Anyone know the differences between the GT2359 and GT2559 turbos?
I read somewhere that the housing is the same size but the 25 has a clipped wheel and doesn't flow as well, elsewhere the 25 flows better! there seems to be so much contradictory information out there on the interweb, hence asking here.
There is no GT2359
, there is however a GT2259, also there is no GT 2559
, there is however a GT2554R and GT2560R.. this in in accordance with Garett's latest catalogue for 2009 so i think, probably these turbos you are asking about have been discontinued. I reckon through that the difference between is the type of bearing and cooling method used.
For a comparison, and to illustrate the differences better see below with the closest turbo in production to the ones you mentioned in your post;
The GT2259 is an oil cooled journal bearing
turbo...(160 - 180HP)
The GT2554R and GT2560R are ball bearing oil and water cooled
. (170 - 270HP and 200 - 330HP respectively)
A type of plain bearing designed to reduce friction by supporting radial loads. Journal bearings are often used when the load is light and motion is relatively continuous, such as in crankshafts. Journal bearings are also called radial or sleeve bearings.
A type of anti-friction bearing designed with metal balls that provide rolling motion and reduce friction between moving parts. Ball bearings are capable of operating at high speeds but cannot carry as great of a load as roller-element bearings.
According to Garett.....
"The journal bearing has long been the brawn of the turbocharger, however a ball bearing cartridge is now an affordable technology advancement that provides significant performance improvements to the turbocharger. Ball bearing innovation began as a result to work with the Garrett Motor Sports group of several racing series where it received the term the 'cartridge ball bearing'. The cartridge is a single sleeve system that contains a set of angular contact ball bearings on either end, whereas the traditional bearing system contained a set of journal bearings and a thrust bearing.
Turbo Response - When driving a vehicle with the cartridge ball bearing turbocharger, you will find exceptionally crisp and strong throttle response. Garrett Ball Bearing turbochargers spool up 15% faster than traditional journal bearings. This produces an improved response that can be converted to quicker 0-60 mph speed. In fact, some professional drivers using Garrett ball bearing turbocharged systems claim that they feel like they are driving a big, normally aspirated engine.
Reduced Oil Flow - The ball bearing design reduces the required amount of oil to provide adequate lubrication. This lower oil volume reduces the chance for seal leakage. Also, the ball bearing is more tolerant of marginal lube conditions, and diminishes the possibility of turbocharger failure on engine shut down.
Improved Rotor Dynamics and Durability - The ball bearing cartridge gives better damping and control over shaft motion, allowing enhanced reliability of both everyday and extreme conditions. In addition, the opposed angular contact bearing cartridge eliminates the need for the thrust bearing, commonly a weak link in the turbo bearing system.
Additional Ball Bearing Options - Another option one will find is a hybrid ball bearing. This consists of replacing only the compressor side journal bearing with a single angular contact ball bearing. Since the single ball bearing can only take the thrust in one direction, a thrust bearing is still necessary and drag in the turbine side journal bearing is unchanged. With the Garrett ball bearing cartridge the rotor-group is entirely supported by the ball bearings, maximizing efficiency, performance, and durability."
Hope this helps to explain the difference...
I will do some more research on the cooling aspects and post for you..