VATN, blowers, etc.

[d houlton x0710]

Jason wrote:
> 
> With this talk about superchargers and turbos running rampant, I'll
> throw in my two cents regarding street cars, turbos, and blowers...
> 
> The VATN unit is a good idea, but unfortunately they don't make larger
> trim levels. The concept of having a variable exhaust turbine is great,

Some more info on the Aerodyne.  I talked with them a couple weeks ago
as I was looking at getting one to replace what I have now.  Their largest
turbo isn't available anymore.  It would handle up to 300-350 or so hp,
but the entire lot is already allocated.  They may make more in the 
future, but as of right now, you can't get one.

Also, they are extremely expensive.  Like $2500 minimum.  Reason being
that they have to be custom made because of the self-contained oiling
system.  Basically, they send you and empty shell that you use to fab
up your manifolds and intake tracts.  Then send it back with details
about the position and orientation of the turbo that you want and they
build it so the oil wicking will work at that angle.  i.e., you can't
just take any Aerodyne and put it at any angle.  It can be built for
a specific angle but must then stay there.

He said really, that unless you were a company planning to make a 
large number of kits to justify (and lower) the per unit cost, it
would be very expensive.


> 
> Garrett (Allied Signal) also has a special variable geometry exhaust
> turbine unit too, although it's not popular in the aftermarket scene.
> Probably does more duty in large turbo diesel engines...

I'm actually looking at these too.  The VNT25.  Used on the early 90's
Dodges.  A lot of info on them on the Dodge sites.  Some seem to think
they're great, others hate'em.  I think it boils down to lack of info
on them.  Those that have figured them out like'em.

One downside for some (not me though) is the relative small size.  
They generally make up to around 16 psi or so and can support about
200 - 225 hp.  Trying to crank up the boost over that leads mostly
to heating the air rather than compressing it.  There are a couple
places that can machine and fit a larger compressor (a T3 I think) to
the turbo that flows enough for about 300 or so hp, but it about 
doubles the cost of the turbo.  

Stock ones would make a nice low-to-no-lag twin-turbo system on a V
engine.

Also, Garrett quit making them several years ago because Dodge dropped
them and they (Garrett) dumped all the remaining stock on the aftermarket
and for spares.  They're about all gone now.  TEC in Colorado for one
has them.  1.800.950.TURBO  About $535 I think.

I think Garrett has recently started re-making them (or another version,
VNT15) though, but I haven't been able to verify that or find a source.

There's a very good article from someone at Garrett on them at 
http://idt.net/~vnt4/vntrpt.html


--Dan
houlster at inficad.com
http://www.inficad.com/~houlster/amigo.htm