RS2 turbocharger

[QSHIPQ at aol.com]

A couple points, then I'll take the bow.

Javad, TRY the RS2 in your EFI conversion.  The 10vt makes some serious
exhaust energy at low RPM's (btdt).  I think you will gain more low rpm than
the T3/4 combo especially if you put a v stack on the turbo inlet.  Unless
it's your intention to attempt over 400hp, the RS2 is going to be enough, and
lose little.

Bernard is looking the hardest at this, and comes up with many of the
questions I do.  Looking at Mances RS2 beast dyno run causes many to go
"see?"  I look at it, and ask, OK where is the baseline k24 dyno run.  Right
now, what I can see from ALL the numbers I've experienced or seen posted so
far, is that however audi is getting the test results of the MOTOR output,
I'm not convinced it's in a car on a road.  Which means, that both the 1950
peak AND the 2500 peak audi publishes aren't REALIZED in performance measures
until hundreds of rpm's later.

I went from a k26 to an RS2 on the same day a couple times on the 10vt, with
great results.  I've gone from a k26 (87 5ktq) to a k4 on the urq, with good
results.  But both Bob and I agree (both driving the same car, and comparing
the same car with his) that the 24 hits the low end better, but barely.  And
certainly by intake tuned (3000rpm range), the 26 just takes off all the way
to redline.  AND can do it consistently.  Damn that 24 just COOKS IC's
quickly.

Dave.  Forget the numbers you are "observing".  I'm with Bernard on this one,
plop the k24 in your RS2, see what you get, back to back on a car TUNED for
the RS2 turbo.  I don't think it will be near as impressive as you have
conjectored.  I'd put my turbo MAPS on that comparo quickly.

Optimizing the RS2.  Luckily for the urs4 owners, 16+lbs can come off the
clutch/flywheel.  It's also time for the nerds (a couple have) to revisit the
Boost and timing maps in the 20vt cars.  A lot of "copying" happening, not a
lot of "optimizing" going on.  While you are at it, I also encourage you boys
to ditch that MAF sensor all together, you don't need it.

Without question if you are topping the 400hp mark, the stock RS2 turbo is
prolly not your best choice.  But I've also seen the maps of the 57-60+
Garrett trim, and laugh a bit that one would consider running something that
big, since you never get it to it's maximum turbo efficiency in I5
application.

Hope I helped a few understand the workings of turbo maps.  As anyone can
tell, turbochargers interest me fanatically.  After getting one of the first
stateside RS2 turbo units in Jan '95, by March '95 it was apart and getting
bigger cold side combos.
Certainly there are better out there, but pick and choose wisely folks, the
sacrifices big turbos have are in low end response.  Porsche did some great
homework that is dirt cheap in comparo to some of the better homework MTM
did.

I'd also encourage anyone to ADD DISPLACEMENT.  Displacement rocks turbo
maps.  At 2.6 liters, the RS2 becomes the k24 of turbos.

And my offer still stands, any RS2 owners "disappointed", I'll be happy to
trade you into the k24.

My .02

Scott Justusson
QSHIPQ Performance Tuning