[93 R1]

O.K. who wants to do it? I've heard alot of people asking questions about this and I'm curious myself.

What do these things mean?
Inducer
Exducer
A/R
Wheel trims (P,Q,R...)
Clipping
Dynamic, carbon seals
And who wants to explain how to read compressor maps?

Heres my guess about what these mean. Inducer is the size of the top of the compressor/exhaust wheel? Exducer is the size of the base of the wheel? The trim is the angle that the blades are tilted? And A/R is the amount of air the housing can compress?

[93 R1]

I was gonna see if we got some real answers before I requested that, but good lookin out ;)

Heres what Clipping is:
Clipping is the technique of cutting away some of the material on the fins of the impeller wheel of the turbocharger. In other words, to 'clip' a turbo is to make the fins in the exhaust path smaller. The cut is usually done at an angle of between 10 and 20 degrees - the bigger the angle, the more material is removed from the fins.

This may seem like a dumb thing to do, since smaller fins mean that the exhaust gases will impart less force to the turbine wheel and consequently increase turbo lag. This is true, but the benefit of clipping is found in the high RPM range of the motor. At higher RPMs, the turbo may have already surpassed the required user-set boost levels and is not contributing to engine power.

Since the impeller wheel in the exhaust stream partially blocks the exhaust gas flow (by design), it can act as a significant restriction at high RPMs, when the exhaust flow rate is highest. Clipping the turbo reduces this restriction and allows more air to flow past the turbo wheel at high RPMs, thereby improving airflow through the engine and increasing top-end response.

[94touring]

From what I understand clipping the turbo's would be equivant to upgrading the exhaust A/R. So if you already had a 1.0 A/R, you would basically have the equivalant to a 1.15 A/R, depending on the percentage of clip.


P trim is what is normally used on street cars. Q trim flows more exhaust and is more for heavily ported cars or bridgeports. You don't want a P trim on a bridgeport, cause after a certain boost level the turbo will actually begin to cause too much backpressure and result in a loss of power.


Umm, inducer is compressor, exducer is exhaust. A/R is how the turbo is measured, either on the compressor (intake side) or exhaust side of the turbo.

[1Revvin7]

94touring, on Mar 31 2003, 11:14 PM, said:

Umm, inducer is compressor, exducer is exhaust.  A/R is how the turbo is measured, either on the compressor (intake side) or exhaust side of the turbo.

I thought the exducer is the base part of the compressor wheel and the exducer is the upper half of the compressor wheel? :scratch:

[94touring]

1Revvin7, on Mar 31 2003, 08:18 PM, said:

I thought the exducer is the base part of the compressor wheel and the exducer is the upper half of the compressor wheel? :scratch:

I should have put a question mark behind that. I was just assuming there. I'm going to research around and see what i find.

[94touring]

Here is one diagram to show some turbo details.

[94touring]

A simplified diagram.

[BigTurbo74]

Might help from turbonetics,,,,how come we can't edit?

[little rotor]

Inducer = small side (inlet) of compressor wheel
Exducer = small side (oulet) of turbine wheel
The large part of either wheel is refered to as the major.
The A/R refers to the housings only. Area divided by radius at any point is a constant ratio.

[93 R1]

Someone explain this:

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•  t91_flow.jpg (117.34K)
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[little rotor]

Sometimes the large measurement of the compressor wheel is refered to as the exducer as in the specifications at the top of the Compressor Map shown by 93 R1. Its a little inconsistent.

Fully explaining compressor maps takes a while. If I get a chance I'll write some stuff on it.

[Dragon]

Here's a nice pic..

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[Dragon]

#2

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[Dragon]

1. The ground radius on the hub diameter creates a pressure differential to prevent oil transfer through the seal

2. The piston rings seat in the seal bore and form a vital element of the air/oil seal

3. The thrust cooler turns at shaft speed, oil is pumped out of the seal cavity through the drilled holes in the collar.


4. This seal land surface helps prevent oil from entering the seal bore


5. The higher pressures of the compressor air and turbine exhaust gases serve to prevent oil leakage through the seals

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[Dragon]

more

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[Dragon]

my turbo

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[93 R1]

Now if you could explain the last 2 pics.

Is the pressure on the vertical axis measured in BAR? Whats p1/p2?

[little rotor]

Sorry I havn't had time to write some crap on compressor maps, but to hold you over I'll tell you what the pressure ratio part means.

Pressure Ratio = P1/P2

P1 = Boost pressure + Atmospheric pressure
P2 = Atmospheric pressure (approx 1Bar or 15psi at sea level)

So with no boost P1 = P2 and the Pressure Ratio = 1
With 1Bar of boost P1 = 2Bar so PR = 2
2 Bar of boost gives PR = 3
you get the picture. :)

[jspecracer7]

good stuff little rotor :bow:

[evilT2]

read maximum boost by corky bell
its the book for turbocharging, it will tell you anything you need to know

[93 R1]

I'll trade someone a brand new hard back yamaguchi RX7 book for the corky bell book

[93 R1]

Q: What is the difference between an "on-center" turbine housing and a "tangential" turbine housing?


A: The difference is the way that they mount in the engine compartment and the manner in which the exhaust is evacuated from the housing. The "on-center" uses a standard T4 inlet flange, as well as a four-bolt discharge flange. The reason that it is called on-center is just that, the housing sits right on top of the inlet flange.

The "tangential" turbine housing differs both in form and function. The housing sits off to one side, similar to that of a snail shell. The other difference is that to connect an exhaust down-pipe, a V-Band flange-and-clamp assembly must be used. This setup sometimes proves to be more convenient for race applications. The "tang" housings are 4 to 5 percent more efficient in flow. Neither the "on-center" nor "tangential" perform better than the other. The decision to use one over the other should depend completely upon the installation of the turbos in the engine compartment.

[93 R1]

Some good turbo info from a NISSAN site NOT ROTARY SPECIFIC

The "BIG" turbochargers
Here are the big dogs of the turbo community, the biggest turbos, that are mostly used for drag strip use only.

HKS T-51R
This is the crown jewel of HKS single turbos (although the GT3245 in the HKS drag celica is probably bigger, i've NEVER seen it in the US) This turbo in size, is slightly bigger than a T66, but has an exhaust housing that is quite a bit bigger, it ships with 0.96 stock, and makes TONS of power. Bryce Danna made his ~830 rwhp with 75 shot of nitrous with this turbo, that looks like ~760+ rwhp without bottle most likely, which is plenty. Its probably possible to make 800 rwhp on turbo alone with this turbo, which is very impressive. You will want upgraded internals most likely, along with cams, Gforce computer to raise rev limiter, a BIG fuel system, and either a high-stall torque converter, or a stick, with a very nice clutch. This turbo is BIG and has significant lag. You are waiting for it quite a bit, probably 800 rpm if not more of noticable lag. I would say its POSSIBLE to have this turbo on a "street" car, but I wouldn't do so personally because i'd want nitrous to spool this big boy up, its pretty laggy makes full boost around 5k. No one has really made any passes with this turbo yet that have been very fast, but maybe this year someone will.

HKS GT2835
This is probably the most common twin turbo setup, these are pretty big twin turbos, about the size of a TS04 0.58 for each turbo, but most often they come with 0.70 exhaust housings... I would switch these with 0.63s personally, unless you are a glutton for lag, with the stock housings they make full boost in the early 5k range with cams. You do have quite a bit of potential here, I believe you can make 800 rwhp on the HKS GT2835s with the proper setup, which is PLENTY of power. With the smaller housings, you can probably have 700 rwhp with lag in the mid 4k range, which is quite a bit too. Very nice setup, but insanely expensive for what you get, almost twice as expensive as the RPS kits.

Turbonetics T70, T72, and T76
These turbos are similar to the T66, but bigger. Most of the T70s are pretty similar to the T66, although they have a slightly bigger turbine wheel. This allows them to make somewhat more power, but at the cost of somewhat more lag. A T70 is good for probably 30-50 rwhp more than a comparable T66, but has about 2-300 rpm more lag. T72 is correspondingly bigger, it uses a different compressor and turbine wheel setup, and allows for significantly more power, but quite a bit more lag. Supposedly capable of 800-900 rwhp, the T72 makes full boost in the low/mid 5k range. I haven't heard of anyone using the T76 as this is simply too big a turbocharger, it would make TONS of power, but probably not make full boost till ~6k rpm. RPS sells kits with all of these turbos, although I believe that the T72 and T76 have to be special ordered.

Greddy T78 and T88
These turbos are made by mitsubishi and modified by Greddy, the T78 uses a TD07 exhaust housing with a TD08 compressor, T88 has TD08 on both sides. T78 is capable of an insane amount of power, at the cost of monumental lag, although with a stock motor, the T78 may make full boost in the mid 4k range with proper tuning. T78 can make ~750 rwhp on the turbo alone if tuned right, you do need electronics, a higher rev limiter, cams, probably headwork... T88 is good for maybe 20% more power... this is one of the few turbos that is theoretically capable of flowing enough air to approach 900 rwhp, although you would need a SERIOUS engine build up to do this. Ara from NJ has run 141 mph traps with a T78 w/o bottle, Humberto has run 9.8@14x with T78 with nitrous, and a number of other people use the T78 as well, mainly because its quite inexepensive today, selling for under $4k. The downside to the T78 and T88 is that they need ALOT of work to get them working to their potential, and they lag into the low/mid 5k range for the T78 and even more with the T88, a car with this turbo is almost non-streetable in my opinion.

HKS GT3037
These are the biggest twin turbos available from HKS as far as I know. Craig Paisley uses this setup, as does the UPRD car. This is one of those turbos that should have a tag on it that says "DO NOT USE WITHOUT NITROUS" in my opinion. You will probably see lag in the ~6500 rpm range, which is fine for the strip, with nitrous, but for a streetable car? remember the supra's stock rev limiter is 6800 rpm, although obviously you would raise it if you had these turbos... These turbos are probably capable of 1000-1100 rwhp w/o nitrous, but you need headwork, internals, fuel system, and probably lots of other custom stuff to use these turbos, don't do it unless you have nearly infinite money.

[93 R1]

Cool pic I found

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[93 R1]

-TD05, GT2530, T78, T72... What do those terms mean?
There're two commonly used types of turbos, Mitsubishi and Garrett turbos. There are others but as not common...
Mitsu and Garrett turbos have totally different designations.

-Mitsu turbos:

Mitsubishi uses TD04, TD05, TD06, TD07, TD08...to designates turbo housing.

For example, TD05H-16G 7cm^2 is a turbo with,

TD05 turbine housing with 'H' style turbine housing/wheel. There are S, SH, H... style of turbine wheel/housing.
16G compressor wheel. 16 is the size of the wheel, 1.83 inducer, 2.37 exducer. G is the style of wheel (alternating height of blades). C, B, T style wheel's blades have the same height. Blades are always evenly spaced, but the number of and pitch of the blades can change between models.
8cm^2 is referring to exhaust discharge area in the turbine housing. More specifically, it is the cross-sectional area of the smallest intake passage in the turbine housing before the passage spreads around the circumferential volute that leads to the turbine wheel. Very similar to Garrett turbo's A/R. The smaller number means faster spool-up but more back pressure at higher rpm. Bigger number means longer spool up but less back pressure, thus more top end power.
Greddy modifies Mitsu turbos. Bisides, TD04, TD05, TD06, TD07 turbos, Greddy also makes hybrid turbo, T67 is TD07 compressor and TD06 turbine, same turbo as TD06SH-25G. T78 is the compressor of TD08 and turbine of TD07, T88 uses compressor and turbine from TD08.


-Garrett Turbos:

Garrett basically has two lines of turbos. The older T series turbos and new ball bearing GT series turbos.

T family has T22, T25, T28, T3, T350, T370, T4, To4B, To4E, TS04, To4R ...
The new line of GT turbos are ball bearing, GT20, GT22, GT25, GT30, GT35, GT40, GT45, GT50... GT turbos produce slightly more hp then older T series turbos with the same number. Turbonetics and many domestic makers use T series turbos. A T3/To4E 60 T .63A/R is a hybrid turbo with T3 turbine, To4E compressor, 60 Trim compressor wheel and .63 A/R. Wheel "trim" refers to the squared ratio of the smaller diameter divided by the larger diameter times 100. Generally, the larger the trim number the more flow the wheel has. For compressor wheels , larger trim tends to mean slightly lower efficiency. For "families" of turbine wheels (those with the same inducer diameter), larger trim usually means better flow with less backpressure but longer spool time. A/R is a ratio of the exhaust discharge area vs the distance from the center of turbine wheel to the center of the discharge area. The so called "T-series': T60, T61, T66, T70, T72, T76... are T4 turbos as well. The number means the compressor inducer size. ie: T76 means it has 76mm compressor inducer.

HKS uses Garrett turbos. HKS GT series turbos use Garrett GT's turbine with T's compressor. For example, HKS GT 2530 is GT25 .64A/R turbine with T3 63 trim compressor.