cLAYH

Have noticed that a lot of people are running a 16cm turbo. What are the pro/cons of this upgrade? Especially when towing and EGTs. I know that it will spool up faster and cause less black smoke on takeoff, but going to a smaller housing seems to me that you would be giving up something.

Bushy

Using the 16cm exhaust housing on your turbo will give you roughly 2-3 psi more boost over a stock 18.5 cm housing. Generally the rule is add 2-3 psi for every size DOWN you go in housing.
The down side is that as you go UP in fueling/speed/load the smaller housings can become restrictive to the exhaust gases as they attempt to get into the housing inlet. This results in higher BOOST temps, and consequently higher EGT's.
Keep in mind that this is at the very upper end of the scale of things.... the 16 is a good all around housing for around town, and towing since it makes a bit more boost than an 18.5 or even more than that over a 21cm housing. It also is so close to the 18.5 housing that it is just as "cool" as the 18.5.
I started with the 18.5 on my stock truck, went to the 16 then down again to the 14cm non-gated and back to the 16.
It is the best bang for the buck in most cases. Keep in mind that it's not always a good thing to have "tons more boost".
You want enough to burn the fuel and you want it to be cool boost too.

Pastor Bob.
Our Lady Of Acceleration Church,
Corner of: 1st and Floorit.