DIY Turbo Discussion greddy on a 1.8? homebrew kit?

T28 vs T25

Old 07-11-2014, 04:58 AM
  #1  
Newb
Thread Starter
 
JasonNA's Avatar
 
Join Date: Oct 2013
Posts: 15
Total Cats: 1
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?
JasonNA is offline  
Old 07-11-2014, 05:14 AM
  #2  
Junior Member
 
Lloyd_D's Avatar
 
Join Date: Aug 2010
Posts: 81
Total Cats: -10
Default

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.
Lloyd_D is offline  
Old 07-11-2014, 05:27 AM
  #3  
Newb
Thread Starter
 
JasonNA's Avatar
 
Join Date: Oct 2013
Posts: 15
Total Cats: 1
Default

Originally Posted by Lloyd_D
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.
JasonNA is offline  
Old 07-11-2014, 05:31 AM
  #4  
Junior Member
 
Lloyd_D's Avatar
 
Join Date: Aug 2010
Posts: 81
Total Cats: -10
Default

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
Lloyd_D is offline  
Old 07-11-2014, 05:37 AM
  #5  
Junior Member
 
Lloyd_D's Avatar
 
Join Date: Aug 2010
Posts: 81
Total Cats: -10
Default

My recommendations on a 1.8L in Garrett journal bearing world:

6-12psi T2554
12-16psi T2560
14-18psi T2860 disco
16-22psi T2871
Lloyd_D is offline  
Old 07-11-2014, 06:49 AM
  #6  
Newb
Thread Starter
 
JasonNA's Avatar
 
Join Date: Oct 2013
Posts: 15
Total Cats: 1
Default

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?
JasonNA is offline  
Old 07-11-2014, 07:10 AM
  #7  
Junior Member
 
Lloyd_D's Avatar
 
Join Date: Aug 2010
Posts: 81
Total Cats: -10
Default

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
Lloyd_D is offline  
Old 07-11-2014, 07:17 AM
  #8  
Junior Member
 
Lloyd_D's Avatar
 
Join Date: Aug 2010
Posts: 81
Total Cats: -10
Default

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/
Lloyd_D is offline  
Old 07-11-2014, 07:55 AM
  #9  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,483
Total Cats: 4,076
Default

why not just fix the "buggered" seals?
Braineack is offline  
Old 07-11-2014, 07:56 AM
  #10  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,483
Total Cats: 4,076
Default

Originally Posted by JasonNA
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.
Braineack is offline  
Old 07-11-2014, 07:59 AM
  #11  
Newb
Thread Starter
 
JasonNA's Avatar
 
Join Date: Oct 2013
Posts: 15
Total Cats: 1
Default

Originally Posted by Braineack
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.

Originally Posted by Braineack
yes, your friend has no clue what he's talking about.
And why is that?
JasonNA is offline  
Old 07-11-2014, 08:13 AM
  #12  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,483
Total Cats: 4,076
Default

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.
Braineack is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Full_Tilt_Boogie
Build Threads
84
04-12-2021 04:21 PM
nbdooey
Miata parts for sale/trade
9
08-30-2017 09:50 PM
Corky Bell
Prefabbed Turbo Kits
18
11-22-2016 09:01 PM
itsMikey
MSPNP
3
09-28-2015 06:40 AM
AnotherDamnMiata
WTB
13
09-11-2015 10:56 AM


Thread Tools
Search this Thread
Quick Reply: T28 vs T25



All times are GMT -4. The time now is 12:07 AM.