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Turbo Selection for 350-450hp (thinking T-61), opinions pls

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  • Turbo Selection for 350-450hp (thinking T-61), opinions pls

    Here are the specs for my 86T:

    86 300ZXT -- 87+ front end conversion and SS front spoiler, maxima intake with 370CC injectors, chipped ecu (now with expanded maps up to 7200rpm and increased load range), full T4 turbo, external wastegate, Z32 MAF, BOV, 944T intercooler, 3 inch mandrel bent exhaust, walbro HP fuel pump, 88T LSD, FS5R30A with short shifter, ACT S/S clutch, ACT HD pressure plate, Fidanza flywheel. ST springs, tokico illuminas and poly bushings. Schneider cams (280/270, part# 17076 with schneider valve springs). Port and polished cylinder heads/intake manifold. External Oil Cooler.

    I'm going to get new injectors (550's or so) and the T4 turbo that I've got is probably not going on. The specs on it are: p-trim .81 a/r, 50-trim .63 a/r. I bought this turbo off of ebay a long time ago and it WAS NOT WHAT WAS IN THE AUCTION. I dont even want to tell all of the problems with this thing (custom machined turbine housing, had to modify exh. manifold to accect T4 turbo etc..) and on top of all this, I can't even trust that it was rebuilt properly.

    Criteria for turbo selection:
    350-450hp (I guess I'm governed by the stock pistons)
    7000-7500 RPM (max)
    Prefer to use T3 exhaust manifold... but I guess I could do T4

    Thinking about a T61 with a T3 turbine housing (compressor map seems to be real nice, IN MY OPINION superior to the 60-1)

    So my questions are: what a/r on the hot side? Stage 3 or stage 5? Is watercooled center section a must?

    OR - other suggestions on turbo selection?

    Jason - how do you like the GT35? Anyone else running one? Any dyno graphs?
    '86 300ZX Turbo
    '94 968
    '84 944

  • #2
    Throw the Ebay Turbo away it will do more good in the trash than on your car

    The Garrett T61 uses the same compressor thier GT35

    .63 a/r Stage 3 Turbine will well let you spool mighty quick, but a .82 Stage 5 will give you much more headroom with a still resonable spool time.

    Watercooled center sections are far from required just give the car some time to cool before turning it off after some spirited driving.
    2005 whore magnet

    Comment


    • #3
      for 350-400rwhp get a holset hy35 and run 20-25 psi

      Comment


      • #4
        got boost? wrote: for 350-400rwhp get a holset hy35 and run 20-25 psi
        Heh heh. I got my HY35 for about $400 shipped NEW! She'll be going on as soon as the snow melts. 8)

        Comment


        • #5
          hmmm I dunno about the HY35.

          What kind of spool time am I looking at for the stage 5 .81a/r for the T61?

          Should I consider a .63a/r stage 5?

          I would like to go a bit on the big side, but I dont want a lag-daddy. Very soon I'm going to rebuild and turbocharge the 944 and use a GT28RS, that should spool instantly.
          '86 300ZX Turbo
          '94 968
          '84 944

          Comment


          • #6
            Any thoughts on this turbo?:

            T3/T4 T61 .82 a/r stage 5

            When do you think it would spool and boost 15psi?

            Is it overkill - should I just go with a .63 a/r hot side?
            '86 300ZX Turbo
            '94 968
            '84 944

            Comment


            • #7
              300guy wrote: Any thoughts on this turbo?:

              T3/T4 T61 .82 a/r stage 5

              When do you think it would spool and boost 15psi?

              Is it overkill - should I just go with a .63 a/r hot side?
              you will have 15 psi by 3400 rpms give or take 100 rpm.
              85 Z31 6.0 LSX turbo 766whp/792wtq
              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

              Comment


              • #8
                Thanks Satan,

                is this a good selection for mid-upper RPM power? I want to get a turbo that give good numbers in the top end... to go along with my schneider cam (280/270, part# 17076)

                OR - do you think that I should kick it up a notch and go with a O or P trim hot side?

                Is the stage 5 T3 going to restrict the engine running 15-20 psi up to 7000rpm?
                '86 300ZX Turbo
                '94 968
                '84 944

                Comment


                • #9
                  300guy wrote: Thanks Satan,

                  is this a good selection for mid-upper RPM power? I want to get a turbo that give good numbers in the top end... to go along with my schneider cam (280/270, part# 17076)

                  OR - do you think that I should kick it up a notch and go with a O or P trim hot side?

                  Is the stage 5 T3 going to restrict the engine running 15-20 psi up to 7000rpm?
                  Sounds like you need to get your priorities straight. Do you want a low end spooling turbo that responds well. Or do you want a turbo that can supply larg amounts of unrestricted upper end power? Unless you are running variable geometry you cant have both.

                  If you are asking if your car will make more power on the upper end using the P-trim .81a/r then yes it will. But its give and take. It will be more laggy.

                  I had a T-66 with a P-trim and an .81 a/r and I thought it was fine for street use. I had full boost by 3700 which was fine for me.
                  85 Z31 6.0 LSX turbo 766whp/792wtq
                  04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                  Comment


                  • #10
                    thanks Satan!

                    I understand that its a give and take type relationship.

                    T61/T3 Stage 5 .81 a/r - Spool RPM: 3400

                    T61/T4 p-trim .81 a/r - Spool RPM: 3700

                    So the question is - how do the top end power capabilities compare?

                    How do the O trim turbine wheels compare to Stage 5 or P-trim?
                    Attached Files
                    '86 300ZX Turbo
                    '94 968
                    '84 944

                    Comment


                    • #11
                      300guy wrote: thanks Satan!

                      I understand that its a give and take type relationship.

                      T61/T3 Stage 5 .81 a/r - Spool RPM: 3400

                      T61/T4 p-trim .81 a/r - Spool RPM: 3700

                      So the question is - how do the top end power capabilities compare?

                      How do the O trim turbine wheels compare to Stage 5 or P-trim?
                      Honestly I dont have the trial and error experiance to give you an exact answer. The best bet is to look up the size of each wheel and couple that with your A/R. The larger the wheel and A/R the more top end power you will make (within reason of course)
                      85 Z31 6.0 LSX turbo 766whp/792wtq
                      04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                      Comment


                      • #12
                        I wonder what a O-trim, .81 a/r T61 would be like? I guess if I found it too laggy, I could get a smaller a/r housing.
                        '86 300ZX Turbo
                        '94 968
                        '84 944

                        Comment


                        • #13
                          dude for only 350-400rwhp i always say holset is the way!!! a HX35 would be perfect, flows the same as a 60-1 and have about a .80 A/R and about a stage 3 turbine wheel. It will do 400rwhp easy and spools quick and gives enough top end for 400rwhp. BUT, if you must have a garret then just get a .63 A/R stage 3 w/ a 60-1 or T61 on the cold side, that will be plenty for 400rwhp and will spool darn near as quick as a stock T3 and will have decent top end up to 7000rpm, look at Jasons dynos, thats the turbo he uses and he puts down 500rwhp

                          Comment


                          • #14
                            roastin300 wrote: dude for only 350-400rwhp i always say holset is the way!!! a HX35 would be perfect, flows the same as a 60-1 and have about a .80 A/R and about a stage 3 turbine wheel. It will do 400rwhp easy and spools quick and gives enough top end for 400rwhp. BUT, if you must have a garret then just get a .63 A/R stage 3 w/ a 60-1 or T61 on the cold side, that will be plenty for 400rwhp and will spool darn near as quick as a stock T3 and will have decent top end up to 7000rpm, look at Jasons dynos, thats the turbo he uses and he puts down 500rwhp
                            Yeah but look at where he puts down the 500. it damn sure aint at 7k with his .63 stage3. He peaks and then drop dramatically.
                            Attached Files
                            85 Z31 6.0 LSX turbo 766whp/792wtq
                            04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                            Comment


                            • #15
                              anyone know major and minor diameters of a T3 stage 5 turbine?

                              I found this site that has A LOT of specs... but not the specs for stage 5.

                              http://web.telia.com/~u58303675/garrett/index.html

                              Turbo Turbine Trim Inducer (in) Exducer (in)
                              GAR T3 Stock 1,898 2,319
                              GAR T3 Stage 2 2,122 2,559
                              GAR T3 Stage 3 2,229 2,559
                              GAR T4 O 2,296 2,922
                              GAR T4 P 2,544 2,922
                              GAR T4 Q 2,693 3,111

                              Something else thats interesting is that a lotta places say that the GT40/GT35R wheel is the same as the T61 - but not according to the compressor maps at the above sights - what gives?
                              Attached Files
                              '86 300ZX Turbo
                              '94 968
                              '84 944

                              Comment

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