Disclaimer: All of the following is correct to my knowledge. Please feel free to jump in and correct anything that is wrong or feel free to add anything. This post is pretty long, but hopefully it will help out some newbies that are getting into turbochargers.
There seems to be some confusion about there about what all of the numbers mean when looking at a turbochargers specs. Awhile back, BlueShadow wrote an excellent post on how to read a compressor map. Find that post, read it, and combine it with this one...voila, you'r a guru! (not really)

Garrett makes several "families" of turbochargers that are targeted for different sized engines, HP goals, and drivability characteristics. Crafty tuners, manufacturers, etc, have mixed and matched these components to produce hybrid turbos that can provide the benefits of several turbo families. The possibilities really are endless, but I'm just gonna list some common ones or else this post would be reeeeeeallly long.

Turbocharger families
The T25 family = super fast spooling "small" turbo that makes good low rpm torque, but lacks top end power. This turbocharger is commonly used where throttle response and low rpm torque are desired without much regard to high rpm power.

The T3 family = "intermediate turbo" that spools slower, but has the ability to make substantially more power than the T25 family. This turbocharger has been used on A LOT of production vehicles (Ford, Nissan, Volvo, Saab). They can make impressive power, but were known to be laggy.

The T04 family = "big turbo" that makes huge power, but is very very laggy. Without the beauty of being able to make a hybrid turbo, a T04 would probably not even be an option.

The 3 main components that have the biggest impact on performance are the a/r of the turbine housing, the size (aka trim) of the tubine wheel, and the size (aka trim) of the compressor housing.

Common turbine housing a/r "sizes"
T25: .64 a/r, .86 a/r
T3: .36 a/r, .48 a/r, .63 a/r, .82 a/r
T4: not listed...see why later

In a nutshell, the larger the a/r, the later the power comes. A small a/r gives you a fast spooling turbo but limits top-end power. A large a/r gives you a laggy turbo with big top-end power.

Common T25 turbines:
DSM trim (?? not sure how big it is, but it's quite small)
60 trim (small)
76 trim (medium)

Common T3 turbines:
Stage 1 (small -- most common turbine on junkyard turbos)
Stage 2 (med)
Stage 3 (large -- most common turbine on new T3/T04 hybrids)
Stage 5 (very large)

Common T04 turbines:
I'm not gonna list any because I don't have info on them and the T4 turbines require so much exhaust energy to spin that they are practically unusable in our application unless you want insane lag and have got a motor that will spin to 10k every day.

Common T25 compressors:
I'm not gonna list any. I do have some info on them, but for the most part, a T25 compressor will struggle to stay in its efficiency range on a boosted Honda.

Common T3 compressors:
40 trim (20lb/min -- haha...don't even think about it)
45 trim (21lb/min)
50 trim (30lb/min -- probably one of the most common on junkyard turbos, works well for SOHC and LS engines)
60 trim (34lb/min -- biggest "production" T3 compressor, excellent power on D series/LS)
"Super 60" (36lb/min -- note: this is NOT the "60-1" compressor)

Common T04B compressors:
S trim (37 lb/min)
V trim (48 lb/min)
H trim (49 lb/min)

Common T04E compressors:
40 trim (36 lbs/min)
46 trim (41 lbs/min)
50 trim (47 lbs/min)
54 trim (45 lbs/min -- note that the 54 trim flows less than the 50 trim)
57 trim (49 lbs/min)
60 trim (50 lbs/min)

Common T04S compressors:
60-1 (flows a shitload, never seen a compressor map for it)
62-1 (bigger yet -- I believe this is a T04S compressor...correct this if it is wrong)


Performance (listed in order of increasing performance):
A T25 is a straight T25 turbo --> T25 turbine + T25 compressor
A T28 is a hybrid T25/T3 turbo --> T25 turbine + T3 compressor
A T3 is a straight T3 turbo --> T3 turbine + T3 compressor
A T3/T04B is a T3/T04B hybrid turbo --> T3 turbine + T04B compressor (used in Drag kits)
A T3/T04E is a T3/T04E hybrid turbo --> T3 turbine + T04E compressor (more performance than T3/T04B
A T3/60-1 is a T3/T04S hybrid turbo --> T3 turbine + T04S (60-1) compressor

good tech article, finally something tuners can use, here is a similar article that was in Sport Compact Car - more proof that you should be subscribing to this mag if you are a performace tuner,

vtwin, I have no experience with turbos so how could I tell the size of a turbo if i saw one in the foreign used yard?
Does it have the size writen on it?
What's the diference between a turbo from a diesel engine and a turbo from a gasoline one?

Turbos have the a/r housing size typically on the inside of the compressor housing (at the inlet) and is normally stamped. (Most garrett turbos are like this) The turbo size is typically printed on the outer shell of the turbo.

For addition and recommendation's sake, for DOHC honda motors, a good street use turbo w/ decent spool and good top end (stock internals) The VERY COMMON Garrett T3 turbine, sporting a .48 a/r housing is an excellent piece. This turbo, I believe is found on the saab and thunderbird (mercury) turbo cars of yore...lol

ALSO: If you are considering going boost, I HIGHLY recommend you read as much as possible and talk to as many people that have already gone boost before making a single move or buying anything. Boost is a very carefully thoughtout science and if you do it the wrong way or with the wrong parts... you could 1) Waste your money or 2) Blow your motor... or both...heh heh...

AND: Typically boost isn't cheap, if you're in a tight money situation... don't do it.

real life example: Years ago, my VERY FIRST boosted motor (LS integra) ran great until it blew 6months later due to my newbie status. It cost me an engine and 2 months of downtime... which I used to educate myself and learned why it happened. After that, I was surprised it lasted as long as it did. Cost ? USD$2000 ... back then... if I had taken the time to learn before jumping into boost like most idiots do, that additional USD$2000 investment woulda been in other parts, instead... I had to get a new engine.

X2 (Former Idiot)

_________________
I'm not a Guru... I just know more than you.

The easiest way to win an argument with a woman... is to stop talking.

I recommend we sticky this post to help beginner 2nr's, MODERATOR.

_________________
There are no facts, only interpretations. - Nietzsche

I agree.

Well presently I have some head problems and as soon as that is complete i'll try turbocharging. I already know most of the basics, but what i can't figure out is the fueling. Any suggestions on that?

Alot of foreign used yard turbo's could be the MHI (Mitsubishi Heavy Industries, like in CA19DET's article) and IHI japanese series.
Stuff like MHI- TD04, TD05, sleeve bearing
IHI- VF22, VF23, 24, 29, what have you. these are ball bearing I beleive,
Theres a bit more stuff to spot besides the Garrett

Turbo Charging 101

The advent of improved international standardized manufacturing techniques and standards has led most folks to come to the realization that cars are made a lot better than they were ten years ago. Simply put, improved mechanical tolerances and increased reliability have greatly increased. If anything, that should encourage you to coax a little (or a lot) more power out of your car.

A lot of folks go down the path of traditional powertrain modification. They do your average "breather mods" (intakes, headers, exhaust), play with fuel maps, modify ignition timing. Those with more time, know-how, and money on their hands resort to headwork -- porting, polishing, cams, etc.

However, it's the dream of many an automotive tuner to seek power through forced induction (turbocharging, for one) and creating more power from less displacement, which, essentially, is what turbocharging is. There are some VERY expensive aftermarket turbo kits out there. Those with money will trust experts to install such a setup. For those who don't have so much money but KNOW WHAT THEY ARE DOING, there are turbo setups that are more cost effective. This article is just to give you insight on some of the possibilities that exist.

IF YOU DON'T KNOW WHAT YOU ARE DOING, don't proceed! Turbocharging your engine improperly is a VERY easy way to cause thousands of dollars in damages, not to mention serious risk of damage to one's self.

For the laymen who can't distinguish a camshaft from a halfshaft, here's turbocharger theory 101 in a nutshell.

Engines are designed to work like a pump. Air and fuel are mixed together, and then ignited. The explosion provides power. Air and fuel must be combined in a specific ratio -- 14.5 of air to one part of fuel. If there is too much fuel in relation to air, the engine runs in a state of "richness". This leads to poor performance and lower fuel economy. An excess of air in relation to fuel will cause the engine to run in a state of "leanness". This leads to bad bad things -- detonation (explosions happening before they should, when the engine is in a poor position to receive the benefits of it), and high combustion temperatures (which, if hot enough, WILL melt parts of your engine). The point is to maintain that magical "stoichiometric" ratio of about 14.5 to 1. Pay attention -- this part is where power comes in. The more of this 14.5-to-1 air/fuel mixture you can force into your engine and ignite, the more power it will make. A turbo charger is essentially a double-sided pinwheel. The rapidly flowing exhaust gases spin the exhaust side (the hot side). This is connected via a turbine shaft to the compressor side (the cold side), which spins up in the range of tens of thousands of RPM. This action pressurizes the air intake charge -- thereby forcing more air into the engine. Now, if you've been following along this whole time, you should be asking yourself, "won't all this extra air cause the engine to run in a state of leaness?" That's correct! Specially designed fuel injection setups provide the extra fuel your engine needs.

At this point, you reach the two most important questions involved with turbocharging. 1) How do I get a turbo attached to my car and 2) how do I provide enough extra fuel in the right amounts at the right time to accommodate this influx of air?

The easy way.

If there is a turbocharged version of your engine on the market, you'll have an easier time finding parts and doing the installations. This makes things MUCH easier and cheaper, seeing as A) chances are, your car's manufacturer has designed proper clearances and tolerances into your car to accept turbocharging and B) these parts will be quite plentiful.

The parts you'll need from your car's turbo big brother will include the turbo, oil lines, turbo manifold, intercooler, compressor bypass valve (more commonly known as the blow-off-valve), downpipe, ECU, injectors, fuel pressure regulator, fuel pump, air flow meter and as much as the intake/intercooler piping as possible. Here's a breakdown of what each part does.

The Turbo

It's the power adder. When picking one up used, make sure the turbine wheel spins freely. Also, make sure the wheel has no play. It should spin--period. It shouldn't wobble, it should wiggle, it shouldn't move in and out. Try to get the factory oil lines that go to and from the turbo. You will need to tap the sender line into your engine block someplace and the return line into the oilpan to ensure a flow of oil through the turbo.


Turbo Exhaust Manifold

This replaces your stock exhaust manifold. Rather than guiding spent exhaust gases straight into your downpipe and out of your exhaust, the turbo manifold directs the exhaust gases into your turbo to spin it. If one isn’t in existence for your vehicle, it can be fabricated by an experienced muffler shop.

Turbo Downpipe

Chances are, your factory non-turbo downpipe will not mate up properly with the turbo exhaust outlet. If the turbo downpipe is unavailable for your car, your local muffler shop can fabricate one.

Intercooler

Much like a radiator for the incoming air charge, the intercooler cools the intake air charge to temperatures closer to ambient, condensing it and allowing you to fit more into each combustion stroke. This also helps in reducing combustion temperatures and helping prevent against detonation.

Compressor Bypass Valve (CBV) or Blow Off Valve (BOV).

This is what usually makes that cool pffffsssshtt sound on turbocharged cars. This valve does more than make that funny noise, however. Its main purpose is to relieve the pressure on the intake air charge between shifts. When you shift, you usually let off the gas pedal. That in turn slams the throttle plate shut. Your pressurized intake charge now has no where to go. What the CBV does is vent this pressurized air -- either back into the metered intake stream in the plumbing before the turbo, or out into the atmosphere. If this air is not vented, it will send a pressure wave back down to the turbo, trying to reverse the direction that the turbo is spinning. This is not good for turbine longevity. There are benefits of going with aftermarket units like the Greddy Type S, which is adjustable.

ECU/Injectors/Fuel Pressure Regulator/Fuel Pump

This is primarily, the fuel system from the turbo version of your car. Chances are, the turbo version of your car will have larger higher capacity fuel injectors and have a different air metering system than your normally aspirated car. This system, when functioning properly, will inject the proper amounts of fuel, proportionate with the incoming air, at proper intervals and duration. Several sensors (air flow meter being the major one) detect the volume, temperature, (and in some cases, velocity) of the intake air charge. This information is sent to the ECU, or computer, which in turn computes how much fuel is required to mix with this air. Once this is calculated, the ECU fires the injectors. The fuel pump and fuel pressure regulator are in place to see to the fuel demands of the injectors.

Oil/Coolant Lines

These are very important systems and should not be ignored. Simply put, to remain lubricated and within operating temperatures, a turbocharger needs a constant supply of oil and coolant flowing THROUGH it. Your stock cooling system can usually be teed off with radiator hose and redirected through the turbo to supply coolant. Oil on the other hand will require a certain grade of hose that withstands much higher temperatures. Fittings will need to be created both in your oilpan for the oil drainage line from the turbo and in a source of fresh oil somewhere before the turbo.

Intake/Intercooler Piping

This is what holds everything together. This piping, held together by friction fit, hose joints, and clamps, will allow air to flow through the air filter to the turbo, from the turbo to the intercooler, and finally from the intercooler to the throttle. Stock factory pieces are usually made of plastic, but tend to fit fairly well. Pieces that you're missing can usually be made from large radiator hoses or pieces of generic muffler piping of varying lengths and bends. If you're feeling extravagant and want a better flowing system, we recommend taking this task to your local muffler shop. You should see to it that beads are welded into the piping where clamps will be used to ensure a fit that will not come apart should you start running large amounts of boost.

Gauges/Monitoring Equipment

Ideally there are three different gauges you should have when you embark upon this project. First and foremost is an aftermarket boost gauge. Decent units are made by Autometer. Best thing is, these units read in ENGLISH, that is, in PSI. These gauges will tell you what kind of negative and more importantly, positive manifold pressure your turbo is creating. Next is an air/fuel ratio gauge that will tell you how far you are from having a stoichiometric mixture by reading the signal coming from your O2 sensor. Finally there is the EGT (exhaust gas temperature) gauge. When an engine is in good running order, it should be at about 1450 degrees Fahrenheit. Temperatures below that will indicate a state of richness, and temperatures above that will indicate a state of leanness. An EGT gauge is essentially a voltmeter that displays the output from a thermocouple, or pyrometer, that sits in the exhaust stream and converts heat to an electric signal. A full complement of these gauges, coupled with some good common sense, we go a long ways in keeping you from turning your motor into a scrap heap.


What you’ve read are some basics of a turbo conversion. Don’t you consider doing this until you understand turbo selection, advanced turbocharger theory, intercooler selection, fuel management, pros/cons, monitoring, tuning, and installation.

WOW, this is some GREAT info....thanks guys, will be spending some hard-working night shifts going through this thread

excellent thread....

nissan turbos

S13 SR20DET: T-25, 60 trim 56mm BCI-1 compressor, 53.8mm 62 trim
T-25 turbine, .64 A/R turbine housing. Journal
bearings.

S14 SR20DET: T-28, 60 trim 60 mm BCI-1 compressor in T-04B housing,
62 trim 53.8mm T-25 turbine. .64 A/R turbine housing.
Ball bearing center section.

S15 SR20DET: Same as S14, but with Inco turbine wheel (instead of
GMR), cast divider wall between turbine discharge and
wastegate.

Pulsar GTi-R: T-28, 60 trim 60 mm BCI-1 compressor in standard T-3
housing. 79 trim 53.8mm Inco T-250 turbine wheel .86
A/R turbine housing. Journal bearings.




this is off another forum some of the info needs correction... but good info all the same





OEM:

S13 SR20DET: T-25, 60 trim 56mm BCI-1 compressor, 53.8mm 62 trim
T-25 turbine, .64 A/R turbine housing. Journal
bearings.

S14 SR20DET: T-28, 60 trim 60 mm BCI-1 compressor in T-04B housing,
62 trim 53.8mm T-25 turbine. .64 A/R turbine housing.
Ball bearing center section.

S15 SR20DET: Same as S14, but with Inco turbine wheel (instead of
GMR), cast divider wall between turbine discharge and
wastegate.

Pulsar GTi-R: T-28, 60 trim 60 mm BCI-1 compressor in standard T-3
housing. 79 trim 53.8mm Inco T-250 turbine wheel .86
A/R turbine housing. Journal bearings.

BB SR20DET: T-25. Basically, the same as the S13 Silvia.

HKS:

GT2510: T-28, 63 trim 60 mm BCI-1 compressor in T-04B housing.
62 trim 53.8mm T-25 turbine. .64 A/R turbine housing.
ball bearing center section.

GT2530: T-28, 63 trim 60 mm BCI-1 compressor in T-04B housing.
76 trim 53.8mm NS-111 turbine. .64 A/R turbine housing.
Ball bearing center section.

GT2540: 46 trim 76.2mm BCI-8 compressor in T-04E housing. 76 trim
53.8mm NS111 turbine. .64 A/R turbine housing. Ball
bearing center section.

GT2835: I believe that the following is the spec for this, but I could be
wrong:
48,52, or 56 trim 71mm BCI-18C compressor in T-04E housing.
84 or 90 trim UHP turbine cut down from 60mm to 56.5 mm.
.64 or .86 A/R turbine housing. BB center section.

GT3037: 48,52, or 56 trim 76.2mm BCI-18C compressor in T-04E housing.
84 trim 60mm UHP turbine. .61, .73, .89, and 1.06 A/R
turbine housing. Ball bearing center section.

Turbonetics:

Super 60 T-3: This could be about anything, but is usually a 65 trim
60mm BCI-1 compressor wheel in either a standard T-3
or a T-04B compressor housing, with a 62 trim 58.x mm
T-3 turbine wheel in a .49 A/R turbine housing.

Stage 3 T3/T-04E hybrid turbo. 40-60 trim 76mm BCI-4 or BCI-8
compressor wheel in T-04E housing. 76 trim 65 mm T31
turbine in .49-.82 A/R housing.

Stage 5 T3/T-04E hybrid turbo. 40-60 trim 76mm BCI-4 or BCI-8
compressor wheel in T-04E housing. 76 trim 72 mm T350
turbine in .63 or .82 A/R housing.

Now, my opinions:

Stock:

The T-25 seems to be OK up to around 1 bar of boost with a 3" exhaust and no
cat. This can support about 240 whp with no cat. With a cat, I would run
no more than 10-12 psi. Expect about 220 whp.

The S14 T-28 spools really nice, but has the same tiny turbine as the T-25.
It can't support much more hp. I'd say 240-260 or so wheel hp max. You can
get more power by running more boost, buy you do so at the risk of breaking
things.

GTi-R T-28 is a really good turbo. I think that it is better if you lose
the T-3 compressor housing and get a housing off of the S14. This is a big
improvment. With the T-04B compressor housing, the GTi-R turbo can support
about 16 psi and 280+ wheel hp. Makes pretty good boost by 3500 RPM, too.

HKS:

GT2510 is expensive and only has marginally better performance than the
Bluebird and S13/14 standard turbos. Yes, it has better transient response
because it is ball bearing, but it's not like a stock journal bearing T25 is
a spool dog. I would personally buy something else first. I don't think
you will be able to measure any improvment over a standard S14 turbo with
this one, and it costs a *LOT* more.

GT2530: This is a pretty good turbo, but I don't understand why HKS won't
offer it with the larger .86 A/R turbine housing. This with the larger
turbine housing will outperform a GTi-R turbo. This should be good for 300
whp and good response from 3000 RPM on up.

GT2540: IMO, this turbo is a big piece of ****. This is my opinion as I
haven't tried one. But, looking at the maps, it looks like a pile of ****.
I have heard annecdotal evidance from people I respect that it works pretty
well, but I wouldn't put one my car and find out. There is too big of a
size mismatch between the 53.8mm turbine and the 76mm compressor. Also, it
is insane to run a .64A/R on the turbine given the flow capacity of the
compressor. This turbine and this compressor are both really good on their
own, but they are worthless together. Total mismatch. Save your money.

GT2835: If this turbo is actually what I described above (check to make sure
before you buy), this should be a pretty good turbo. Get the 56 trim
compressor wheel and the 90 trim turbine wheel with a .86 A/R turbine
housing. This should make good boost by 3500 RPM and should support 375-400
or so wheel hp.

GT3037: This is the mother load of turbos. Get the 52 trim compressor and
.73 A/R turbine housing for good streetability and ~400-425 or so whp. Get
the 56 trim compressor and .89 A/R turbine housing is you can live with a
little more lag and want ~475+ hp.

Turbonetics:

Straight T3 is an OK 2.0L turbo. Gets good boost about 3k RPM, will make
about 250-275 whp. Cost and installation is the same as other, larger
turbos, though, so I'd just rather go bigger and take 500 RPM later
response.

Stage 3 T3/T04E hybrid. Get the 50 trim compressor wheel, and only the 50
trim compressor wheel. Get the .63 A/R turbine housing for boost response
by 3500 RPM. This will support about 320 whp. Get the .82 A/R turbine
housing is you can live with full boost ~800 RPM later. This will support
~400 whp.

Stage 5 T3/T-04E hybrid. Only run the .82 A/R turbine housing. If you want
less lag, get a smaller wheel. Run the 60 trim compressor wheel. Don't run
a 60-1 wheel (****) or the smaller trim T-04E wheels. This turbo will
support about 475-525 whp (don't know on the top end--we haven't maxed one
out yet!). Expect soggy boost repsonse below 4500-5000 RPM.

Great info here , But it will take me a Week to read

_________________
Chrome in it's self is a Defect .

wen yu look at a RB20DET yu see, ceramic turbo, what does this mean?

why do most people say these turbo eh no good, and the mash up easily?

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Side-B Keep on Truckin!!!
Offroad Express SURF gone,Offroad Express PATROL coming soon!!!

lord O lord this is way great....much thanks

_________________
Trying to be the very best that I can be!! Supernaturally.

Sober since 9/12/2010

Teana JK stuff For Sale

wayyyy..............some real info there...............I'll have to print it to re-read !!!


thanx a million

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Mudaholics Crew
................ _____
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............... [..SUZUKI..]@
.................(@)=+=(@). ......

very good info here......

i didn't know about the EGT guage. damn good info.

_________________

excellent info...need to go through with a fine tooth comb though...

_________________
Back 2 my 1st love... NISSAN...



NISSAN... or walk...

loads of very useful and valuable info

Can I ask what happened that it blew, and should have blown months before?

_________________
Coilovers + CD Playing = Jack Warner.

This has been good guys... I haven't read through the entire thread but can anyone recommend a good mechanic who can service an old turbo.

_________________
"You have to trust something-your gut, destiny, life, karma. And most important have the courage to follow your heart and intuition" SJ

what he said. What are some of the precautions that should be taken to care for the engine?

great info

_________________
PSN - aarif10

very very useful info....

really good read

Another great info i picked up off the net, do not turbo engines with direct injection port...the multi points engines are better to turbo. Eg. DET- good...DDT-not good...and DiT- also not good.

996vtwin, u said that the T04 has lots of lags, but the Subaru STI and Lancer Evolutions uses the TD04 Turbo. Is the T04 and TD04 related in any way?

_________________
(Rep. CS3A Lancer)
(Rep. QG15DE AD wagon)
Evo 9
Nissan Tiida

2 all d mitsu turbo fans out dere i have some info on how to hybrid ur stock turbo, intrested email me @ cramnarine12@hotmail.com

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quick is d word !! www.mitsucrew.com

nice info here!

_________________
4A-GTE ....

this is about the 3rd time reading this thread...every time i read it i understand it bit more

i just realized how much need tuh do/learn about turbo before even considerin it again!!!

tanx.............

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when i feel spontaneous my bank account reminds me to calm tuh f@#k down!!!