[s-cars] RE: RS2 turbocharger

[Charlie Smith]

Earlier, Chris Covington wrote:
>
> I don't think an extra half-liter or so of displacement will do much.
> I've also driven 2000/2001 S4s and they too lack torque.

I beg to differ with you a whole bunch.

Let's talk just 2600cc instead of 2200cc - that's 18% bigger.
That means that much more exhaust gas flowing through the same
size valves, ports, and exhaust manifold at a given rpm.

That translates into more turbo rpm and a lot less lag than
the smaller engine at the same rpm & conditions.

I've done a lot of experimenting with NA engines with very hot cams,
and displacement (which increases gas velocities) does wonders to
make that cam seem much milder.  An example was a 906 cam in a 2.0L
Porsche 911 engine - it didn't have enough torque below 5000 rpm to
back up a tilt bed trailer.  The same cam in a 2.7L and later a 3.2L
engine was a very streetable cam; the 3.2L engine had good torque at
3000 rpm with that cam.

The point of all this, is that displacement increases intake and
exhaust gas velocities - which makes a whole different engine than
you thought you had.  With a turbo engine, intake isn't critical
but it really matters on the exhaust side.


> Somebody send the RS6 over with a stick or a sequential!

I wouldn't complain about that either!  I was pestering our local
Audi sales dweeb about RS6 futures the other evening.  I don't think
they *really* know anything and there's a whole lot of wishful thinking
going on.  :-(

    - Charlie


  Charlie Smith   charlie at elektro.cmhnet.org  614-471-1418
  http://www.elektro.com/~charlie      Columbus Ohio   USA
  http://www.elektro.com/~audi     photos & technical info

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features
  96 Dodge Ram   -  30 PSI, w/Cummins turbo diesel