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20psi of boost
Brendan Rudack asked:
>Just wanted to know what you have done to run 20lbs of boost. People have
>told me it is easier to run higher levels of boost with the 5k tq engines
>since they have lower compression. What did you have to do to compensate?
>I am really wondering because I am looking around for a turbo motor for my
>90Q and I have the opportunity to buy a 200 Q 10V motor.
And then tracy m finnegan asked:
>is there an inexpensive modification i can do to the wastegate spring
>to boost pressure on a 89 200 turbo, or does the fuel mapping chip
>need to be upgraded also? right now i think the car delivers 162 hp
>at 5500 rpm. i've read where this can be increased to approximately
>220 hp? if anyone has done this, or knows some info, please let me
>know, i need more passing power (one hour commute to work).
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?
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.
Thirdly, you need a blow-by valve, wich is stock on a 20v 200 and S4, but not
present on a 10v 200. I have installed the OEM S4 valve (Bosch# 280 142 102,
Audi# 034 145 710), cost me $28. Thanks, Scott(PDQSHIP), for detailed
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.
My '89 200 is the one with a lower compression (and, therefore, only one knock
sensor). It has also a larger K-26 turbo. Audi built cars like mine 'till mid '89
(through vin#_44_K_038262). I would highly recommend this car 'coz it lends itself
to more performance upgrade potential than later a 10v 200 with higher compression
(MC engine with two knock sensors) and a smaller K-24 turbo.
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.
I would highly recommend installing an ANALOGUE(!) boost gauge. Mine is from
(don't laugh) J.C.Whitney catalogue, was only $15 on sale. It covers the range
from -30in Hg to +25psi. For all the purists out there: VDO sells two models @$80
each: with the range from -15psi to +15psi (the positive end is too low) and with
the range from 0psi to +30psi (no negative end, you can't monitor the vacuun at
idle). So get the better unit from Whitney for less price!
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.
Hope this helps.
in Tornado "arrest-me-officer" Red
20psi of boost