My O2s worth....
There is a major difference between the two companies ball bearing turbos.
T-netics bb turbos use a single ball bearing on the compressor side of the shaft and a journal bearing on the turbine side of the shaft.
It does not need water cooling because it still takes the same amount of oil to cool the CHRA. However, you are not realizing the full benefit of a fully rollerized rotating assembly, although they do spool slightly faster than a regular journal bearing unit and cost less than a Garrett Dual bb equipped unit.
PTE uses a Duall Ball Bearing cartridge that is produced by Garrett. The entire cartridge is a self contained dual roller bearing assembly.
TurboByGarrett.com - Turbo Tech101
The reason you have to run water to the cartridge is because it only takes in a very small amount of oil for lubricating the bearings. Not only does the cartridge have a built in restrictor, but these turbos come with a special reducer fitting that is made for a -4 AN line. The turbo does not rely on oil to cool the cartridge, (like their journal bearing cousins) it couldn't if it wanted too because of the very small amount of oil that is required to lubricate the cartridge. So Garrett added the water jacket to pull the heat out of the cartridge. According to Garrett, it is mandatory to run the water coolant lines to the cartridge on a street driven application, or else you will fry the CHRA, as well as void the Garrett warranty. Not pretty. On some all out racing applications, you will see GT42R series turbos with no water lines run to them. This is because typically, these cars will shut down at the end of a run and get towed back. Not enough time for the CHRA to really get hot enough to fry.
Garrett tested and perfected these new cartridges for years in WRC Rally Racing. Then they gave them to HKS to help further refine and perfect the dual ball bearing cartridges and to help design the product line up based off the the import market. GT28R, GT28RS, GT30R, GT35R, GT40R etc etc. Finally, after about 6 years of waiting, Garrett finally brought the dual bb chras to the US. Sold first in the GT28R, GT28RS, GT30R and GT35R. With the growing popularity of the T3/T4 based turbos, Garrett took the opportunity to offer an upgrade dual ball bearing chra and came out with the T3/T4 dual ball bearing cartridges. This allowed PTE to make some custom rotating assemblies for not only the Buick market but for other applications as well. They took the 6031R cartridge and added the GT35R compressor wheel and created the PT6131R turbo. (same compressor wheel used in the very popular 6152 turbo) Very popular and capable of around 615-620 fwhp when maxed out.
Then came the PT6176R. Same compressor wheel, but combined with the small shaft P-trim turbine wheel. Not many have made their way into Buick applications because in testing, we found that this combo was not very friendly in the journal bearing combo. However with the dual bb cartridge, this might change.
Next up came the ever popular PT6776R. Oh boy what an awesome turbo. This turbo was specifically created at the request of vendors who dealt with two very popular applications. Toyota Supra Turbos, and the Mitsubishi Evolution VIII. After both camps struggled to make decent power with the GT40R for months on end (decent meaning 600-700 hp to the wheels on decent boost levels) PTE finally created this new monster. The PT6776R with the TO4S compressor cover. From the get go it would support around 785 fwhp when maxed out. On those two applications the world blew up. We couldn't make them fast enough. That was 2 years ago and at the time, Don and myself were trying to come up with the next killer street combo, not only for his car, but for others as well. We knew the 60(65#) Mototron injectors where the best thing since sliced bread and he and I both agreed that when they finally got the water coolant lines and oil lines finalized for the Buick application, this would be the next Killer combo.
A good bolt on combo with aluminum heads, 60# Mototrons, alky injection, a good intercooler and one of these PT6776R turbos with a 3200 stall converter. A very basic high 10, low 11 second combo that would live. This is the combo that Don eventually wound up with on his GN. And from what others have reported, this turbo is capable of some very fast times with a purpose built 109. Now, I'm not bad mouthing the T-netics turbo as they have their purpose and have worked and continue to work very well for many people. But with the price that we have to pay to be able to run these types of turbos, I personally want a turbo that will spool up the fastest and has a rock solid reliability record. I really love my current dual bb TE-60R turbo. The spool up is insane. It's like putting a 3500 stall 9" converter on a stock turbo. Stupid fast. Now, I'm not trying to be a salesman here, nor am I trying to get everyone to buy PTE turbos,(
subliminal suggestion to follow, get them from Hartline, Full Throttle or Cotton,
subliminal suggestion ended) but in my own experiences, these Garrett dual bb equipped turbos are the bees knees.
I run the water coolant line kit that PTE makes that is specific for Buicks and the lines and hoses work and route perfectly over to the factory T-body coolant lines located on the stock heater lines. No issues and no leaks here.
Once more people start upgrading to the new 70 series turbos with the dual bb CHRAs, and learn that they can lower the stall on their converter, you will start to see crazy mph numbers pop up as a result of less drivetrain loss by running tighter converters. Sorry so long, just trying to spread the word and report my own experiences.
Thanks for reading.
Patrick
