RS2 turbocharger - turbo maps 101

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Bob:
Be careful as to the hot side.  The hot side wheel and housing of the RS2
isn't the same design as the common k24/26/27 etc housings.  The hot side
wheel and housing are machined specifically for the RS turbo, which, the
single application for this turbo is the audi I5 20vt.  Which is exactly why
it mimics the k24 at low rpm, and does great things at the higher rpm.  The
bore does have effect, but so do wheel and housing design, blade cut angle
(the RS2 is more agressive).

I'm with you on the rest of your summary (and you spent a whole bunch of time
there I can tell).  The k24 heat soaks lightning quick, and was never
designed to run over the 2.1PR of the audi application.  The RS2 can run
2.1PR well within the accepted rpm parameters targetted by turbo
manufacturers.

Remember too tho, many folks run 22psi thru k24's regularly (ingo), which it
can do remarkably well for very (read VERY) short bursts.  Your summary is
dead nuts on, eventually, the 24 wheezes, and the RS2 becomes the better
choice.

You have changed the thread to include the total rpm band Bob.  Which I'm
happy to entertain (it's a no brainer), but the initial thread started on the
"advantages" of k24 at low PR.  That doesn't appear to be the case in
reality.  By way less than 7000rpm the RS2 advantages are clearly documented
on the turbo maps.

Thanks

Scott J


In a message dated 6/12/02 12:29:32 PM Central Daylight Time,
rpastore at animalfeeds.com writes:
>
>
> The point I tried to make in the earlier post was that the sacrifice in low
> end is on the hot side, not the cold.  With the rs2's larger turbine wheel
> and shaft come more inertia and slower spooling. With it's larger exducer
> diameter, it takes more energy ( & time) to get it spooled and you
> sacrifice some low end for the added high end flow.  Keeping in mind all
> the exhaust gas has to exit from that tiny exducer opening, and I can only
> put into the engine as much air as I can get out.....................I am
> starting to envy the twin turbo guys.
>
> Bob
>