K26 vs K27 size...?

[Jukka Majanen]

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 :)