High flowing heads and LS6 intake?
TECH Apprentice
Joined: Aug 2002
Posts: 331
Likes: 0
From: Gambrills, MD
Re: High flowing heads and LS6 intake? Couple of reasons. Those heads that flow 300+ CFM at .600" lift usually also have great flow #'s at lower lift. The cam is only at peak lift for a very short period of time, so most of the flow occurs in the low & mid-lift range. THe better the flow is at those lift numbers, the more power you will make.
Also, the total flow #'s for the LS6 intake is an estimated number. In reality, the LS6 intake does reduce the flow #'s at all lifts, but the reduction is not linear. At .200" lift, the flow reduction is only 3 CFM, at .550" it's 7 CFM, and at .600" lift it's around 10-11 CFM. These numbers are taken right off the flow sheets for my Absolute Stage 1x heads, which were flowed with and without an LS6 intake section attached.
So, the LS6 intake does not reduce the flow by 20 CFM across the board --- the actual restriction is much, much lower.
Also, the total flow #'s for the LS6 intake is an estimated number. In reality, the LS6 intake does reduce the flow #'s at all lifts, but the reduction is not linear. At .200" lift, the flow reduction is only 3 CFM, at .550" it's 7 CFM, and at .600" lift it's around 10-11 CFM. These numbers are taken right off the flow sheets for my Absolute Stage 1x heads, which were flowed with and without an LS6 intake section attached.
So, the LS6 intake does not reduce the flow by 20 CFM across the board --- the actual restriction is much, much lower.
TECH Fanatic
Joined: Feb 2002
Posts: 1,089
Likes: 0
From: New Jersey
Re: High flowing heads and LS6 intake? I agree with the above statement, my R&D has shown that you have to flow high 290's-300 cfm in order to max out 280 cfm capibility of the LS6 intake manifold. Excellent Low lift numbers along with a strong .550 lift value will actually out flow on average a mediocre low lift runner with higher 300+ flowing top end heads. I have the % of losses well documentd at each lift position through the LS6 intake manifold with the TB bolted on, there is about a 12-14% flow loss towards the higher lift flow numbers. Point is, recognize weaknesses and work around them, ie use better than average low lift flow values, (because the intake won't flow high top end figures) and choose a cam lift that will dwell in your head flow range.
Joe.
Joe.
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Joe.
