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-   -   Cam LSA question (https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/cam-lsa-question-289480/)

2003blue5.7 Mar 13, 2005 03:07 PM

Cam LSA question
 
what is the difference between a 224/224-114 or a 224/224-112 I'm doing heads and a cam at the same time but I'm unsure what cam to go with.

litreddevil Mar 13, 2005 03:28 PM

The higher the dur. and lobe sep. the higher you move your low end tq with a 112 lobe you might need a small stall little over stock are some gear may need both with the 114 you could get away with just one are the other.my next cam will be on a 115 lb are 117 lb

one03sierra Mar 13, 2005 08:48 PM

i belive that the lsa is a thing that has been argued about every day on here. valve events play the most major role in it. i firmly believe that all cams for a turbo or supercharger application need the higher lsa to keep boost from bleeding off. you run nos. there are several f body people that are running the 112 lsaq with nos and it is running tops. and you have the 5.7 so i belive that it will work fine for the 112. i am going to go to a 224-224-581-581-112+4.

litreddevil Mar 13, 2005 09:22 PM


Originally Posted by 02denali
i belive that the lsa is a thing that has been argued about every day on here. valve events play the most major role in it. i firmly believe that all cams for a turbo or supercharger application need the higher lsa to keep boost from bleeding off. you run nos. there are several f body people that are running the 112 lsaq with nos and it is running tops. and you have the 5.7 so i belive that it will work fine for the 112. i am going to go to a 224-224-581-581-112+4.




JUST HAVE TO REMBER THAT AN F-BODY IS ABOUT 5 TO 6 HUNDRED LBS. LIGHTER THAN A RCSW TRUCK THIS IS WERE THE DIFFERENCE IS TO GET THE HEAVY TRUCK ROLLING.I DON'T KNOW HOW N2O WORKS I HAVE NEVER HAD IT IT MIGHT BE FINE JUST GOT TO TAKE WEIGHT IN TO CONSIDERATION.

one03sierra Mar 13, 2005 09:57 PM

oh yay i know on the weight. but he is running an ls1 in there. even thought there is a weight difference he has the motor that will like one of these cams.

PappyDan Mar 14, 2005 02:31 AM

there is a guy in the FI section bitching about his cam bleeding off his boost and not geting all of it in the chamber, it is running a 112 lsa.

one03sierra Mar 14, 2005 05:44 AM

oh man do not run a 112 lsa on a boosted engine no matter who tells you to. nitrous wil work good on a 112lsa cam. but tuning is a biatch as well.

Sport Side Mar 14, 2005 06:06 AM


Originally Posted by PappyDan
there is a guy in the FI section bitching about his cam bleeding off his boost and not geting all of it in the chamber, it is running a 112 lsa.

I'd guess something else is wrong with his setup. He could nearly pass smog with the camshaft. (-2* @ .05)

A near smoggable grind, bleeding off boost...?

Think about this. Bleeding off boost. We are talking about overlap correct? Low LSA create more overlap. A 110* lsa is not a bad mfer. It's how the duration is paired to it. For example,

210/210 110lsa = -10* overlap
220/220 115lsa = -10* overlap

The 210 doesn't need a 114* lsa to be used with boost. It can make the same overlap with a lower lsa, that the 220 makes with a high lsa. If we are shooting for X amount of overlap and are using a small grind. YOU DO NOT NEED a wide lobe seperation angle.


Here are some quotes, I took from the ''blower lsa'' thread.


Blower LSA...Ha! As you say, it's a by-product. The more overlap you give a blower motor, the more power you'll make, just like N/A. You just don't *need* as much overlap to make power....since upping the boost 1psi would give more gains then 5 degrees of added overlap.

Yes, you should design a cam that is ment to work in the 'sweet' spot of the blower/motor combo. Small, more aggressive lobes on a tight LSA keeping near the stock IVC/EVO .006 events will give great results.
Overlap increases cylinder pressure. Boost increases cylinder pressure.

More boost requires less overlap to make a given cylinder pressure. That certain cylinder pressure being the desired power. If we want X amount of power. And we add a blower. It doesn't take as much overlap to get us to (x).

Perhaps the internet hype has raised the "no overlap" scare to a far far extent. People are so affraid of blowing boost out of the tail pipes they've limited themselves to no tighter than 114* lsa, on ANY 2 given lobes.

Why? Is it really necessary to decrease overlap on a small grind w/ low boost?


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