^+1 there are hundreds of sizes, hybrids, etc
QUOTE (Zizman @ Mar 20 2009, 11:08 AM)

Evo III is a company that makes turbos similar to those found in (wait for it) Evo IIIs. The latter turbos range from 14b to 18g from everything I've seen...
But how the heck does size of a turbo work? I know smaller turbos spool faster, getting more low end "boost", versus a larger turbo which gives top end speed because it takes longer to spool. But what sizes are there?
Evo III has nothing to do with a company. It doesn't really even mean anything in regards to describing the turbo itself. the Evo III turbo is actually a td05 16g turbo that is larger than the big 16g which is larger than the small 16g. All are td05 16g turbos with different sizes of compressor wheels. The Evo III being the largest.
So the TRUE designation of the "Evo III" turbo is TD05 16g with the last part numbers being 01470. It's "street name" of Evo III only came about because this turbo was only found in the Mitsubishi Lancer Evolution III (if thats wrong someone please correct me) and dsm'rs wanted to identify it ouside of the rest of the 16g family.
This will give you more information on the other TD05 turbos and their part numbers:
http://www.mitsubishi-forums.com/index.php...mp;#entry178788the size of a turbo was slightly explained earlier in this thread.
http://www.mitsubishi-forums.com/index.php...st&p=239307Some important things to consider outside of the physical size of a turbo are it's wheels. Housing flow isn't as important as wheel flow. Wheel pitch, blade spacing and blade surface area are big factors to consider in the peak amount of power a turbo can make. After that you get into physics with cavitation, turbulence, etc. I only know a little bit about the physics so i'm not going to go into that stuff.
The td05 turbos are great examples of different wheel sizes in common housings. Assuming all of these turbos are using a 7cm^2 turbine housing think about the difference between the 14b and the evo III. When installed they look identical. Take them off the car and you can see the difference, not only in wheel size, but blade spacing, blade height, blade surface area.