Measuring A/R of a turbo--------how to-----

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Old May 18, 2004 | 08:11 PM
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Default Measuring A/R of a turbo--------how to-----

I have a Airesearch T3. It has the A/R 48 stamped on the hot side but i have no clue what the compressor is. Should i just measure it with a caliper or something or what. I wish i knew what this turbo was, only thing i can find on it is a M4 stamp.
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Old May 18, 2004 | 08:11 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

btw- i tried searching so please don't flame
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Old May 19, 2004 | 01:18 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

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Old May 19, 2004 | 01:31 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

What did you get it off of.. Its probably a .42 compressor side.. Mine is the same one and it came off of a Mercedes diesel..
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Old May 19, 2004 | 01:56 PM
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Default Re: Measuring A/R of a turbo--------how to----- (tgreaves)

there is a post on it somewhere. its the ratio of the inducer to something, i cant remember. there is a diagram and everything in the post. ill try to find it.

Landon
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Old May 19, 2004 | 02:10 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

face it dylan

my 14B is close in size to it also
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Old May 19, 2004 | 03:33 PM
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Default Re: Measuring A/R of a turbo--------how to----- (USDM 4G VTEC)

the a/r's are .42 compressor and .48 exhaust

i divide the Compressor inducer 42 mm by the Compressor exducer 60 mm which comes out to .7, then i square that, which is .49 and times that by 100. which give me the trim. so it's a 50 trim T3. i looked up the compressor map and it's perfect for a B16 running 8psi

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Old May 19, 2004 | 04:31 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Del_Slowest &raquo;</TD></TR><TR><TD CLASS="quote">the a/r's are .42 compressor and .48 exhaust

i divide the Compressor inducer 42 mm by the Compressor exducer 60 mm which comes out to .7, then i square that, which is .49 and times that by 100. which give me the trim. so it's a 50 trim T3. i looked up the compressor map and it's perfect for a B16 running 8psi
</TD></TR></TABLE>

Yeah, you're not even close.

Dividing the inducer by the exducer, and then squaring it, is how you get the trim of the compressor (or turbine) wheel.

The A/R is the area of the scroll, divided by the radius from the center.

Basically, it's not easy to measure yourself.

I wouldn't worry about the compressor A/R though.
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Old May 19, 2004 | 05:18 PM
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Default Re: Measuring A/R of a turbo--------how to----- (Del_Slowest)

For a future search

compressor wheel -

(inducer x inducer) / (exducer x exducer) (100)

turbine wheel -

(exducer x exducer) / (inducer x inducer) (100)
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Old May 19, 2004 | 07:47 PM
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Default Re: Measuring A/R of a turbo--------how to----- (kpt4321)

i got the measurements off of another site. i didn't whip out the caliper and do it myself. I don't understand how i messed up. Are you saying it's not a 50 trim then?

EDIT- now i understand what you were saying. I wasn't asking how to measure my a/r's anymore. I just looked at my exhaust turbine and it was stamped .48 so i just assumed that the compressor was a .42 since it looked a lil smaller. Therefore since it also had M4 stamped on it i concluded that it was a T03 II turbo from 87-89 that has been rebuilt. I then looked up the site that gave the inducer and exducer or whatever they're called and did the math which gave me the 49 or 50 trim. At first i was thinking this was a 40 or 45 trim turbo which would have sucked, but now i'm happy since it's a 50 trim.
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Old May 24, 2004 | 04:38 AM
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It doesn't really matter what the trim is, if you know the inducer and exducer size.
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Old May 24, 2004 | 02:26 PM
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Default Re: (kpt4321)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">It doesn't really matter what the trim is, if you know the inducer and exducer size.
</TD></TR></TABLE>

all the compressor maps are using the trim though, thats why i thought it was important to figure out
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Old May 24, 2004 | 03:16 PM
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Default Re: (kpt4321)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">The A/R is the area of the scroll, divided by the radius from the center.</TD></TR></TABLE>

And furthermore,

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">It doesn't really matter what the trim is, if you know the inducer and exducer size.</TD></TR></TABLE>
I can't see how I could possibly agree more.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">all the compressor maps are using the trim though, thats why i thought it was important to figure out</TD></TR></TABLE>

Yeah, but the tragic thing is that trim dosen't tell you jack **** about the actual size of either compressors. In A/R's case, you just know "okay..so Area is 60% of Radius....so now what?!" and trim is the same basic concept. You still aren't told what the actual size of either of them are, you're just told of them in relation to one another. Big friggin deal. There's so much bullshit surrounding "turbo selection" that I'd almost swear that it were intentionally done to throw someone off course. Trim means less than nothing because you still have no idea what size the exducer or inducer are and you'd have to figure backwards to determine which ever portion of the info were not given, which would make trim completely useless.

The fact that NOT ONE turbo manufacturer shows the compressor flow for turbines is another piece of extremely vital info that isn't given to the public. It's not like they don't have it. They just don't give it. WTF...
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Old May 25, 2004 | 02:18 PM
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Default Re: (Del_Slowest)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Del_Slowest &raquo;</TD></TR><TR><TD CLASS="quote">

all the compressor maps are using the trim though, thats why i thought it was important to figure out</TD></TR></TABLE>

But they also show what SERIES the wheel is from, as well as information about how well it flows. The trim is only useful for differentiating between the different wheels of a series (like the different T4 wheels, for example).

Just having a 50 trim means nothing. Having a T04E 50 trim means something, because we now know which specific compressor wheel you are talking about, and can look up its capabilities.
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Old May 26, 2004 | 08:08 AM
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Default Re: (kpt4321)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">
Just having a 50 trim means nothing. Having a T04E 50 trim means something, because we now know which specific compressor wheel you are talking about, and can look up its capabilities.
</TD></TR></TABLE>

Or they could just tell you "T04E 1.59in. Ind. & 2.48in Exd."

If you look at how trim is calculated, it dosen't even look like a realisitc formula. It's like someone said "ah hell, multiply these by them selves, then divide them against one another....**** that number looks low....umm...then multiply by 100. Sweet!!"

If they really wanted to keep it consistant, they'd do it A/R style, which is still someone useless without figures, but what's the sense in that? It's not difficult enough that way.
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