jgkurz Posted July 17, 2011 Share Posted July 17, 2011 HI Everyone, I just purchased a Garrett GT35R ball bearing turbo for my L28ET setup. My current turbo is a T3/4 hybrid that has surpassed my expectations but I knew could never be as efficient as a modern ball bearing turbo. The GT35R is visually larger than the T3/4 which was expected but one thing I was surprised about was how freely the wheel spins. For some odd reason I thought the ball bearing turbo would spin more freely than the journal bearing in my T3/4. It does not. The GT35R spins with about the same resistance as the T3/4. I'm confident my GT35R is a the real deal (not a knock off) but I was surprised is did not really spin more freely. For those of you with ball bearing setups, is this normal? I'm wondering if I should send it in to be checked out. -John Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 17, 2011 Share Posted July 17, 2011 (edited) The bearings are probably covered with a break-in/storage grease. I have a hunch that once they "break in" they will feel much looser. The bearings should consume much less energy than the bushings, once the turbo is at speed. Edited July 17, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted July 17, 2011 Share Posted July 17, 2011 My first thought was similar to cygnus'. Once the turbo is in and those ball bearings have warm oil flowing over them I bet they will move MUCH more freely Quote Link to comment Share on other sites More sharing options...
stprasinz Posted July 17, 2011 Share Posted July 17, 2011 yes, I agree with both above statements. Also the journal is probably well seated(broke in well) and also has thinner oil(affirming the thicker break in oil/grease) Quote Link to comment Share on other sites More sharing options...
jgkurz Posted July 17, 2011 Author Share Posted July 17, 2011 Thanks guys.The journal turbo is broke in with probably 10K miles. Now the part I left out. The ball bearing setup is used, not a lot of miles but used nonetheless. It was a friends who upgraded to the new GTX35R. I would think that would be broke in enough to spin more freely than my journal setup. I'll probably have it checked out professionally to be sure. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 17, 2011 Share Posted July 17, 2011 (edited) If it's used, and does not spin freely, I would go for a rebuild while it's out or let a pro look at it like you said. If you have the thought, you have to go with your hunch. Edited July 17, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted July 17, 2011 Share Posted July 17, 2011 If it's used, and does not spin freely, I would go for a rebuild while it's out or let a pro look at it like you said. If you have the thought, you have to go with your hunch. The only issue with the GT series turbo's is.. if the center section is bad or anything wrong with it, Im 99@ sure you have to get a whole new center section. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 17, 2011 Share Posted July 17, 2011 Send it in, JeffP's GT35R will spin after shutdown for a good minute. You can hear it still spinning away freely after all the commotion of the engine is shut down! You can blow in the inlet with a good puff and get it to move. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted July 17, 2011 Author Share Posted July 17, 2011 (edited) The only issue with the GT series turbo's is.. if the center section is bad or anything wrong with it, Im 99@ sure you have to get a whole new center section. Ugggg. Oh well. I guess I'll wait to see what the expert says. On another note, I took apart my current turbo and measured both inducers and exducers. Looks like I have a 50 trim compressor and a T350 stage V 10-blade turbine wheel. I use a heavily modified version of the Nissan .63 turbine housing that has been machined to fit the T350 wheel. On the dyno I made 455rwhp. That equates to 536 crank HP if 15% driveline loss is calculated. This matches my 1/4 miles times as well so it seems accurate. I am surprised the 50 trim compressor made the power it did. Cool. Since I need to use my Nissan turbine housing so I don't have to re-invent my DP and external wastegate setup I am going to have the GT35R turbine wheel changed to a T350 wheel. My research suggests the T350 wheel may actually work better than the GT35R turbine wheel. Regardless, they are nearly identical in specs. Edited July 17, 2011 by jgkurz Quote Link to comment Share on other sites More sharing options...
jgkurz Posted July 17, 2011 Author Share Posted July 17, 2011 (edited) Send it in, JeffP's GT35R will spin after shutdown for a good minute. You can hear it still spinning away freely after all the commotion of the engine is shut down! You can blow in the inlet with a good puff and get it to move. That's how I expected it to spin. My GT35R is relatively dry of oil which may have an effect. I wonder if oil pressure would make a difference? Edited July 17, 2011 by jgkurz Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 18, 2011 Share Posted July 18, 2011 Ball bearings run fine dry unless they are rusted. Actually the worst thing you can do is put a coating of oil onto the bearing before it starts rotating. This will cause the ball to 'slide' and possibly flat-spot the ball. This induces vibration. One of the hardest thing I had to do at a former manufacturer was fight other engineers about 'pre-lube pump operation' before startup on our ball bearing machines. Since API called for an prelube circuit, it was hell convincing them that was for journal bearings, not BALL bearings! Ball bearings work best starting dry, then having coolant introduced shortly thereafter before significant head builds and damages any races or balls. They should run fine dry, unless pitted, corroded, or gummed up with remnants of prior substandard lubricants. You may flush light solvent through that lube orifice, and see what you get out. Rotate it, and see what happens when it's all dried out. BTW, JeffP is now up in Reno, halfway there man... now all we got to do is get him to quit playing around and changing things and we all make a road-trip for a visit! Quote Link to comment Share on other sites More sharing options...
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