Egil Kvaleberg wrote:
> > point, gas streams start to go back up pipes they shouldn't. If you've
> > got a cam that broad, you aren't heading for the street.
>
> Not so, at least not in my neck of the woods.
>
> The *standard* TR5/early TR6 PI cam has a 280 degrees duration, and it is
> very civilized. There are lots of cam profiles in the 280 to 300 degree
> area that are perfectly suited for street use.
Yup. Got one.
> A high lift 280 degree cam
> would produce improved low end torque as well as much improved high end
> compared to a, say, 240 degree cam.
Knew this would come up, but I'm referring to the duration at which gas
flow actually occurs... so, to be more precise, duration at a valve lift
of about 0.050". Just didn't want to complicate the issue for someone
new to pipe theory. In fact, on a six-cylinder, cylinder-to-cylinder
interference starts at an _effective_ duration of about 240 degrees. At
an effective duration of 240 degrees, some interference will begin with
the type of manifold previously described, especially from idle to the
lower ranges, when gas speed is high compared to piston speed.
Cheers.
--
My other Triumph doesn't run, either....
|