eboggs_jkvl
03-27-2007, 06:45 PM
I read this on the Corvette Forum and I thought it would be good to put in here.
Here is the link:
http://forums.corvetteforum.com/showpost.php?p=1559555045&postcount=12
Here is the text in case the link gets broken.
The LSA is only one factor that will affect your idle, the other is the duration. There is a formula for determining your overlap and resultant idle quality. Average your duration (add the intake & exhaust duration, divide by 2), then subtract your LSA X 2. The more negative the result, the better your idle.
For example, I ran a 218/224 cam on a 114 LSA in my previous LS1. Adding the two durations together, then dividing by 2 gives an average duration of 221. Doubling the LSA gives 228. Result is a -7, which gives an excellent idle. It was almost impossible to tell that it had an aftermarket cam in it.
Let's take another example, a 228/232 on a 112 LSA. Average duration is 230, LSA doubled is 224, resulting in a +6. This cam will barely idle at all. Even with a 115 LSA, the result would be 0, which would still result in a rough idle.
You could run a 224/228 (very popular grind) on a 115 LSA, would result in a -4, should give you a very tolerable idle. A 224/224 on a 114 LSA would be about the same, and a 224/224 on a 115 would give you a -6, and a very stock-like idle.
One good thing about the LS2 is that it will idle better than an LS1 with the same exact cam, due to the extra displacement (cubes).
Original poster is: HITMAN99
Elmer
Here is the link:
http://forums.corvetteforum.com/showpost.php?p=1559555045&postcount=12
Here is the text in case the link gets broken.
The LSA is only one factor that will affect your idle, the other is the duration. There is a formula for determining your overlap and resultant idle quality. Average your duration (add the intake & exhaust duration, divide by 2), then subtract your LSA X 2. The more negative the result, the better your idle.
For example, I ran a 218/224 cam on a 114 LSA in my previous LS1. Adding the two durations together, then dividing by 2 gives an average duration of 221. Doubling the LSA gives 228. Result is a -7, which gives an excellent idle. It was almost impossible to tell that it had an aftermarket cam in it.
Let's take another example, a 228/232 on a 112 LSA. Average duration is 230, LSA doubled is 224, resulting in a +6. This cam will barely idle at all. Even with a 115 LSA, the result would be 0, which would still result in a rough idle.
You could run a 224/228 (very popular grind) on a 115 LSA, would result in a -4, should give you a very tolerable idle. A 224/224 on a 114 LSA would be about the same, and a 224/224 on a 115 would give you a -6, and a very stock-like idle.
One good thing about the LS2 is that it will idle better than an LS1 with the same exact cam, due to the extra displacement (cubes).
Original poster is: HITMAN99
Elmer