T-25 Has a bad rap

[AngelOfPassion]

I really have nothing to back this thought up, but I wonder if t25 failures stem from an oil restrictor? I converted my t25 feed line to a ss line without a restrictor (when I didn't know better), and it's been boosting fine at 18psi since.

...knock on wood...

Justin might know if that made a difference...

On topic I didn't like my t25 on my stock setup. I have been running an evo III 16g for about a year at wastegate pressure (about 9 psi) and I even liked that better than my t25. I preferred the mhi turbo even on a stock setup...

I just now upgraded my fuel finally and am starting to up the boost a little on the 16g and just think if it was the stock turbo... You wouldn't have to do a whole turbo swap to get relatively decent hp... I would have preferred the t25 to have never been on the car in the first place...

I am totally making my t25 into a lamp now after seeing this thread...

 

[Rock2610d]

If you had 200K on a T25, it was long overdue a failure. The factory thrust hardware in a T25 is horrible- thin with zero load-bearing capability. Literally every T25 failure I've seen in a decade of messing with these cars was thrust-related.[/I]"

This is very interesting, and probably one of the best responses on this thread. It does not help the T-25s rep but has to be taken into account.

As I have only rebuilt 1 and Justin has had much more experience with these than me. I believe it needs to be taken into consideration.

Based on this input the T-28 would have issues too? Are there T-25 rebuild kits that address this flaw? IE thicker/stronger thrust hardware? Better oiling options?

Is there anything that could be done (besides replacement with a MHI) that could compensate for the T-25s flaws?

 

[Boosted98gsx]

This is very interesting, and probably one of the best responses on this thread. It does not help the T-25s rep but has to be taken into account.

As I have only rebuilt 1 and Justin has had much more experience with these than me. I believe it needs to be taken into consideration.

Based on this input the T-28 would have issues too? Are there T-25 rebuild kits that address this flaw? IE thicker/stronger thrust hardware? Better oiling options?

Is there anything that could be done (besides replacement with a MHI) that could compensate for the T-25s flaws?

Not necessarily. The FP Big28 more than likely rectified this issue. Robert knows his stuff.

 

[WES_393]

Based on this input the T-28 would have issues too? Are there T-25 rebuild kits that address this flaw? IE thicker/stronger thrust hardware? Better oiling options?

Is there anything that could be done (besides replacement with a MHI) that could compensate for the T-25s flaws?

Even if the T25 could be modified with a better thrust system, you still have an inefficient compressor bolted to a tiny turbine.

And even if the T28 uses stronger thrust parts (which isn't likely), you still have a turbo that won't perform any better than a Small 16g.

I don't want to be "that guy" and just shoot everything down, but there's a reason nobody uses Garrett T25/T28 turbos.

 

[Boosted98gsx]

I just talked to Robert. He said they increased the surface area of the thrust plates of the big28, which would increase the load they can take, which SHOULD result in longer turbo life, provided the turbo isn't starved of oil.

 

[LandSpeed-DSM]

Even if the T25 could be modified with a better thrust system, you still have an inefficient compressor bolted to a tiny turbine.

And even if the T28 uses stronger thrust parts (which isn't likely), you still have a turbo that won't perform any better than a Small 16g.

I don't want to be "that guy" and just shoot everything down, but there's a reason nobody uses Garrett T25/T28 turbos.

*Ding ding ding* We have a winner! For the money vs. performance... Why even bother? Why risk a thrust surface issue that could potentially cost you a motor for that matter?

 

[95talongirl]

As stated, no one really uses them because if you are on these forums, you are *probably* looking for ways to make the car faster.

For a stock application, the T25 is ok. I used to run it on my old white car with no issues; but once the bug to go faster hits, it is hard to deny the durability/perfomance/price of the mitsu turbo options.

But to say they don't belong on the car, I'd have to disagree. One of the complaints with turbocharged cars back in the day was turbo lag. For people who just daily drive their car without any intent on performance upgrades, the "lag" is annoying. So in order to combat this, the 2g cars went with the small turbo to make it feel like a naturally aspirated car. Of course now, nearly 20 years later turbo technology is leaps and bounds better, so we have things like twin-scroll, VGT, ect so using larger turbos are viable options in respects to the lagging issue.

BTW, the t25 lamps are awesome!

 

[JusMX141]

Based on this input the T-28 would have issues too? Are there T-25 rebuild kits that address this flaw? IE thicker/stronger thrust hardware? Better oiling options?

There are kits with steel 270* plates which retain the factory oiling and don't explode like the OEM Garrett T25 thrust plates do, and there are also kits with 360* plates which have larger oiling holes which can modify the way the rest of the turbo receives oil...so one may consider opening up the factory restrictor a bit when swapping to a 360* thrust plate in a T25.

All of the Garrett-built DSM T28's (which are Garrett TB2578's) use a Garrett-designed 360* thrust plate for better durability which does not exist anywhere in the aftermarket- you must use factory Garrett parts to rebuild a TB2578. You can't interchange thrust parts between a T25 and a TB2578 without modification to the mounting holes.

Not necessarily. The FP Big28 more than likely rectified this issue. Robert knows his stuff.

FP never disassembled the T28's/TB2578's they sold to my knowledge...all modification was done externally. There was no way to further-improve the factory thrust system which came in the turbo.

I just talked to Robert. He said they increased the surface area of the thrust plates of the big28, which would increase the load they can take, which SHOULD result in longer turbo life, provided the turbo isn't starved of oil.

"They" meaning "Garrett". Trouble is most of the T28's/TB2578's I've received for service still suffered from some sort of excessive thrust wear, often resulting in compressor damage.




So is the TB2578 thrust system better than the T25's? Yes- it had to be. The factory thrust plates which exploded from T25 use would never be able to stand up to the abuse of a heavier rotating assembly at higher boost levels.

Was it improved enough to be more-durable than a factory MHI TD05H thrust system? Absolutely not. Even FP chose to stick with the factory MHI thrust system for their 68HTA turbos, many of which are being used at or above 30psi; so an even-larger rotating assembly and higher operating boost level than a T28/TB2578.



The problem is the TB2578 uses the largest compressor and largest turbine available in the entire T2 lineup. Run one of these units at high boost for a long period of time and there's a good chance you're going to cause rapid thrust wear simply because the improved thrust system was offset by the largest rotating assembly being installed.

This is the same reason journal bearing PTE turbos have such horrendous thrust issues- they're using 67mm compressor wheels and giant turbines at retarded-high boost levels on a T3 center housing which was designed in the 1960's and originally intended for 8psi on slow-spooling diesel applications. At some point the thrust loads became more than the turbo was designed for, so they band-aided the problem with steel thrust plates instead of completely redesigning the turbo. There's a reason that Garrett's entire high-performance lineup consists of ball-bearing GT units, and that reason is any time you adapt something to an application which it doesn't belong, reliability of that part or something it's attached to will likely suffer.

 

[Archer Fabrications]

PTE did diesel turbos? Guess that puts holset really above them then .

 

[LandSpeed-DSM]

PTE did diesel turbos? Guess that puts holset really above them then .

Garrett developed those turbos for diesel applications.. PTE turbos are Garrett based. After the dust-up with turbines coming apart and PTE's finger pointing I seem to recall Garrett stating they no longer distribute to PTE in the dissection of the problem posted on YB.

 

[T is for TURBO]

I really have nothing to back this thought up, but I wonder if t25 failures stem from an oil restrictor? I converted my t25 feed line to a ss line without a restrictor (when I didn't know better), and it's been boosting fine at 18psi since.

...knock on wood...

I had to run the same setup you described on a T-25 while my T-28 was out for rebuild a few years ago. My boost controller was still set for 16-17psi and I killed it within 2-3 weeks. About 2 weeks in, it started burning oil on boost. About a week after that I heard the death howl. Shaft play + bent fins. It was previously on my buddies car set at stock boost levels w/ maybe 80k in it.

 

[Archer Fabrications]

Yeah i saw the ote battle with garrett, apparently they used to modify garrett parts and when customers could try and claim warranty garrett wouldn't help PTE because they machined the shaft and put larger bearings in or something like that. All i know is pte was Modifying turbine shafts that were genuine garrett, now they don't use any garrett parts.

 

[JusMX141]

You can't interchange thrust parts between a T25 and a TB2578 without modification to the mounting holes.

More on this....

Genuine Garrett TB2578 thrust plate on the left, new aftermarket T25/T28 360* thrust plate on the right.

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...as you can see, shit don't line up.

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^ That is why you can't rebuilt a Garrett TB2578 / FP Big T28 with an actual T28 parts kit....because it's not a T28. The photo also illustrates that despite Garrett's attempt at making the TB2578 thrust system more durable over the standard T25 270* plate, it still fails.