[s-cars] urS4 chipped boost level?

[Eric Phillips]

> Date: Wed, 15 Nov 2006 18:22:13 +0000
> From: cody at 5000tq.com
> Subject: [s-cars] urS4 chipped boost level?
> To: s-car-list at audifans.com
>
> What boost level do the chippers commonly go to on an urS4? I guess
> MRC to be a bit specific, but a broad knowledge wouldn't hurt ;-). I'm
> looking at some compressor maps trying to ick which way to go with the
> '93 project car here. The current plan is exceptionally mild (owners
> choice, not mine!), hes thinking MRC stage 1 or such. The stock turbo
> is shot, so we are trying to decide to rebuild or not, and I've got a
> dozen compreessor maps in front of me :-).

MRC Stage 1 is stock K24, runs 20-24psi (I get 24 max, 22 sustained)
and is good for somewhere near 270HP.  These are rough numbers, BTW.

When you start going up on turbo airflow, many of the lists brighter
lights say that's the time to get the exhaust manifold upgrade - the
RS2 version, which can be had for $1000, or close.  This is due to
potential overheating problems with the stock EM, and possible valve
burning on cyl. #5.  The List here is not unanimous on that caveat.

Since a rebuild is somewhere near $400-500, the owner saves a boatload
of cash going that way.  To get higher than 270HP, getting ahold of
the RS2 EM, turbo and properly-flowing injectors, you can get 320HP.
And this is with off-the-shelf ECU tuning maps.  Adding a front-mount
intercooler could bump the 270 to 280 or so, and the 320 to 340 or so.

The FMIC adds another $1300 to the mix.  To go higher than 320, custom
exhaust manifolds and bigger exhaust systems start to pile on the
cash, and once you're in the 400HP range, bottom-end work is starting
to become necessary (so say some - not everyone agrees.)

There has been talk here that the Garrett T03/T04 hybrid is a good
choice for longevity and decent flow, plus nice driving
characteristics.  If it were me, I'd do some sort of hybrid that
allows me to retain the KKK hotside, and use a Garrett journal-bearing
cold side.  Plus the fact that the car is a street car, I like the
boost to come on a bit earlier than some of the monster turbos that
can be placed on these cars.

I don't know if this helps at all, but you've plumbed the depths of my
knowledge on the issue, and you can see that it ain't much.

Eric