Re: lowering compression ratio for turbo

["Jonas K." <jkarlsso@metabolex.com>]

On 11/21/01 10:13 AM, "Jeff Toomasson" <jtoomasson@yahoo.com> wrote:

> I have 9A 2.0 block (mileage to low to justify ripping
> it apart) sitting in my carport begging me to do
> something, anything with it. Need to sell my M3 for
> funds before I can afford to do anything though.

Hmmm, yeah, must be a tough life... <grin>

Anyway, There's always 8vturbo.com who (contrary to their domain-name) have
parts to turbo every watercooled A-series gas VW made.

With the 9A motor you have other options. The 9A has 82.5mm bore, which
means that any High compression 82.5mm piston from a 2v/cyl VW or Audi will
fit. The compression will be drastically lowered due to the difference in
head combustion chamber volumes between the 8v and 16v heads. The
compression will roughly be down at 7.5:1 Which works great, and you still
have the squish area. The cars to look for are:
87-up 5 cyl non-turbo Audi 5000/100 or 4000
88-90 4 cyl Audi 80 2.0
99-up VW 4cyl 2.0

The rods should transfer right over too.

You could also use a VW ABA 2.0l block, but you'd need the whole thing, and
transfer over the crank pulley, intermediate shaft, etc. This is what B.
Honnold is doing. 


> I'm just still struggling with the dilemma of going
> with the "traditional" bolt-on's or do something
> that'll turn heads. The idea of having to feel my way
> through tuning a turbo'ed system makes me slightly
> uneasy - it's supposed to be a daily driver

Well, you can do it yourself without too much trouble. If you can remove and
install a cylinder head, then you can do this. It would help to have a
backup car to drive during the install, though. With CIS fueling you're
going to be limited, and the cost of an aftermarket system is about $1000.

There's no reason why a turbo'ed car would not be a great daily driver. You
just have to resist the temptation to "just turn up the boost a little bit".
Once you start down that road, eventually you'll overboost and blow up the
motor as you exceed your ability to pump fuel.

Again, HTH, 
Jonas




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