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Old 07-03-2009, 11:47 AM   #1
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Default Biggest T2 flanged Journal Bearing Turbo?

So as my signature says, I am using an SR20 turbo. I have it mounted to an FM manifold, with the cast turbine outlet, and SS DP. I want a bigger turbo, plain and simple. Word on the street is that I won't make more than 250hp on this turbo, and 250 is really pushing it and most likely not with my manifold. I would like to keep everything I have on there that way it is, but just replace the turbo. What journal bearing T25's have the same footprint, and also turbine bolt pattern, as my current SR20; but are way bigger? (Bigger as in comparable to a GT2860.) I am looking for something I can pull at a yard, or buy at a swap meet and rebuild cheap, so don't tell me anything ball bearing.
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Old 07-03-2009, 01:05 PM   #2
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Making a compressor housing work with a different sized inlet/outlet than you currently have is just a matter of a couple new couplers, so that shouldn't be a problem... maybe better in fact, because you can sell your adapters if you get a turbo that doesn't require them. Depending on where your manifold places the turbo, you may have to notch the fenderwell lip to get the compressor housing to fit.

The critical part of the footprint is the turbine housing. If you get a standard T2 5-bolt turbine housing, ANY turbo will fit, no matter what the actual CHRA/wheelset are. In other words, you don't need to limit yourself to journal bearing units. WHAT IS YOUR END POWER GOAL?

For example, ATP carries a 3071 flanged in T2 that would be a direct bolt-in provided you had clearance for the compressor:
GT3071R-WG Dual BB, 86AR, 90 Trim Turbine: atpturbo.com

I think that some JDM Nissans came with turbo's larger than your T25, but the nomenclature in the Nissan world has never been uniform, so one man's small T25 is the exact same thing another guy will call a big T28 if he's coming from a CA18det and not the SR20 world. I know there is a GT2860 journal bearing out there, no idea if it was ever oem. What most guys there call a T28 was a BB unit that came on GTir cars... but standard black/redtop motors all use the same .80/.64 unit.

Your best bet for a direct drop-in upgrade to that turbo is a GT2554r... can find them used for under $500, see them all the time on CL and the Protege forums... have you considered a Chinacharger?

Last edited by samnavy; 07-03-2009 at 01:16 PM.
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Old 07-03-2009, 10:21 PM   #3
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My first turbo was a chinacharger and it had bearing failure. J-U-N-K. Never again. So this is also why I am weary of ball bearings, Garrett or not. Plus journal bearings are cheap and easy to rebuild.
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Old 07-03-2009, 11:15 PM   #4
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Yes, Chinese ball bearings, which are NOTORIOUS for failure, should absolutely be used to judge high-quality US ball bearings with a failure rate of nearly zero.
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Old 07-04-2009, 12:09 AM   #5
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^Agreed. 3rd, your logic makes no sense. Start hitting the likely places that you might find a used 2554r and go with that.
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Old 07-04-2009, 01:16 AM   #6
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I always thought a Nissan t28 would be a nice upgrade. I vaguely remember Brain mentioning a way it could be done on your current t25.

Found on a Nissan forum:

T28 [Semi hybrid turbo, between T25 and T3. Commonly found on some Avenir SR20DETs, some Silvia SR20DETs, GTiR SR20DET's, as well as the Skyline RB26DETT and maybe some others I don't know about] T28's have been known to make up to 300whp on SR20DE's. I believe Wes is currently making 250whp on a GA16DE with a T28.
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Old 07-04-2009, 09:04 AM   #7
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I thought about that a while ago, but I just wonder if it would be signifigantly beneficial. I don't wanna go spending money and swapping parts if I'm gonna get a minimal increase.
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Old 07-05-2009, 02:08 PM   #8
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i have a gt3076r on my FM manifold
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Old 07-05-2009, 02:52 PM   #9
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a t28 will support more than a minimal gain]
gt2554r= ball bearing t25
gt2560r= ball bearing t28
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Old 07-05-2009, 03:07 PM   #10
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Quote:
Originally Posted by kenzo42 View Post
T28 [Semi hybrid turbo, between T25 and T3. Commonly found on some Avenir SR20DETs, some Silvia SR20DETs, GTiR SR20DET's, as well as the Skyline RB26DETT
Yup, that's the one, and it will be a significant upgrade in spool and midrange torque. I believe the highest I've ever seen on the standard SR20det T25 was like 230whp on a '99. You should have no problem reaching up towards 260-270whp with one of the Nissan T28's. The "minimal" upgrade of 30-40whp is nothing compared to the spool increase and huge area under the torque curve you're gonna get... not to mention that the T28 isn't going to have near the torque falloff above 5k that the T25 will. It's a huge step up. All of the OEM Nissan's are gonna require the ATP adapters... plus maybe a wastegate actuator bracket.
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