[urq] More boost : what is the easiest, fastest, safest bang for the buck ?

Fri Nov 5 19:59:02 PDT 2010

Good call Keith. 

I did the manual boost controller mod this afternoon, (a TurboXS on the top
WG nipple) and plug the MityVac on the line for test. Way too much to look
for a single man, so I will try your trick with a tire pressure gauge. But
the firsts results show a cut-off point in the 2.2 bar neighborhood (18
psi). I dialed it just under 2.0 bar for now. That was my initial goal, and
I do want to play safe. Kick in the pants is stronger, but turbo lag is, as
always, infinite...

But I have access to Brady's 4-wheel drive dyno, that is a big plus for
tuning. He will monitor the air-fuel ratio with a wide-band sensor in the
exhaust, so this will be better than my standard narrow band gauge... More
to come when the car sees the dyno.

Also, the spare wastegate I have is of the adjustable perch variety (with a
10 mm allen socket inside, so one can add more pre load by unwinding the
perch). However, the one on the car doesn't have that 10 mm allen socket
inside, it's just a plain spring perch. Brady thinks the adjustment is
available from the outside on this one, when the steel plug is removed.
Anyone knows ?

Finally, a bit of useless information : I skinned completely the old OEM
muffler that I removed from the car a while ago. Inside, I found a y-shaped
piece, and that's it. So the 2.5in inlet separates in two 2in outlet tubes,
without any interference or restriction. Therefore, that muffler is a
straight-through design, that may explain the nice, rich, quality sound it
produced. The y part and the twin tubes are perforated with hundreds of
small holes, and the inside of the cavities are filled with steel/fiberglass
wool, but the exhaust flow can't be more direct. 

Louis-Alain

-----Message d'origine-----
De : Keith Lloyd [mailto:spotatashleys at hotmail.com] 
Envoyé : 5 novembre 2010 15:57
À : Louis-Alain Richard; 'urq'; quattro at audifans.com
Objet : Re: [urq] More boost : what is the easiest, fastest,safest bang for
the buck ?

L-A
The first thing I would do is fit (temporarily at least) a pressure gauge 
with a tell tale. I converted a tyre pressure gauge - and tapped it in to 
the same line that feeds the instrument panel boost gauge.
This way you can test boost levels whilst keeping your eyes on the road. I 
also fitted an air fuel meter to keep an eye on things (welded a nut to the 
downpipe for the o2 sensor)
Then you can go and play.
Hope this helps
Regards

Keith
'87 WR

----- Original Message ----- 
From: "Louis-Alain Richard" <laraa at sympatico.ca>
To: "'urq'" <urq at audifans.com>; <quattro at audifans.com>
Sent: Thursday, November 04, 2010 10:19 PM
Subject: [urq] More boost : what is the easiest, fastest,safest bang for the

buck ?

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'être", 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

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