The truth about LSA
12-02-2001, 10:49 AM
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The truth about LSA Ok, I would like the truth on cam LSA, because I get mixed answers. I'm interested in 112 and 114 LSA, obviosuly. Which makes the power lower in the band? Which has better street characteristics? And finally, which is better for NOS? I think 114 is better, but does that mean I CAN NOT use a 112 for nitrous-duty? I ask because I want the best cam for N/A that will work with NOS. Thanks.
12-02-2001, 11:07 AM
#2
Re: The truth about LSA Sure, you might get mixed answers, but you will learn who to pay attention to if you stick around. I'll even be nice enough to reply again although you must have deleted my last reply.
Cam Basics 101:
Increasing Lobe Seperation Angle moves your powerband higher in the rpm range, and lowers your low/mid rpm torque output. It also helps with emissions testing and makes the idle smoother. "Increasing LSA" means the same thing as "decreasing overlap". So, a 114 LSA cam will idle better, make less emissions, and show peak HP higher in rpm than a 112 LSA cam.
Increasing intake duration will move your powerband up also. It also will hurt midrange torque most of the time. Bigger is NOT better, and alot of people make that mistake. Increasing duration makes the idle rougher also.
Increasing exhaust duration is intended to extend the HP curve a little further on the high rpm. Not always the case. It is meant to help support a restrictive (stock manifolds and cats) exhaust setup. If you have headers, you will most likely see no gains by having more exhaust duration than intake duration. This is known as a "split duration" cam and those tend to idle worse than single pattern cams and cause more misfire SES codes. "single pattern" means cams with the same intake and exhaust duration.
Increasing lift moves the entire power curve upwards if all else is kept equal. More lift means those valves open up further. Has no effect on drivability, but more lift does wear out your valvetrain faster.
About nitrous cams, don't choose a cam based on nitrous unless you are serious about using nitrous and plan on shooting 200+ rwhp into that motor. Most guys use 75-150 hp shots and will not see any gains from messing with cam specs. Build your motor to run well n/a and then just use the nitrous as a boost. 114 LSA is better for nitrous, it has less overlap, less scavenging, and keeps more nitrous in the cylinder after the intake charge. But, on a small nitrous shot, you won't notice any difference between 112 and 114.
Tony
Cam Basics 101:
Increasing Lobe Seperation Angle moves your powerband higher in the rpm range, and lowers your low/mid rpm torque output. It also helps with emissions testing and makes the idle smoother. "Increasing LSA" means the same thing as "decreasing overlap". So, a 114 LSA cam will idle better, make less emissions, and show peak HP higher in rpm than a 112 LSA cam.
Increasing intake duration will move your powerband up also. It also will hurt midrange torque most of the time. Bigger is NOT better, and alot of people make that mistake. Increasing duration makes the idle rougher also.
Increasing exhaust duration is intended to extend the HP curve a little further on the high rpm. Not always the case. It is meant to help support a restrictive (stock manifolds and cats) exhaust setup. If you have headers, you will most likely see no gains by having more exhaust duration than intake duration. This is known as a "split duration" cam and those tend to idle worse than single pattern cams and cause more misfire SES codes. "single pattern" means cams with the same intake and exhaust duration.
Increasing lift moves the entire power curve upwards if all else is kept equal. More lift means those valves open up further. Has no effect on drivability, but more lift does wear out your valvetrain faster.
About nitrous cams, don't choose a cam based on nitrous unless you are serious about using nitrous and plan on shooting 200+ rwhp into that motor. Most guys use 75-150 hp shots and will not see any gains from messing with cam specs. Build your motor to run well n/a and then just use the nitrous as a boost. 114 LSA is better for nitrous, it has less overlap, less scavenging, and keeps more nitrous in the cylinder after the intake charge. But, on a small nitrous shot, you won't notice any difference between 112 and 114.
Tony
Last edited by Nine Ball; 10-14-2005 at 02:58 PM.
12-02-2001, 11:26 AM
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Re: The truth about LSA Excellent imformation! <img src="images/icons/grin.gif" border="0">
Class 102? Does Hot cam have a smaller
base dia. or not? If so will it just not pre-load
lifter(center)or just be noisy ex. more
ticking? <img src="images/icons/confused.gif" border="0">
Class 102? Does Hot cam have a smaller
base dia. or not? If so will it just not pre-load
lifter(center)or just be noisy ex. more
ticking? <img src="images/icons/confused.gif" border="0">
12-02-2001, 11:48 AM
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Re: The truth about LSA [quote]Originally posted by Nine Ball:
<strong>Sure, you might get mixed answers, but you will learn who to pay attention to if you stick around. I'll even be nice enough to reply again although you must have deleted my last reply.
[ December 02, 2001: Message edited by: Nine Ball ]</strong><hr></blockquote>
Are you talking to me, Tony?
I've been involved in the LS1 boards for a year or so, and usually only listen to a select group of people when it comes to this stuff. <img src="images/icons/smile.gif" border="0">
BTW, i'm only talking about a 150 shot at most, but was kinda leaning towards the Hammer cam (112 LSA). Thanks.
[ December 02, 2001: Message edited by: bigSS ]</p>
<strong>Sure, you might get mixed answers, but you will learn who to pay attention to if you stick around. I'll even be nice enough to reply again although you must have deleted my last reply.
[ December 02, 2001: Message edited by: Nine Ball ]</strong><hr></blockquote>
Are you talking to me, Tony?
I've been involved in the LS1 boards for a year or so, and usually only listen to a select group of people when it comes to this stuff. <img src="images/icons/smile.gif" border="0">
BTW, i'm only talking about a 150 shot at most, but was kinda leaning towards the Hammer cam (112 LSA). Thanks.
[ December 02, 2001: Message edited by: bigSS ]</p>
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12-02-2001, 11:57 AM
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Re: The truth about LSA If you can get the duration at .050 and the duration at .006 it can greatly help you choose a cam, because it helps you see the speed of the ramps. Or you can nose around and find the Intake Valve Open, Intake Valve Close, Exhaust Valve Open, and Exhuast Valve Close which will do the same thing. 2 cams might have the same duration at .050, but one might have a lot less duration at .006, which effects power characteristics (especially torque).
J.
J.
12-02-2001, 02:19 PM
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Re: The truth about LSA [quote]Originally posted by Crazyquik:
<strong>2 cams might have the same duration at .050, but one might have a lot less duration at .006, which effects power characteristics (especially torque).</strong><hr></blockquote>
So if you take a 221/221 cam and one has an adv. duration of 283 and another has 275, the 275 will make more torque in the low to midrange is what you're saying?
Thanks
<strong>2 cams might have the same duration at .050, but one might have a lot less duration at .006, which effects power characteristics (especially torque).</strong><hr></blockquote>
So if you take a 221/221 cam and one has an adv. duration of 283 and another has 275, the 275 will make more torque in the low to midrange is what you're saying?
Thanks
04-25-2004, 11:18 PM
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Originally Posted by Nine Ball
Sure, you might get mixed answers, but you will learn who to pay attention to if you stick around. I'll even be nice enough to reply again although you must have deleted my last reply.
Cam Basics 101:
Increasing Lobe Seperation Angle moves your powerband higher in the rpm range, and lowers your low/mid rpm torque output. It also helps with emissions testing and makes the idle smoother. "Increasing LSA" means the same thing as "decreasing overlap". So, a 114 LSA cam will idle better, make less emissions, and show peak HP higher in rpm than a 112 LSA cam.
Increasing intake duration will move your powerband up also. It also will hurt midrange torque most of the time. Bigger is NOT better, and alot of people make that mistake. Increasing duration makes the idle rougher also.
Increasing exhaust duration is intended to extend the HP curve a little further on the high rpm. Not always the case. It is meant to help support a restrictive (stock manifolds and cats) exhaust setup. If you have headers, you will most likely see no gains by having more exhaust duration than intake duration. This is known as a "split duration" cam and those tend to idle worse than single pattern cams and cause more misfire SES codes. "single pattern" means cams with the same intake and exhaust duration.
Increasing lift moves the entire power curve upwards if all else is kept equal. More lift means those valves open up further. Has no effect on drivability, but more lift does wear out your valvetrain faster.
About nitrous cams, don't choose a cam based on nitrous unless you are serious about using nitrous and plan on shooting 200+ rwhp into that motor. Most guys use 75-150 hp shots and will not see any gains from messing with cam specs. Build your motor to run well n/a and then just use the nitrous as a boost. 114 LSA is better for nitrous, it has less overlap, less scavenging, and keeps more nitrous in the cylinder after the intake charge. But, on a small nitrous shot, you won't notice any difference between 112 and 114.
Now, don't delete this!
Tony <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />
[ December 02, 2001: Message edited by: Nine Ball ]</p>
Cam Basics 101:
Increasing Lobe Seperation Angle moves your powerband higher in the rpm range, and lowers your low/mid rpm torque output. It also helps with emissions testing and makes the idle smoother. "Increasing LSA" means the same thing as "decreasing overlap". So, a 114 LSA cam will idle better, make less emissions, and show peak HP higher in rpm than a 112 LSA cam.
Increasing intake duration will move your powerband up also. It also will hurt midrange torque most of the time. Bigger is NOT better, and alot of people make that mistake. Increasing duration makes the idle rougher also.
Increasing exhaust duration is intended to extend the HP curve a little further on the high rpm. Not always the case. It is meant to help support a restrictive (stock manifolds and cats) exhaust setup. If you have headers, you will most likely see no gains by having more exhaust duration than intake duration. This is known as a "split duration" cam and those tend to idle worse than single pattern cams and cause more misfire SES codes. "single pattern" means cams with the same intake and exhaust duration.
Increasing lift moves the entire power curve upwards if all else is kept equal. More lift means those valves open up further. Has no effect on drivability, but more lift does wear out your valvetrain faster.
About nitrous cams, don't choose a cam based on nitrous unless you are serious about using nitrous and plan on shooting 200+ rwhp into that motor. Most guys use 75-150 hp shots and will not see any gains from messing with cam specs. Build your motor to run well n/a and then just use the nitrous as a boost. 114 LSA is better for nitrous, it has less overlap, less scavenging, and keeps more nitrous in the cylinder after the intake charge. But, on a small nitrous shot, you won't notice any difference between 112 and 114.
Now, don't delete this!
Tony <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />
[ December 02, 2001: Message edited by: Nine Ball ]</p>
If possible, what kind of gains should i see from this with tuning (around 35 to 40 or more?) and where do you think my power band would be (if that is even possible). Sorry i ask this, but i have not seen enough dyno graphs to really have a good picture of this.
also, how does a 222/222 compare with the 224/224 (i didnt think there was much difference, but was just wanting to ask to be sure)
thanks in advance
04-26-2004, 12:16 AM
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Would it be better for drivability vs power to have less duration and a tighter LSA than more duration / wider LSA for a N/A setup? eg: a 234/232 106LSA with XE-R lobes vs a larger 238/240 112LSA.
04-26-2004, 12:57 AM
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With reference to the GM Hotcam mentioned above...it is a great nitrous cam from what I hear. I run it n/a but had minimal gains with it until I added longtubes to go along with it.
The 238/240 112LSA would be the way to go between those to cams, there will be a minimal power difference but it should idle and behave much better than the 234/232 106LSA with XE-R lobes. Just my opinion.
The 238/240 112LSA would be the way to go between those to cams, there will be a minimal power difference but it should idle and behave much better than the 234/232 106LSA with XE-R lobes. Just my opinion.
04-26-2004, 06:12 AM
#14
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Where did you guys dig this post up from? Its from 2001 ???
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
04-26-2004, 06:23 AM
#15
Originally Posted by J-Rod
Where did you guys dig this post up from? Its from 2001 ???
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
and 
04-26-2004, 07:47 AM
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Originally Posted by J-Rod
Where did you guys dig this post up from? Its from 2001 ???
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
As for lift, you're not going to move the power of your motor 1000 rpm by going from .566 to .588. With the selection of valvesprings these days, I'd run a .580 with no worries. It and the .560 lift cam will make about the same power in about the same range assuming the ramps on the cam are the same, but I would bet they aren't.
Question: where could i get the ramps of each cam at??? Should i just call tsp???
thanks
04-26-2004, 07:51 AM
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Many cam companies talk about the LSA as if it is an adjustable feature. They will usually spec a wide LSA for street use and a tighter one for race use. The justification is that the wider LSA gives a better idle. The real truth here is that the LSA for optimum results, within a specified power band, for a given engine, is not adjustable. Only one LSA will produce optimal torque and power for a given engine spec and powerband. Any time it is suggested that the LSA be spread to improve idle quality it is a sure sign that the duration chosen is too long for the job! Sure a wider LSA will spread the powerband and improve the idle, but the price paid for spreading the LSA to achieve a certain idle quality is a substantial reduction in torque and power.
It is little known outside the cam industry that cam grinders often deliberately spread the LSA to protect overzealous hot rodders from the negative effects of an excessively long duration cam they insist on wanting to install.
Although the LSA is an important entity, its determination alone is still not enough to allow an optimally specced cam to be produced. In actuality it is more part of the answer rather than part of the question.
A call to the mfg wouldn't hurt. As for the DIY way to check the speed of the ramp on the cam, a simple way is too look @ the .006 (gross lift), .050, and .200 lift of the two cams, and see if they are different... This will help you get an idea if the ramps are similar. Best way is to cam docotor the cam.
It is little known outside the cam industry that cam grinders often deliberately spread the LSA to protect overzealous hot rodders from the negative effects of an excessively long duration cam they insist on wanting to install.
Although the LSA is an important entity, its determination alone is still not enough to allow an optimally specced cam to be produced. In actuality it is more part of the answer rather than part of the question.
A call to the mfg wouldn't hurt. As for the DIY way to check the speed of the ramp on the cam, a simple way is too look @ the .006 (gross lift), .050, and .200 lift of the two cams, and see if they are different... This will help you get an idea if the ramps are similar. Best way is to cam docotor the cam.
04-26-2004, 07:53 AM
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the reason i am asking this is b/c i am trying to figure out what cam will give me awesome AUC power. I would really like to have good/high numbers after dyno, but I am willing to sacrifice that since I dont want to rev my engine over 6000 just to get some good power.
Does anyone have before/after dyno graphs of the different 224 duration cams, so i can see the power range and the torque curve against stock??
Also, I have a 99, and i think it has like a 202/210 (or 208) on a 116 lsa. So, does that mean that i probably will not see as good of a gain as everyone with the 01-02 (i think they have under a 200 duration on a 115 lsa)
thanks again and sorry for the double post
Does anyone have before/after dyno graphs of the different 224 duration cams, so i can see the power range and the torque curve against stock??
Also, I have a 99, and i think it has like a 202/210 (or 208) on a 116 lsa. So, does that mean that i probably will not see as good of a gain as everyone with the 01-02 (i think they have under a 200 duration on a 115 lsa)
thanks again and sorry for the double post
04-26-2004, 07:58 AM
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thx j-rod
you are very quick at replying, in fact i thought i was double posting, yet you had already replied.
What about this??? something like a 224/224 (not sure which lift (either a .566 or a .588) and i will check on the ramp rates) on a 110 lsa..
Would this be to narrow of an lsa (in fact i dont even know where i would find this cam??
thanks alot
you are very quick at replying, in fact i thought i was double posting, yet you had already replied.
What about this??? something like a 224/224 (not sure which lift (either a .566 or a .588) and i will check on the ramp rates) on a 110 lsa..
Would this be to narrow of an lsa (in fact i dont even know where i would find this cam??
thanks alot
