Gartrac Mike

this may sound stupid but how do u identify what type of turbo u have aned what houseing it has on it .also when u change the house for a larger one do u change the turbine in it as well ,say it has a 63 houseing on it what does the 63 count for cheers

COSSIE 1

very good question mate ill be watching for some answers

Disabled Account

BTTT for Mike's questions:

a. This may sound stupid - but how do you identify what type of turbo you have and what housing it has on it?

b. Also, when you change the housing for a larger one, do you change the turbine as well?

c. If it has a .63 housing on it what does the .63 part mean?

Karl

Most turbines have the A/R ratio either on the outside near the exhaust flange or just inside the entrance.

If you are keeping with the same family of turbo, e.g. T3's/34 then you can change between any of the turbine housing A/R's without having to change the turbine wheel.

However different families of turbos are not interchangable due to differing turbine wheel sizes, thus the housings are not interchangable.

E.g. a 0.63 GT30 turbine housing will not fit a 0.63 T34.

Lastly A/R stands for the area/radius ratio, and in laymans terms for a given family of turbo allows us to differentiate between turbine throat sizes. (larger number is bigger but also more laggy)

(You cannot compare A/R's between different families of turbo (e.g. GT35 to T3) as the radius will be different and thus the area for the same A/R ratio will also be different.)

Stavros

You identify that a/r the exhaust housing is by opening your eyes and looking
Its written somewhere on the ex housing, on cossie turbos its right by the turbine inlet, so viewable on a car with the 2wd manifold fitted even when fitted on car.
Might need a torch tho.

When you change the housing you dont generally change the turbine wheel as well.
You COULD, but if we talking general cossie/RST tuning they dont very often, but depending on the application you could.

.63 is the A/R ratio.
Im too tired/busy to explain in too much detail, but A and R are 2 measurments inside the turbine housing and the number is the one divided by the other.

Basically the larger a/r number it is the more it will flow compared to the other exhaust husing a/r options for that particular turbo, with lower backpressure, but at the expensive of low down grunt.

Its all very relative to other things tho, and the number isnt the physical size like said, its just 1 part divided by another.
For example T34 and T4 both run .63 a/r housings, and a S13 T25 runs a .64 one. But the S13 one is smallest, then the T34 one, and the T4 one is bigger.


EDIT- Karl beat me oh well