Ferrari Mailing List: Re: Cam timing

[Steve Jenkins (steve]

Rick:

You're spot on. A couple years ago, my F40 was putting out darn close to 500
HP at the rear wheels. That's way above factory spec. The idle sounded
terrible, but when you mashed the throttle, the acceleration shared the
cheese out of me.

I had a major done by a dealership, and they informed me that the cam timing
was "way off." So they reset it to "factory specs." The idle sounds awesome.
The car is way more drivable. The acceleration, however, even though it's
still scary, it's not AS scary. And the HP, even though still above factory
claims, is about 50 HP lower than before. I can feel it.

I'm having the timing but back to "way off" this winter. :)

SJ

-----Original Message-----
From: Rick Lindsay [mailto:rolindsay [at] yahoo.com] 
Sent: Wednesday, December 03, 2008 2:17 PM
To: Steve Jenkins
Cc: 'The FerrariList'
Subject: Re: [Ferrari] Cam timing

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
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