cam specs? what the heck?
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From: Friendswood TX
cam specs? what the heck? Alright, I know the basics of the LS1. But when yall talk about cams specs it goes over my head. Did a few searches and didnt find much to help. So can some one explain the sets of numbers, i know its lift and duration and blah blah i just got myself all confused. No really though can someone help a brother out? <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Holmez
Holmez
Re: cam specs? what the heck? Don't panic. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
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.
Hope this helps!
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.
Hope this helps!
Tony
Launching!
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From: Houston, Texas F-Body Heaven!!!
Re: cam specs? what the heck? 
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Joined: Nov 2001
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From: Lexington, SC
Re: cam specs? what the heck? Here...one of the best cam discussions on this site yet: https://ls1tech.com/ubb/cgi-bin/ulti...c;f=1;t=000045
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From: Friendswood TX
Re: cam specs? what the heck? You all rock! thanks for the lengthy reply Tony! I did read about 8 times, and then the link to comp cams, thanks a bunch! I am getting there
Holmez
Holmez
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From: Iowa :-/~
Re: cam specs? what the heck? Drew2G2
I really would like to encourage you to read and read again what NineBall wrote!!! I read that months (6 or 7) ago and then got a small understanding on cams. From that time on I've read and read and now know what the people are talking about when they give out some specs. Just so a search on cam in this forum and then read EVERY post you will then get a great understanding what all of the variations will do.
I really would like to encourage you to read and read again what NineBall wrote!!! I read that months (6 or 7) ago and then got a small understanding on cams. From that time on I've read and read and now know what the people are talking about when they give out some specs. Just so a search on cam in this forum and then read EVERY post you will then get a great understanding what all of the variations will do.
