Some of you may be saying "This guy must be crazy, there ARE no T25 compressor maps freely available on the internet!"

This was true, until now. In a HMT exclusive, I have some original T25 compressor maps from Garrett, but as they are ~20 years old and were hand-drawn on graph paper originally (they didn't use computers back in those days), they were in pretty bad shape. I'm in the process of retracing them all and cleaning 'em up in photoshop for everyone to enjoy.

I will add to this thread as I finish finding and cleaning up the rest of them.

To start the ball rolling...

 

T25, 45 trim - note how little it flows (under 16lb/min, or < 230cfm)

 

T25 - 60 trim.

Flows much better than the 45 trim (upwards of 330cfm), but watch the wheel speed as the pressure ratio goes up! At 23psi at the compressor outlet, it's spinning ~200,000rpm! For those of you using map sensors in your intake plenum and such, that may be closer to like 18-19psi at the plenum. It's no wonder the bearings in the DSM T25's disintegrate when run at higher boost levels (although the DSM T25 is a 55 trim, IIRC, its map is close to this one)

EDIT: I took apart a DSM T25 i had kicking around - it's actually a standard Garrett 60-trim T25 wheel with a 1.57" inducer and 2.02" exducer, so this flow map should be the one you're using when doing calculations with a DSM T25.

http://img33.echo.cx/my.php?image=t2560trim2kw.gif

 

Some of us are thinking "This guy must be crazy, who looks at compressor maps when using a T25"

 

Amen.

The t25 is garbage. Don't push it past 13-14psi or your just blowing red hot air. /thread

 

It's not "garbage" at all - it's just designed for a smaller engine, that's all.

It's the only thing I'd put on, say, a 1.3L Mazda B3 engine, or, say, a 1.0L Suzuki Swift, or any of a number of smaller displacement engines.

By your logic, a 500HP NOS kit would be "garbage" because when installed on your typical 1.6L Honda engine, it'd mean instant death every time. I'm sure people with built domestic big block engines would disagree with you, however.

Use an item for its intended purpose, and it'll probably do quite well.

 

No, the turbo is garbage.

They have one of the worst efficiency islands ever, can't hold boost, and the compressor blade is garbage. You have to spin thing way to fast to flow air and it heats up and fails at life, just like you.

 

Actually, interestingly enough, the turbo you have listed in your sig on your Galant VR-4 has one of the lowest efficiency compressors of any modern turbocharger.

Note the peak efficiency of the TD05h-16g is only 71%, in this flow map directly from the manufacturer itself, MHI.

http://www.stealth316.com/images/td05-16glarge-raw.gif

Compare that to the compressor flow map for the 60-trim T25 which tops out at 75%. I don't know where you got your "worst efficiency islands ever" data from, but it was either:

a) incorrect
b) correct, but you don't know how to read a compressor map
c) you'd never seen a DSM T25 flow map until today and were talking out your ***.

Of course, if you were basing your comment on the map I posted above, then the answer is b) - otherwise, my money is on c).

As for your comment about the "compressor blade is garbage", I'm not even going to get into that with you unless you have some way to show me that you have some sort of mechanical engineering or materials science degree, as the people at Garrett who designed the compressor wheel DO, and they're likely a hell of a lot better at turbine design than you are.

The turbo didn't work too well in Mitsubishi's case on the 2g DSMs because the engine they chose to use it with was way too large. This has nothing to do with the design of the turbo, however.

Oh, and by the way - if you don't have anything constructive to say, considering I'm spending my time trying to help people who might want to use these in a homemade turbo setup, why don't you go ---- right off?

 

The t25 at a PR of 2.0 is flowing a whopping ~220CFM on the 60% island.

Where as a b16g at a PR of 2.0 flows ~515CFM on the 60% island, and as you put it, it's "horrible" 71% island owns the t25's up and down the wall.

The t25's ability to spool in the effiency peak efficiency only spans from PR's of 1.6 to 2.1, the B16g can be in the 71% island from PR's of 1.3 to 2.3.

It makes more power down low, at lower boost, and more power at higher boost.

I don't think you understand fully how turbo's work. Let alone making power. GTFO

 

Koby.... shut up. Nobody cares what you think. People want the map, not your stupidity.

Why is that every single DSM owner I have talked to tells me that the T25 is junk, bad, worthless, pos... yet not one of them has ever used one. Especially on a 1.6l engine. The t25 was worthless on the 2nd gen due to the size of the engine as previously stated, but when you put it on an engine that is 20% smaller, it works fine. The only reason you guys do not like them is because you push everything so far past the manufactures expectations and then call it crap when it is blowing well past it's own efficiency. If it is such a crap turbo, why is that almost half the people with homemade turbo setups use it?

To ThingyNess, thank-you so much for posting this. I spent some time looking for one to compare it with other maps, and ended up with nothing. This is awsome.