Aggressive cam lobes?
We discussed nitrous! I will give you a call with some more questions.
Launching!
Joined: Jul 2004
Posts: 205
Likes: 3
From: Valencia Ca
Have caught some flack over my SR Im using as the profile isnt "extreme" and trendy...guess what it works, and doesnt do funny stuff at higher rpms like the last 3 with the type of profile mentioned above did. 2 Hyd flat tappets and 1 hyd roller.Yes, roller.
IMO if youre going to twist the motor up/want to leave it together for awhile Kips line of thinking....yep.
Good friend of mine who runs a cam motion SFT has had it in since I was a kid still runs hard today nice to see you guys are still around.
IMO if youre going to twist the motor up/want to leave it together for awhile Kips line of thinking....yep.
Good friend of mine who runs a cam motion SFT has had it in since I was a kid still runs hard today nice to see you guys are still around.
Most people here want aggressive cam lobes. Why? Because someone told them they are better. So what is an aggressive cam lobe? To take the most advantage of the LS Chevy engine design the cam lobe must be smooth and stable. Generally in this LS Chevy engine, the smoother and more stable the cam lobe, the more power and RPM capability the engine will have. So generally the less aggressive lobe will make for the most aggressive (powerful) engine.
There is no need in having 8 different lobe styles or variations for the LS Chevy hydraulic cams. Most of the engine combinations I see on here run from idle to 6500 RPM with a valve lift from .550” to .650” lift and with spring seat pressure 130lbs to155lbs with 350lbs to 400lbs open pressure. The measurable differences in these lobes are very slight, the real difference is that some of them operate very well and others do not. The “hard” or “aggressive” lobes may make a small amount more vacuum at idle and may show a two pound gain in torque at 4000RPM but will cause more valve noise and float the valves sooner plus having a destructive affect on valve train parts and valve seat sealing. The “softer” lobes will have a little less vacuum at idle but provide quite valve train operation and extend the valve “float” RPM 300-500 RPM and do not destroy valve train components.
What do you call “aggressive? Is it high acceleration or high velocity? Which is harder on the valve train? The cam with higher lifter acceleration rates will be harder on the valve train.
Let us compare technical data on two lobes both with 230 degrees duration at .050” with .350” lobe lift. One lobe we’ll call “hard” the other “soft” even though I don’t like to use the word “soft”, but it is soft compared to the hard lobe. I prefer to call it the correct lobe for your engine.
Compare:
HARD SOFT
MAX ACCELERATION: .00037 .000323
MAX VELOCITY: .0073 .00775
NOSE ACCELERATION: .00023 .000212
So which one is more “aggressive”? The soft one moves the valve FASTER or higher speed. So what is aggressive? One of the reasons the hard lobe floats the valve sooner is because it has higher “nose” acceleration, which is negative acceleration at the top of the lobe.
There is no need in having 8 different lobe styles or variations for the LS Chevy hydraulic cams. Most of the engine combinations I see on here run from idle to 6500 RPM with a valve lift from .550” to .650” lift and with spring seat pressure 130lbs to155lbs with 350lbs to 400lbs open pressure. The measurable differences in these lobes are very slight, the real difference is that some of them operate very well and others do not. The “hard” or “aggressive” lobes may make a small amount more vacuum at idle and may show a two pound gain in torque at 4000RPM but will cause more valve noise and float the valves sooner plus having a destructive affect on valve train parts and valve seat sealing. The “softer” lobes will have a little less vacuum at idle but provide quite valve train operation and extend the valve “float” RPM 300-500 RPM and do not destroy valve train components.
What do you call “aggressive? Is it high acceleration or high velocity? Which is harder on the valve train? The cam with higher lifter acceleration rates will be harder on the valve train.
Let us compare technical data on two lobes both with 230 degrees duration at .050” with .350” lobe lift. One lobe we’ll call “hard” the other “soft” even though I don’t like to use the word “soft”, but it is soft compared to the hard lobe. I prefer to call it the correct lobe for your engine.
Compare:
HARD SOFT
MAX ACCELERATION: .00037 .000323
MAX VELOCITY: .0073 .00775
NOSE ACCELERATION: .00023 .000212
So which one is more “aggressive”? The soft one moves the valve FASTER or higher speed. So what is aggressive? One of the reasons the hard lobe floats the valve sooner is because it has higher “nose” acceleration, which is negative acceleration at the top of the lobe.
Kip.....thanks for taking the time.
I have a few questions for you, if you will. And please excuse my limited knowledge and any questions that seem elementary.....
-Is this a blanket statement for "Cam Motions" line of hydro cams (would you spec the same seat intensity for a "max effort" {1.8+per cube} LS as a cam only setup ) ??
-Do you believe in the theory of power under the "area" of the curve (when stability is controlled) ??
-Do you believe 0.006" - 0.020" intensity should be a function of the specific induction and exhaust system (differential pressure, reversion, limited fill..etc)??
-Do you believe that ramp rates influence the "time" it takes the hydro lifter to go "solid" (because technically the seat duration, IVO, is not what is printed on the cam card, its the point where the lifter goes "solid") ??
-So wouldn't preload effect "true" IVO...and when coupled with different seat intensities your presented with an array of variables when talking hydro cams...... ?? (since we are splitting hairs...lol)
.
I've always been of the mindset.....lift the valve as quick as possible without sacrificing stability, zero loft and set it down as soft as possible.
But I guess it all depends on what it is you are trying to achieve.
I don't believe there is a perfect cam profile.
If there was, we would all be using it by now.~per Warpspeed
Thanks again Kip
.
Thread Starter
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Joined: Feb 2014
Posts: 328
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From: Baton Rouge La
Kip.....thanks for taking the time. ^^^^^^^^
I have a few questions for you, if you will. And please excuse my limited knowledge and any questions that seem elementary.....
-Is this a blanket statement for "Cam Motions" line of hydro cams (would you spec the same seat intensity for a "max effort" {1.8+per cube} LS as a cam only setup ) ??
Most of the time I would. Here is why. We had to re design and re grind 50 BBC cams that were made by another company. These 50 cams were made for a stationary engine that turned 1800 rpms
so this company designed the lobe and ground the cams. They were so volant they beat the hell out of the valve seats turing only 1800 rpms.
We redesigned the lobes reground the cams ( they were new cams BTW)
Now they have been running for the last three years. Guess who designed the cams?
-Do you believe in the theory of power under the "area" of the curve (when stability is controlled) ??
I do not understand this question
-Do you believe 0.006" - 0.020" intensity should be a function of the specific induction and exhaust system (differential pressure, reversion, limited fill..etc)??
Did you mean .006 to .200?
-Do you believe that ramp rates influence the "time" it takes the hydro lifter to go "solid" (because technically the seat duration, IVO, is not what is printed on the cam card, its the point where the lifter goes "solid") ??
The lifters are solid when they are pumped but the valve does not open at .001 cam lift it may not open until .010 cam lift or .030 at high rpms. What you have is deflection.
-So wouldn't preload effect "true" IVO...and when coupled with different seat intensities your presented with an array of variables when talking hydro cams...... ?? (since we are splitting hairs…lol)
Almost same as above.
.
I've always been of the mindset.....lift the valve as quick as possible without sacrificing stability, zero loft and set it down as soft as possible.
You are correct on the statement but you are limited to what you can do.
But I guess it all depends on what it is you are trying to achieve.
I don't believe there is a perfect cam profile.
If there was, we would all be using it by now.~per Warpspeed
Thanks again Kip
.
I have a few questions for you, if you will. And please excuse my limited knowledge and any questions that seem elementary.....
-Is this a blanket statement for "Cam Motions" line of hydro cams (would you spec the same seat intensity for a "max effort" {1.8+per cube} LS as a cam only setup ) ??
Most of the time I would. Here is why. We had to re design and re grind 50 BBC cams that were made by another company. These 50 cams were made for a stationary engine that turned 1800 rpms
so this company designed the lobe and ground the cams. They were so volant they beat the hell out of the valve seats turing only 1800 rpms.
We redesigned the lobes reground the cams ( they were new cams BTW)
Now they have been running for the last three years. Guess who designed the cams?
-Do you believe in the theory of power under the "area" of the curve (when stability is controlled) ??
I do not understand this question
-Do you believe 0.006" - 0.020" intensity should be a function of the specific induction and exhaust system (differential pressure, reversion, limited fill..etc)??
Did you mean .006 to .200?
-Do you believe that ramp rates influence the "time" it takes the hydro lifter to go "solid" (because technically the seat duration, IVO, is not what is printed on the cam card, its the point where the lifter goes "solid") ??
The lifters are solid when they are pumped but the valve does not open at .001 cam lift it may not open until .010 cam lift or .030 at high rpms. What you have is deflection.
-So wouldn't preload effect "true" IVO...and when coupled with different seat intensities your presented with an array of variables when talking hydro cams...... ?? (since we are splitting hairs…lol)
Almost same as above.
.
I've always been of the mindset.....lift the valve as quick as possible without sacrificing stability, zero loft and set it down as soft as possible.
You are correct on the statement but you are limited to what you can do.
But I guess it all depends on what it is you are trying to achieve.
I don't believe there is a perfect cam profile.
If there was, we would all be using it by now.~per Warpspeed
Thanks again Kip
.
Thread Starter
TECH Apprentice
Joined: Feb 2014
Posts: 328
Likes: 1
From: Baton Rouge La
I have a solid roller in my 2010 vette. We make solid rollers everyday everything from AMC GM Ford Chysler. Most of the LS cams are hyd. For some reason Most LS guys are stuck in the Hyd world even if they have a High Dollor build. All of cams are custom so it's no big deal to make one.
I started gathering parts for my build and went straight to solid roller. But then again im not trying to build a full street motor.
Would love to see what you would come up with for a cam for my build. Kinda wanting a 60mm core thats gun drilled as im going for high rpm.
Would love to see what you would come up with for a cam for my build. Kinda wanting a 60mm core thats gun drilled as im going for high rpm.
Thread Starter
TECH Apprentice
Joined: Feb 2014
Posts: 328
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From: Baton Rouge La
I started gathering parts for my build and went straight to solid roller. But then again im not trying to build a full street motor.
Would love to see what you would come up with for a cam for my build. Kinda wanting a 60mm core thats gun drilled as im going for high rpm.
Would love to see what you would come up with for a cam for my build. Kinda wanting a 60mm core thats gun drilled as im going for high rpm.
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To do this you take the duration @.006 and subtract it from the duration @ .050. A number of 53 or higher denotes an XE lobe or other mild lobe and a number of 49 or lower denotes an XE-R lobe or other aggressive lobe
Thread Starter
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Joined: Feb 2014
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From: Baton Rouge La
From the early days in racing all engines including Pro Stock had stock diameter cam cores. The better the springs became the higher the rpms became. The high rpms and springs presser the more parts started braking and loss of valve control mainly from deflection. So we went from std cam bearing size of 1.949 the 55mm 2.165 to 60mm 2.363 to 70mm on and on. Each time with the larger cam core the power and rpms increased. Going from std 1.949 to 60mm increased rpms 400 and 50 average in power plus parts held up better. So one of the Pro Stock guys had a 60 mm core making good power but he wanted his cam gun drilled because that is what to other guy does. OK same everything but cam gun drilled lost 20 average. Why ? Deflection. Our 55mm LS core are smaller than the stock core but are just as strong because they are not gun drilled. We did that so we could put a .505 lobe on the cam for all out racing.
Thread Starter
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From: Baton Rouge La
They are not one size fits all. The only part that is command is the off the seat .000 to .006 from there each lobe is a little different. I just like a smooth acceleration to get it going. I could make 10 different lobes and give them some kind of cool name, that seams to work well. I can make some with more area under the curve for a given lift and duration but they will not make enough difference in power to justify doing it. One reason we don't is because I want the cam you get from us to last more that 5000 miles and not beat up your valve train.
They are not one size fits all. The only part that is command is the off the seat .000 to .006 from there each lobe is a little different. I just like a smooth acceleration to get it going. I could make 10 different lobes and give them some kind of cool name, that seams to work well. I can make some with more area under the curve for a given lift and duration but they will not make enough difference in power to justify doing it. One reason we don't is because I want the cam you get from us to last more that 5000 miles and not beat up your valve train.
Your saying the opening and closing ramps (seat - 0.006") are what you hold as a "standard". But beyond the 0.006" you will get as "aggressive" as the build/valve train demands ??
I understand your seat - 0.006" stance, if you lose control of the valve train early in the cycle it makes it that much more difficult to control. We have all seen those crazy spintron videos.
-Does Cam Motion believe in the lift curve has a correlation to the flow curve and crank angle/cylinder depression (thus, power under the curve) ??
-Does Cam Motion agree with this example of an average hydro 0.630" cam ??
.000-.100 68 degs 22%
.100-.200 40 degs 13%
.200-.300 26 degs 8.5%
.300-.400 34 degs 11%
.400-.500 32 degs 10.5%
.500-.600 60 degs 20%
.600 + 44 degs 14.5%
And when cleaned up a little looks like this.
35% of it's time below .200"
30% of it's time between .200-.500"
35% of it's time between .500-.630"
~per D.M.
-If a costumer is running a competitors camshaft with one of the more "aggressive" hydro lobes on the market (LSK) and has zero float or loft at 7500rpm (per the dyno graph), does the Cam Motion "softer" lobe make more power in the usable rpm range (5000 - 7500). Using the same 0.050" events ??
-Does Cam Motion believe that there is always power on the table...up to the point of valve train chaos ??
Aggressive.....as in, taking more spring, lighter valve train parts or a combination of the two...to control at the rpm the induction systems wants.
Thanks Kip for your time.
Last edited by LSOHOLIC; Oct 11, 2014 at 03:25 PM.
That doesn't really make sense. My LSL lobed intake is at 50 difference between the two and the LXL lobed exhaust is at 52 difference. I was under the impression that 1) these lobes were pretty mild, and 2) the LXL was milder than the LSL but it actually has a higher difference. Heck, the LXL at 52 is borderline pushing the "XE-R lobe" territory in terms of aggressiveness which is not true from what people have said about that lobe.
Russ Kemp
Thread Starter
TECH Apprentice
Joined: Feb 2014
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From: Baton Rouge La
Ok......I misunderstood you Kip.
Your saying the opening and closing ramps (seat - 0.006") are what you hold as a "standard". But beyond the 0.006" you will get as "aggressive" as the build/valve train demands ??
I understand your seat - 0.006" stance, if you lose control of the valve train early in the cycle it makes it that much more difficult to control. We have all seen those crazy spintron videos.
-Does Cam Motion believe in the lift curve has a correlation to the flow curve and crank angle/cylinder depression (thus, power under the curve) ??
-Does Cam Motion agree with this example of an average hydro 0.630" cam ??
.000-.100 68 degs 22%
.100-.200 40 degs 13%
.200-.300 26 degs 8.5%
.300-.400 34 degs 11%
.400-.500 32 degs 10.5%
.500-.600 60 degs 20%
.600 + 44 degs 14.5%
And when cleaned up a little looks like this.
35% of it's time below .200"
30% of it's time between .200-.500"
35% of it's time between .500-.630"
~per D.M.
-If a costumer is running a competitors camshaft with one of the more "aggressive" hydro lobes on the market (LSK) and has zero float or loft at 7500rpm (per the dyno graph), does the Cam Motion "softer" lobe make more power in the usable rpm range (5000 - 7500). Using the same 0.050" events ??
-Does Cam Motion believe that there is always power on the table...up to the point of valve train chaos ??
Aggressive.....as in, taking more spring, lighter valve train parts or a combination of the two...to control at the rpm the induction systems wants.
Thanks Kip for your time.
Your saying the opening and closing ramps (seat - 0.006") are what you hold as a "standard". But beyond the 0.006" you will get as "aggressive" as the build/valve train demands ??
I understand your seat - 0.006" stance, if you lose control of the valve train early in the cycle it makes it that much more difficult to control. We have all seen those crazy spintron videos.
-Does Cam Motion believe in the lift curve has a correlation to the flow curve and crank angle/cylinder depression (thus, power under the curve) ??
-Does Cam Motion agree with this example of an average hydro 0.630" cam ??
.000-.100 68 degs 22%
.100-.200 40 degs 13%
.200-.300 26 degs 8.5%
.300-.400 34 degs 11%
.400-.500 32 degs 10.5%
.500-.600 60 degs 20%
.600 + 44 degs 14.5%
And when cleaned up a little looks like this.
35% of it's time below .200"
30% of it's time between .200-.500"
35% of it's time between .500-.630"
~per D.M.
-If a costumer is running a competitors camshaft with one of the more "aggressive" hydro lobes on the market (LSK) and has zero float or loft at 7500rpm (per the dyno graph), does the Cam Motion "softer" lobe make more power in the usable rpm range (5000 - 7500). Using the same 0.050" events ??
-Does Cam Motion believe that there is always power on the table...up to the point of valve train chaos ??
Aggressive.....as in, taking more spring, lighter valve train parts or a combination of the two...to control at the rpm the induction systems wants.
Thanks Kip for your time.
Your saying the opening and closing ramps (seat - 0.006") are what you hold as a "standard". But beyond the 0.006" you will get as "aggressive" as the build/valve train demands ??
Lets put it this way I get aggressive after .05 with high velocity/lifter speed. lobes that has a low .006 get aggressive before .05 which is noisy and harder on the lifters.
I understand your seat - 0.006" stance, if you lose control of the valve train early in the cycle it makes it that much more difficult to control. We have all seen those crazy spintron videos.
That is mostly caused by truing to get to much duration @ the .200 number with higher negative acceleration at the nose.
-Does Cam Motion believe in the lift curve has a correlation to the flow curve and crank angle/cylinder depression (thus, power under the curve) ??
-Does Cam Motion agree with this example of an average hydro 0.630" cam ??
.000-.100 68 degs 22%
.100-.200 40 degs 13%
.200-.300 26 degs 8.5%
.300-.400 34 degs 11%
.400-.500 32 degs 10.5%
.500-.600 60 degs 20%
.600 + 44 degs 14.5%
And when cleaned up a little looks like this.
35% of it's time below .200"
30% of it's time between .200-.500"
35% of it's time between .500-.630"
~per D.M.
You can out trick yourself with all these numbers. You always want the valve to be open as much as the application will allow for the intended use.
-If a costumer is running a competitors camshaft with one of the more "aggressive" hydro lobes on the market (LSK) and has zero float or loft at 7500rpm (per the dyno graph), does the Cam Motion "softer" lobe make more power in the usable rpm range (5000 - 7500). Using the same 0.050" events ??
It could go rather way. Just because something is big it does not mean it’s better.
-Does Cam Motion believe that there is always power on the table...up to the point of valve train chaos ??
Sure but you have to find it.
Aggressive.....as in, taking more spring, lighter valve train parts or a combination of the two...to control at the rpm the induction systems wants.
Most people over spring just like most people want a cam that is to big for there application.