd sure like to do some more with them as all the other comp stuff has done us well so far. What installed height are you running with those 921s and what seat and open and how far from coil bind? Maybe that 231 lobe is happy with tha exact combo if it is that stable? Turn the rev limiter way up and post the graph so we can see what happens.

What does Brian@CompCams say? Why the silence? Let's here whether these lobes are mainstream or not yet. They're certainly nice on paper but maybe need a little different setup possibly although we have only run taht one deal so far so I'm glad someone else is playing with them.
Old 08-14-2005, 06:00 PM
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Originally Posted by KingCrapBox
I tried to keep it simple for it's own sake, but yes, I was wrong.
No Ben you were fairly right actually just not 100 % but probably more like 98.2348976 % right.
Old 08-14-2005, 06:33 PM
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Originally Posted by gtovan
Here are the specs on the whole series:

Comp Cams LSK lobes
Lobe#, Dur. @ .006", .050", .200", & Lift w/1.7 rocker

2129 285 235 160 .646"

Anyone have an idea how something like this (on a 114-115 LSA) would act in a 408 with ported AFR's and morel Hyd lifters??? opinions would be great (since i haven't picked out my cam yet for this motor)
Old 08-14-2005, 06:45 PM
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Originally Posted by dame
Anyone have an idea how something like this (on a 114-115 LSA) would act in a 408 with ported AFR's and morel Hyd lifters??? opinions would be great (since i haven't picked out my cam yet for this motor)
It should run great depending on your exhaust sizing and if it doesn't float. I want to see more of Patrick's data. He's a good guy so I am glad he has gotten these crazy LSK lobes to work on his setup because I think these are great lobes on paper with the right parts to support them. Lift is usually all good but can sometimes have a bad effect on reliability without the right supporting cast of backup parts!

What springs did Comp have in mind for these lobes is what I would like to know as I would love to do more testing.
Old 08-14-2005, 08:20 PM
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I have a fairly long winded explanation as to why these lobes will work just fine in any application under 7200 RPM (possibly more if everything is set up correctly). When I have time tomorrow I will give further explanation. Patrick's motor shows NO sign of shutting down at 6800 RPM. The power is carrying out just fine. There is ZERO sign of them being 'valve floatings ****'s at 6500 RPM'. I have Patrick's dyno graph and a dyno graph of a 408 with a 251/259 LSK lobed cam we did. Both motors would rev out just fine. Needless to say rockerarm choice (stock!!!) and proper spring selection and setup are what is going to make or break these lobes.
Old 08-14-2005, 09:06 PM
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It's interesting to think of how these will compare with the XE-R lobes. Although they seem to be less aggressive @ .600, they are more aggressive at .200". This means that the valve is coming open sooner than an XE-R, but it's also hanging open longer than an XE-R. It seems as if the cam would provide more cylinder filling with a givin lobe as compared to it's counter part, but let the valve close just a bit easier so spring life could actually be longer. Other than the valve lift it's self, I don't see where the cam is any more aggressive, on springs, than the XE-R. It sounds like a winner, but I'd like to see a few more results.
Old 08-14-2005, 09:26 PM
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Originally Posted by racer7088
It should run great depending on your exhaust sizing and if it doesn't float. I want to see more of Patrick's data. He's a good guy so I am glad he has gotten these crazy LSK lobes to work on his setup because I think these are great lobes on paper with the right parts to support them. Lift is usually all good but can sometimes have a bad effect on reliability without the right supporting cast of backup parts!

What springs did Comp have in mind for these lobes is what I would like to know as I would love to do more testing.

1 7/8" QTP's with the HVMC, 3" y pipe, 3" I pipe going through the FACTORY muffler (cutout right before the mufler inlet)

when you say float: what would keep it from floating? morels, stock rocker arms, a double spring like the PRC gold or platinum? whatelse would be needed to avoid valve float.... or rather IS IT avoidable.....sorry to hijack this thread, but Im really interested in a small (mid 230's) duration HIGH lift (to take full advantage of the heads) cam
Old 08-14-2005, 11:26 PM
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Originally Posted by dame
1 7/8" QTP's with the HVMC, 3" y pipe, 3" I pipe going through the FACTORY muffler (cutout right before the mufler inlet)

when you say float: what would keep it from floating? morels, stock rocker arms, a double spring like the PRC gold or platinum? whatelse would be needed to avoid valve float.... or rather IS IT avoidable.....sorry to hijack this thread, but Im really interested in a small (mid 230's) duration HIGH lift (to take full advantage of the heads) cam
Many things really but I will let Geoff tell us also what he thinks. We just used the one set so I will try some more and see what happens probably.
Old 08-15-2005, 06:37 PM
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Originally Posted by KingCrapBox
Lift doesn't affect PTV. Duration and LSA do. That cam would clear no problem.
Originally Posted by Brian@CompCams
Yes it does. If you kept the same duration and LSA, then keep adding lift...sooner or later it will hit.
Sooner or later but Pro Stock hasn't gotten there even.... KingCrapBox you were right, ICL/ECL and duration have everything to do with PTV not the max lift.

Bret
Old 08-15-2005, 06:41 PM
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Originally Posted by SStrokerAce
Sooner or later but Pro Stock hasn't gotten there even.... KingCrapBox you were right, ICL/ECL and duration have everything to do with PTV not the max lift.

Bret
Like Erik said I am only about 98.999% right, but for all practical purposes, lift will not affect PTV.
Old 08-15-2005, 07:45 PM
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I'm still trying to get this 346*-308*-226*-.550"-.935" lobe to work!

Ed
Old 08-15-2005, 11:05 PM
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Originally Posted by EDC
I'm still trying to get this 346*-308*-226*-.550"-.935" lobe to work!

Ed
Ed,

Quit playing with those girl scout cams!
Old 08-16-2005, 01:16 PM
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Does he have any lightweight stuff in the valvetrain: Ti retainers, Ti or hollow stem valves, Jesel/TD shaft rockers, Ti keepers, double taper pushrods, etc.?

I think the 921s come with Ti retainers
Old 08-16-2005, 01:35 PM
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My setup has the stainless steel valves that come stock on the AFR 205 heads, Ti retainers (that came on the 205s) and Comp 921 springs (shimmed to .090" of coil bind on exhaust and .050" of coil bind on the intakes). Stock rocker arms, stock lifters, and conventional chrome moly 7.35" pushrods. Rev ability is tremendous. The 6800 rpm rev limiter feels like 6000. I'd raise it but I'd like my short block to last a while longer.
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Old 08-16-2005, 06:41 PM
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How does the higher lift of these lobes affect low end torque, or does it? What exactly is the advantage of these new lobes?
Old 08-16-2005, 07:56 PM
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Originally Posted by BlueSix
How does the higher lift of these lobes affect low end torque, or does it? What exactly is the advantage of these new lobes?
The biggest advantage I see it more valve area under the curve from seat to seat. The duration numbers at .200" lift for the LSK lobes are very aggressive. More area under the curve means the valve is open a greater amount during the same duration compared to other cam profiles. This will make you more power (all else being equal).
Old 08-16-2005, 07:56 PM
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Originally Posted by BlueSix
How does the higher lift of these lobes affect low end torque, or does it? What exactly is the advantage of these new lobes?
When looking at the lobe, the .200" number is larger than your average XE-R lobe with the same duration. This means air will get into the cylinder faster, which should inturn increase low-end power. The increased lift should help a bit, but not as much as the added duration in the low-lift area.
Old 08-17-2005, 10:37 AM
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Originally Posted by BlueSix
How does the higher lift of these lobes affect low end torque, or does it? What exactly is the advantage of these new lobes?
The engine "sees" the heads and intake "through" the camshaft's apperature in time and lift so when you get the valves open further for longer the heads can be more fully utilized and the engine will experience better VE and torque if it needed the extra cam and it will also almost always go further in rpm before running out of air increasing total horsepower and lengthening the powerband.

It's all good as long as you can handle the lift as far as springs and valvetrain geomtry are concerned otherwise you can have less reliability and less rpm if the springs can't control the new cam. Anotherwords lift is usually all good for performance but not always for reliability. Of course the LSK lobes aren't like .800 lift or anything so I don't think that's a huge problem in this case as long as everything is done right.


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