I'm pretty sure installing cams retarded or advanced effects spool time and maximum power production. I'm just not sure what benefits a 4 banger with DOHC the most. The car is a 2003 Nissan Spentra Spec V with an unmodified Turbonetics kit and BC Stage two cams. What makes me unsure is this: On a OHV V8 it is said that retarding the cam improves top end, advancing the cam improves bottom end. Why is this and how can I determine what is best when using separate cams for my intake and exhaust? Might it be best to advance the intake to enhance cylinder filling while also retarding the exh. cam to improve scavenging?

The reason I ask is as follows: This car was faster before an engine replacement. The engine installed is brand new, and the cams were removed from the old one and installed in this new one without any other changes made. Now the car feels slower and less responsive. This leads me to believe the cams were timed differently in the previous motor.

 

have you checked compression on all cyl?
How much boost are you running?
Is this a stock replacement engine or a performance build?

 

Turns out I was leaking boost through the wastegate, fixed now. Thanks.

FYI the engine is a completely (except cams and oil return into pan) stock motor.

 

cool, glad to hear you got it all straightened out.

 

how much power is that qr pushin? spec v was my first car before i saw the light and built a turbo stang.

 

I never did dyno my setup. A buddy of mine with a very similar one did low 320ish with a good tune. I think that was around 12 psi.

I've since sold the Spec V and my LX hatch, now I'm just getting school done