Re: Big mistake

[ti@bazooka.amb.org (Ti Kan)]

From: "Karl Nordstrom" <KXN2@PSUVM.PSU.EDU>
>Are there any engine mods that can make significant improvements to a
>normally asperated 10 valve Audi engine?

Assuming you don't want to convert to a turbo (expensive and difficult),
one way to make real gains is to go to a larger displacement ("There
is no substitute for cubic inches").  The stock Audi 5-cylinder block
can be safely bored and stroked to beyond 2.5L (The new VW Eurovan/Caravelle
uses a 2.5L version of the Audi 5-cylinder, tuned for less power but
more torque).  This, of course, requires changing the pistons and
crankshaft, and is not a simple nor cheap way to go.  However, performance
costs money, and unlike turbo cars, you can't just dial up the boost.

For smaller gains, improving the breathing of the engine (enlarging
the intake and exhaust) may give tangible benefits.

If you use high octane gasoline you might realize a small gain
in power (no more than a few hp) by advancing the ignition timing a
little.  The specific results will vary depending upon the model year
of the car.

Remember, the 5-cylinder Audi engine is basically the same as the
water-cooled VW 4-cylinder engine with an extra cylinder.  Thus,
most of the performance tricks for VW Golf/Jetta/Scirocco will
work about as well in an Audi.  Depending upon the model year and
engine code, the 4-cylinder and the 5-cylinder shares many of the
same components.  These include valve train components, pistons,
rings and rods, etc.  Other 5-cylinder specific things are not
interchangeable, of course; such as the camshaft, crankshaft,
etc.  Bumping the displacement on the 4-cylinder yields nice
improvements, likewise on the 5-cylinder.

Techtonics is the premier engine builder for the VW 4-cylinder
(they have 2045cc versions of the VW 4-cylinder that are quite
incredible), and they should be equipped to work their magic on
the 5-cylinder as well.

There are several sources for 5-cylinder performance camshafts.
Depending upon the specific grind, they can provide some increase
in horsepower.  Be careful when swapping cams though, because
many cams will buy you increased high-end power while sacrificing
low-end torque, and generally roughens the idle characteristics.

Happy tweaking...  Watch that wallet for fast disappearing $$.

-Ti
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