Universal meaning that you only purchase the turbo charger for your application, your engine. Different sized engines flow more air, so optimally you would want a turbo properly sized to fit. There is some leaway inbetween a too big and a too small turbo. There are a lot of varibles to take into consideration when picking a turbo for a engine that i am not going to go into right now.
Speak about this dry and wet housing? i dont understand or have heard of wtf you are talking about.
A wastegate is a valve that is regulated via a spring. The wastegate has a boost source nipple on it which you run a line to a boost source. Once the vehical is in boost, the air pressure pushes aginst the spring to open the valve. This valve is placed on the turbo manifold (between the cylinder head and turbo. This bleeds off exhuast gasses in a different route then what is directed towards the turbo, in result controls turbine speed, which controls the amount of boost that is made.
There are 2 different kinds of wastegates, internal and external. All factory manufacutered vehicals come with an internal wastegate for simplicity and easy design of all parts. External wastegates are used more for race applications where specific boost regulationis nessacary; and where higher amounts of exhuast gasses are needed to be rerouted before they hit the turbine.
You can pick taylor these different specifications per your application of compressor and turbine.
Housing
Housing a\r.
Wheel size
Wheel trim
and you can choose different cartrage construction.
You can alter these varibles to achive a device that flows air the way you want your engine to make power.
You have a lot to learn, do not expect to turbo your future car for more then a year after you have been reading a educated forum about turbocharging. There are SO many things to take into consideration, purchasing decisions, equipment type, installation procedure, maintence, after installation tuning, more maintence, paying attention to your car and setup, and maintence, and paying attention to your setup. I know alot, ive been reading about this thing called turbo charging about 3 years now and have a pretty good grasp about alot of stuff. I still had things that i had to deal with when i turbod my ka that i did not expect.
Here are some links for your reading that you should know:
www.howstuffworks.com and
www.google.com for more advanced \ particular directed information.
It is good to know how these things work, 4 Cycle engine (otto cycle engine), 2 stroke engine, Turbochargers, Limited Slip Differentials, Intercoolers, Wastegates (might be covered in the turbo articals), Manual Transmissions.
Look over the articals that were written at
www.turbosaturns.net This place has a lot of
detailed tutorials on how to read compressor maps, another how wastegates work, ebc
instalations, nitrous, bleh bleh bleh lots of other crap.
things that make a kit proprietary to a particular car and engine setup, injectors size and type, turbo size, intercooler piping, engine management, equipment, lots of things. universal means you get the turbo in about any size you want for your engine any size it is.
my fingers are tired.