Ferrari Mailing List: Re: Cam timing

[Rick Lindsay (rolindsay]

An issue we haven't discussed at all but is important, is that the factory 
marks that happen to be there, if any factory marks are present, are a 
best-case 'recommendation'.  Like everything else in an engine, valve timing is 
a compromise.  To make a car perform at its maximum potential at 7000rpm means 
that you probably couldn't get it to idle below 2000 rpm!  This is why they 
invented the word "drivability".  And of course, that's why the most modern 
cars have variable cam timing.   My '98 M-B SL500 had variable exhaust cams but 
they just had two end-member states, switching over at about 4400rpm - and you 
could feel it switch.  My new C300 has continuously variable intake and exhaust 
cams and modulates valve timing continuously.  That way the car takes advantage 
of the fluid (charge and exhaust) dynamics at all engine speeds and all loads - 
while honoring the limits of fuel economy and emissions (read: still a 
compromise).  

So this all begs the question; What is the right cam timing for your 308?  The 
answer is going to be in the definition of "right".  Do you want it set the way 
Enzo put it, for the market to which it was delivered?  Or do you want it to be 
smoothly drivable?  Or do you want a top-end screamer with 
drivability-be-damned?  Or perhaps do you just want to pass the emissions 
tests?  Each definition of "right" will have a different valve timing solution. 
 And each setting is a compromise.

Sorry for preaching to the choir but sometime folks (including me) get out in 
the weeds and forget the fundamentals - not that any of us would do that.

Woohoo,

rick