speeder Posted July 7, 2002 Share Posted July 7, 2002 Just checked the part number on my T3/T4's turbine housing and it turns out to be a tiny .48! No wonder I have problems controlling boost! It was marginally good (just a little creep but real responsive) until I put on a full 3" exhaust with a straight - thru muffler, now I have hardly any boost control above 4000 rpm. Do any of you straight 6 guys have any recommendations? (.63 or .82?) I have a "Super V" compressor on this beast. Would like to hear what turbo trim you are running and how you like it. I'll try a new turbine housing before going to an external wastegate. Thanks. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 7, 2002 Share Posted July 7, 2002 A Super V huh? That aught to push large amounts of air. How much boost are you running/looking to run? A stage III (.63) will steer you in the range of 300rwhp, with its 2.23" exducer. Its large to flow 400-500 cfm (at compressor), your current wheel is probably about 2" exducer, suited to flow only about 400 cfm (it sounds like to me). You may want to measure it before getting a new compressor housing. You aught to be making good boost by 3000rpms with a stage III .63, still netting you good flow at 5000, which is great for the street. Good luck! -980mak Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted July 7, 2002 Share Posted July 7, 2002 I have the .63 on a stage III with an H3 compressor and have no boost control issue's with an internal gate. My turbo came with a .48, and it motivated off the line, but I always felt the top end was soft. Have not tried the .82 yet, and will likely got to a T4 instead. Quote Link to comment Share on other sites More sharing options...
speeder Posted July 7, 2002 Author Share Posted July 7, 2002 Thanks Lockjaw and 980mak - Looks as if the .63 is it. 300 rwhp is about where I want to be (for now ).I'm looking to run about 15-16 psi boost. I'll remove the turbo and measure the exducer tomorrow - If I have to do more than replace a turbine housing I'll accelerate my plans for the T4/60-1 and Racegate. I have been planning to move my T3/T4 to my '78 daily driver and upgrade the turbo on the '77ZT which is a much more serious car. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 8, 2002 Share Posted July 8, 2002 Rick, I looked through your setup and it is very nice. Why run the Super V wheel though? You need to be thinking much bigger than that for your monster setup. I would go full T4 if you could and a minimum of a 60-1 wheel. The .49 is way too small for your app. A properly sized T4 is a P-trim .58 a/r. Quote Link to comment Share on other sites More sharing options...
speeder Posted July 8, 2002 Author Share Posted July 8, 2002 As with so many other aspects of this project, my problem was that my objective kept changing during the 6 years it took to get this far. This car was originally going to be a super light, stock bodied, Weber'ed 4:11'ed fun car! Then when I was buying a turbo, I went for max response. I quickly outgrew the turbo as tuning progressed. The car will remain primarily a street car - but is definitely going the "max effort" route. I already have the built motor, big Spearco, Electomotive, and 52 lb. injectors. I really appreciate the help with turbo trim - I'll be buying my T4 this week, the manifold is being adapted as we speak. Is there a better compressor than a 60-1 for me? Man, gotta love Hybrid Z - should have found it sooner. Quote Link to comment Share on other sites More sharing options...
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