mtnickel Posted April 5, 2015 Share Posted April 5, 2015 (edited) Hi guys, I know this won't be the MOST informative thread, but i thought i'd get the info out there. I've got what I presume is a S2 RB25DET stock turbo. Upon receiving it, i checked for axial shaft play. Wah Waaa, it had about 5-6 thou of axial shaft play. Thought it was a junker (and also suspected my engine may not have been well cared for if the turbo was cooked). Everywhere I read online led me to believe next to No axial play was acceptable (usually less than 1.5 thou or so). What I didn't realize was that the S2 turbo I have is actually a ball bearing Centre! I figured since the turbo was junk, I may as well attempt a rebuild. I know they say these are often unserviceable, but I thought I could get to the thrust bearing only possibly. I didn't take many pics, however, here's the compressor wheel (I have the plastic wheel version). I did mark the nut, turbine shaft and wheel for alignment. Took the backing plate out... And look what we have here!!! A Ball Bearing Centre!!! Ah, so now that I know it was ball-bearing, and it dawned on me the axial play limits of a ball bearing turbo might be different. A quick google search and forum posts indicated that even ball bearing turbos should have no axial play. Now, I figured, might as well check the service manual! (should have done that first). Reading the manual showed me the axial limit for the R33 is: .12 - .2mm That's .0047 - .0079". Now, my 5.5-6 thou doesn't seem so BAD! Dang, I just disassembled a turbo that was perfectly fine!!! So regardless what you read on forum XYZ, look at your service manual, or ask the turbo manufacturer. I think I found some ball bearing turbos were taper design and so also shouldn't have much play, but the garrett design however might have some, such as this. While i and it apart, i took a few readings and pics: Plastic wheel factory balancing... weight (didn't come out 32.5g) evo3 16g weight: (I think about 56.5...i can reweigh, mad the photos didn't come out). Small 16g, rb25, evo3 16g inducer 48.3 Exducer 66.6 I was most impressed with how incredibly thin the plastic blades were, as well as how light the whole assembly was. It felt like it had very little mass. I know these turbos aren't POWER monsters in that you can't crank the boost on them, but just thought it'd be nice to get some info out there. I plan on cleaning it up nicely (had a lot of carbon/sludge and such from PCV circulating) and then using on my honda accord build. I was originally gonna use a small 16g turbo I had, but this seems to fit the bill better as far as spool and efficiency for a 250-280hp build. Good luck with all your RBing! Mark For other RB turbo info: All R33 RB engines are said to have a Ball-bearing centre (perhaps some R32, though I can't confirm). Series 1 typically came with aluminum (alloy) compressor wheel, ceramic turbine Series 2 typically has the shown nylon wheel and ceramic turbine R34 Neo has same nylon wheel and ceramic turbine but turbine housing is slightly bigger (labeled op6). Rumor is there is a Neo turbo as well that has a garrett branded compressor housing that has alloy compressor and steel turbine wheel. I have not seen definitive proof of it however. Edited April 5, 2015 by mtnickel Quote Link to comment Share on other sites More sharing options...
mtnickel Posted April 5, 2015 Author Share Posted April 5, 2015 As a side note. If any rb users here have their turbo off or the part available, would be able to measure the orifice diameter on the stock feed line banjo bolt (turbo side bolt). Just wanting to know how much Nissan decided to restrict the feed to this turbo so I can do the same on other build. Quote Link to comment Share on other sites More sharing options...
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