TAP modded K26?

[JShadzi at aol.com]

> I'd like to understand more about these turbo >mods, like clipping.  What
does this mean and do?  >I have Maximum Boost by Corky Bell, and I 
> think it's been a great source of info for me, but I >don't think I saw a
single reference to these types >of mods.  Where are the resources for this
type of >info?
Clipping the turbine slightly will help increase flow throught the turbine,
allowing greater flow through the exhaust side.  Its kind of a way to make
the AR ratio bigger, withougt actually phisically changing the AR ratio. 
Granted, it will soften initial boost response by up to a few hundred RPM,
but turbos are about compomise, you take a little away here, and get it
there.  Not sure about good resources, I know alot of people in the industry.
> There was a criticism of ball bearing turbos, probably here, stating that
they can give out and let those ball bearings into the motor (that was a 
> crazy post with link to the Miata forum where the guy dumped BB's into his
motor by mistake, btw!)  It seems to me the ball bearing stuff is a great
idea, >better spool up and all.
> 
Ha!  Thanks for the great laugh, that is funny, unbelieveable what you can
find on the internet...most "ball bearing" turbos, a technology popularized
by www.turbonetics.com, uses a ceramic ball bearing on the intake side of the
impeller shaft, the hot side still uses an oiled 360 degree thrust bearing. 
Ball bearing center sections help increase life of the center bearing, and
also reduce rotational friction and allow slightly quicker spool up, in the
range of 20% or so.  Frankly, they are not necessary, but nice if the budget
is right.  Figure the option adds about $600 to any turbo, so its very
pricey.  A properly sized Garrett turbo will be a considerable improvment
over any of the kkk products, so I don't recommend it if your budget is
limited, I am not using it.
> I like the idea of the Garrett stuff, it seems like there are many more
options available.
> 
Yes, many more options.  Also, even though the Garrett T series turbos was
initially designed in the 70's probably along with the KKK turbos, its the
impeller technology that has been driven forward, and nothing done on the kkk
front.  The impeller in the T3/T4 I have, despite being twice as big as the
k26's, spins with much less intertia to over come, because its lighter,and
its design is much more advanced (in the last few years) than the k26's
impellers which really are from the 70's!
> In particular, are there any VATN options for our cars?  How about a 
little adapter piece to go from Triple-K to whatever the VATN stuff is?  I
know they are expensive, but they cost what they cost since there's not  a
lot of competition apparently.  Corky Bell seems to be a fan of them.
No comment really, they are nice, but not worth the cost and effort in an
older Audi IMO.
Javad
80tq.com