Should I re-profile a set of GTS cams?
#16
To elaborate a bit further, the desired idle rpm, emissions concerns, exhaust manifold/header pulse separation, intake restrictions dictate how much valve overlap you want. With stock exhaust manifold, you don’t want too much valve overlap in the camshafts. Then the engine redline rpm and the desired rpm for peak power determine how much exhaust and intake duration you want. With the stock intake manifold and stock rotating assembly, you want the peak power under 7000 rpm for sure, likely something in the 6300 rpm neighborhood. 114 LSA of GTS and S3 cams is what falls out.
With headers but a nice idle still required, 110 LSA of GT cams is probably close. If you have headers and stock intake but don’t care about idle, like with a race car, I wouldn’t rule out 106.5 LSA of S4 cams.
To the extent I have a point here, it’s that the useful way to think about cams is start with the desired valve events and then have numbers like LSA be whatever they end up being.
With headers but a nice idle still required, 110 LSA of GT cams is probably close. If you have headers and stock intake but don’t care about idle, like with a race car, I wouldn’t rule out 106.5 LSA of S4 cams.
To the extent I have a point here, it’s that the useful way to think about cams is start with the desired valve events and then have numbers like LSA be whatever they end up being.