I just found a pic to help my explanation.

Compressor A/R is determined by dividing the radius of the compressor housing by the smallest diameter of the compressor outlet . Exhaust housing A/R is determined by dividing the radius of the exhaust by the smallest diameter of the exhaust inlet . As the A/R numerically increases so does the housings ability to induce/exduce a specific volume of air. Lag and effective power range will also be affected by A/R changes. Look at the A/R pic below.

Pic was ganked from a post on RX-7 Forum.

 

good info, thanks

 

No problemo! I figured a couple people would want to see this.

 

does this work for the hot side also?

because the hot side A keeps getting smaller the farther u go into the turbo!!

hhhah

 

I dont care about A/R, where the hell have you been?

art

 

A/R only matters when your turbo doesn't spool up quick enough and you need to change your housing, but that's why you buy the biggest one and a ball bearing center.

 

yeah, just throw all factual turbo charger selection theories out the window.........

geeez

Rob

 

Very informative post. Thank you !

 

formula for determining trim

[(minor wheel diameter)x(minor wheel diameter) / (major wheel diameter)x (major wheel diameter) ] x 100= trim


T04E 60
[(2.290)(2.290)/(2.950)(2.950)] x 100= trim
(5.2441/8.7025) x 100= trim
.6026 x 100 = trim
60= trim

 

 

[Modified by Daniel, 5:55 AM 1/13/2003]

 

10 month old post...where the hell this come from? lol...

 

Ask Shortyz

 

i use the search button.
i think
o wait no i think i got this off that other post..
who the hell knows.
its great info though.

 

Great info!

 

wow.. somebody actually uses the search engine

 

that is the compressor wheel formula

flip that to determine turbine wheel trim


[(exducer)(exducer)/(inducer)(inducer)]x100 = turbine wheel trim

 

[(exducer)(exducer)/(inducer)(inducer)]x100 = turbine wheel trim
???
i am confused on what u guys mean by minor wheel diameter and such..
u mean from small fin to small fin and big fin to big fin?

 

it works.. and looks like i chose the right turbine side - i wish i had this formula - woudld't have to guess all this time..

 

i might be wrong.. but i think its the other way around

 

example:

http://64.225.76.178/catalog/comp_wheels.html - compressor sides
http://64.225.76.178/catalog/twheel.html - turbine side
http://64.225.76.178/catalog/thousing.html - turbine side


heres my turbocharger - T3/T04B S:

Specs for compressor: 1.904" - inducer, 2.750" - exducer - it says major but i guess its the same thing

(1.904 x 1.904) / (2.750 x 2.750) / 100 = 47.93 for turbine size which is i went with, but wish i had this formula at the time..



[Modified by vtec.dc2, 1:16 AM 1/15/2003]

 

informative post, and this is an old aZZ thread!

 

I am always posting crap like this since Geoshities killed my site

 

I guess humor is't a good part of my personality. Sorry I was atempting to make a joke noticed the sarcastic .

 

but how do you chose the inducer and exducer?