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turbo boost adjustment


Due to popular demand I am posting my turbo 1990TQ turbo mischief on the net.  
I, like a baby-boomer lawyer assume no responsibility for anyone who blows up  
their turbo, their engine, their car, their house, or themself by installing my  
el-cheapo boost adjuster.

1. you need one 1-way valve (adjustable) (the kind they use for paint sprayers  
that connect 1/4" NAPA tube)
2. you need one 1-way T-valve (adjustable) (same tubing applies)
3. you also need several feet of 1/4" NAPA tubing
4. you also need a boost gauge that fits this wire

Step 1 is to install the T-valve in the line between the in-take manifold and  
the waste-gate. I recommend running a line from the in-take manifold into the  
drivers compartment (under the steering wheel), to the T-valve, and back out to  
the wastegate in the engine compartment. That way you can connect another tube  
to the third nozzle on the T-connector and connect the boost gauge to that.
IMPORTANT: You really need a gauge because it is really easy to run too much  
boost and blow up your engine/turbo/house/self

=================                    ========                    ===========
Intake Manifold|  -----------------  T- valve -----------------  Waste Gate   

=================                    ========                    ===========
                                    boost gauge

Now here is the sneaky part: If you do this you will get approx 10% more boost  
and nothing more. Why? you ask.  Well because the Germans are not only sneaky,  
but smart, and they don't want you to blow yourself up. What they did was put  
an electronic shut-off somewhere in the computer (MAP sensor thing) in front of  
the passenger seat under the carpet. This guy senses the boost and decides how  
much to retard the ignition and whether or not to shut down the boost  
altogether. So you need to install an adjustable 1-way valve just before this  
MAP sensor. This is easy, just take out your carpet, pull the line of the  
computer box, and put the valve in-between.

Now the fun part:

Gentlemen: Start your engines, but don't hit the GAS

Now you need to adjust both valves. Close the valve in-front of the MAP sensor.  
Play with the valve near the steering wheel until you don't run more than  
1.8bar or roughly 16psi (above 1 atmosphere). Just accelerate and turn down the  
valve until the car can't generate more than 1.8bar. Try this somewhere where  
you can drive with the windows open and hear any knocking. If you hear  
knocking, get off the gas immediately.  

If you see your boost gauge (the audi gauge on the dash) go to 1.8 and stop  
short you need to adjust the gauge before the map sensor, the computer is  
cutting in and spoiling your fun.   

Once you get it going take it on a highway and test it, make absolutely sure  
you cannot generate enough boost to "knock" otherwise someone driving your car  
will innocently floor it on the highway and blow up your turbo.  

They key is to set the MAP sensor valve to the point "just before" it cuts off.  
That way you get the maximum ignition retarding you can get under boost. Just  
keep testing and letting it kill the boost turn it each time until you reach  
the point just before it cuts out and leave it there. Tape it and put your  
carpet back in.

You should test the valve under your steering wheel in dry/humid whether and  
really get it set right before you recess it back under the wheel. You may want  
to mount the boost gauge so you can see it. (Your Audi gauge won't know what  
the fuck is going on since you bypassed the MAP sensor)

Why Intended Acceleration is better: these guys actually replaced the chip in  
the computer and retard the ignition correctly under boost. this is more  
efficient and probably allows them to run more boost before knocking.

Why mine is better: It costs approx $40.00  

How much faster is it?   A hell of a lot. Trust me, I am not a gear-head and  
wouldn't risk screwing up my engine if I didn't get a hell of an improvement  
out of it.

Anyway, have fun and remember kids: it's all fun and games until someone looses  
a turbo.