[s-cars] installing a hybrid turbo

[djdawson2 at aol.com]

A T3/T4 hybrid is a Garrett turbo that uses a T4 compressor housing mated to a T3 turbine housing and wheel.  What most of the Audi folks use is still a T3/T4 hybrid, but instead of the T3 turbine housing, a modified or aftermarket casting KKK turbine housing is used... so that we can bolt them to our OE exhaust manifolds.
 
Garrett's complete current turbo offerings are listed here:
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/turbo_comparison_sheet.htm
 
These are all the "medium frame" sized turbos... both ball bearing and journal bearing turbos are offered.
 
You won't find a T04E 50 trim on this list.  That is their "old" stuff.  However, they do still produce them, and you can still buy them, and it is a journal bearing turbo.
 
Optimal match of KKK housing?  Well, it depends on who makes the KKK turbine housing, and how well it is matched to the Garrett turbine wheel.  Let's just say that the T3 housing was designed in conjunction with the T3 turbine wheel, the KKK was not.  For this reason alone, I think you can bank on them working better together.  Using the T3 housing also allows you to actually choose the A/R of your hot side, instead of having only one option.  Most folks running a stage 3 wheel with the aftermarket KKK housing do not like the boost threshold... too high.
 
Summary:
1) If you are trying to get the best output and drivability from a Garrett turbo, it ought to be a complete Garrett turbo, not a KKK hybrid.
2) If you want the best reliability, use a journal bearing turbo.
3) The best results for a 2.2 Audi running high boost come from the older T04E 50 trim compressor.
 
These are just my personal opinions.  But they do come from dozens of dyno runs using at least 10 different Garrett turbo configurations.
 
Dave
 
 
-----Original Message-----
From: shr42 at msn.com
To: djdawson2 at aol.com
Cc: S-Car-List at audifans.com
Sent: Wed, 2 Aug 2006 3:35 PM
Subject: Re: [s-cars] installing a hybrid turbo


 
------ Dave , thanks for the info ,  I am not clear what you mean about a ,  T03/T04 turbo ... Is it a kkk with a garrett compressor cold side , or does Garrett supply the hot side, the T3 and  the T4 - 50 trim compressor side also , I thought they only did ball bearing turbos ?   If you are favoring a T3/T4 turbo , for the street ,  is that a complete bushing turbo ?  You said that you did not care for the kkk/Garrett combo, because it did not work "optimally together...  If I get it right , the T3/T4 complete bushing turbo is what I want , Even if it means modifying the exhaust manifold    ...Stephen
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