[s-cars] Why audi I5 started as 2.1 liters - AudisportHistorical Trivia

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In a message dated 10/20/2004 12:32:56 PM Eastern Daylight Time, James Bufkin <jbufkin at austin.rr.com> writes:

>Jimmy and Scott,
>
>I'm not going to support the idea that we are completely blind about what 
>Turbos Audisport used and its misleading people to suggest that the K26 was 
>possibly as prominent as the K27 in the Audisport program because "we don't 
>know".   Put simply its not even close.
>
>The manifolds... Have you ever seen an audsiport tubular manifold with a 
>K26 flange?   I've seen lehmann 10V manifolds.  They had a K27 
>flange.  Audisport used a Sport Quattro cast manifold with a K27 
>flange.  Lehman 20V tubular manifolds had a K27 flange.
>
>2ndly.  The sizes of K27 hotsides. #7 to #13 offers a much more usuable 
>range of sizes along with a more robust shaft and bearing system.   It also 
>allowed the fitment of K28 and K29 compressor housings.   I've also read 
>what you described.  And there is certainly no way of knowing exactly what 
>turbo was used on what car.  Its a hodge podge of stuff.  However, that 
>doesn't mean we should assume they used K26s because they could and it 
>suits someone's arguments and beliefs about an RS2.  Why not then argue 
>that they used K24s!?!?! 

Hold on James.  I'll give you some trivia.  I know some nutball that owns a special k26 turbo.  I'm hoping he'll jump in at some point here.  I will tell you that if you know your "sizing" on turbos, this trivia might prove interesting.

K26 3472
k27 3470 

Either one of those numbers look familiar or make ya think a bit?

>
>I'm not bashing the RS2.  Its a great turbo.  I do have an issue with those 
>who say its a good track/race turbo.  Its not.

IT IS!  If you are looking for 350cHP and a massive amount of torque, it's great for both.  With peak HP at 400+, it certainly won't lose much on the straights.  Will it experience almost no lag in getting there?  Sure.  Can you  win races (group a)?  Sure you can, it's documented.  And certainly for street and occasional track in use in miss piggy it's fine.  In a 10vt car it's about the flattest torque to HP curve you will find.

Blindly going after HP is a mindset James.  I won't argue with a mindset.  I only offer that the RS2 turbo on a 20vt motor on a car dedicated for track use, will be tough to beat with a k27.  


>  too small for prolonged use 
>at 4000-7000 rpm so its not the end all be all turbo some say it 
>is.  Others have already done the math(correctly) and seen what its doing 
>at high RPMs.   And thats why you just don't see K26s in the 20V race 
>cars.  Its a GREAT street turbo.  I'd use one in a heartbeat for that 
>purpose.

See Group A 20vt efforts James.  See Group A stage times vs Group B.  k26 in Group A. I say it's more turbo than you and others give it credit.  And the RS2 has documented racing history.  Remember Group A rules were to limit the dangerous group B cars (HP wars).  All that did was shift the technology to the suspension, brakes, etc.   I say it was quite successful (finally a decision within FIA I can say was good for motorsport)in racing.  Be careful with the RS2 bashing, I spent a lot of time in the engine bay of a FIA Group A S2.  I spent quite a few seat miles in it too.  I disagree with your conclusions that the RS2 just isn't big enough.  Big enough for what exactly?

>
>Regarding Garret. I said before and feel compelled to say it again.  The 
>Audi R8 uses a twin Garret turbo.  That speaks for itself.   So.. If not an 
>RS2 then a larger Garret.   K27s don't even play into the equation anymore 
>when going for pure performance.  Technology has moved forward.
>There are still some great 20V cars out there with K27 based 
>turbos.  Especially in Europe where the Garret craze isn't so predominant 
>and they can easily get modern K27 turbos with titanium wheels and water 
>cooling.

I say it's cold side tweeks.  The ball bearing turbos and lightweight components are already on the hot sides.  That hasn't moved 'sizing' down enough not to see compromises to torque on the 2.226 20vt application.

I haven't seen a dyno sheet yet that supports your thinking.  The RS2 torque figures are just too high.  The quesion only becomes how to supply more air so it doesn't start wheezing at 5900rpm.  That's hardly rocket science IMO.  BTDT.

My .02

Scott J