More boost : what is the easiest, fastest, safest bang for

[Ben Swann]

The Schrapnel (Pressure Regulator) knob is the best (simple, economical, effective) way
to provide boost adjustment beyond the spring pressure.  The UrQ spring is already
fairly stiff - good pre-load.  The knob will give you the top level of boost and let you
dial in to just be low the threshold where bad things may happen.  Just take measured
steps to add  pressure to the top of the wastegate - don't overdo it or you'll be
blowing hoses out.

If you are hitting an overboost, there are some means other than the chip to get around
it - the most common and inexpensive is to use a Zener Diode (sometimes in conjuction
with a resistor) on the pressure transducer inside the ECU.   The resistor mod will give
some timing advance too, good for this car with extremely conservative timing.  The chip
may already be advancing timing, so resistor mod may be too much advance, however adding
fuel will want to see more advance.

Supplementary injector  or piggyback EFI - if allowable by rules will give additional
fuel when CIS begins to piter out.  

The combination of timing advance, added boost and fuel will add great amount of power.

Exhaust:
I don't know if  remnoveing the center muff will buy you a lot of power.  It will make
the car much louder - both inside and out.  I wouldn't do it, because I like to enjoy
driving the car long distances.   Doesn't it sound good already?  If you really wan't
the sound and power potential then 3" system downpipe on back!


[Date: Thu, 4 Nov 2010 18:19:40 -0400
From: Louis-Alain Richard <laraa at sympatico.ca>
Subject: More boost : what is the easiest, fastest, safest bang for
	the buck ?
To: "'urq'" <urq at audifans.com>,	<quattro at audifans.com>
Message-ID: <BLU0-SMTP720597AB81AA87668A688BCE4B0 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"

Now that my stock urQ is repaired, and since it?ll only see limited road duties for the
foreseeable future, it?s time to tamper with it a bit.

 First, more boost. 

My engine was recently rebuilt, there is no issues now, and the car is strong and
powerful, as in 160 hp anyway. It feels faster than that modest output, even to my car
buddies.

I already have a chipped ECU (supposed to be a Lehmann ECU according to the previous
seller), but still the stock spring. I don?t know yet what is its cut-off point for
overboost. I will also have access to another chipped ECU, from another car that is
awaiting its built 20V in the shop as of now. That ECu was bought from Andrew Finney, or
another guy on the urq list from California IIRW?

I just want to give it a little raise in HP, as much as a 2.0 bar boost could give,
that?ll be fine for me. According to my master tuner, Brady from the Dynodoc tuning shop
here in Montreal, K26s don?t like more than 2.0 bar.
We have 94 octane fuel here at Petro-Canada, about a mile from my home, so this will be
its regular diet.

Faster ice racing laps is my goal. Read, more snow spray at the back of the car to
impress the youngsters? 

Should I :

1-      Do the shrapnel knob mod on a spare wastegate ? Adjust with a boost gauge or
until boost cut-off.

2-      Install a manual boost controller on the pressure line of the wastegate ?

3-      Install a manual boost controller on the top nipple of the wastegate with a
supplemental feed line from the intake ?

4-      Buy a 45$ 1.9 bar spring from 034 ?

5-      Find a 2.0 bar spring elsewhere ?

Second, a bit of exhaust sound would do the trick too as good noise=speed in the eye of
these same youngsters?

The exhaust is still stock. And I want to keep the twin tailpipes as they are. 

I don?t use a cat, it?s now a straight pipe with a flex, attached with two
4 in long 65 mm collars from a TT. The exhaust is still 65 mm all the way, that is 2.5
in.

Should I :

1-      Get rid of the center muffler and keep the ?sport? Ansa rear muffler that I
have,

2-      Keep the center muffler and install the emptied OEM stock muffler that I rebuild
a few years ago.

3-      Remove the center, install an aftermarket box custom built to the car. 

Please chime in with your mods or thoughts, I?m preparing this car for its sole ?raison
d??tre?, that is a fun old car on an ice track. I want it to make honor to the glory
days of the Group B monsters? at least in the boundaries of my modest means.


Louis-Alain]