Re: twin turbos?

["Graydon D. Stuckey" <graydon@apollo.gmi.edu>]

On Wed, 5 Jun 1996, Steve Powers wrote:

> Mazda uses a sequential setup on the RX7. The small
> turbo spools up quickly to provide HP down at lower
> exhaust pressures while the big one will kick in at
> greater exhaust pressures. I believe that both actually
> work at higher pressures.

One minor point here, both turbos on the Mazda twin turbo setup are
identical.  Other than that, you are right on. 

> Other than space (and budget) limitations, control
> complexity, etc., is there any fundamental reason why
> this approach hasn't been developed for Audis?

Since the Audi is a 5 cylinder, that compounds the difficulty in 
designing and fabricating an exhaust manifold.  I _think_ that a plenum 
that fed the two turbos could be made to work though.  I like the idea.

Later,								
Graydon D. Stuckey								
graydon@apollo.gmi.edu								
Flint, Michigan   USA
'86 Audi 5000 CS Turbo Quattro, GDS Racing Stage II