[s-cars] Adjusting pre-load (keep adolescent thoughts out of this post)

[John Petersen]

Pizzo,
    If you still have one, install the stock Bosch recirc-valve. See if it
does the same thing. If yours is blown the one from the 225hp TT is a good
fit, and I think it's cheaper than the old stock one (or Porsche 944T
part), I also think it is stronger. It was easy to find when I was in need
of one in NY.

A car I was working on was having a somewhat similar problem, turns out
that the turbo was surging, they tried doing what effectively would be
equivalent to shimming the BOV, and the surging got worse, and blew the
bearing in the (rather expensive after-market) turbo.

The 1+ upgrade is known to cause surging at moderate RPMs (below 4k or so).
MTM did this intentionally, I suppose knowing that the turbos can take a
little abuse. Low RPM surging isn't typically a big problem, high RPM
surging can be, and will break bearings on turbos.

Hope this helps
-John
92 S4, 302kmiles, lotsa mods


From: Joseph Pizzimenti <pizzoman at yahoo.com>
To: s-car-list at audifans.com
Subject: [s-cars] Adjusting pre-load (keep adolescent thoughts out of this
post)
Guys,
Just had a new rack, bomb and complete drain of the
steering/hydraulic system done and I love it, but I
get what can only be described as a "weirdness" around
center. When starting off in 1st gear (or 2nd, just
in case this was my 1st gear leaving me), I get what
feels like a hydraulic related vibration, kind of like
a pump hiccup. I also get this intermittently when I
return the wheel to center or am starting to make a
turn. I'm thinking, pre-load adjustment. Great, if
only SJM's site didn't go down when I needed it, I'd
be in business...so how do I tune this? Should I
tighten? Loosen? Fuhgheddaboudit and try to convince
myself that chicks think that lots of pre-load is a
good thing? Come on guys, help me out here...
In other news (probably shouldn't say that, because
last subject I started with that started a tiny flame
battle), I think I fixed a boost leak. I noticed that
the MTM was binary (yeah, takes a whole lot, huh?), so
I figured boost coming on all of a sudden at 3k wasn't
normal given the PUNY K24 (puny being directed towards
guys with budgets I dream of in loan-payoff
post-college land), so I did some thinking over beers
with fellow amateur bench racers and thought that
maybe I broke in the spring (didn't actually break
something this time, woohoo!) and had to throw the
remaining 3 shims in addition to the existing 3.
What's the worst that can happen, I go into limp mode
right? (Or probably blow the K24 to bits) Put the 3
shims in and viola! Boost is a lot smoother now, but
I beg the question: Is it letting enough air out?
It's not audible, really, so I figure I have it tuned
right...boost does flutter on the needle in 4th gear
at part throttle, but part throttle should do that,
right? Other than that, boost is as solid and beefy
(for a K24) as it's ever been and the car feels really
strong, BUT! (Always a but) I feel that I hit the
throttle and it takes a 1/4 sec for boost to build.
This is normal, right?
I know.
I'm paranoid and anal about this BPV thing, but let's
not mention anti-seize here, shall we, folks? :-)
As always, thanks for the help / criticism / Pizzo
tomfoolery. And thanks most of all for listening to
my rants. Long day at work, had to get flowery.
Joe, making mountains out of molehills but praying
that pre-load doesn't happen this weekend in Montreal
w/hottie, Pizzo