Does the Comp 212/218 high lift cam have advance ground in?
Nov 13, 2004 | 07:53 AM
#14
With your radix less overlap.
Most of the camshafts being used are in the negative range. Less than X amount of overlap. And low boost at that.
Take the 212/218 @ 114lsa. It has -13* of overlap relative to top dead center. The exhaust valve closes 7* before the piston reaches the top. And the intake valve opens 6* after the piston has reached the top. So theres a gap there of -13* of overlap.
So worrying about overlap with a smallish camshaft shouldn't be a big concern. Obviously, there wont be any bleeding of boost if there isn't really an "overlap" phaze.
A 220 @ 109 has 1 degrees of overlap relative to TDC.
A 220 @ 113 has -7 degrees of overlap relative to TDC.
Up to the cam grinders to decide when they feel the need to back down overlap in fear of bleeding.
Most of the camshafts being used are in the negative range. Less than X amount of overlap. And low boost at that.
Take the 212/218 @ 114lsa. It has -13* of overlap relative to top dead center. The exhaust valve closes 7* before the piston reaches the top. And the intake valve opens 6* after the piston has reached the top. So theres a gap there of -13* of overlap.
So worrying about overlap with a smallish camshaft shouldn't be a big concern. Obviously, there wont be any bleeding of boost if there isn't really an "overlap" phaze.
A 220 @ 109 has 1 degrees of overlap relative to TDC.
A 220 @ 113 has -7 degrees of overlap relative to TDC.
Up to the cam grinders to decide when they feel the need to back down overlap in fear of bleeding.
Nov 13, 2004 | 07:56 AM
#15
14 Second Truck Club
Joined: Aug 2003
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From: Tucson, AZ
Originally Posted by SportSide 5.3
With your radix less overlap.
Most of the camshafts being used are in the negative range. Less than X amount of overlap. And low boost at that.
Take the 212/218 @ 114lsa. It has -13* of overlap relative to top dead center. The exhaust valve closes 7* before the piston reaches the top. And the intake valve opens 6* after the piston has reached the top. So theres a gap there of -13* of overlap.
Most of the camshafts being used are in the negative range. Less than X amount of overlap. And low boost at that.
Take the 212/218 @ 114lsa. It has -13* of overlap relative to top dead center. The exhaust valve closes 7* before the piston reaches the top. And the intake valve opens 6* after the piston has reached the top. So theres a gap there of -13* of overlap.
Nov 13, 2004 | 08:01 AM
#16
So worrying about overlap with a smallish camshaft shouldn't be a big concern. Obviously, there wont be any bleeding of boost if there isn't really an "overlap" phaze.
A 220 @ 109 has 1 degree of overlap relative to TDC.
A 220 @ 113 has -7 degrees of overlap relative to TDC.
Up to the cam grinders to decide when they feel the need to back down overlap in fear of bleeding.
A 220 @ 109 has 1 degree of overlap relative to TDC.
A 220 @ 113 has -7 degrees of overlap relative to TDC.
Up to the cam grinders to decide when they feel the need to back down overlap in fear of bleeding.
Nov 13, 2004 | 08:11 AM
#17
ahhhhh... so since it is letting in more air, you want more flow of fuel to even it out?
http://www.chevytalk.com/tech/101/Cam_Theory.html
try reading thru this. its a bit detailed....let me search some more. i know j-rod has some good basic tech on camshafts.
Nov 13, 2004 | 02:31 PM
#19
Originally Posted by 02denali
i think with a radix or F.I. you want no less than a 114 lsa. i think they made good power with a ls1 119.5 lsa cam.
Nov 13, 2004 | 02:33 PM
#20
I found this, but I'm not sure if it works...
"If you have the duration at .006,add the intake and exhaust duration,divide by 4,subtract the LSA and multiply by 2,that will give overlap."
"If you have the duration at .006,add the intake and exhaust duration,divide by 4,subtract the LSA and multiply by 2,that will give overlap."