Re: 20psi of boost

[PDQSHIP@aol.com]

In a message dated 96-11-12 00:46:11 EST, you write:

<< And then tracy m finnegan asked:
 

 I'll try to answer both questions in one post.
 
 First off, you can't do it inexpensively. My kit was from TAP @$360 ($400
regular 
 - 10% less as a member of "another" (now deseased) Audi club). IA kit is
$800.
 You do need a remapped chip for increased fuel delivery to maintain the
optimal 
 14:1 air to fuel ratio under high boost.The WG spring with a higher module
of 
 elasticity alone will only increase the boost level. Keep in mind that a
turbo is 
 nothing more than a high-rpm spinning fan, it delivers only air. If you
increase 
 the air flow without the adequate increase in the fuel delivery you are
doomed to 
 overlean the mixture. Have you ever seen the burned valves/pistons? 
>>>>>  My understanding of the 2 vendors above, Igor, is that neither remaps
the chip for increased fuel delivery....
>>>>
 
 Secondly, you will need a reinforced turbo (accordeon) hose, the one that
connects
 intercooler to the throttle body. I guarantee that you will be blowing up
the 
 rubber OEM hoses once a year. I have gotten mine from TAP @$115. It's a 
 British-made Samco hose, made of silicon rubber and reinforced with steel
rings.
>>>>   That SAMCO hose is a beefy unit, installed a couple of them....
 Beware of some leaks around the IC flange, tho, that hose doesn't bend
well...
>>>
 
 Thirdly, you need a blow-by valve,cost me $28. 
 BTW, Scott, the valve did improve the transitional responce! Now, when I
shoot out
 of a corner, upshift and nail the right pedal, it picks up immediately, as
if the 
 turbo kept indeed spinning, while I was on the brakes -- I don't really have
to 
 heel-and-toe all that much now.>>>>  Like to hear that it worked well for
you, Igor...
 
 I can run up to 20psi of boost on a cold damp day, before the engine starts 
 pinging. In the summer I have to back off the WG screw to lower the spring 
 stiffness. For example, this July @ Watkins Glen I had to reduce the boost 
 pressure to 17psi.
>>>>  20 is pretty high if you are using the stock turbo and IC...  You have
prolly the same output from the turbo by running a much lower (like 17-18psi
max) boost level....  beyond a 2.0 Pressure Ratio, the stock turbo loses
efficiency in a big way....  A very cold day could help, but you are
overspinning the turbine beyond it's design, and the stock IC is also losing
efficiency too...   Sounds to me, Igor, like there isn't a computer protect
of overboost on the TAP mod you have....  Be careful with that....  The fact
that you can hear pinging doesn't bode well either, the knock sensor should
adj for that way before you hear it significantly....  And is a good
indicator that your boost level is too high....  I would highly suggest that
you ck your turbo outlet temps and t-body inlet temps at various boost
levels, Igor, the results may surprise you....  And you are spinning pretty
close to 120,000 rpm....  And turbo efficiency (assuming sea level here) is
now about 20% less than it would be at 1.9-2.0 PR....  Be careful running
this boost, you are at the handgrenade stage...
 
 I have also installed a device that analyzes the mixture at any given moment
and 
 displays it as a moving colour LED bar. ORANGE for RICH, GREEN for NORMAL
and RED 
 for LEAN. This device cost me nothing, 'coz I designed and built it myself.
It is 
 amazing, how much more accurate can this device show the lean mixture under
full 
 boost by the tell-tale RED LED bar. Far more accurate and way before my ear
can 
 actually spot the detonation. Especially on a race track, when you go under
full 
 boost for prolonged periods of time. Open windows, whining turbo and houling

 exhaust make pinging almost impossible to hear.
  >>  Cyberdyne Industries has one in a 2 1/16 guage that hooks up to the O2
sensor, is pretty accurate, and can be had for less than 50USD....   Your
local speed shop can order it....

Scott