I picked up a turbo kit a couple months back that came with FOUR used turbos. I am getting to the point where I could see installing it all in the next month or two, but I want to create a part list before I start, and to do that I need to know for sure wither or not I need to buy a new turbo.
First - goals: While I do autocross, I value street enjoyment over autocross performance. Having a stock block, I have a limit on the amount of torque I can handle on stock rods. I'd like as much power for street as possible while still having good response. In an ideal world i'd either have a GT2560 or just run an EFR 6258 on low boost until I build the engine. I figure if I can MAX OUT between 230-250hp with corresponding torque I would be happy. I would rather run less HP/torque and be safe than play at the razors edge.
Current situation: I have a 2001 LS with six speed and everything is stock. I am doing a build of jumper harness number two for the megasquirt because I buggered up the first one so bad I have no idea if it is a harness problem or a programming problem on the MS3x. I plan on running pump 93 for now (e85 in the future) and have 460cc injectors. I have a BEGI log manifold and a 2.5" exhaust all the way to the back, which might limit the efficiency of the system.
Turbo #1: Labeled a Garrett KTT. (A/R .48) Supposedly this is a predecessor to a GT2554 turbo. It has a good bit of lateral shaft play on the compressor side, but never rubs. I have to double check the turbine side still...
Positives: Extremely unlikely to hit my performance ceiling. I would anticipate good response. Already owned.
Negatives: more shaft play than I am comfortable with, but that could be a result of this being the first turbo I have messed with out of a car since about 1996. Max HP and torque is a little low for my goals.
Turbos #2 & #3: Part number 14411-05u21. Supposedly the twin turbos out of a RB26DETT R33. (supposedly .48 exhaust A/R, .60 compressor A/R).
Positives: The turbo is obviously physically larger than the KTT mentioned above. Already owned. Shaft play seems ok.
Negatives: No idea what so ever as to the performance capabilities of this turbo in regards to a Miata.
Turbo #4: Godspeed 2871 China Turbo. This looks like a second generation model, not the earlier. (if that makes any sense)
Positives: Likely to make my power goals. Turbo is in great condition, almost new. Already owned.
Negatives: Might be too much turbo for my first build. It has a 14psi wastegate and I would prefer to start a little lower. I can buy a new wastegate, but that is an additional expense. It's a churbo, and thus a more likely failure point compared to some options.
Turbo #5: Godspeed 2560 China Turbo. New off ebay.
Postives: Likely a better match for my performance goals with current longblock. Comes with lower PSI wastegate that I can use my EBC on to raise as I feel comfortable.
Negatives: Churbo. I don't own one yet.
Turbo #6: Be a man and just get a GT2560 because I haven't seen any good used ones around.
Positives: It is what I would want if I was willing to spend the money.
Negatives: I need to be willing to spend the money.
If you have other ideas or comments, please let me know what you think.