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Old 07-11-2014, 05:58 AM   #1
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Default T28 vs T25

Here's the deal.

My 1.6 Mk1 is currently running a T28 which is unfortunately coming to the end of its life, plumes of smoke coming out when giving it the beans due to buggered seals.

I've been looking for a T28 for a few days now and can't seem to find one but a T25 has cropped up for decent enough money. Would I notice any difference if I used the T25 instead of a direct replacement T28?

There is also a T28 from a S15 which is a ball bearing turbo compared to mine which is a journal one that has cropped up for a bit more than the T25. Would a BB turbo be any better on such a small, revvy engine as the B6ZE?
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Old 07-11-2014, 06:14 AM   #2
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BB turbo will give better spool up (300rpm-500rpm)

The T25's such as T2554 (journal version of the GT2554) or T2560 Garrett's are great.

T28's are a bit laggy on a non built engine running less than 14psi boost.

You can get the T28 rebuilt at home using online parts and then get it balanced. Or mark the compressor wheel to shaft and re assembly in the same orientation and take your chances.
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Old 07-11-2014, 06:27 AM   #3
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Quote:
Originally Posted by Lloyd_D View Post
BB turbo will give better spool up (300rpm-500rpm)

The T25's such as T2554 (journal version of the GT2554) or T2560 Garrett's are great.

T28's are a bit laggy on a non built engine running less than 14psi boost.

You can get the T28 rebuilt at home using online parts and then get it balanced. Or mark the compressor wheel to shaft and re assembly in the same orientation and take your chances.
Would there be much of a noticable difference between my T28 and a T25?

I've noticed no lag using my T28 at 9psi.

I've looked into rebuilding it but I'd prefer just doing a swap as I've already spent a load of money in the last few months replacing the engine so just want a relatively cheap, quick fix for now.
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Old 07-11-2014, 06:31 AM   #4
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Yes the T25 will spool much faster at that boost level

The T28 turbine is larger, has less blades and is heavier

If on a budget get the S14 T2554 for 9psi, it should be fully spooled before 2500rpm with the right downpipe
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Old 07-11-2014, 06:37 AM   #5
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My recommendations on a 1.8L in Garrett journal bearing world:

6-12psi T2554
12-16psi T2560
14-18psi T2860 disco
16-22psi T2871
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Old 07-11-2014, 07:49 AM   #6
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Just got offered a hybrid turbo, t25 compressor, t28 turbine he thinks it is but he has to double check.

Any benefits/drawbacks to this set up?
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Old 07-11-2014, 08:10 AM   #7
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Usually you get the T25 turbine & "T28" disco 60mm (exducer) compressor in hybrids

I ran one they're good

But I would avoid the T28 turbine as it's to big and heavy on non built engines at low boost
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Old 07-11-2014, 08:17 AM   #8
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The correct T25 turbine should look like this
postimg.org/image/hjbdde10d/

This was my T25/T28 hybrid
http://postimg.org/image/wj3q18hwd/

http://postimg.org/image/4x0ygjyjh/

http://postimg.org/image/qfm5hbrml/
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Old 07-11-2014, 08:55 AM   #9
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why not just fix the "buggered" seals?
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Old 07-11-2014, 08:56 AM   #10
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Quote:
Originally Posted by JasonNA View Post
Just got offered a hybrid turbo, t25 compressor, t28 turbine he thinks it is but he has to double check.

Any benefits/drawbacks to this set up?
yes, your friend has no clue what he's talking about.
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Old 07-11-2014, 08:59 AM   #11
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Quote:
Originally Posted by Braineack View Post
why not just fix the "buggered" seals?
Because the area around the wastegate penny is cracked and there's a lot of play on the wastegate arm also.

Quote:
Originally Posted by Braineack View Post
yes, your friend has no clue what he's talking about.
And why is that?
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Old 07-11-2014, 09:13 AM   #12
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because a T28 is a T25 turbine with a 60mm T3 compressor wheel on it. T25 + 3 = T28

so if he has a turbo with a T28 turbine and a T25 compressor, he has as T25.
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