Originally Posted by
A80Girl
Turbonetics GT-K turbos are nothing special. They are comprised of Borg Warner cartridges. Borg Warner turbos do not last long, however, they are becoming increasingly popular. They are intended for Truck use (mostly Semi). Very good bang for the buck....but not the GT-K series. Overpriced.
Turbonetics USED to use Garrett cartridges, but Garrett dropped them a couple years ago. Thats why they are using Borg Warner cartridges now.
Garrett BB technology is the best.
The main reason why they spool faster is because they reduced bearing friction. Basically, they have MUCH less moving parts, therefore, making the cartridge lighter. This allows for much faster spool time.
Also, they can handle higher boost pressure (partly in fact because they are oil and water cooled).
The type of bearing section used in a turbocharger has very little effect on spool time. This is a common internet misconception that seems to be perpetuated on forums such as these.
The largest factor in determining spool time is the rotating MASS of the center rotating section of the turbo. This includes the turbine and compressor wheels. The enhanced spool time on the Garrett dbb turbos is more derivative of the design of the wheels than of the bearing housing. This is the reason why Turbonetics went with Inconel turbine wheels was the vast weight savings over standard turbine wheels. This is how they claim to have lower spool time than the gtdbb turbos.
I have no idea where you heard Turbonetics is using BW cartridges. I've always been under the impression they used their own ceramic ball bearing cartridges. I'll verify this today.
Both companies offer water-cooled bearing housings. Garrett turbos will burn up without a water source due to the high temp operation inherent with a dual ball bearing cartridge. However, the single ball bearing turbonetics turbos will run just fine even with no water cooling.