KKK turbo aspect ratio?

alan pritchard alanthecelt at alanthecelt.screaming.net
Sun Dec 9 20:29:48 EST 2001

I have a load of compressor maps, and reasonably accurate excel spreadsheet
for exactly this task, let me know if you need any info!
----- Original Message -----
From: "mlp" <mlped at qwest.net>
To: <mdg3369 at mac.com>
Cc: "Audi - Lists - AudiFans" <quattro at audifans.com>;
<s-car-list at yahoogroups.com>
Sent: Sunday, December 09, 2001 4:14 PM
Subject: KKK turbo aspect ratio?

> From: "Michael Gough" <mdg3369 at mac.com>
> To: <quattro at audifans.com>
> Sent: Friday, December 07, 2001 2:31 AM
> > Hello list,
> > I am considering moving from the KKK turbo to a Garrett. I am
> wondering if
> > anybody knows the A/R of the exhaust housing on the K26 (MC1) or K24
> (MC2,
> > 20v) Does anybody have any data on these, or is this some of the
> "secret"
> > info KKK won't give up? I'll probably go with a T3 Garrett with a
> .48 A/R,
> > though......
> > Thanks
> > Mike
> Your secret KKK code is (? should be) cast inside the throat of the
> hot side "scroll."
> Most KKK units (YMMV) that I've seen use a Number 6 scroll.  That's
> certainly been the case in the K24/K26 units I've seen on the UrS4/6
> cars I know of.  A few cars, such as the hi-po 944 Turbo S 944 (vs.
> the regular 944 Turbo) use a Number "8" scroll.  The "regular" 944
> Turbo uses a Number 6 K26 hot side scroll.  There may be a couple of
> "mystery" AudiSport K26 based units floating about that may use a
> different hot side, but my guess would be they are not very common.
> In my limited experience (i.e., I needed to find one), Number 8
> scrolls are harder to find than Number 6's, at least in North America.
> I don't know if the K24 configuration ever came with a #8 scroll, but
> if you were willing to swap the center bearing sections my guess would
> be that you could mix & match.
> As for the relationship between KKK's #6, #8 and Garrett's A/R .48 or
> .63 (or as low as .36 & as large as  an .82 A/R in the Garrett
> T3/T31/T350 family), I don't know of any definitive answer or source
> for information.
> A guess bare naked guess on my part would be that the #6 and .48 would
> be comparable; likewise the #8 and .63.  A better "rough" guess would
> be to get the hot side exhaust bore diameters and compare those to one
> another vs. your best guess as to the relative rough diameters of the
> housings.
> If I recall correctly, a K24's exducer is roughly 46mm/@ 1.8"; and the
> RS2's #6 housing is @ 55mm or 2.16"  If you have access to Bell's
> "Maximum Boost" take a look at his chart for a very rough
> approximation of Exducer Bore vs. sustainable compressor delivery,
> figure 3-10.  From my 'eyeball' of the flow rates vs. what Audi
> reports the 20valve engines as making, his figure biased towards the
> "low" side, but then again it is only a rough approximation, & YM and
> manufacture's claims I suppose do vary.
> Oh, the K26's have a bigger "r" for the same size A/R in comparing the
> K24 family to the K26.
> mlp

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