Picking a turbo for my new set up was a hard decission. My heart was wanting a ball bearing turbo. The little experience I had with my dual ball bearing T66 was enough to convince me that I really liked them. I also was very interested in the new Garrett GT turbos. I liked alot of things I read about them, and you can get them in dual ball bearing. There where some issues that drove me away from the new GT turbos in the end. This may have been a mistake, and down the road I may look back into them.
I don't want to get too involved with all the details of my decission, but lets just say there where alot of extra things to consider for my project. The biggest factor of all is that this will be a stage headed motor in a TTA with yours truly fabricating the headers. Read that last sentence again because that a huge statement.
Two weeks ago I finally decided on what to get and I ordered them. I ordered a pair of Turbonetics TS04 ball bearing turbos with P-trim turbine wheels and 4 bolt .69 a/r turbine housings. The TS04 are the smallest of the T-series turbos that T-netics lists. They have 58.5mm compressor wheels. The small diameter (Inducer) is sized between a TE44 and a TE60, the large diameter (exducer) is right around what a TE63 is. This wheel coupled with the T-netics compressor housing yeilds a fairly verticle compressor map. From a compressor stand point this pair of turbos should be happy from the 700 to 1000 hp range and should be happy from 12 to 30 pounds of boost. This wide HP and boost range, and my projected/target of 800hp @ mid to low 20psi range, is why I picked the TS04 compressor.
I was recommended smaller turbine wheels than the ones I picked (which could be another possible mistake). I have read that two smaller turbos will spool better than one large one. These are ball bearing turbos which also promotes better spool up. The headers will be short and should take maximum advantage of exhaust pressure pulses, which promotes spool up. With these advantages listed, then why not go to bigger turbine wheels to lower the back pressure on the motor? Also by going to P-trim and 4 bolt housings there is a wide range of a/r ratio housings out there that are cheap and easy to find. I decided for starters to go with the middle of the road .69 a/r housings. I will have to compare spool up to back pressure once the car is running and then decide if a different a/r ratio is needed.
The rest of the motor pieces are still being collected but this is a list of what I have so far:
ported BMS stage 2 heads
BMS 4 bbl intake that I'll personally be converting to efi
BMS std/std 3.4" stroke steel crankshaft
BMS on-center stage 2 block @ stock 4.1 bore with no damage or sleeves.
6.350" Mechart or 6.5" carrillo rods, I have both but don't know which ones I'll be using, I'm leaning towards the Mecharts.
Weaver Bros 3 stage dry sump set up.
Comp cams 230/230 solid roller w/ iskendarian lifters
This will be a 252" motor, and compression ratio will be my next decession to be made. I have most of the other items I need and I'm basically down to pistons, pushrods, and some of the gaskets. The other things Ill need will be suplies to convert the intake and to build the headers and down pipes. The other thing I'm looking into is going to a larger liquid IC. Anyone interested in an old style ATR liquid? ATR told me not to sell mine because its better than the one they make now. The one I have is supposed to have a better core.
Jason
I don't want to get too involved with all the details of my decission, but lets just say there where alot of extra things to consider for my project. The biggest factor of all is that this will be a stage headed motor in a TTA with yours truly fabricating the headers. Read that last sentence again because that a huge statement.
Two weeks ago I finally decided on what to get and I ordered them. I ordered a pair of Turbonetics TS04 ball bearing turbos with P-trim turbine wheels and 4 bolt .69 a/r turbine housings. The TS04 are the smallest of the T-series turbos that T-netics lists. They have 58.5mm compressor wheels. The small diameter (Inducer) is sized between a TE44 and a TE60, the large diameter (exducer) is right around what a TE63 is. This wheel coupled with the T-netics compressor housing yeilds a fairly verticle compressor map. From a compressor stand point this pair of turbos should be happy from the 700 to 1000 hp range and should be happy from 12 to 30 pounds of boost. This wide HP and boost range, and my projected/target of 800hp @ mid to low 20psi range, is why I picked the TS04 compressor.
I was recommended smaller turbine wheels than the ones I picked (which could be another possible mistake). I have read that two smaller turbos will spool better than one large one. These are ball bearing turbos which also promotes better spool up. The headers will be short and should take maximum advantage of exhaust pressure pulses, which promotes spool up. With these advantages listed, then why not go to bigger turbine wheels to lower the back pressure on the motor? Also by going to P-trim and 4 bolt housings there is a wide range of a/r ratio housings out there that are cheap and easy to find. I decided for starters to go with the middle of the road .69 a/r housings. I will have to compare spool up to back pressure once the car is running and then decide if a different a/r ratio is needed.
The rest of the motor pieces are still being collected but this is a list of what I have so far:
ported BMS stage 2 heads
BMS 4 bbl intake that I'll personally be converting to efi
BMS std/std 3.4" stroke steel crankshaft
BMS on-center stage 2 block @ stock 4.1 bore with no damage or sleeves.
6.350" Mechart or 6.5" carrillo rods, I have both but don't know which ones I'll be using, I'm leaning towards the Mecharts.
Weaver Bros 3 stage dry sump set up.
Comp cams 230/230 solid roller w/ iskendarian lifters
This will be a 252" motor, and compression ratio will be my next decession to be made. I have most of the other items I need and I'm basically down to pistons, pushrods, and some of the gaskets. The other things Ill need will be suplies to convert the intake and to build the headers and down pipes. The other thing I'm looking into is going to a larger liquid IC. Anyone interested in an old style ATR liquid? ATR told me not to sell mine because its better than the one they make now. The one I have is supposed to have a better core.
Jason
Sounds like you're enjoying the planning stages. I'm sureyou will end up with a super combination. 
