K26 vs K27 size...?

Tue Apr 23 00:57:36 EDT 2002

Hi

I think You do not mind, if I put this to the list too.
No personal things in the mail and maybe someone
else might find this helpful, or if somebody thinks
I am bullshitting, one can correct me ;)

You have a 10v MC-1 and want no more than 250Hp.
That is quite easy. ( not talking how to raise the boost
etc. there are several ways, easiest is to fool WG and
ECU with a regulator ). I did it to my MC2 engined
100 TQW this way:

http://groups.yahoo.com/group/audifinns/files/10vboost/Drawing10vmc3.jpg

More clever way is to modificate the ECU ( chip )

Before I this year started two projects: big BMW Turbo
and Audi 20v, I played a lot with MC 10Vs and found
something: K-24 is much faster than K-26, but there is
lots of backpressure at 17 Psi. K-26 makes heat soak
after 15 Psi, bad effiency. K-24 has few millimeters bigger
compressor than K-26, but I remember 6-7mm smaller
turbine.

What to do with Your setup? IMHO You have two good
possibilities ( for 250 Hp ):

1. Buy a K-24, it is just enough for 250, good response,
but torque decreases at the top.

2. Modify Your OE. 55/42 K-26 to a 55/48 one, not bad
lag and better top end than with K-24

If You are going to keep Your CIS and not making major
modifications, the K-26/27 charger does not give You
anything but lag. That hybrid is good for 250-320 range,
or with special EM to +350.

2-piece EM is a little better than older, and with 55 turbine
You will have quite nice ex. flow. 48mm compressor and
MC´2´s single pass IC will make effiency of intake a lot better.
With everything else ok. and 17 Psi boost there will be some
++230 Hp. ( 100/S4 AAN has ~ 230 Hp and car is heavier
than Your 5000/200 T-44 :-))))

Best

Jukka

----- Original Message -----
From: "gerard" <gerard at poboxes.com>
To: "Jukka Majanen" <jiipm at sci.fi>
Sent: Monday, April 22, 2002 10:47 PM
Subject: Re: K26 vs K27 size...?

> Damn! That's a lot of information. I will be keeping my stock K26
> turbine on my MC-1 engine. I might be looking at the 53mm compressor
> side. I also will be fitting the 2-piece EM, which I hear flows a little
> better, but ofcourse it's stock and is still restrictive. I don't have
> plans as yet of going for a custom EM, perhaps a few years down the line
> once I've exhausted the setup I am building and money comes in. I want
> about 250HP maximum for now. In your opinion, what kind of lag would a
> stock turbine and the 53mm compressor be like on the MC-1?
>
> Jukka Majanen wrote:
> >
> > Hi all
> >
> > Gerard wrote
> >
> > > Does anyone know how much larger the ports are on a K27 turbo compared
> > > to a K26? I've seen a photo of a K29. One would have to extend the
> > > fenders to fit that thing. :)
> >
> > The answer in not simple, because the size of both chargers vary a lot.
> > The only KKK, that doesn´t do it, is K-24 -if we don´t count RS2
> > turbo as a K-24.
> >
> > There are even two shaft sizes for K-26:s, lots of in- and exducer
> > diameters and more turbine and compressor wheels. KH engined
> > T-43 A200 (170Hp in Europe) used a small shaft K-26 with 46mm
> > turbine and 42mm compressor. Later T-44 A200 had a bigger one,
> > like urq too, it was 55mm turbine and same 42mm compressor wheel.
> >
> > Nowadays ( allmost ) all aftermarket K-26:s have 55 turbine and
> > compressor vary from 42 to 52. ( if I remember...)
> >
> > K-27´s smallest turbine is 60mm and compressor 53mm. For
> > example in my BMW 745:s K-27 turbo those dimensions are
> > 64/53. The biggest K-27 is something like 68/64. I´ve seen in a Volvo
> > marine engine a hybrid turbo K-27/29, it had 68 turbine and 70
> > compressor ( interesting ratio, diesel )
> >
> > > What would a K27 measure up to in terms of Turbonetics/Garrett style
> > > designation (eg. T3, T4, T78!)?
> >
> > We can say that T-3 is in the K-26 size and T-4 range is pretty
> > close to K-27 range.
> >
> > > Final question: any leads on a junk K27? Just missed one on eBay. It had
> > > a seized shaft, but all I really would be interested in is the front
> > > plate, compressor wheel and housing. I can get them here, the helpful
> > > guy at the turbo shop has so far tried to convince me twice to go for
> > > the K27 front end. I just to look at pricing.
> >
> > Local turboshops have done lots of K-26/27 hybrid modifications. They
> > use OE 55 turbine, it´s housing and shaft. Then put there a K-27´s cold
> > side ( the smallest one, 53mm ). You may not want to put there bigger
> > compressor :) Costs for that have been about 500 Euros. I think there
> > must be a shop, which can arrange parts and make that modification.
> > Scott J ?
> >
> > Also that big 55/48 K-26 has been popular. ( RS2´s turbo is same sized )
> > Also it has less lag than K-26/27.
> >
> > This hybrid is good for 350 Hp, but Your problem will be that restrictive
> > EM, if You are putting it to a 10v. 250 is enough for that -too much back
> > pressure to work well. Also that CIS...
> >
> > If You have a 20 valver. It´s EM works allmost as well as RS2´s one.
> > ( good up to 350 Hp ) Then all You need is a better software and charger.
> > That hybrid is good for that, but it´s a little old design. There are lots of
> > better for that, like T-3 or 4 and Holset´s H1 or HX series etc. My final
> > decision for a 20 valver was a H1 59/50mm and ( allmost ) impulse type
> > tube header. You can see the pic of those here:
> >
> > http://groups.yahoo.com/group/audifinns/files/TEMP/H1ps.JPG
> >
> > Best regards
> > Jukka
> >
> > BMW 745i Turbo ( KKK-27 64/53 A/R? )
> > Audi V8/200TQ project ( Holset H1 59/50 A/R 0.65 )
> > Audi 80 GTE ( Not even a clean air filter :)