turbo sizing question

[acidflux]

I have a turbo. I dont know how to classify it because it doesnt say anything like t04 or what trim it is or anything. How do you figure out what trim a turbo is and what type it is?

its .50 a/r on compressor side and .84 a/r on the exhaust. impeller wheel is about 2 inches and turbine is about 2.5.

who decides if a turbo is a t04s or a t04e or a t04b etc. ive seen plenty of turbos with NOTHING but the a/r on them. do you just point at it and say "that looks like a ..."

i can spot a small turbo from a mile away and usually tell what it is/from. when you talk about bigger turbos it just seems like a guessing game

 

[kenamond]

Trim is a ratio based on the inducer and exducer diameters. Namely, it is (D_Inducer^2/D_Exducer^2)*100. So a 50 trim compressor has an inducer that is 70% the diameter of the exducer. The inducer is the side where air enters, and the exducer is the side the air exits. So the trim on a turbine will be >1 and the trim on a compressor will be <1. If you can pull the turbo and pull the compressor and turbine housings, you could measure the trim.

The A/R is the ratio of the inlet area A divided by the radius from the shaft centerline to the center of A. As you coil around the compressor or turbine wheel, the area and radius decrease such that A/R does not change.

But I don't know what kind of turbo you have

 

[1993eclipseGS]

The compressor housing sizes, as in: t04s or a t04e or a t04b etc...

 

[lasertim]

Pics might help.

 

[acidflux]

compressor and turbine wheel trims

i measured the wheels and did the math as per instructions

the compressor wheel read out at 49 so id say its a 50trim.
turbine came out to 81 so...i guess a 80trim?

so 50trim with .50 a/r and 80trim with .84 a/r

closest garrett match is a gt3076r variant

serial no is ffm48860
part no is 466334-5004

those are the only numbers on the tag thats with it

 

[kenamond]

Just realize that the trim and A/R can be the same for two completely different turbines/compressors. If you have more data on different turbos such as the inducer/exducer diameters, that would probably help narrow it down.

You might try going to www.turbobygarrett.com and see if they have a search engine based on the part number. However, this will only identify the center section; the compressor/turbine wheels/housings could be any number of different parts that just happen to be mated to that center section.

 

[kenamond]

A very informative site is the turbo 101, 102, and 103 pages at Garrett's site. Here is the link to the 102 site with the A/R and trim stuff. Much more is in there, too. A good read.

 

[acidflux]

Compressor housing - all measurements in inches
-inlet 2.75 narrows to 1.75
-outlet 1.5

Compressor wheel
-inducer 1.75
-exducer 2.5

--------------------------------------------------------------

Turbine housing
-divided flange t04 style (1.15x1.75) x2 ports
-outlet 2.25

Turbine wheel
-inducer 2.25
-exducer 2.5

thats all the measurements i could take from it. wish i had something metric to measure with for accuracy

 

[kenamond]

wish i had something metric to measure with for accuracy

You should pick up a dial caliper:

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You can get a decent model for under $60, and they give you 1-mil (0.001" *not* one millimeter) accuracy.

Also, a picture paints a thousand words (or roughly 10 posts)

 

[stevenm357]

Thanks for the info and links it really helped!

 

[Sam@RRE]

Also, to accurately measure things, you have to take the covers off and measure the actual wheels. Inlet and outlet sizes on a compressor housings don't effect the turbo characteristics at all if anything. It MUST be taken apart and molested with a dial caliper to accurately say what it is, or give you and idea of power/characteristics.