1985-1998 [Subscribe to Daily Digest] |
[Profile/Gallery]
, Mon, 9 Apr 2007 18:03:39
Members do not see ads below this line. - Help Keep This Site Online - Signup
Hello there,
I was just curious about this thread, since i'm interested in later model 9000 turbo trim specifications as well...
however...
what you were refering to as the number stamped on the cold side housing of the turbo, is actually refered to as the A/R... or area ratio i believe.
This number is basically signifying the size of the HOUSING of the compressor section or the turbine section. And .42 is usually the stock A/R on an older 9000 for the compressor, and an A/R of .48 for the turbine housing (for a garrett stock T3)
The larger the A/R number, such as .64 or .82, the larger the housing is, or basically the area inside of the housing which the air flows through.
This comes into play for SPOOL UP time only...as if you have a larger A/R on your turbine side, then more exhaust gas is able to flow around the turbine wheel, bypassing it completely if the A/R is too high...
...which would in turn cause a slower spool up time, but... would allow for much higher volumes of air to flow through the turbine in the higher RPM range... allowing more total horsepower for the system in the end, but obviously sacrificing your low end power.
Adjusting the A/R on the compressor housing doesn't have much of a dramatic effect on anything however...
but...
the TRIM on the compressor WHEEL is key to making more power.
The TRIM is also a ratio, so to speak...
A compressor wheel on a turbo is shaped like a cone.
The top of the cone has a smaller diameter than the bottom of the cone.
They are refered to as the "inducer" for the top part, and the "exducer" or overall diameter for the bottom part.
If you were going to look inside your compressor housing at the compressor wheel down inside the inlet... you would only be able to see the very top part of the inducer section, as the exducer section will be hidden from view by the compressor housing.
For pictures to help solodify this concept, go to this link, and there is plenty more reading too...
-gavin
posted by 74.76.4...
, Mon, 9 Apr 2007 18:03:39, Sun, 15 Apr 2007 23:23:18, Tue, 10 Apr 2007 10:03:14
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
