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Gt28 Turbine Stuff I Never Knew - Until Now ...

discopotato03

By discopotato03,
in Engines & Forced Induction

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discopotato03 Grand Master

discopotato03

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Posted (edited)

I sort of burned myself recently getting a hybrid Garrett GT BB turbo made up for the old dinosaur Subie daily - mainly because of something I didn't previously know .

In the past there has been confusion over what the differences were between GT25xxR turbos and GT28xxR ones .

How it works is that the GT25 turbine based ones use an older style 53mm major diameter 11 bladed 62 trim turbine .

The GT28 ones use a 53.8mm major diameter 9 bladed turbine in either 62 or 76 trim . For some obscure reason I'd always thought the 53.8mm 62T one was just a slightly enlarged version of the GT25's 53mm 62T one but that's not the case . I will find out later today but ATM I think the GT28 62T turbine may be a smaller trim version of the 76T NS111 turbine and most likely why the 28's small trim turbine has higher efficiency numbers than the same trim GT25 turbine .

Now this GT28 62T turbine I believe is std in the GT2854R and GT2859R/GTSS and the GT2860R-7 . What I had built was a GT2554R with the GT28 76T turbine fitted and its proving laggy on yon dinosaur flatulence four . I'd say its got a bit too much turbine for my engines exhaust gas flow so its not spinning the compressor wheel fast enough to make boost where I need it engine speed wise .

Anyhow I found a few pics of the bum end of a GT2860R-7 and a GTR spec GTSS/GT2859R so you'll know what this GT28 62T turbine looks like . Highly unlikely but if anyone has a trashed one with a usable turbine let me know .

Added two right hand pics of the old style GT25 62T 11 bladed turbines , note they can have hex head or three point stars on their centers for tightening/stripping .

Cheers A .

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Edited by discopotato03

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