measured the 7a cams again

[rash]

yeah... three guys, three recommendations... ...and I`m not smarter

...actually I'm using both 7As..

[JP]

What I don't understand is how someone can recommend cams on a desired hp level? Without knowing stroke/bore configuration, turbo specification and cylinder head flow rates?

Look at the plots below on standard chip and turbo that's K24 at 1.1bar. The cylinder head flow figures have been tweaked through valve and seat work resulting in more flow under the lift curve of the cams when opting for 7A exhaust with stock AAN intake.

End result is that the 7A exh mod is more suitable than stock cams for the particular application in question throughout the rev range and especially mid to top.



Cam timing is not a straightforward concept as it is dependent on stroke/bore and desired rev range of operation, whereas lift is relative to flow figures when seeking optimum results. In the same token when going FI you throw other variables into the boiling pot such as Exhaust manifold configuration, turbo a/r ratio on hotside, optimum pressure ratio for desired hp target etc...

Running a stock cam setup on a turbo for 500hp will result in surge issues low down in the range unless the boost is correctly dialled in through aftermarket management or a decent boost controller. Change the cam configuration and you may end up with the same peak or even slightly less hp figure but a lot more in the midrange leading upto it as you don't have to lower boost figures in the lower rpm band. Every tuner has their own ways of getting to the end target which nowadays seems to be more about clipping those peak pub figures as opposed to having a car with slightly less peak power but more under the curve making it a more desirable and faster car to drive.

just my 2p