From the Turbo Charging Dynamics Web Page: 745i upgrades
k27-60 Hybrid Turbo
Name: k27-60 Hybrid Turbo
Description: Rebuilt k27 featuring Garrett 60 trim compressor wheel. The k27 is extensively modified to accept the 60 trim wheel. This combination will support 480rwhp. $200 core charge.
Price: $799.00
Shipping Weight: 20
The turbine flanges are not interchangeable. The Stage 4 turbo fits the TCD manifold. The K27 upgrade is for those that choose to retain the 745i manifold.
When I had the factory turbo on my 745i fail, I went to Todd for the upgraded k27. He made me a very generous offer on an entire upgrade kit for the car. Knowing the limitations of the k27, I opted for the kit.
If there is room that can work. Makes packagine even more difficult. The 745i manifold itself would still present a restriction. It could possibly be made to work more efficiently with porting. I know I was able to open up my old 524td manifold substantially.
So is the upgraded k27 worth while? I'm not experienced in reading compressor maps, but how does it compare to stock? And how does it compare to the stage 4 TCD?
I'm about to have my upgraded k27 up and running in a week. I can report back how it compared to the stock K27. You can't really compare it to the stage 4 turbo. It uses a better manifold and that turbo is still 25 years newer.
turbocar wrote:Is there any other options or just that one turbo if I want to keep my manifolds?
Miller up in Canada used to modify T4 flanged turbochargers (Precision based) with a custom plate welded to the turbine housing to fit the 745i/K27 manifold.
I have one sitting in my attic, if anyone is interested in seeing it let me know and I will post some pictures. From what I recall it has a 60mm inducer on the cold side, journal bearing, and around a 0.60 A/R
